CA1331914C - Micro-electronics devices and methods of manufacturing same - Google Patents
Micro-electronics devices and methods of manufacturing sameInfo
- Publication number
- CA1331914C CA1331914C CA 530049 CA530049A CA1331914C CA 1331914 C CA1331914 C CA 1331914C CA 530049 CA530049 CA 530049 CA 530049 A CA530049 A CA 530049A CA 1331914 C CA1331914 C CA 1331914C
- Authority
- CA
- Canada
- Prior art keywords
- thick film
- dielectric constant
- hollow glass
- glass microspheres
- low dielectric
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K1/00—Printed circuits
- H05K1/02—Details
- H05K1/03—Use of materials for the substrate
- H05K1/0306—Inorganic insulating substrates, e.g. ceramic, glass
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L101/00—Compositions of unspecified macromolecular compounds
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C03C14/00—Glass compositions containing a non-glass component, e.g. compositions containing fibres, filaments, whiskers, platelets, or the like, dispersed in a glass matrix
- C03C14/004—Glass compositions containing a non-glass component, e.g. compositions containing fibres, filaments, whiskers, platelets, or the like, dispersed in a glass matrix the non-glass component being in the form of particles or flakes
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
- H01L21/48—Manufacture or treatment of parts, e.g. containers, prior to assembly of the devices, using processes not provided for in a single one of the subgroups H01L21/06 - H01L21/326
- H01L21/4803—Insulating or insulated parts, e.g. mountings, containers, diamond heatsinks
- H01L21/481—Insulating layers on insulating parts, with or without metallisation
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
- H01L21/48—Manufacture or treatment of parts, e.g. containers, prior to assembly of the devices, using processes not provided for in a single one of the subgroups H01L21/06 - H01L21/326
- H01L21/4814—Conductive parts
- H01L21/4846—Leads on or in insulating or insulated substrates, e.g. metallisation
- H01L21/4867—Applying pastes or inks, e.g. screen printing
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L23/00—Details of semiconductor or other solid state devices
- H01L23/12—Mountings, e.g. non-detachable insulating substrates
- H01L23/14—Mountings, e.g. non-detachable insulating substrates characterised by the material or its electrical properties
- H01L23/15—Ceramic or glass substrates
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L23/00—Details of semiconductor or other solid state devices
- H01L23/48—Arrangements for conducting electric current to or from the solid state body in operation, e.g. leads, terminal arrangements ; Selection of materials therefor
- H01L23/488—Arrangements for conducting electric current to or from the solid state body in operation, e.g. leads, terminal arrangements ; Selection of materials therefor consisting of soldered or bonded constructions
- H01L23/498—Leads, i.e. metallisations or lead-frames on insulating substrates, e.g. chip carriers
- H01L23/49866—Leads, i.e. metallisations or lead-frames on insulating substrates, e.g. chip carriers characterised by the materials
- H01L23/49883—Leads, i.e. metallisations or lead-frames on insulating substrates, e.g. chip carriers characterised by the materials the conductive materials containing organic materials or pastes, e.g. for thick films
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C03C2214/00—Nature of the non-vitreous component
- C03C2214/04—Particles; Flakes
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
- H01L2924/0001—Technical content checked by a classifier
- H01L2924/0002—Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
- H01L2924/095—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00 with a principal constituent of the material being a combination of two or more materials provided in the groups H01L2924/013 - H01L2924/0715
- H01L2924/097—Glass-ceramics, e.g. devitrified glass
- H01L2924/09701—Low temperature co-fired ceramic [LTCC]
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
- H01L2924/30—Technical effects
- H01L2924/301—Electrical effects
- H01L2924/3011—Impedance
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S428/00—Stock material or miscellaneous articles
- Y10S428/901—Printed circuit
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/24—Structurally defined web or sheet [e.g., overall dimension, etc.]
- Y10T428/24802—Discontinuous or differential coating, impregnation or bond [e.g., artwork, printing, retouched photograph, etc.]
- Y10T428/24917—Discontinuous or differential coating, impregnation or bond [e.g., artwork, printing, retouched photograph, etc.] including metal layer
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/24—Structurally defined web or sheet [e.g., overall dimension, etc.]
- Y10T428/24802—Discontinuous or differential coating, impregnation or bond [e.g., artwork, printing, retouched photograph, etc.]
- Y10T428/24926—Discontinuous or differential coating, impregnation or bond [e.g., artwork, printing, retouched photograph, etc.] including ceramic, glass, porcelain or quartz layer
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
- Y10T428/2982—Particulate matter [e.g., sphere, flake, etc.]
- Y10T428/2991—Coated
- Y10T428/2993—Silicic or refractory material containing [e.g., tungsten oxide, glass, cement, etc.]
- Y10T428/2996—Glass particles or spheres
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/31504—Composite [nonstructural laminate]
- Y10T428/31551—Of polyamidoester [polyurethane, polyisocyanate, polycarbamate, etc.]
- Y10T428/31609—Particulate metal or metal compound-containing
- Y10T428/31612—As silicone, silane or siloxane
Abstract
IMPROVED MICRO-ELECTRONICS DEVICES AND METHODS
OF MANUFACTURING SAME
Abstract of the Disclosure A low dielectric constant material for use in the formation of thick film circuits such as VLSI devices.
The material comprises a thick film insulation matrix of standard viscosity; a thick film organic vehicle; and a plurality of dry, hollow, glass microspheres. The insulation matrix, vehicle, and microspheres are thoroughly combined into a homogeneous material of standard viscosity.
OF MANUFACTURING SAME
Abstract of the Disclosure A low dielectric constant material for use in the formation of thick film circuits such as VLSI devices.
The material comprises a thick film insulation matrix of standard viscosity; a thick film organic vehicle; and a plurality of dry, hollow, glass microspheres. The insulation matrix, vehicle, and microspheres are thoroughly combined into a homogeneous material of standard viscosity.
Description
133191~
IMPROVED MICRO-ELECTRONICS DEVICES AND METHODS
OF MANUFACTURING SAME
Background of the Invent;on The present invent;on relates to micro-electron;cs devices and methods of manufacturing same, and more particularly to improvements in low d;electr;c constant materials for use in the formation of m;cro-electronics devices. The invention has particular utility for the manufacture o-f integrated circuits of the so-called "thick fiLm" type and will be described in connect;on w;th such ut;l;ty although other uses are contemplated. ~-0 In manufacturing very large scale integrated (VLSI) dev;ces accord;ng to thick f;lm procedures, alternat;ng layers of electrically conductive and electrically ;nsulative materials typ;cally are d;sposed on a r;g;d support substrate formed of an insulative material in a ~ -~
process much like the traditional silk screening process used ;n the graph;cs arts ;ndustry.
In the standard thick film process for produc;ng VLSI dev;ces the f;rst step in the process is to screen ~ ~-print a so-called ";nk" onto a r;gid dielectric base or 20 substrate board, air dry the ink, and fire the ink to -¦ form a first metal pattern on the substrate board. -~ TypicallyJ the substrate board comprises glass~
j~ porcelain-coated metal or a ceramic such as alumina or ~! beryllia, and the ink comprises a relatively high -~
viscosity mixture of electrically conductive metals such ~ as silver, gold or copper or metal alloys such as ;~ gold-palladium, or silver-palladium and a vitreous binder suspended ;n an organic vehicle or thinner. The ¦ screen printing typ;cally is performed through a silk or fine stainless-steel mesh screen that has been prev;ously patterned in the desired pattern of the metal layer or c;rcuit. The screen ;s placed over the substrate and a squeegee ;s used to force the screen :~' . ,,. ' : ..
,: , , ~;r ~
~3~191~
IMPROVED MICRO-ELECTRONICS DEVICES AND METHODS
OF MANUFACTURING SAME
Background of the Invent;on The present invent;on relates to micro-electron;cs devices and methods of manufacturing same, and more particularly to improvements in low d;electr;c constant materials for use in the formation of m;cro-electronics devices. The invention has particular utility for the manufacture o-f integrated circuits of the so-called "thick fiLm" type and will be described in connect;on w;th such ut;l;ty although other uses are contemplated. ~-0 In manufacturing very large scale integrated (VLSI) dev;ces accord;ng to thick f;lm procedures, alternat;ng layers of electrically conductive and electrically ;nsulative materials typ;cally are d;sposed on a r;g;d support substrate formed of an insulative material in a ~ -~
process much like the traditional silk screening process used ;n the graph;cs arts ;ndustry.
In the standard thick film process for produc;ng VLSI dev;ces the f;rst step in the process is to screen ~ ~-print a so-called ";nk" onto a r;gid dielectric base or 20 substrate board, air dry the ink, and fire the ink to -¦ form a first metal pattern on the substrate board. -~ TypicallyJ the substrate board comprises glass~
j~ porcelain-coated metal or a ceramic such as alumina or ~! beryllia, and the ink comprises a relatively high -~
viscosity mixture of electrically conductive metals such ~ as silver, gold or copper or metal alloys such as ;~ gold-palladium, or silver-palladium and a vitreous binder suspended ;n an organic vehicle or thinner. The ¦ screen printing typ;cally is performed through a silk or fine stainless-steel mesh screen that has been prev;ously patterned in the desired pattern of the metal layer or c;rcuit. The screen ;s placed over the substrate and a squeegee ;s used to force the screen :~' . ,,. ' : ..
