CA2101881A1 - Electroless copper deposition - Google Patents
Electroless copper depositionInfo
- Publication number
- CA2101881A1 CA2101881A1 CA002101881A CA2101881A CA2101881A1 CA 2101881 A1 CA2101881 A1 CA 2101881A1 CA 002101881 A CA002101881 A CA 002101881A CA 2101881 A CA2101881 A CA 2101881A CA 2101881 A1 CA2101881 A1 CA 2101881A1
- Authority
- CA
- Canada
- Prior art keywords
- copper
- plating bath
- compound
- deposit
- mol
- 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.)
- Abandoned
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
- C23C18/16—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by reduction or substitution, e.g. electroless plating
- C23C18/31—Coating with metals
- C23C18/38—Coating with copper
- C23C18/40—Coating with copper using reducing agents
- C23C18/405—Formaldehyde
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- 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
- H05K3/00—Apparatus or processes for manufacturing printed circuits
- H05K3/10—Apparatus or processes for manufacturing printed circuits in which conductive material is applied to the insulating support in such a manner as to form the desired conductive pattern
- H05K3/18—Apparatus or processes for manufacturing printed circuits in which conductive material is applied to the insulating support in such a manner as to form the desired conductive pattern using precipitation techniques to apply the conductive material
- H05K3/181—Apparatus or processes for manufacturing printed circuits in which conductive material is applied to the insulating support in such a manner as to form the desired conductive pattern using precipitation techniques to apply the conductive material by electroless plating
- H05K3/187—Apparatus or processes for manufacturing printed circuits in which conductive material is applied to the insulating support in such a manner as to form the desired conductive pattern using precipitation techniques to apply the conductive material by electroless plating means therefor, e.g. baths, apparatus
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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
Abstract
ABSTRACT
An improved method of manufacturing fully-additive or partly-additive printed wiring boards by electrolessly depositing copper on an insulating substratum and the walls of plated-through holes, wherein the copper deposit has increased resistance to failure due to thermal stress or thermal cycling. The electroless copper plating bath contains a copper compound, ethylenediaminetetraacetic acid as a complexing agent for copper, a reducing agent capable of reducing the copper compound to metallic copper and addition agents selected from inorganic germanium and silicate compounds and combined with a polyethylene glycol. The pH of the electroless copper bath is monitored and maintained between 11.2 and 12.0 to reduce the trace iron codeposited with the copper and improve the resistance to plated-through hole failure in thermal cycling. The addition of vanadium to the electroless copper bath increases the smoothness of the deposited copper and further increases the number of thermal cycles before failure.
An improved method of manufacturing fully-additive or partly-additive printed wiring boards by electrolessly depositing copper on an insulating substratum and the walls of plated-through holes, wherein the copper deposit has increased resistance to failure due to thermal stress or thermal cycling. The electroless copper plating bath contains a copper compound, ethylenediaminetetraacetic acid as a complexing agent for copper, a reducing agent capable of reducing the copper compound to metallic copper and addition agents selected from inorganic germanium and silicate compounds and combined with a polyethylene glycol. The pH of the electroless copper bath is monitored and maintained between 11.2 and 12.0 to reduce the trace iron codeposited with the copper and improve the resistance to plated-through hole failure in thermal cycling. The addition of vanadium to the electroless copper bath increases the smoothness of the deposited copper and further increases the number of thermal cycles before failure.
Description
2101~1 ED S~AT~S PATENT A~P~ICA~ON
RiohA~d ~rthux~ Mayernlk ~cr IMPROYE~ ELæCTROLESS COPPEg D~POSITION
This ln~r~ntion ~Dncexns electroless copper ~positio~ and it~ uee in thQ manu~acturQ of ad~ive printad wiring boards. More ~p~cifio~lly, i~ oono~rn~
~n improvement in a method o~ manu~acturing an ~lec:trole~ coppar deposit and ~h~ el~ctrola~ly d~po~it~d aopp~r with ~mp~o~t~d ~moothnes3 and elongation.
~XGRO~Nl:) O~ ~IE ~ENTIQN
United ~tates Patent ~o . 4, 632 ~ 85a to Akaho~hi e~ al. des~ribRs Rn ~l~ctrole~ oOpp~ pl~ting p2oce~
~or addltive p~inted wirlng boarde. ThQ copper d~po~lt~
ob~ined are ~Lescri1~e~ ~æ havlng tan~ trangth~ o~
276 to 442 P~ and ~lon~tion on 30 ,~Lm th$ok te~ otripe ranging ~rom 3 . ~: to 11.1~6 . The el~o~rol~s~ ooppe~
plating ~o:Lution~ are operated a~ temperatures of 40-80'C, a ~odl~m hydroxide eonoentratlon whloh will giv~ ~ pH of 12.~ (mea~ured at ~5-C), an~ e~rR
.. ... .