,: , , ~;r ~
~3~191~
- 2 - ~ -down to the substrate and, s;multaneously, force the ink through the patterned mesh of the screen and down onto the surface of the substrate. The patterned substrate is then a;r dr;ed to evaporate off at least a port;on of the organic veh;cle, and the patterned, dr;ed substrate then ;s f;red ;n an oven to bond the electr;cally ~ ;
conduct;ve metals to the substrate. A coat;ng or layer of d;electric/insulating material, typically a glass ceram;c ;n a vitreous binder and organ;c veh;cle is then lo appl;ed over the f;red metal pattern, the insulating mater;al ;s air dried to evaporate at least a port;on of the organic veh;cle, and the dr;ed coat;ng is then fired ;n a furnace or k;ln as before to bond the ;nsulat;on coat;ng to the metal-patterned substrate.
Alternat;veLy, the conduct;ve patterns and d;electr;c/;nsulat;ng layer may be co-f;red. The process ;s repeated w;th alternating patterned metal layers and dielectr;c layers unt;l the des;red number of layers are completed. ~y prov;ding passageways ;n the 20 insulating layers (referred to as "v;as"), conduct;ve paths can be created therethrough ;nterconnecting the metal conducting layered patterns enabl;ng a three d;mens;onal ;nterconnected pattern to be fabr;cated.
¦ The v;as for layer to layer ;nterconnect;on may be 25 formed as part of the layering process. Alternat;velY, ~ ~
the v;as may be formed by us;ng a laser to create -overlapp;ng holes ;n the dielectric insulat;ng layers wh;ch then may be back f;lled w;th metal to create the conduct;ve ;nterconnect;ons between layers. In th;s 1 30 manner, structures of ten and more metal layered '~ patterns have been fabricated for high reliability hybrid microcircuit devices.
'~ The dielectric propert;es of the insulating layers are a limiting factor ;n the size and performance ; 35 character;st;cs of the VLSI c;rcu;t. For example, where ~' :~ . ,~
. .. >
'l ".
there is averlap between me-tal on adjacent layers, there is a capacitance created. Thus, higher frequenc;es occurring at higher circuit operating speeds and the L;ke~ may cause capacititive coupling (slow;ng the -signal or causing cross talk), between the layers at these points by this unavoidable capacitance. The presently employed d;electric materials for forming the insulating layers generally comprise gLass ceram;cs and ceramic/glass compos;tes. Glass ceramics are glasses which are devitrified by heating to form a very fine network of crystalline phase material. Glass ceramics are mechanically strong and have relatively low thermal -~
expansion coefficients which makes them particularly suited for VLSI chip attachment and thick film device 5 processing techniques as above described. However, -~
commercially available glass ceramics and composites -have a dielectric constants in the range of 9 to 12, and I an electrical insulation resistance of about 1012 Ohms and higher at room temperature and 300 volts. Due to the;r electrical properties and process constraints, line/space sizing of circuits on thick film devices made using glass ceramic d1electrics generally ;s about l 0.007/0.007 inches minimum, via sizes generally are ;
iI about 0.010 inches min;mum width, and the thickness of ;
the d;electric material to attain satisfactory performance generally ;s about 0.0015 ;nches minimum.
Accord;ngly, if a material having a lower dielectric ¦ constant could be employed for forming the insulating layers in VLSI circuits, the useful frequency range before interlayer-capacitance becomes a problem can be increased and propagation delay decreased.
Uherefore, it is the object of the present invention -to overcome the aforesa;d and other d;sadvantages of the prior art. A more specific object is to provide an 35 improved thick film process characterized by the use of ~, .. ' ~, . ~ ~, i ., : .~ ' ' .
, ~' ~-- 1331914 I a new and improved low dielectric constant ;nsulat;ve material~ Still other objects and many of the attendant advantages of the invention will become clear from the following description.
Summary Generally, in accordance with the present invent;on, a mult;layer thick film device is formed in which the insulating layers comprise fired-in-situ hollow glass ~-' microspheres~ preferably of a size not exceed;ng about o 400 mesh (U.S. Standard Sieve Series~. More -particularly, in accordance with the present invention, starting with a rigid insulative substrate such as ' ~' ¦ ceramic, the first layer of metallic pattern or patterns is formed on the surface of the ceram;c substrate by convent;onal means such as by screen~printing a metallization pattern using a conventional thick-f;lm ink comprising a matrix of conductive metallic particles and a vitreous binder suspended in a conventional organ;c carr;er. The screen-printed material then ;s 20 a;r dr;ed to evaporate the carr;er at least ;n part, and '' the result;ng structure then is fired at h;gh temperature to fuse the metall;zat;on pattern ;nto a ¦ continuous conductor or conductors r;g;dly aff;xed to ¦ the ceramic substrate. An overlay of dielectr;c ¦ 25 insulating material comprising a conventional glass '1 ceram;c or ceramic/glass composite matrix material I ~hereafter referred to as the matrix material), and `;' contalnin~ hollow gl'ass microspheres in accordance with the present invention and as w;ll be descr;bed ;n deta;l 30 hereafter, and d;sposed in a conventional th'ick film organ;c carrier vehicle, then is applied to the 1 result;ng structure, the insulating dielectr;c overlay "~ material is a;r dried and fired ;n place at a h;gh ¦ temperature. Alternàt;vely, the screen-printed material 35 and the ov'erlay of ;nsulating dielectric material may be '~
' :~, :., ~:
13~19~4 co-fired at high temperature.
Firing of the screen-printed material causes the conductive particles of the metallization pattern to be sintered and fused into a continuous conductor or conductors in the shape of the desired pattern. Fir;ng also evaporates any residual carrier, and fuses the vitreous material around the hollow glass microspheres to form a rigid pancake-like structure with the hollow glass microspheres imbedded therein. Preferably a second layer of insulating dielectric material ! comprising a conventional glass ceramic or ceramic/glass composite matrix material, and conta;n;ng hollow glass microspheres, suspended in an organ;c carr;er as before, ; ;s then squeegeed onto the structure to f;ll any pinholes that may have formed in the first insulating layer. And, if further desired, in a preferred ~
embodiment of the invent;on~ a th;rd layer of d;electric ~ `
material comprising a conventional glasslceramic dielectric in an organic binder may be applied, dried 20 and fired so as to level or planer;ze the d;electr;c top `~
surface.
The a-foresaid screen-printing and firing procedures ¦ may then be repeated to establish as many layers of ~1 c;rcuits as may be desired~ typically 8-10 25 screen-printed circu;t metal layers are formed, separated by d;electr;c layers above-descr;bed.
Thus, us;ng the ;nsulat;ng d;electr;c material of the present ;nvent;on in the preferred manner, three layers of mater;al preferably are depos;ted between each ~, 30 metal pattern layer. The overall preferred process ;¦ comprises the steps of:
l (a) forlning a low d;electric material by , 1 blending a conventional thick film insulat;on matrix `~¦ rnaterial, a conventional organic carrier veh;cle and a j~ 35 `
'i' ,~ :
:
plurality of dry hollow glass microspheres into a homogeneous .3 material;
j (b) depositing the dielectric material blend from step (a) onto the preferred circuit, and drying and firing the deposited :~
blend;
(c) depositing a second layer of dielectric material from `1 .
step (a) onto the resulting structure, and drying and firing the ;, deposited blend; and 3 (d) depositing a conventional (unmodified) thick film 10 insulating material comprlsing a s~andard glass/ceramic in a conventional organic carrier vehicle onto the resulting structure, and drying and firing the deposited materlal.
.' According to a broad aspect of the invention there is `~
provided a low dielectric constant material for use in the formation o~ thick film devices comprising a subs~antially homogenous blend of a thlck fllm insulation matrix material comprising ceramic or glass ceramic composite said material having ~ a dlelectric constant less than about 4.5, a thick film organlc l~ vehicle and a plurallty of hollow glass mlcrospheres.
,l 20 According to another broad aspect of the invention there ~ is provlded the method of making a low dielectric constant ~ f ~
~ material for use in the formation of thick film devices comprising : .
~.. , . :.
the steps of, .~.
(a) thoroughly blendlng a quantlty of dry hollow glass .. :~
mlcrospheres with a thick fllm organic vehicle, and, ,i, . -: .
(b) thorouyhly mlxing the blend produced from step (a~ with a ~ quantity of thlck film lnsulation matrix material compri ing ~ :~
;,., ,1 , - 6a - 72857-21 ceramic or glass ceramic composite to provide a material having a dielectric constant less than about 4.5.
According to another broad aspect of the invention there is provided a method of forming a low dielectric constant in-sulation layer according to thick film procedures comprising the steps of: :
(a) forming a low dielectric constant material by combining a thick film insulation matrix material comprising ceramic or ~:
glass ceramic composite, a thick film organic ~ehicle, and a I lO plurality of hollow glass microspheres into a homogeneous material;
(b) depositing the low dielectric constant material from step ~a) onto a circuit portion to a desired thickness for the insulation layer; and (c) drying and firing the deposited material ~rom step (b). :
According to another broad aspect of the invention there is provided a method of producing a low dielectric constant insulation layer according to thick fi.lm procedures comprising the il steps of: . :
il ~a) forming a low dielectric constant material by combining ;l 20 a thiek film insulation matrix material comprising ceramic or ;l glass eeramie eomposite, a thiek film organic vehicle, and a plurality of hollow glass microspheres into a homogenous material;
~ b) depositing the low dielectric constant material from step ~b) onto a metal pattern to a desired thickness;
~ e) drying and firing the low dielectric constant material deposited in step ~b); ~:~
.
, ~. C~ .
'' i` l j . ,: ::' . . ` ' . , . ! .. .,.~ .
-` ~33191d~ ;
- 6b - 72857 21 :~
(d) repeating steps (b) and (c) until the final desired : :
thickness of the insulation layer is approached; .-"~
(e) depositing a conventional thick film dielectric insulating material onto the structure resulting from step (d) to a desired thickness to planarize the resulting structure; and :
(f) dryiny and firiny the material from step (e).