1728-4~33 2 ~
cha~cteri~ed by ~he st~llizer~ comprlolng 1-1000 mg~L
of 3ilicon or germanlum in th~ 801ut~0n ~nd at lea~t .01 ~/mln per liter ot in~ct~d air per liter o~
platlng solution.
S 1, ~nited 8t~te~ Pa~ent No. 4,~65,888 to Akaho~hi et ~l. de~ribe6 an improv~m~nt ln the proce~ of United Statet Pat~nt No. 4,632,85~ wherei~ the ~$r 18 in~cted in flna bubbles wlth ~ bubble d~a~e~er of 1 mm or le8~.
The copper depo~lt~ formed by the proce~6es of ~nited Stat~a PatRnto Noo. 4,632,85~ and 4,865,~88 ha rough surface. BecAuse many ad~itive prlnte~ wlring applicatlQns r~quirQ a ~mooth ur~aoa, th~ sux~e rougbne~ o~ ~he copper llml~ u~e. ThR roughneao of th~ doposit6 1~ d~on6tr~t~ in unlt~ St~ta~ Patent No. 4r~70,l07 to ~aho~h~ e~ al. ~hiqh d~oribe~ A
pro~e~s whexein tha eleotroless c~pper depo~ition b~h de~oribed ln Uni~ed S~a~e~ Pa~on~ No. 4,632,85~
employed ~o plat~ o~er a ~moo~h.oopper ~ur~ace with an , 41~ctrolQs~ oopp~r ~posit ~o ~ th~ckn~s of 5 ~m. The ~urfac~ thu~ produoed has knl~ hap~ pro~octlon~ ~or lmproving tho bond when the Goppor ourf~aQ $~ l~mina~d ln ~ multilay~r pr~nt~d wirlng bosFd. An aaditive : oeleot~ ~rom oxoacid~ of ailicon, g~m~nium, v~nad~um !
2101~1 or ~ar~on ia employed in the electrole~s ba~h to pro~ote ~o~A~ion o~ the ~ni~e-~hAped pro~ections.
l Unlt~ Stata~ Patent No. 3,9Ss,~Sl to Schn~bl~
j at al. lndiaat~ that lron in QlQ~trolea~ aopper depo~ition ~olutions ~hould b~ below 2~ mg/l, p~e~3rabl~r below 10 ~/1 ln or~er to r~aduce extraneou oopp~r dQpos~t~ ~nd avold ~p`ontaneous ~composit~on of th~ plAting 801ution. TherB i8 no t~aohing ~n Un~t2d ~ta~e~ Patent No. 3195g,~51 that trace guantitiss o~
oodeposited iron ~e~t th~ physical properties o~ the el~ctrole~sly depos~ed copp~ he control o~ the iron cont~nt wa~ lmportan~ only for th~ ot~bllity o~ :
the electrole~Q copper b~th, not ~or the quality o~ the ~op~er depq~it.
Unl~ed 8tates Patent No. 3, 485, 643 to ZebliE~ky ~t al. a4~crtbe~ h~xa~yanoforrat~ a6 8t~iliz8rs in ela~trole~ aopper ~posl~ion ~olutlon~. Unitea State~
Pat~n~ No. 4,650,691 ~o Xinoshlta e~ al. rQports that the h0xacy~ 0~erxate~ decompose in the plat~ ng bath and that the dec~po~ltion product~ lnhiblt ~urther elactrol~e~ coppe~ plating And ~orm precipitAt~s ~n the b~h. X1no~hita 4t al~ lndlcat~ thAt th~ uj~ o~
trle~hAnolA~in~ at one to thre~ tlms~ the molar ~oncent~ation of ~h~ hQx~cyanof~rrate ln the ~5 ~l~ctrol~ bath will pre~nt de~truotion of the bath l72a-40~3 2101881 by lnhibition o~ the plating reactlon ~nd the ~o~m~tion o~ prec$pi~ate~. The use o~ ~riethanolamlne 1~ taught ~or preventing lron precipitatlon ln tho plstlng ~olutlon, and not ~or lmprovlng the quality of the ~I copper ~epo~
Unit~d 8tate~ Patent No. 3,31~,430 to ~hnable et al. deRribe~ elactroles~ ~opper baths containing A
vAnadiu~ ~4~pound as a hydro~en inclu~ion re~a~din~
agent. ~opper i3 depo3ited Re thln foil6 ~5-12 ~m thick) with ~u$flcl~nt duotllity to permit fold1ng th~
~O~lB in half, areasing th~m and unfol~ing the foil~ up to 5 tlm~s ~efo~e the ~4il bXR~k~ at the crease.