According to another broad aspect of the invention there is provided a method of producing a thick film device according to ¦;
thick film procedures comprising the steps of:
(a) providing a rigid dielectric subs~rate; ;
(b) depositing a predetermlned metal pattern on said , substrate;
! (c) providing a low dielectric aonstant material which ~ :
comprises a substantially homogeneous blend of a thick film insulation matrix material comprising ceramic or glass ceramic compo~ite, a thick film organic vehicle and a plurality of hollow glass microspheres;
~d) depositing the low dielectric constant material from step ~c) onto the deposlted metal pattern; :
~¦ 20 ~e) drying and firing the low dielectric constant material deposited in step ~d); and (f) repeating steps (b) to (e) until the desired number of : .
i metal patterns separated by layers oi low dielectric material are completed.
Accordin~ to another broad aspect of the invention there is provlded in a thick film device of the type comprising a rigid ~ ;
~: insulating substrate and having one or a plurality of circuit ~
,' ~''' ,'' "', - 6c - 1 3 3 ~ 9 ~ 4 72857-2l layers separated by insulation layers, the improvement wherein at least one of said insulation layers comprises a fired-in-place thick film insulating material comprising ceramic or glass ceramic composite, having a plurality of hollow glass microspheres substantially homogeneously dispersed therein.
According to another broad aspect of the invention there is provided a method of forming a low dielectric constant insulation layer according to thick film procedures comprising the :.
steps of: :
(a) combining a thick film insulation matrix material comprising ceramic or glass ceramic composite, a thick film organic vehicle, and a plurality of hollow glass microspheres having a maximum size not exceeding about 400 mesh (U.S. Standard Sieve Series) into a homogeneous material;
(b) depos.iting material from step (a) onto a circuit portion .
to a desired thickness for the insulation layer; and :
(c) drying and firing deposited material from step (b) to .
provide a material having a dielectric constant less than about 4.5 said firing causing conductive particles of a metallization ;`
:: .
pattern constituting the circuit portion to be sintered and fired into a continuous conductor in the shape of a desired pattern, said ~ firing also evaporating any residual carrier and fusing the said i~¦ deposited material around the hollow glass microspheres to form a i~ rigid structu.re with the hollow glass microspheres embedded therein.
According to another broad aspect of the invention there :~
is provided a method of producing a low dielectric constant in- :~
~, "
. sulation layer according to thick film procedures comprising the .!
.. . .
:; ~ .
' ~:
il :~h,~
- 6d - 1331914 72857-21 steps of:
(a) combining a thick film insulation matrix material comprising ceramic or glass ceramic composite, a thick film organic vehicle, and a plurality of hollow glass microspheres having a maximum size not exceeding about 400 mesh (U.S. Standard Sieve Series);
(b) depositing material from step (a) onto a metal pattern to a desired thickness;
(c) drying and firing the low dielectric constant material . ~.
deposited in step (b) to pxovide a material having a dielectric ~-constant less than about 4.5 said firing causing the conductive .:~
particles of the metal pattern to be sintered and fired into .. :
a continuous conductor in the shape of the desired pattern, said firing also evaporating any residual carrier and fusi.ng the said , ~ - ...
deposited material around the hollow glass microspheres to form a . ;
rigid structure with the hollow glass microspheres embedded .~
therein; .. `:
i ~d) repeating steps ~b) and ~c) until the fina]. desired ! thickness of the insulation layer is approached;
~e) depositing a conventional thick film dielectric in- ::
sulating material onto the structure resulting from step ~d) to .
a desired thickness to planarize the resulting structure; and ; ~f) drying and firing the material from step ~e). .
. According to another broad aspect of the invention there .:.. ::~
is provided a method of producing a thick film de~ice according to thick film procedures comprising the steps of: :
.j .~ (a) providing a rigid dielectric substrate; :
, .
,'1 C
133191~
- 6e - 72857-21 .
(b) depositing a predetermined metal pattern on sald substrate;
! (c) provid1ng a low dielectric constant material which ~.
comprises a substantially homogeneous blend of a thick film insulation matrix material comprising ceramic or glass ceramic composite, a thick fllm organic vehicle and a plurality of hollow ? glass microspheres having a maximum size not exceeding about 400 mesh ~U.S. Standard Sieve Series);
(d) depositing material from step (c) onto the deposited .
? 10 metal pattern;
(e) drying and firing the material deposited in step (d) to ~ provide a material having a dielectric constant less than about ¦ 4.5 said firing causing the conductive particles of the . predetermined metal pattern to be sintered and fired into a ~:~
contlnuous conductor in the shape of the desired pattern, said . flrlng also evaporatlng any residual carrier and fusing ~he said i material around the hollow glass microspheres to form a rlgld . structure with the hollow glass mlcrospheres embedded therein; and ~ .
. (f) repeatlng steps (b) to (e) until the desired number of s: 20 metal patternsi sieparated by layers of low dielectric material are completed.
. Description of the Drawlnqs For a further understanding of the nature and objects of ~ .
::l the present invention, reference should be had to ~he following 1. ::;, 1 :¦ detailed description taken in connection wlth the accompanying drawings wherein like number depict like parts, and wherein, :
1l B
.
~` 133191~
- 6f - 72857-21 Figure 1 is a simplified drawing of a cutaway segment of a thlck film VLSI device made in accordance with the present invention;
Figure 2 is a block diagram diagrammatically illustrating one process for producing a thick film VLSI device in accordance with the teachings of the present invention; and Figure 3 is a block diagram diagrammatically , illustrating an alterna~ive process for producing a thick film : -I
', VLSI device in accordance with the teachings of the present -invention. ~-Description of the Preferred~Embodiment A portlon of thlck film VLSI device made according to the present inventlon is shown in Figure 1. The substrate 12 and .
metal pattern 10 are as prevlously descrlbed and are produced in I the manner a~ above .`1 .
.~ :
;, :.' ' ,"~
, ' '.
~ ~ ' .~j ,.
i~31914 , described. In the embodiments described herelnafter, ~, the substrate 12 comprises a conventional substrate ~ material such as Alumina, and the metal patterns ;¦ comprising a sintered or fired gold ink. The dielectric layer 14 preferably is comprised of three layers 20, 22 and 24 where the first two layers 20, 22 each contain hollow c,lass microspheres 26 ~shown in exaggerated size) in accordance with the present invention and the top or sealing layer 24 compr;ses standard thick film ;nsulation material.
A key feature of the present ;nvent;on ;s the ;ncorporation of hollow glass microspheres in the th;ck film dielectr;c layer(s). Hollow glass microspheres are ~-available commercially from a number of vendors. The -~ 15 presently preferred hollow glass microspheres compr;se ;~
hollow silica microspheres available from Emerson and Cumming~ Inc, Canton, Massachusetts, under the trademark Eccospheres. The manufacturer describes this material as comprising hollow silica microspheres of average size 12 to 40 microns, and hav;ng average wall size of 0.5 to 2.0 microns. In order to assure maximum performance, the glass microspheres preferably comprise , a mixture of different size glass microspheres, dry-screened to about 400 mesh (U.S. Standard Sieve Series). It has been found that the use of a m;xture of different size glass microspheres produces a product of more un;form filling and maximum packing, while the inclusion of appreciable quantities of microspheres in excess of about 40û mesh causes unacceptable dielectric film disruption of the resulting insulation layer(s) made using the materials in accordance with the present invention. The use of hollow glass microspheres 20 to ~, 200 microns in diameter and having wall thickness of 0.5 ;I, to 2 microns as fillers for lowering the dielectric 1 constant of the epoxy laminating board resins for , :
., ~
~., ,,1 ""~, .. , .~ .. ,, .. ,,, . , .. , . . ,. , . . , . , ; , -, .
~ ~$
1, -- 8 ~
I pr;nted circu;t boards ;s d;sclosed ;n I6tM Techn;cal t D;sclosure ~ullet;n Volume 22, Number 5, October 1979.
However, there ;s no disclosure or suggestion in the aforesaid I~M Techn;cal Disclosure ~ulletin that such ;- -hollow glass microspheres may be subjected to the h;gh temperature mult;ple f;r;ng cond;t;ons encountered ;n ;~
th;ck f;lm processes so as to be useful ;n the ¦~ manufacture of thick film devices, or of the advantages as w;ll result from such use as ;n accordance w;th the present ;nvention.
' The dry-screened hollow glass m;crospheres are -¦ blended w;th a convent;onal thick f;lm glass ceramic matrix mater;al and organic veh;cle. In general, the 3 th;ck film glass ceram;c matrix material comprises a convent;onal glass/ceramic powder in an organic vehicle. A particularly preferred vehicle comprises -DP8250 ava;lable from E.I. DuPont de Nemours~
Wilmington, Delaware. Alternatively, semiconductor ~-grade terp;neol may be used as the vehicle.
The followlng blending procedure has been ;~
established ;n order to assure a substantial un;form blend of the hollow glass microspheres in the thick film matrix and organic vehicle. First, the hollow glass microspheres are dry-screened to about 400 mesh, and the 25 screened hollow glass microspheres are added to the thick film organic vehicle and blended. In order to assure aga;nst poss;ble lntroduct;on of metal fines, -etc~, into the blend, the hollow glass microspheres and vehlcle should be blended ;n a glass lined or plastic 0 lined containers. The overall procedure is to first ~ spatula stir followed by high speed jar rolling ¦ ut;lizing a conventional ball mill drive. In order to maintain the integrity of the hollow glass microspheres, ~-I no medium should be added to the jar which could ~;~
; ~ 35 possibly grind the microspheres. The resulting blend is I .
.~ ' ~, ~ '.~: ~
,, ,~
;'~ t~
13~1914 -_ 9 ~
then added to a conventional glass/ceram;c th;ck film matrix in a carrier, and the resulting mixture h;gh speed jar rolled as before.