Unlted State~ Patent No. 4,563,217 to Kikuchi et al. do~o~ibes eleotroles~ coppe~ ba~hs oompri~ing a ca~lonla wett$ng ~gon~ an~ an inorg~nlc compound oont~in~ng ~ on, germ~n~um o~ v~n dium to ~mprove the stablllty of the pla~ing ~a~h and t~n~ile str~ngth and perc~nt elonga~ion o~ ~he. d~po~ited ~opper. The copper depo~ite repor~ad ha~ to~lloe ~trengths of 324-6S7 ~Pa and peraent elongati~n ~or 50 ~m th$o~
~oil~ oS 2~7~ the~e p~r~ent Qlonqatlons ar~ ~
~ or~all~ed to copper ~oll ~0 ~m thick, th~ ran~ woul~
!, be 2~5~.
... . . . .
1728-4093 21~8~1 ~h~s ln~rentlon comprlse~ an ~snp~oved ~nethod o~
; ~lectroles61y deposl~ing copper ~rom a platlng bath ~on~ninlng a aopper Gompound, EDTA ~ the oo~plexing ~nt ~or coppQr, 2 rQ~ucing ~g~nt ~or oopp~r, a pH-ad~u~ting agent, ~n additiv~ ~slect~d from ~ha group - consis~ng o~ ~zol~ble lnorganic ~llicon ownpound~ ~nd ~olubl~ ~norganlo g~rmanium compoundo, snd ln which method an oxy~on containing 9'elE ~ n~ ected lnto ~he plating bath. The lmprovement produc4e a coppQr depo~i~ on A prlnt~d wiring board h~Y~ng at ~aa~t one pl~ted-th~ough hol~ ~nd capable o~ with~nding 25 r~p&titivQ ~h~r~ai cycle~ without ~ailu~e~ or an lncr~a~ of more ~h~n 10% in the re~etance o~ the pla~ed-through hole. Each thermal ~ycl~ con~ o~
i~mer~ion $n w~ter At~ 25'~ followed ~y lram~r~ion ln A
~l~idi~d ~nd bed at a~ooc. The ~p~ovemen1; compri~e~
monltoring ~na ma~ntalnlng ~ho pH of the plat~ng bath ln the ~ang~ o~ 11.2 to 12 when ~a. ured a~ 25'C ~o that the P~nt~nt o~ trace iron in the depo~ited copper layer i~ ~ain~alned ~elow 1.5 ~g per ~nole copper.
Xn ono embodi~nt, the plating ~ath ~urther co~prl~as a &ompl~xing a~nt for iron ~n an amount su~icient to complex the irorl in the plating bath and ~728-4093 2~018~1 li~it codep~slte~ i~on in th~ copper lay~r to leEi~ thAn 1.5 mg per mol~l copp~r.
~n ~nother embodiment, tho lnYention ~omprlees ~! the ~ur~her lmp~o~eme~ o~ ln~r~2slng the ~moo~hn~s ` and~or ~ncr~a~ln~ th~ ~ue~lity of ~he ~ormQd coppex depo~t. Smoot~n~o~ incr~as~d by ~dding ~o tha plating ba~b ~ vana~iu~ oompound in ~n amount siu~ ient to r~du~ th~ roughn~ o~ th~ surrace of the d~posi~ad copper ~ayer to no greater than 1 micron~
~uc~ility of th~ ~orm~ coppex ~poslt i8 incr~ased by add~ng to the platlng bath ~ Y~nadium compound in an Amount ~ufflcient to increas~ the p~rcent ~l~ngation of the dep~t~d copper ~yer ~o 1.5 to Z tim~6 the p~rcent ~longation oP a ~opper depo~lt ~rom a comparAbl~ pl~tln~ bath without th~ ~ana~lum o~mpound and in an amount ~ufficient to w~hetand at 12a5t 30 of the r~p~it~a thermal ~ycles.
Thus, th~ plating bath i~ op4rat~d to depo~it CQ~pl31~ h}~Ylng a ~mooth ~urf~cR, high ductllity and a O trace iron oontent le~ than l.S ~g per m~le by ~Qntrolllng tb~ aonc~ntr~t~on of th~ p~-a~u~ting ~g~nt to ~lntain a E~ o~ o ~h~n ~ea~ur~d ~ 25 c, ~nd incr~a~lng th~ ~moothnes~ anfl duct41ity o~ the copper deposit ~y op~ra~ing the plat;~ng ~th wi$h an addi~ion a~nt comprielng ~ van~lum oo~pound.
172~-~093 21018~1 In anothQr ombod$~nt, th~ in~ehtion com~rie~e a ~ethod o~ m~nufaoturlng printed wlrlng boar~, wherein the pl~tlng ~Ath i~ operate~ ~o d~poRit copper Il ~or a pr~n~ed wlrin~ board. In p~rt~cul~ h~ platlny bs~h i~ u e~ to depo~i~ tha con~u~tive pattern o~ a p~i~ted wlr~ng ~oard i~ a ~ully-additlve proce~, or the aopper depos~t on th~ hol~ w~lls in a "partly-additive~ ~roçe~.
LO ~A~ED ~ESC~I~TION OF
~h~g lnv~ntlon 15 conoe~ned wl~h improvement~
in the products, pro~sse~ And electrole~ copper platlng ~ath~ de oxib~d in Unite~ S~te8 P~tent~ No~.
4,~32,85z 2nd 4,855,888, the ~clo~ure~ of whioh are in~o~porat~d her~in ~y ref~ren~e.
It has been found that l~miting th~
ao~epo~ited iron ~on~ent o~ el~ctrolQs~l~ depo~itæd copp~r ~o 1~ thAn 1.5 m~ lron per mole or copp~r sub~t~n~ially l~lpro~e~ th~ qu~lity of th~ deposited ~opper in duo~ility, and porcen~ elongatlon and the r~ no~ to th~rm~ t~e60 and ~hermal cycling o~
copper plated-throu~h hol~ re~erably, the tr~c~
iron ~onten~ ~f th~ d~po~ d aopper hould ~e 1~
: th~n 0.~ mg p~r ~o~e o~ dQpo~it~d copper. Appllcant h~ found that ~ollowing ~uch t~aching gubst~ntially ........
1728-4093 21~18~1 lmprov~t th~ ductility o~ the fo~m~d copp~r depo~lt a~
$nd~ cRted by a ~hree to four ~old incr~Rse in the Il peroRnt elon~a'cion as co~npar~d to ~ co~np~rablQ ~la'cing .I bath at a hi~her p~l. Further, it h~ been ~oun~ th~t l wh~n the iron ~ol~tent 1~ malntQined bal4w 1.5 Plg per mole aopp~r, ~oppex depo~t$ ~n print~ wlring bo~rds c~n wi~hstan~ the therm~l stre~ c~ ~our, 10 seoon~, ~old~r ~yoles at 288 n C ~
~h~ amoun~ of co~eposlte~ iron depend~ on the 0 ~t~angth o~ ~h~ ~ron compl~x pre~ent in th~ electrol3ss copper pl~t~ng bath. It ha~ ~e4r~ ~ound that ~or QlQatroles~ copper pl~t~n~ ~aths ~o~pri~ing ethylene~ls~ etet~a~etic acld ~ED~A) as th~
co~plexing a~e~lt ~or soppe~, tha optim~lm plating ~ox ~ln~mum iron in ~le~trol~a~ly depos~ted copper ~a obtalned wh~n the pl~ting bath ha~ a pX oae' 11.~ t~ 12 ~m~a~ur~ ~t 25-c).
Addi~elonal oomplex~ng ag~nts ~h~t ~quQster iron prQf~re~ltially can be a~ded to th~ plat~ng bath a~ ~
ad~itlon agen~ to ext~nd the operntin~ range. ~uah compl~xing ad~lition agorlt~ 6hould f o~ a ~oluble com~lex with iron (III) at the operatlng ~e~p~r~'cur~
and p~ ~f t)~e plating b~th. Th~ çomplexing addition I, a~en~ ~hould ee~ r ~ron (III~ more ~trongly than coppea~. Su~t~ble complexing addltion R~ents lnclude - R -.. . . .... . . .
l72~-40g3 21~1881 ~lcine ~N,N-bl~2-hydroxyothyl)gl~cinel which pr~erentially o~ ter5 iron (III) but not copper Con~pl~x~ ng A~d.ltlon Ag~nt~ th~t ~t~ongly ~e~ue~ter col?por (~ ay be utlli~ad in p~tlng b~th~
whQr~ ~h~ mbin c:omploxing 3gent ~or copp~r form~
~ronger c:Dmpl~x w~th copper than th~ compl~xing Aædl~ion ager~t, ~o that the c:omplex~ng A~lt~on ag~nt ~emains fr~ ~o ~eque~ter iron ~III).
It now ha~ b~on ~oun~ th~t additi-re printRd wirin~ board~ w~th pla~ed-th~ough hsle5 in which ~he 21ectrolas~ ~opper depo~lt~ con~Ain tr~o~ irOh in exc~s OI 1. 5 mg pe~ ~nGle Co~?er ~eil in therhlal ~hock and~or ther~al ~ycling test~, Fu~her it h~ ~een found th~t th~3 ~ddition o~
lS small amount~ of van~d~um c:~mpound~ to c~rtaln platlng bath forr~ulatlon~ following applic:~n~ ' ~ invention ~urther i~prove~ the duGtility o~ the copper depoalt ~o th~ the p~ro~r~ olorl~a~clon of th~ copper ~5epo~it i8 lnor~a~ad to 1.~ to 2 t~m~ ~he percent elongatlon of a ao copper produc~d by ~ oo~parabl~ pla~cing b~th wi~hout ~he vanAd~um oo~pourld.