While not wishing to be bound by theory it ;s 1~-~
conduct;ve metals to the substrate. A coat;ng or layer of d;electric/insulating material, typically a glass ceram;c ;n a vitreous binder and organ;c veh;cle is then lo appl;ed over the f;red metal pattern, the insulating mater;al ;s air dried to evaporate at least a port;on of the organic veh;cle, and the dr;ed coat;ng is then fired ;n a furnace or k;ln as before to bond the ;nsulat;on coat;ng to the metal-patterned substrate.
Alternat;veLy, the conduct;ve patterns and d;electr;c/;nsulat;ng layer may be co-f;red. The process ;s repeated w;th alternating patterned metal layers and dielectr;c layers unt;l the des;red number of layers are completed. ~y prov;ding passageways ;n the 20 insulating layers (referred to as "v;as"), conduct;ve paths can be created therethrough ;nterconnecting the metal conducting layered patterns enabl;ng a three d;mens;onal ;nterconnected pattern to be fabr;cated.
¦ The v;as for layer to layer ;nterconnect;on may be 25 formed as part of the layering process. Alternat;velY, ~ ~
the v;as may be formed by us;ng a laser to create -overlapp;ng holes ;n the dielectric insulat;ng layers wh;ch then may be back f;lled w;th metal to create the conduct;ve ;nterconnect;ons between layers. In th;s 1 30 manner, structures of ten and more metal layered '~ patterns have been fabricated for high reliability hybrid microcircuit devices.
'~ The dielectric propert;es of the insulating layers are a limiting factor ;n the size and performance ; 35 character;st;cs of the VLSI c;rcu;t. For example, where ~' :~ . ,~
. .. >
'l ".
there is averlap between me-tal on adjacent layers, there is a capacitance created. Thus, higher frequenc;es occurring at higher circuit operating speeds and the L;ke~ may cause capacititive coupling (slow;ng the -signal or causing cross talk), between the layers at these points by this unavoidable capacitance. The presently employed d;electric materials for forming the insulating layers generally comprise gLass ceram;cs and ceramic/glass compos;tes. Glass ceramics are glasses which are devitrified by heating to form a very fine network of crystalline phase material. Glass ceramics are mechanically strong and have relatively low thermal -~
expansion coefficients which makes them particularly suited for VLSI chip attachment and thick film device 5 processing techniques as above described. However, -~
commercially available glass ceramics and composites -have a dielectric constants in the range of 9 to 12, and I an electrical insulation resistance of about 1012 Ohms and higher at room temperature and 300 volts. Due to the;r electrical properties and process constraints, line/space sizing of circuits on thick film devices made using glass ceramic d1electrics generally ;s about l 0.007/0.007 inches minimum, via sizes generally are ;
iI about 0.010 inches min;mum width, and the thickness of ;
the d;electric material to attain satisfactory performance generally ;s about 0.0015 ;nches minimum.
Accord;ngly, if a material having a lower dielectric ¦ constant could be employed for forming the insulating layers in VLSI circuits, the useful frequency range before interlayer-capacitance becomes a problem can be increased and propagation delay decreased.
Uherefore, it is the object of the present invention -to overcome the aforesa;d and other d;sadvantages of the prior art. A more specific object is to provide an 35 improved thick film process characterized by the use of ~, .. ' ~, . ~ ~, i ., : .~ ' ' .
, ~' ~-- 1331914 I a new and improved low dielectric constant ;nsulat;ve material~ Still other objects and many of the attendant advantages of the invention will become clear from the following description.
Summary Generally, in accordance with the present invent;on, a mult;layer thick film device is formed in which the insulating layers comprise fired-in-situ hollow glass ~-' microspheres~ preferably of a size not exceed;ng about o 400 mesh (U.S. Standard Sieve Series~. More -particularly, in accordance with the present invention, starting with a rigid insulative substrate such as ' ~' ¦ ceramic, the first layer of metallic pattern or patterns is formed on the surface of the ceram;c substrate by convent;onal means such as by screen~printing a metallization pattern using a conventional thick-f;lm ink comprising a matrix of conductive metallic particles and a vitreous binder suspended in a conventional organ;c carr;er. The screen-printed material then ;s 20 a;r dr;ed to evaporate the carr;er at least ;n part, and '' the result;ng structure then is fired at h;gh temperature to fuse the metall;zat;on pattern ;nto a ¦ continuous conductor or conductors r;g;dly aff;xed to ¦ the ceramic substrate. An overlay of dielectr;c ¦ 25 insulating material comprising a conventional glass '1 ceram;c or ceramic/glass composite matrix material I ~hereafter referred to as the matrix material), and `;' contalnin~ hollow gl'ass microspheres in accordance with the present invention and as w;ll be descr;bed ;n deta;l 30 hereafter, and d;sposed in a conventional th'ick film organ;c carrier vehicle, then is applied to the 1 result;ng structure, the insulating dielectr;c overlay "~ material is a;r dried and fired ;n place at a h;gh ¦ temperature. Alternàt;vely, the screen-printed material 35 and the ov'erlay of ;nsulating dielectric material may be '~
' :~, :., ~:
13~19~4 co-fired at high temperature.
Firing of the screen-printed material causes the conductive particles of the metallization pattern to be sintered and fused into a continuous conductor or conductors in the shape of the desired pattern. Fir;ng also evaporates any residual carrier, and fuses the vitreous material around the hollow glass microspheres to form a rigid pancake-like structure with the hollow glass microspheres imbedded therein. Preferably a second layer of insulating dielectric material ! comprising a conventional glass ceramic or ceramic/glass composite matrix material, and conta;n;ng hollow glass microspheres, suspended in an organ;c carr;er as before, ; ;s then squeegeed onto the structure to f;ll any pinholes that may have formed in the first insulating layer. And, if further desired, in a preferred ~
embodiment of the invent;on~ a th;rd layer of d;electric ~ `
material comprising a conventional glasslceramic dielectric in an organic binder may be applied, dried 20 and fired so as to level or planer;ze the d;electr;c top `~
surface.
The a-foresaid screen-printing and firing procedures ¦ may then be repeated to establish as many layers of ~1 c;rcuits as may be desired~ typically 8-10 25 screen-printed circu;t metal layers are formed, separated by d;electr;c layers above-descr;bed.
Thus, us;ng the ;nsulat;ng d;electr;c material of the present ;nvent;on in the preferred manner, three layers of mater;al preferably are depos;ted between each ~, 30 metal pattern layer. The overall preferred process ;¦ comprises the steps of:
l (a) forlning a low d;electric material by , 1 blending a conventional thick film insulat;on matrix `~¦ rnaterial, a conventional organic carrier veh;cle and a j~ 35 `
'i' ,~ :
:
plurality of dry hollow glass microspheres into a homogeneous .3 material;
j (b) depositing the dielectric material blend from step (a) onto the preferred circuit, and drying and firing the deposited :~
blend;
(c) depositing a second layer of dielectric material from `1 .
step (a) onto the resulting structure, and drying and firing the ;, deposited blend; and 3 (d) depositing a conventional (unmodified) thick film 10 insulating material comprlsing a s~andard glass/ceramic in a conventional organic carrier vehicle onto the resulting structure, and drying and firing the deposited materlal.
.' According to a broad aspect of the invention there is `~
provided a low dielectric constant material for use in the formation o~ thick film devices comprising a subs~antially homogenous blend of a thlck fllm insulation matrix material comprising ceramic or glass ceramic composite said material having ~ a dlelectric constant less than about 4.5, a thick film organlc l~ vehicle and a plurallty of hollow glass mlcrospheres.
,l 20 According to another broad aspect of the invention there ~ is provlded the method of making a low dielectric constant ~ f ~
~ material for use in the formation of thick film devices comprising : .
~.. , . :.
the steps of, .~.
(a) thoroughly blendlng a quantlty of dry hollow glass .. :~
mlcrospheres with a thick fllm organic vehicle, and, ,i, . -: .
(b) thorouyhly mlxing the blend produced from step (a~ with a ~ quantity of thlck film lnsulation matrix material compri ing ~ :~
;,., ,1 , - 6a - 72857-21 ceramic or glass ceramic composite to provide a material having a dielectric constant less than about 4.5.
According to another broad aspect of the invention there is provided a method of forming a low dielectric constant in-sulation layer according to thick film procedures comprising the steps of: :
(a) forming a low dielectric constant material by combining a thick film insulation matrix material comprising ceramic or ~:
glass ceramic composite, a thick film organic ~ehicle, and a I lO plurality of hollow glass microspheres into a homogeneous material;
(b) depositing the low dielectric constant material from step ~a) onto a circuit portion to a desired thickness for the insulation layer; and (c) drying and firing the deposited material ~rom step (b). :
According to another broad aspect of the invention there is provided a method of producing a low dielectric constant insulation layer according to thick fi.lm procedures comprising the il steps of: . :
il ~a) forming a low dielectric constant material by combining ;l 20 a thiek film insulation matrix material comprising ceramic or ;l glass eeramie eomposite, a thiek film organic vehicle, and a plurality of hollow glass microspheres into a homogenous material;
~ b) depositing the low dielectric constant material from step ~b) onto a metal pattern to a desired thickness;
~ e) drying and firing the low dielectric constant material deposited in step ~b); ~:~
.
, ~. C~ .
'' i` l j . ,: ::' . . ` ' . , . ! .. .,.~ .
-` ~33191d~ ;
- 6b - 72857 21 :~
(d) repeating steps (b) and (c) until the final desired : :
thickness of the insulation layer is approached; .-"~
(e) depositing a conventional thick film dielectric insulating material onto the structure resulting from step (d) to a desired thickness to planarize the resulting structure; and :
(f) dryiny and firiny the material from step (e).
According to another broad aspect of the invention there is provided a method of producing a thick film device according to ¦;
thick film procedures comprising the steps of:
(a) providing a rigid dielectric subs~rate; ;
(b) depositing a predetermlned metal pattern on said , substrate;
! (c) providing a low dielectric aonstant material which ~ :
comprises a substantially homogeneous blend of a thick film insulation matrix material comprising ceramic or glass ceramic compo~ite, a thick film organic vehicle and a plurality of hollow glass microspheres;
~d) depositing the low dielectric constant material from step ~c) onto the deposlted metal pattern; :
~¦ 20 ~e) drying and firing the low dielectric constant material deposited in step ~d); and (f) repeating steps (b) to (e) until the desired number of : .
i metal patterns separated by layers oi low dielectric material are completed.
Accordin~ to another broad aspect of the invention there is provlded in a thick film device of the type comprising a rigid ~ ;
~: insulating substrate and having one or a plurality of circuit ~
,' ~''' ,'' "', - 6c - 1 3 3 ~ 9 ~ 4 72857-2l layers separated by insulation layers, the improvement wherein at least one of said insulation layers comprises a fired-in-place thick film insulating material comprising ceramic or glass ceramic composite, having a plurality of hollow glass microspheres substantially homogeneously dispersed therein.
According to another broad aspect of the invention there is provided a method of forming a low dielectric constant insulation layer according to thick film procedures comprising the :.
steps of: :
(a) combining a thick film insulation matrix material comprising ceramic or glass ceramic composite, a thick film organic vehicle, and a plurality of hollow glass microspheres having a maximum size not exceeding about 400 mesh (U.S. Standard Sieve Series) into a homogeneous material;
(b) depos.iting material from step (a) onto a circuit portion .
to a desired thickness for the insulation layer; and :
(c) drying and firing deposited material from step (b) to .
provide a material having a dielectric constant less than about 4.5 said firing causing conductive particles of a metallization ;`
:: .
pattern constituting the circuit portion to be sintered and fired into a continuous conductor in the shape of a desired pattern, said ~ firing also evaporating any residual carrier and fusing the said i~¦ deposited material around the hollow glass microspheres to form a i~ rigid structu.re with the hollow glass microspheres embedded therein.
According to another broad aspect of the invention there :~
is provided a method of producing a low dielectric constant in- :~
~, "
. sulation layer according to thick film procedures comprising the .!
.. . .
:; ~ .
' ~:
il :~h,~
- 6d - 1331914 72857-21 steps of:
(a) combining a thick film insulation matrix material comprising ceramic or glass ceramic composite, a thick film organic vehicle, and a plurality of hollow glass microspheres having a maximum size not exceeding about 400 mesh (U.S. Standard Sieve Series);
(b) depositing material from step (a) onto a metal pattern to a desired thickness;
(c) drying and firing the low dielectric constant material . ~.
deposited in step (b) to pxovide a material having a dielectric ~-constant less than about 4.5 said firing causing the conductive .:~
particles of the metal pattern to be sintered and fired into .. :
a continuous conductor in the shape of the desired pattern, said firing also evaporating any residual carrier and fusi.ng the said , ~ - ...
deposited material around the hollow glass microspheres to form a . ;
rigid structure with the hollow glass microspheres embedded .~
therein; .. `:
i ~d) repeating steps ~b) and ~c) until the fina]. desired ! thickness of the insulation layer is approached;
~e) depositing a conventional thick film dielectric in- ::
sulating material onto the structure resulting from step ~d) to .
a desired thickness to planarize the resulting structure; and ; ~f) drying and firing the material from step ~e). .
. According to another broad aspect of the invention there .:.. ::~
is provided a method of producing a thick film de~ice according to thick film procedures comprising the steps of: :
.j .~ (a) providing a rigid dielectric substrate; :
, .
,'1 C
133191~
- 6e - 72857-21 .
(b) depositing a predetermined metal pattern on sald substrate;
! (c) provid1ng a low dielectric constant material which ~.
comprises a substantially homogeneous blend of a thick film insulation matrix material comprising ceramic or glass ceramic composite, a thick fllm organic vehicle and a plurality of hollow ? glass microspheres having a maximum size not exceeding about 400 mesh ~U.S. Standard Sieve Series);
(d) depositing material from step (c) onto the deposited .
? 10 metal pattern;
(e) drying and firing the material deposited in step (d) to ~ provide a material having a dielectric constant less than about ¦ 4.5 said firing causing the conductive particles of the . predetermined metal pattern to be sintered and fired into a ~:~
contlnuous conductor in the shape of the desired pattern, said . flrlng also evaporatlng any residual carrier and fusing ~he said i material around the hollow glass microspheres to form a rlgld . structure with the hollow glass mlcrospheres embedded therein; and ~ .
. (f) repeatlng steps (b) to (e) until the desired number of s: 20 metal patternsi sieparated by layers of low dielectric material are completed.
. Description of the Drawlnqs For a further understanding of the nature and objects of ~ .
::l the present invention, reference should be had to ~he following 1. ::;, 1 :¦ detailed description taken in connection wlth the accompanying drawings wherein like number depict like parts, and wherein, :
1l B
.
~` 133191~
- 6f - 72857-21 Figure 1 is a simplified drawing of a cutaway segment of a thlck film VLSI device made in accordance with the present invention;
Figure 2 is a block diagram diagrammatically illustrating one process for producing a thick film VLSI device in accordance with the teachings of the present invention; and Figure 3 is a block diagram diagrammatically , illustrating an alterna~ive process for producing a thick film : -I
', VLSI device in accordance with the teachings of the present -invention. ~-Description of the Preferred~Embodiment A portlon of thlck film VLSI device made according to the present inventlon is shown in Figure 1. The substrate 12 and .
metal pattern 10 are as prevlously descrlbed and are produced in I the manner a~ above .`1 .
.~ :
;, :.' ' ,"~
, ' '.
~ ~ ' .~j ,.
i~31914 , described. In the embodiments described herelnafter, ~, the substrate 12 comprises a conventional substrate ~ material such as Alumina, and the metal patterns ;¦ comprising a sintered or fired gold ink. The dielectric layer 14 preferably is comprised of three layers 20, 22 and 24 where the first two layers 20, 22 each contain hollow c,lass microspheres 26 ~shown in exaggerated size) in accordance with the present invention and the top or sealing layer 24 compr;ses standard thick film ;nsulation material.
A key feature of the present ;nvent;on ;s the ;ncorporation of hollow glass microspheres in the th;ck film dielectr;c layer(s). Hollow glass microspheres are ~-available commercially from a number of vendors. The -~ 15 presently preferred hollow glass microspheres compr;se ;~
hollow silica microspheres available from Emerson and Cumming~ Inc, Canton, Massachusetts, under the trademark Eccospheres. The manufacturer describes this material as comprising hollow silica microspheres of average size 12 to 40 microns, and hav;ng average wall size of 0.5 to 2.0 microns. In order to assure maximum performance, the glass microspheres preferably comprise , a mixture of different size glass microspheres, dry-screened to about 400 mesh (U.S. Standard Sieve Series). It has been found that the use of a m;xture of different size glass microspheres produces a product of more un;form filling and maximum packing, while the inclusion of appreciable quantities of microspheres in excess of about 40û mesh causes unacceptable dielectric film disruption of the resulting insulation layer(s) made using the materials in accordance with the present invention. The use of hollow glass microspheres 20 to ~, 200 microns in diameter and having wall thickness of 0.5 ;I, to 2 microns as fillers for lowering the dielectric 1 constant of the epoxy laminating board resins for , :
., ~
~., ,,1 ""~, .. , .~ .. ,, .. ,,, . , .. , . . ,. , . . , . , ; , -, .
~ ~$
1, -- 8 ~
I pr;nted circu;t boards ;s d;sclosed ;n I6tM Techn;cal t D;sclosure ~ullet;n Volume 22, Number 5, October 1979.
However, there ;s no disclosure or suggestion in the aforesaid I~M Techn;cal Disclosure ~ulletin that such ;- -hollow glass microspheres may be subjected to the h;gh temperature mult;ple f;r;ng cond;t;ons encountered ;n ;~
th;ck f;lm processes so as to be useful ;n the ¦~ manufacture of thick film devices, or of the advantages as w;ll result from such use as ;n accordance w;th the present ;nvention.
' The dry-screened hollow glass m;crospheres are -¦ blended w;th a convent;onal thick f;lm glass ceramic matrix mater;al and organic veh;cle. In general, the 3 th;ck film glass ceram;c matrix material comprises a convent;onal glass/ceramic powder in an organic vehicle. A particularly preferred vehicle comprises -DP8250 ava;lable from E.I. DuPont de Nemours~
Wilmington, Delaware. Alternatively, semiconductor ~-grade terp;neol may be used as the vehicle.
The followlng blending procedure has been ;~
established ;n order to assure a substantial un;form blend of the hollow glass microspheres in the thick film matrix and organic vehicle. First, the hollow glass microspheres are dry-screened to about 400 mesh, and the 25 screened hollow glass microspheres are added to the thick film organic vehicle and blended. In order to assure aga;nst poss;ble lntroduct;on of metal fines, -etc~, into the blend, the hollow glass microspheres and vehlcle should be blended ;n a glass lined or plastic 0 lined containers. The overall procedure is to first ~ spatula stir followed by high speed jar rolling ¦ ut;lizing a conventional ball mill drive. In order to maintain the integrity of the hollow glass microspheres, ~-I no medium should be added to the jar which could ~;~
; ~ 35 possibly grind the microspheres. The resulting blend is I .