Applioant al~ ha~ ~ound that the ~ddit~ on o~
sma~ 1 a~nounts o~ vana~lum c:~pound tG the~ electroless coppe~ pla~lng hath ~urpr~ B~ ngly eliminates the characteri~t~ ~ s-ar~a~ ro~ghnesR of tho c~ppar ~po~
_ g _ 1728-~093 ~1~1881 ~orm~ ln ele~trole~s plating bath~ s~ab$1ized ~y german1um or ~ lic~te aompound~ an~ a poly~thylena glycol. ~hQ sur~ace roughne~ r~du~d to nc~ gre~ter than 1 ,~-~. The~e s~ooth doposlts, ~ro~n the u~e of a ~ van~dium addition agent combined with a g~rmanlum or ~ilica~e a~lt~on agent, ~re p~rtlculArly unQxpa~t~d, in vl~w of the te~ohing o~ A~al~o~hi et al., United ~tate~ P~tant No. 4,970,107/ th~t ~tan~dlum additiorl ;
agent~ produca lcn$f~-~haped pro~eotions ln th~ copper d~pos ~ t .
In the electr~less copper pla~ing ba~h~
d~ribad in ~1} o~ the a~oremen~lon~ AXahoshl 0t al.
patents, ~he ~tan~ar~ ~o~u~ hydrox$d~ concentr~on i~
ad~u~t~ to provide a p~ o~ 12.S-12.8 at 25~C
(0.03-0.~ mole o~ ~ee hydroxl~). It n~w ha~ ~en di~overed th~t depoeit~ from ~lect~oless coppe~
plating ba~h~ operat~d ~ low~r hydroxide conoRntration~, to g~ve ~ p~ o~ 11.2-~2.0 ~t 25~C
~ 0 . ~02-0 . ~10 fflol~ of fra~ hydroxids), p~e~era~ly a pH
. o~ 11.7-11.9 ~t 25-C (~ee hyd~oxid~ conc~ntrstion ~f O.OOS-0.008 ~nolE p~r liter), ~uxp~isingly hav~ a tr~ca iron content an ord~x of m~gnl~u~ ~asa than th~t o~
depo~ from the ~m~ ~opp~r p~at~hq ~aths operated ~he ~ndard hyd~oxide aonc~n~r~tlons o~ the prior art (0.03-0.06 M or a pH Q~ 1~.5-12.8 ~ 25~).
.... . . .
: 17~8-40~3 21~1881 ~orr~pondingly, thQ copper depo~it~ from th plating bQths wlth the low hydro~cide aor.c~ntra~ion ha~ e 1nlgher ~en~ etrength and p~r~nt ~longation~
Aaditive prlnted wi~lng boards wlth pl~ted-through hol~ plAted by ~he el~c~role~ aopp~r pl~t~ng ~athl3 wi~h l~wer ~oalum hydroxi~e cont~nt wlth~tan~ ~herm~l ~ho~k t~3s~ and tharmal ~ycl~ng bett~r than ~h~
additive printed ~irlng board~ wi~h plat~d-~hrou~h hola~ ple.~ed in the ~onv~ntion~l platln~ bat~
~6sGr~b~d ~y Akahoshl ~t al.
A ~ouroe o~ tr~e iron ~n the eleotr~ 3 coppe~ plat~ng bath ~ the Gopp~r salt us~d BC a 60ur~e o~ cQppe~ ln l:h~ pl~ting ~ath, ~nd us~d to replen1~h tha plating bath and rgpl~o~ thel Gopl?er sl~c~roles~ly depo~it~. eopp~r ~ul~ ommonly ~eleot~ for repleni~hment o~ el~c~rol~s~ copper plat~ng ba~s in manU~a~tUring ~aC~ e~ aB ~ th~ PUre~t COPPer ~1t COmmeraia11Y ~V~ b1e~ MO~t e1eqtrO1eO~ COPPer P1a~ing ~;he arR OPeratæd in a "bai1-OUt" m~ 1n Wh1Ch bY-PrOdUCt ~ulfa'ce 1n the P1~ting bath 1B
C~ntrO11~ bY di~Gard1n~ ~ P~rt1On O~ th~ P1ati-~ bath an~ replacin~ the di~car~ed portlon with an ~qual volumQ of î~e3h, ~3y-product frae plating b~th. Th~
~-onaent~ti~ of tha iron in the ele~trol~ opp~r plAting bath w~ll deE~na on th~ lrcn C~n~n~ratiOn~ ~g 1728-40~3 2 ~
F~/mol Cu, $n the copper sul~at~ replen~hment n~lutlon, and will b~ approximately equal to the mg Fa~mol S0$~ ln ~h4 eleotrol~ss plating bath. I~ the by-product ~ulfa~ con~entratlon i~ malntained ~ 0.25 . ~ol~ he copper ~ul~a~ us~d to ~epleni3h the ~le~01~8 plating b~th ~hould ha~e an iron concen~ration no higher th~n 10 ~ iron per ~ole ~opp~r an~ preferably no highQr than 5 mg per mO16 copper.