.~ ' ~, ~ '.~: ~
,, ,~
;'~ t~
13~1914 -_ 9 ~
then added to a conventional glass/ceram;c th;ck film matrix in a carrier, and the resulting mixture h;gh speed jar rolled as before.
While not wishing to be bound by theory it ;s 1~-~
5 believed that the unexpected substantial reduction ;n -~
the dielectric constant of the insulat;on mater;al made -~
;n accordance w;th the present invent;on results from -the large volume of air (Er=1) entrapped in the - -m;crospheres and thus in the insulating layers. The inclus;on of even small quant;t;es of hollow glass microspheres to an insulating layer will have some effect on reducing the dielectric constant of the resulting insulating layer. However~ it has been observed that insulat;ng layers made using hollow glass ` lS~ microspheres in accordance with the present invention ¦ and having in excess of about 10-15% by volume of the ¦ hollow glass microspheres exh;b;t apprec;ably reduced ¦ d;electric constants as compared to conventional glass ~ ceram;c and ceramic/glass compos;te ;nsulat;ng layers.
j 20 On the otherhand, inclusion of hollow glass microspheres in amounts in excess of about 45-50 volume percent I drastically adversely affects the structural strength and thermal resistance of the resulting ;nsulating ¦ layers. Particularly useful compositions in accordance with the present invention comprise about ZO% to about 42% by volume of the hollow glass microspheres~ and preferably comprise from about 35% to about 39% by volume of the hollow m;crospheres.
~I The present ;nvention w;ll now be further descr;bed in connection with a preferred embodiment of the present invention.
To create the low dielectric material of the present invention, five parts by weight of pre-sifted 400 mesh dry, hollow, silica microspheres (Silica Eccospheres(TM)~ available from Emerson and Cummings, , . . ~
'.' ~ ~.
.
:`1 ,j ""ù ~ir~
~i I~
13319~4 ~ o ~
Inc.) are added to thirteen parts by weight of DP8250 standard thick film organic vehicle ava;lable from DuPont. The organ;c vehicle is used as ;t is suppl;ed -by the manufacturer. This mixture ;s then first spatula stirred and then high speed jar rolled on a ball mill for 10 minutes to thoroughly mix the hollow glass I m;crospheres with the carr;er vehicle.
; To thirty parts by w&ight of Englehard Zero Flow(TM) standard thick f;lm glass/ceramic composite lO matr;x material is then added ten parts by weight of the -~
resulting hollow glass microsphere/organ;c veh;cle blend and the resultant m;xture is high speed jar rolled for 15 minutes to provide 3 thoroughly mixed homogeneous m;xture.
The resultant m;xture is the low dielectr;c mater;al to be used according to the present ;nvent;on and ;s of standard viscosity.
I Returning now to Figure 2, the formation process according to the preferred embodiment of the present ~-I 20 invention will now be discussed in greater detail.
! The metal pattern 10 ;s first printed on the j substrate 12, dried and fired. The f;rst layer 20 of the low dielectric material of the present ;nvention produced as above descr;bed ;s then appl;ed over the 2s resulting structure ut;lizing a metal stenc;l screen, 0.005 inches th;ck. Layer 20 ;s then dr;ed and f;red yielding a first d;electric layer 20 of thickness in the range of 0.0015 to 0~0030 ;nches. A second layer 22 of I low dielectric material of the present invent;on ,, 30 produced as above descr;bed then ;s squeegeed over the result;ng structure ;n an identical fashion and layer 22 ;s then dried and fired as before. Layer 22 fills any p;nholes left in layer 20 and helps to planarize the structure. The th;ckness of layer 22 upon f;r;ng w;ll typ;cally be in the range of 0.0010 to 0.0020 ;nches.
:
, ' i;: :::
,~'.
,' -~"
"
Thereafter, ;n order further to planar;ze the structure and to prepare the structure for add;t;onal metal c;rcu;t layers, a layer 24 of a convent;onal th;ck f;lm glass/ceram;c mater;al (Englehard Zero Flow 5 ava;lable from Englehard Corporat;on, Newark, New Jersey) ;n an organ;c veh;cle ;s cast onto the result;ng structure. Layer 24 ;s then dr;ed and f;red ;n a convent;onal manner. Typ;cally, layer 24 will be approx;mately O.S m;ls th;ck. Layer 24 prov;des a lo further d;electr;c substrate wh;le, at the same t;me, -prov;des an opt;mum planar substrate for the next layer of metal c;rcu;t to be pr;nted on top of ;t.
Thereafter, v;as are formed through the insulat;ng J layers using a laser or the like to create overlapp;ng 5 holes ;n the d;electr;c layers, and the holes are then , back f;lled with liqu;d metal to create the des;red conduct;ve ;nterconnect;ons between the layers.
Alternat;vely, as shown ;n F;g. 3, the conduct;ve paths between layers may be produced s;multaneously w;th 20 metall;c pattern format;on us;ng methods well known ;n the art.
The aforesa;d steps then may be repeated w;th alternat;ng pattern metal layers and ;nsulat;ng layers as before being formed unt;l the desired number of 25 c;rcuit layers are completed.
F;nally, the result;ng microc;rcuit may be overglazed ;n a convent;onal manner w;th a convent;onal v;treous glass glaz;ng mater;al so as to seal the circu;t from the environment.
As w;ll be seen from the foregoing, the present ;nvent;on prov;des an ;mproved th;ck film manufactur;ng method and th;ck film devices hav;ng ;mproved performance character;stics as compared w;th the pr;or art.
The process and mater;al of the present ;nvent;on ~,~ . . ~' ~
.' ~ . ,'.
i~ . ~
~1, `. ~ .
.. ,~ ~ .
133? 914 - l2 -prov;des a d;electr;c/;nsuLat;ng mater;al wh;ch ;n VLSI
dev;ces exhib;ts a d;electr;c constant of approximately ¦ 3.5 with some copper systems, and 4.0-4.5 with most gold ~1 th;ck f;lm systems. This ;s a s;gn;f;cant advantage I 5 over the lowest known prior art d;electr;c/insulat;on ~
:! mater;als currently available which are bel;eved to ~i I prov;de a d;electr;c constant of about 7 w;th copper q systems. Moreover, ;n addit;on to ;ts low dielectr;c j constant, the d;electric mater;al of the present 10 ;nvent;on has the benef;t of be;ng compat;ble w;th both ' gold, gold alloy and copper metallurg;es~ It ;s `~` part;cularly suitable for h;gh density, h;gh temperature, h;gh speed appl;cat;ons. In tests conducted the response of line ;mpedance over 15 frequenc;es from 3 to 26 GHz was generally flat.
S;m;larly, data from 1 KHz to 13 MHz demonstrated flat response as well.
Var;ous changes may be made ;n the above process and dev;ce w;thout depart;ng from the scope of the invention 20 herein descr;bed. It ;s therefore ;ntended that all I matter contalned ;n the above descr;pt;on shall be ¦ ;nterpreted ;n an ;llustrat;ve and not ;n a lim;t;ng ~j sense.
~HEREFORE, hav;ng thus descr;bed my ;nvent;on, I
cla;m:
:~
~``'1 .: :
,,,, , L~ . 35 ~, .~, ~
~'~i , :. .
: .:
.:;
"
the dielectric constant of the insulat;on mater;al made -~
;n accordance w;th the present invent;on results from -the large volume of air (Er=1) entrapped in the - -m;crospheres and thus in the insulating layers. The inclus;on of even small quant;t;es of hollow glass microspheres to an insulating layer will have some effect on reducing the dielectric constant of the resulting insulating layer. However~ it has been observed that insulat;ng layers made using hollow glass ` lS~ microspheres in accordance with the present invention ¦ and having in excess of about 10-15% by volume of the ¦ hollow glass microspheres exh;b;t apprec;ably reduced ¦ d;electric constants as compared to conventional glass ~ ceram;c and ceramic/glass compos;te ;nsulat;ng layers.
j 20 On the otherhand, inclusion of hollow glass microspheres in amounts in excess of about 45-50 volume percent I drastically adversely affects the structural strength and thermal resistance of the resulting ;nsulating ¦ layers. Particularly useful compositions in accordance with the present invention comprise about ZO% to about 42% by volume of the hollow glass microspheres~ and preferably comprise from about 35% to about 39% by volume of the hollow m;crospheres.
~I The present ;nvention w;ll now be further descr;bed in connection with a preferred embodiment of the present invention.
To create the low dielectric material of the present invention, five parts by weight of pre-sifted 400 mesh dry, hollow, silica microspheres (Silica Eccospheres(TM)~ available from Emerson and Cummings, , . . ~
'.' ~ ~.
.
:`1 ,j ""ù ~ir~
~i I~
13319~4 ~ o ~
Inc.) are added to thirteen parts by weight of DP8250 standard thick film organic vehicle ava;lable from DuPont. The organ;c vehicle is used as ;t is suppl;ed -by the manufacturer. This mixture ;s then first spatula stirred and then high speed jar rolled on a ball mill for 10 minutes to thoroughly mix the hollow glass I m;crospheres with the carr;er vehicle.
; To thirty parts by w&ight of Englehard Zero Flow(TM) standard thick f;lm glass/ceramic composite lO matr;x material is then added ten parts by weight of the -~
resulting hollow glass microsphere/organ;c veh;cle blend and the resultant m;xture is high speed jar rolled for 15 minutes to provide 3 thoroughly mixed homogeneous m;xture.
The resultant m;xture is the low dielectr;c mater;al to be used according to the present ;nvent;on and ;s of standard viscosity.
I Returning now to Figure 2, the formation process according to the preferred embodiment of the present ~-I 20 invention will now be discussed in greater detail.
! The metal pattern 10 ;s first printed on the j substrate 12, dried and fired. The f;rst layer 20 of the low dielectric material of the present ;nvention produced as above descr;bed ;s then appl;ed over the 2s resulting structure ut;lizing a metal stenc;l screen, 0.005 inches th;ck. Layer 20 ;s then dr;ed and f;red yielding a first d;electric layer 20 of thickness in the range of 0.0015 to 0~0030 ;nches. A second layer 22 of I low dielectric material of the present invent;on ,, 30 produced as above descr;bed then ;s squeegeed over the result;ng structure ;n an identical fashion and layer 22 ;s then dried and fired as before. Layer 22 fills any p;nholes left in layer 20 and helps to planarize the structure. The th;ckness of layer 22 upon f;r;ng w;ll typ;cally be in the range of 0.0010 to 0.0020 ;nches.
:
, ' i;: :::
,~'.
,' -~"
"
Thereafter, ;n order further to planar;ze the structure and to prepare the structure for add;t;onal metal c;rcu;t layers, a layer 24 of a convent;onal th;ck f;lm glass/ceram;c mater;al (Englehard Zero Flow 5 ava;lable from Englehard Corporat;on, Newark, New Jersey) ;n an organ;c veh;cle ;s cast onto the result;ng structure. Layer 24 ;s then dr;ed and f;red ;n a convent;onal manner. Typ;cally, layer 24 will be approx;mately O.S m;ls th;ck. Layer 24 prov;des a lo further d;electr;c substrate wh;le, at the same t;me, -prov;des an opt;mum planar substrate for the next layer of metal c;rcu;t to be pr;nted on top of ;t.
Thereafter, v;as are formed through the insulat;ng J layers using a laser or the like to create overlapp;ng 5 holes ;n the d;electr;c layers, and the holes are then , back f;lled with liqu;d metal to create the des;red conduct;ve ;nterconnect;ons between the layers.
Alternat;vely, as shown ;n F;g. 3, the conduct;ve paths between layers may be produced s;multaneously w;th 20 metall;c pattern format;on us;ng methods well known ;n the art.
The aforesa;d steps then may be repeated w;th alternat;ng pattern metal layers and ;nsulat;ng layers as before being formed unt;l the desired number of 25 c;rcuit layers are completed.
F;nally, the result;ng microc;rcuit may be overglazed ;n a convent;onal manner w;th a convent;onal v;treous glass glaz;ng mater;al so as to seal the circu;t from the environment.
As w;ll be seen from the foregoing, the present ;nvent;on prov;des an ;mproved th;ck film manufactur;ng method and th;ck film devices hav;ng ;mproved performance character;stics as compared w;th the pr;or art.
The process and mater;al of the present ;nvent;on ~,~ . . ~' ~
.' ~ . ,'.
i~ . ~
~1, `. ~ .
.. ,~ ~ .
133? 914 - l2 -prov;des a d;electr;c/;nsuLat;ng mater;al wh;ch ;n VLSI
dev;ces exhib;ts a d;electr;c constant of approximately ¦ 3.5 with some copper systems, and 4.0-4.5 with most gold ~1 th;ck f;lm systems. This ;s a s;gn;f;cant advantage I 5 over the lowest known prior art d;electr;c/insulat;on ~
:! mater;als currently available which are bel;eved to ~i I prov;de a d;electr;c constant of about 7 w;th copper q systems. Moreover, ;n addit;on to ;ts low dielectr;c j constant, the d;electric mater;al of the present 10 ;nvent;on has the benef;t of be;ng compat;ble w;th both ' gold, gold alloy and copper metallurg;es~ It ;s `~` part;cularly suitable for h;gh density, h;gh temperature, h;gh speed appl;cat;ons. In tests conducted the response of line ;mpedance over 15 frequenc;es from 3 to 26 GHz was generally flat.
S;m;larly, data from 1 KHz to 13 MHz demonstrated flat response as well.
Var;ous changes may be made ;n the above process and dev;ce w;thout depart;ng from the scope of the invention 20 herein descr;bed. It ;s therefore ;ntended that all I matter contalned ;n the above descr;pt;on shall be ¦ ;nterpreted ;n an ;llustrat;ve and not ;n a lim;t;ng ~j sense.
~HEREFORE, hav;ng thus descr;bed my ;nvent;on, I
cla;m:
:~
~``'1 .: :
,,,, , L~ . 35 ~, .~, ~
~'~i , :. .
: .:
.:;
"
Claims (29)
1. A low dielectric constant material for use in the formation of thick film devices comprising a substantially homogenous blend of a thick film insulation matrix material comprising ceramic or glass ceramic composite said material having a dielectric constant less than about 4.5, a thick film organic vehicle and a plurality of hollow glass microspheres.
2. The low dielectric constant material of claim 1 wherein said hollow glass microspheres are formed of silica.
3. The low dielectric constant material of claim 1 wherein said microspheres have a maximum size not exceeding about 400 mesh (U.S. Standard Sieve Series).
4. The low dielectric constant material of claim 1 and comprising about 15 to about 50 parts by volume percent of said hollow glass microspheres.
5. The low dielectric constant material of claim 1, and comprising about 20 to about 42 volume percent of said hollow glass microspheres.
6. The low dielectric constant material of claim 1, and comprising about 35 to about 39 volume percent of said hollow glass microspheres.
7. The low dielectric constant material of claim 6, wherein said microspheres comprise a mixture of different size glass microspheres having a maximum size not exceeding about 400 mesh (U.S. Standard Sieve Series).
8. The method of making a low dielectric constant material for use in the formation of thick film devices comprising the steps of:
(a) thoroughly blending a quantity of dry hollow glass microspheres with a thick film organic vehicle, and, (b) thoroughly mixing the blend produced from step (a) with a quantity of thick film insulation matrix material comprising ceramic or glass ceramic composite to provide a material having a dielectric constant less than about 4.5.
(a) thoroughly blending a quantity of dry hollow glass microspheres with a thick film organic vehicle, and, (b) thoroughly mixing the blend produced from step (a) with a quantity of thick film insulation matrix material comprising ceramic or glass ceramic composite to provide a material having a dielectric constant less than about 4.5.
9. The method of claim 8 and including the step of screening said hollow glass microspheres through a 400 mesh screen (U.S. Standard Sieve Series) prior to blending said hollow glass microspheres with said vehicle.
10. A method of forming a low dielectric constant insulation layer according to thick film procedures comprising the steps of:
(a) forming a low dielectric constant material by combining a thick film insulation matrix material comprising ceramic or glass ceramic composite, a thick film organic vehicle, and a plurality of hollow glass microspheres into a homogeneous material;
(b) depositing the low dielectric constant material from step (a) onto a circuit portion to a desired thickness for the insulation layer; and (c) drying and firing the deposited material from step (b).
(a) forming a low dielectric constant material by combining a thick film insulation matrix material comprising ceramic or glass ceramic composite, a thick film organic vehicle, and a plurality of hollow glass microspheres into a homogeneous material;
(b) depositing the low dielectric constant material from step (a) onto a circuit portion to a desired thickness for the insulation layer; and (c) drying and firing the deposited material from step (b).
11. The method of claim 10 and including the step of screening said hollow glass microspheres through a 400 mesh screen (U.S. Standard Sieve Series) prior to said combining.
12. A method of producing a low dielectric constant insulation layer according to thick film procedures comprising the steps of:
(a) forming a low dielectric constant material by combining a thick film insulation matrix material comprising ceramic or glass ceramic composite, a thick film organic vehicle, and a plurality of hollow glass microspheres into a homogeneous material;
(b) depositing the low dielectric constant material from step (b) onto a metal pattern to a desired thickness;
(c) drying and firing the low dielectric constant material deposited in step (b);
(d) repeating steps (b) and (c) until the final desired thickness of the insulation layer is approached;
(e) depositing a conventional thick film dielectric in-sulating material onto the structure resulting from step (d) to a desired thickness to planarize the resulting structure; and (f) drying and firing the material from step (e).
(a) forming a low dielectric constant material by combining a thick film insulation matrix material comprising ceramic or glass ceramic composite, a thick film organic vehicle, and a plurality of hollow glass microspheres into a homogeneous material;
(b) depositing the low dielectric constant material from step (b) onto a metal pattern to a desired thickness;
(c) drying and firing the low dielectric constant material deposited in step (b);
(d) repeating steps (b) and (c) until the final desired thickness of the insulation layer is approached;
(e) depositing a conventional thick film dielectric in-sulating material onto the structure resulting from step (d) to a desired thickness to planarize the resulting structure; and (f) drying and firing the material from step (e).
13. A method of producing a thick film device according to thick film procedures comprising the steps of:
(a) providing a rigid dielectric substrate;
(b) depositing a predetermined metal pattern on said substrate;
(c) providing a low dielectric constant material which comprises a substantially homogeneous blend of a thick film insulation matrix material comprising ceramic or glass ceramic composite, a thick film organic vehicle and a plurality of hollow glass microspheres;
(d) depositing the low dielectric constant material from step (c) onto the deposited metal pattern;
(e) drying and firing the low dielectric constant material deposited in step (d); and (f) repeating steps (b) to (e) until the desired number of metal patterns separated by layers of low dielectric material are completed.
(a) providing a rigid dielectric substrate;
(b) depositing a predetermined metal pattern on said substrate;
(c) providing a low dielectric constant material which comprises a substantially homogeneous blend of a thick film insulation matrix material comprising ceramic or glass ceramic composite, a thick film organic vehicle and a plurality of hollow glass microspheres;
(d) depositing the low dielectric constant material from step (c) onto the deposited metal pattern;
(e) drying and firing the low dielectric constant material deposited in step (d); and (f) repeating steps (b) to (e) until the desired number of metal patterns separated by layers of low dielectric material are completed.
14. A method according to claim 13, wherein said metal pattern is deposited as a firable ink, and including the step of drying and firing the ink.