Th~ oopp~r con~*n~ratlon ln th~ otrol~
plating b~h i~ 0.02-0.08 mol/L, pr~fRra~ly 0sO3~0~0 ~ol/L, and most p~e~e~ably 0.036-0~04~ mol/~ ~he Qopper concen~r~tion in th~ plating bath i6 repleni~hed to matnta~n t~3 aopp~r oonc~ntra~lon a~ copp4r iB
depo~itsd ~om the pla~ing bath. If ~he copp~r ¢ompound ~n ~he repleni~hment ~olu~lon oont~in~ mor~
~h~n 10 mg of ~ron p~r mol~ of copper, An lron complaxing ad~ition sg~nt may b~ n~ad~d. Pr~ferably, the copper replenlsh~ent solu~on will con~ain le~3 th~n ~0 mg of lron p~r mole of copper An~ more pre~er~ly, leas than S mg of lron per mola of aopp~r.
When an i~on co~plexing ~gent i~ requ~red, ~h~
~oncentra~on of th~ lron compl~xing agQnt ~hould b~
1~10 ~ill~m~leY psr ~illimol~ ~ iron~ When biaine iB
u~d ~ th~ iron com~lexing agent ~ulta~le 1728-40~ 2 ~
concentrati;ms are Q . 5-1 g/L ln the copp~r ~posltlon bath .
~he ~oncent~ion o th~ oopp~r compl~ g il agent ln th~ ~oppor a~poo~ion bath ~hould be 0.06-0.15 mol/IJ, ~nd pr~farably 0. 08~0.12 m~ . When th~
conoentration of tho ~omp~xing agent i~ ~oo low, the bath ~pooi~ copper out~de o~ ~e conau~or pa~rr~:
when it i8 toc high, t~Q pl~lng rate 810W8 down.
The formaldehydQ cono~ntration ~ B 0 . 04-0. g mol/L: prege2~bly 0.045-0.0~7 ~ol/L, An~ ~ore pre~erably 0. 053-o. 060 ~ol/L. The formaldehyde repl~nish~ t eolutiPn ~hould ¢ontain le~ than 0 . 2 mg af i~on p~r ~ole formalsl~21yde, ~n~ pre~erably la~ than 0.1 ~g per moll3 formald~hy~
The hydroxid~ repl~nl~hm~n~ ~olutlon should ~ont~in le~ than 0.3 mg of iron per mol~ hydroxia~, ~nd pref~ra~ly le~s thAn 0.15 mg o~ iron per r~ole hydrox~de ~
The el~ctrol~ aopper plating bath may ~0 contain as ~abil~zer~ '~rom lO-lO00 mg/L o~ ~ ~oluble ~no~gan~o ~ on oompQund in ~erm~ of silicon Atom or lO-1000 ~g~ of An inorg nio ger~nium ço~po~nd ~n t~rm~ of g~ niu~ a~om in oon~un~tlon w~th a polyoxyet~ylene ~ompound. P~efer2bly, th~ ~lectrole~
~5 copper plating b~h will cont2in ~ ~tabillz~r6 ~ro~
... . .. . .. .
l72s-4og3 21 Q 18 ~ i ~5-loo ~ng/l, o~ gen~anium or ln ~oh~unction wlth a !~ polyoxyetb~lene oompound. Platlng hath~ with le~s thAn 25 mg~II g~rmanlum 4re ~ignlf ~ aantly 11~8S ~table .
~: Platlng baths oper~od wlth ger~ iu~ ~oncentration~ up ~o 250 mg~ y produc:e deposlt~ w$th a ~llght impro~ra~ent in par~n~ elongation, bu~ the platin~ ra~e ~eoreA~ when the germanium ~on~entratlon 1~ ~bove loo mg/I"
Ths Gon~entr~tion o~ compo~lnd~ Gont~ning lo pQlyoxy~thylene ln the pla~lng solution ~hould be v~lent to 5-50 ~thyl~n~ oxl~ unit~ per litar.