15. A method according to claim 14, wherein said ink and said low dielectric constant material are co-fired.
16. A method according to claim 13, and including the step of depositing a conventional thick film dielectric insulating material onto the structure resulting from step (e) to planarize the resulting structure.
17. In a thick film device of the type comprising a rigid insulating substrate and having one or a plurality of circuit layers separated by insulation layers, the improvement wherein at least one of said insulation layers comprises a fired-in-place thick film insulating material comprising ceramic or glass ceramic composite, having a plurality of hollow glass microspheres substantially homogenously dispersed therein.
18. In a thick film device according to claim 17 wherein said hollow glass microspheres comprise about 15 to about 50 volume percent of said insulation layer(s).
19. In a thick film device according to claim 18 wherein said hollow glass microspheres comprise about 20 to about 42 volume percent of said insulation layer(s).
20. In a thick film device according to claim 18 wherein said hollow glass microspheres comprise about 35 to about 39 volume percent of said insulation layer(s).
21. In a thick film device according to claim 17 wherein said hollow glass microspheres are prescreened to pass through a 400 mesh screen (U.S. Standard Sieve Series).
22. In a thick film device according to claim 21 wherein said hollow glass microspheres comprise a mixture of different size hollow glass microspheres prescreened to pass through a 400 mesh screen (U.S. Standard Sieve Series).
23. A method of forming a low dielectric constant insulation layer according to thick film procedures comprising the steps of:
(a) combining a thick film insulation matrix material comprising ceramic or glass ceramic composite, a thick film organic vehicle, and a plurality of hollow glass microspheres having a maximum size not exceeding about 400 mesh (U.S. Standard Sieve Series) into a homogeneous material;
(b) depositing material from step (a) onto a circuit portion to a desired thickness for the insulation layer; and (c) drying and firing deposited material from step (b) to provide a material having a dielectric constant less than about 4.5 said firing causing conductive particles of a metallization pattern constituting the circuit portion to be sintered and fired into a continuous conductor in the shape of a desired pattern, said firing also evaporating any residual carrier and fusing the said deposited material around the hollow glass microspheres to form a rigid structure with the hollow glass microspheres embedded therein.
(a) combining a thick film insulation matrix material comprising ceramic or glass ceramic composite, a thick film organic vehicle, and a plurality of hollow glass microspheres having a maximum size not exceeding about 400 mesh (U.S. Standard Sieve Series) into a homogeneous material;
(b) depositing material from step (a) onto a circuit portion to a desired thickness for the insulation layer; and (c) drying and firing deposited material from step (b) to provide a material having a dielectric constant less than about 4.5 said firing causing conductive particles of a metallization pattern constituting the circuit portion to be sintered and fired into a continuous conductor in the shape of a desired pattern, said firing also evaporating any residual carrier and fusing the said deposited material around the hollow glass microspheres to form a rigid structure with the hollow glass microspheres embedded therein.
24. The method of claim 23 and including the step of screening said hollow glass microspheres through a 400 mesh screen (U.S. Standard Sieve Series) prior to said combining.
25. A method of producing a low dielectric constant insulation layer according to thick film procedures comprising the steps of:
(a) combining a thick film insulation matrix material comprising ceramic or glass ceramic composite, a thick film organic vehicle, and a plurality of hollow glass microspheres having a maximum size not exceeding about 400 mesh (U.S. Standard Sieve Series);
(b) depositing the material from step (a) onto a metal pattern to a desired thickness;
(c) drying and firing the low dielectric constant material deposited in step (b) to provide a material having a dielectric constant less than about 4.5 said firing causing the conductive particles of the metal pattern to be sintered and fired into a continuous conductor in the shape of the desired pattern, said firing also evaporating any residual carrier and fusing the said deposited material around the hollow glass microspheres to form a rigid structure with the hollow glass microspheres embedded therein;
(d) repeating steps (b) and (c) until the final desired thickness of the insulation layer is approached;
(e) depositing a conventional thick film dielectric in-sulating material onto the structure resulting from step (d) to a desired thickness to planarize the resulting structure; and (f) drying and firing the material from step (e).
(a) combining a thick film insulation matrix material comprising ceramic or glass ceramic composite, a thick film organic vehicle, and a plurality of hollow glass microspheres having a maximum size not exceeding about 400 mesh (U.S. Standard Sieve Series);
(b) depositing the material from step (a) onto a metal pattern to a desired thickness;
(c) drying and firing the low dielectric constant material deposited in step (b) to provide a material having a dielectric constant less than about 4.5 said firing causing the conductive particles of the metal pattern to be sintered and fired into a continuous conductor in the shape of the desired pattern, said firing also evaporating any residual carrier and fusing the said deposited material around the hollow glass microspheres to form a rigid structure with the hollow glass microspheres embedded therein;
(d) repeating steps (b) and (c) until the final desired thickness of the insulation layer is approached;
(e) depositing a conventional thick film dielectric in-sulating material onto the structure resulting from step (d) to a desired thickness to planarize the resulting structure; and (f) drying and firing the material from step (e).
26. A method of producing a thick film device according to thick film procedures comprising the steps of:
(a) providing a rigid dielectric substrate;
(b) depositing a predetermined metal pattern on said substrate;
(c) providing a low dielectric constant material which comprises a substantially homogeneous blend of a thick film in-sulation matrix material comprising ceramic or glass ceramic composite, a thick film organic vehicle and a plurality of hollow glass microspheres having a maximum size not exceeding about 400 mesh (U.S. Standard Sieve Series);
(d) depositing material from step (c) onto the deposited metal pattern;
(e) drying and firing the material deposited in step (d) to provide a material having a dielectric constant less than about 4.5 said firing causing the conductive particles of the predeter-mined metal pattern to be sintered and fired into a continuous conductor in the shape of the desired pattern, said firing also evaporating any residual carrier and fusing the said material around the hollow glass microspheres to form a rigid structure with the hollow glass microspheres embedded therein; and (f) repeating steps (b) to (e) until the desired number of metal patterns separated by layers of low dielectric material are completed.
(a) providing a rigid dielectric substrate;
(b) depositing a predetermined metal pattern on said substrate;
(c) providing a low dielectric constant material which comprises a substantially homogeneous blend of a thick film in-sulation matrix material comprising ceramic or glass ceramic composite, a thick film organic vehicle and a plurality of hollow glass microspheres having a maximum size not exceeding about 400 mesh (U.S. Standard Sieve Series);
(d) depositing material from step (c) onto the deposited metal pattern;
(e) drying and firing the material deposited in step (d) to provide a material having a dielectric constant less than about 4.5 said firing causing the conductive particles of the predeter-mined metal pattern to be sintered and fired into a continuous conductor in the shape of the desired pattern, said firing also evaporating any residual carrier and fusing the said material around the hollow glass microspheres to form a rigid structure with the hollow glass microspheres embedded therein; and (f) repeating steps (b) to (e) until the desired number of metal patterns separated by layers of low dielectric material are completed.
27. A method according to claim 26, wherein said metal pattern is deposited as a firable ink, and including the step of drying and firing the ink.
28. A method according to claim 27, wherein said ink and said low dielectric constant material are co-fired.
29. A method according to claim 27, and including the step of depositing a conventional thick film dielectric insulating material onto the structure resulting from step (e) to planarize the resulting structure.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US06/834,912 US4781968A (en) | 1986-02-28 | 1986-02-28 | Micro-electronics devices and methods of manufacturing same |
| US834,912 | 1986-02-28 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1331914C true CA1331914C (en) | 1994-09-13 |
Family
ID=25268122
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 530049 Expired - Fee Related CA1331914C (en) | 1986-02-28 | 1987-02-18 | Micro-electronics devices and methods of manufacturing same |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US4781968A (en) |
| EP (1) | EP0234896A3 (en) |
| JP (2) | JPS63358A (en) |
| KR (1) | KR940002284B1 (en) |
| CA (1) | CA1331914C (en) |
| MY (1) | MY100118A (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4134848A (en) * | 1976-06-28 | 1979-01-16 | The United States Of America As Represented By The Secretary Of The Navy | Composite for improved stripline board material |
| JPS59111345A (en) * | 1982-12-17 | 1984-06-27 | Fujitsu Ltd | Low-permittivity circuit substrate |
| US4477492A (en) * | 1983-04-22 | 1984-10-16 | E. I. Du Pont De Nemours And Company | Process for preparing superficially porous supports for chromatography and catalysts |
| JPS608355A (en) * | 1983-06-29 | 1985-01-17 | Toshiba Corp | Unsaturated polyester resin composition |
-
1986
- 1986-02-28 US US06/834,912 patent/US4781968A/en not_active Expired - Lifetime
-
1987
- 1987-02-18 CA CA 530049 patent/CA1331914C/en not_active Expired - Fee Related
- 1987-02-23 EP EP19870301527 patent/EP0234896A3/en not_active Ceased
- 1987-02-27 MY MYPI87000199A patent/MY100118A/en unknown
- 1987-02-28 JP JP62044146A patent/JPS63358A/en active Pending
- 1987-02-28 KR KR1019870001780A patent/KR940002284B1/en active IP Right Grant
-
1991
- 1991-04-16 JP JP17628491A patent/JPH0770248B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| EP0234896A3 (en) | 1988-01-07 |
| JPH07111108A (en) | 1995-04-25 |
| US4781968A (en) | 1988-11-01 |
| JPS63358A (en) | 1988-01-05 |
| KR940002284B1 (en) | 1994-03-21 |
| JPH0770248B2 (en) | 1995-07-31 |
| EP0234896A2 (en) | 1987-09-02 |
| KR870008391A (en) | 1987-09-26 |
| MY100118A (en) | 1989-12-18 |
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