Pre~rably, ~he polyoxye~hyl~ oo~pound i~ ~elected ~x3m the group o~ ~thylen2 ~lycol poly~re w~th a mo~cula~ weigh~ bQtw~en ~50 and 250,000 daltona. MorQ
pref~r~bly, t:h~ pol~nnor ha~ a mol~ular wel~ht be~w~n 600 and ~00 daltsns, an~ mo~t preferably ~e~w~en 800 and 1400 dalton~. Ethyl~ne glycol polym4r~ are u6ed a~
conaentr~ti.on o~ 0.1-lo g/L~ pref~rabl~r 0~ 5-4 g/L, ~nd more prefer~bly 1-2 g/~, 2~ Th~ e~entra~lor. o~ ~nadium in the plA~lng bath ~hould be 0.5-~.S ~ h~r6 i9 no ~ignifinant ~n~re~se ~n tho ~oothnasæ or ~e~a~nt elon~ation o~ th~
qopp~r depo~it~d from plating ba~h~ containing 1~B
th~n 0.5 mg~L v~na~ium. ~pooit~ ~rom pl~tlng b~h~
2~ oontaining groate~ thæn 2.5 ~g~ a~adium exhibit a .. . . ~ . . . . . .
1728-40~3 2 1 ~ ~ 8 ~ 1 p~rcent elongation oomparable ~o depo~its ~rom pl~ting b~th~ cont2~ning lowor vanadium c~ncentr~tion~, but thQ
pl~ting ra~ pproxlmately 60~ ~lower.
Finq alr bubble~ ~houl~ ~ lntroduced lnto the ~10ctrol~s ooppar pl~ting bath at a r~t~ of ~.04-3 liters o~ ~lr p~r m~nute p~r li~er of plating bath; and pre~r~bly at ~ rat~ o~ 0.06-o.l liters o~ ai~ p~r mlnute per litar o~ plating bath.
The prR~ent inven~l~n i~ further il~ustr~ted ~n the Qxa~ple~ balow. In ths ~xam~ , th~ copper deposit~ varied in thickne~3. The ~andard ten3ile ~trengt~ c~loula~ion lncluda~ a ~orr~ction for the ~hi~ o~ he depo it, b~lt ~he a~An~Ar~ percent elongation did not. In th~ ~xampl~, the p~3rcent ~longatlon o~ deE~o~lt w~th varylng thlcknes~e~ wa~
compare~ by normalizing th~ thiakne~ses to 30 ~m.
Al~o, ln ~he exampl~, thQ pE~, ~ormaldRhyde ~nd copper conc~ntrQtlon and alr in~ection and the plsting bath t~mper~t~lr~ w~r~ monitor~d and tnaint~ned at the oetate~ vAlues.
1728-~093 ~18~
Examp'~ ~ 1 A~ o~p~rieon to appl$oant'~ lnventlon, ~n ;l eleotrolRse ~opper platlng ba~h Wa~ operat~d wlth the ~ollowing ~ormulation ~cording to the procedures o~
U.S. Patent No~. 4,632,~52and 4,g70,l07s ;
Cu~o"~ 5HzO ~f~ 10 N~,EDTA~ 2H20 g~ 41 NaOH pH at 25~C12.5 ~orm~ldehyde (37% oolu~lon) mL/~ ~ . 2 By-p~oduot NA2~04 ~ool/L 0 . 2 5 By-produc:t NaOOC~ mol/L O ~ 5 P31yoxyethylene (~W=1000) ~;QO~ ~g~L 7 0 A$2 in~e~tlon (l~rg~ buJ~bl~s) L/~(b~th) O. 07 Air in~ctlon (fin~ bubbla~ 1/min~ bath) 0.14 Temperatur~ ~ ~ 7 2 I~r~e ~i~ bu~le~ ~me ~ro~ a plpq wl~h 0.6 mm d~amet~r hole~. ~ine ~lir bubbles cams from a porous w~ plp~. :
Tho platlng hath wa~ ope~t2d with A load o~
1. 5 dm2 of curface b~ing pl~te~ par l~t~ opper w~
~Qpoaitad on printad wi~in~ board~ ~nd ~l~o on a ~talnle~ ste01 ~ub~t~tu~ ~o ob~ain a ~oll suit~ble ... , . . . ~
17~8-4093 ~ 1 3 ~
~or ten~ e~t~ ng. The ratQ of copper d~po~ltlon we~5 6-7 ~m/hr.
i Th~ p1R~ad-through ho1e~ ~n the pr~nt~ wlrin~
~oard~ wer~ je~tea to the ~1uid ~and therm~l ~yclin~
. te~t deseri~ad lrl IPC ~E~H~tICA~ R~CPORT, IP~-TR-~79, ROUND ROBTN RE:~IABII,~TY EVALUATIO~I ~F SMALI. DIAMETER
P~ATE~ THROUGH ~OLE:S IN PRINl ED WI~:tNG; ~OARD5 .
I.inoo1nwood, II.: Institute ~or In~rconneqtin~ and Packagin~ Electroni~ ~iraui~, 19~8, p25. In one cycle ~ th~ te6t, printed wirlng board~ ar~ lmm~sed ln wa'car at ~5'C, withdr~wn arld the ~xc~s water remov~, and immer~ed in a fluidiz~d s~nd bath ~t 260 ' C . ~he boar~e are cy~le~ to ~ai1ure, whi~h ~s an open o~rcuil: -or a 10~ in~roaoe in th~ r~ tarle~ of the ch~in of plat~3d-through ho1a. . Thi~ty cycl~ without fAi1ure i~
con~ide~d ~quivalen~ ~o ~a~sing 400 cycles o~ MIL-8TD-2Q2 the~n~l cy~le t~t.
The prin~çd wir$ng boards prepared in electroles~ oopp~r plating ~th~ ~coording to th~
~4r~ulat~sn ~ailed a~er lg rep6titive thermal cycl~, on av~ra~e.
Th~ pla~ng ~h (prepared ~ccor~ ng to th~ pro~e~ures ~ U . S . Peit~n~ No6 . 4, 632, 8S2 ~n~
4,~70,107) w~ modi~ie~ ~wo:~ding ~o thi~ inven'cion.
~5 The pH of the ~1ec~ro1e~s copper pl~ting b ~h was .
~01~
17~40g3 lowe~d to 11. B and the pl~lng ~ath w~a op~rate~ with the ~ollowing ~xmul~ n:
;
~USO"~ ~2 g/~ 10 Na6 ~rA~ ~H20 ~ 41 ` I NaOH PH ~ 2 5 ~ C 11 . 8 FOrma1d~hYde ~37 I; 001Ut1 On) m~/L 3 .
BY-PrOdU~t NA2604 mol/L O . 2 ~y-product NaOO~H ~ol/~ 0~5 Polyoxy~hyl~na (MW~1000~ g~
2 m~/L 7 Air inje~tion (lar~e bubble~) I4~in~L~ath~ 0. 07 Air in~Q~tlon (fin~ ~ubble~) ~/m~n/~(bath) 0.07 ~rempe~tur~ ~ C 72 The plating ba~h ~ras operated wil;h a l~ad ~f 1.5 dm~ o~ 6urfacQ being plated per ~iter. Coppar al~o was ~posited on a ~inles~ ~teal ~ubstratu~ to ebt~n A l~oll sui~abl~ for tQneil~ t~o~ing. The rat~ o~
' aoppe~ dep~s$tion w~ 7 ~n~/hr.
The plating bath wa~ oper~t~d for ~wo mor~
d~y~ at pH 11 . s ~msa~u~ t 25 ~] .
A~t~3r each day, th~ copper ~epoel~l on ~he ~ta~nle~ 3'ceel ~b~trat~m ~aE dri~d ~or 1 hour at 160DC. AftQr ~rylng, ~ copper ~oil W218 removed from 1~ ~
..
1728-4093 21~ ~gl the etainles~ ste~l. A portion o~ the fo~l w~ u~ed ~or ten~ esting, an~ ~ portion wae analyzed ror th~ j ~rac~ lron aontent~ The result~ ~omp~ring the sa~e plA~lng bath operA~ed at A p~ 0~ 12 . f!!i ~U. ~it . Patent No3 .
4,632,B52 ~n~ 4,970,107) ~nd a platlng ~ath operhtQ~ ~t ~ pH o~ ll.B (a b~h pH wlthln ~pplioantlh in~ention) are reportR~ ln Table 1. Th~3 paroent elong~t~ on 1Y
reported as Pleasured ~t th~ depo~t thicknes6 and A6 normali~ed ~o a thickness o~ 30 ,u~, TABL~ 1 ~_ ~ ~. ~., ., B-thIron Cono.Ton ileP~po~i~ S ~Jon~60n pHIn tho r~lc~Dou _. . ..
~lCcppor S~n~h h~ 1~ 1iz~
25'~ h~ro~ to . . . .
n~/mol MP~ . ~lm 30 ~m __ _ __~ ___ 12.5 3.50 331 ~9~5 2 2 11 ,B 0,~3 413 N,Z 6 7 11 .B 0.5~ 400 ~.2 ~ J
11~0.~3 ~55 3~.5 9 9 ' ....................... .,_.... __ Examplo 2 ThQ ooppRr d~po~it~ pro~u~d in th~ platin~
bath formulations of Example 1 had a rough surfa~e, 2S whieh 1~ ob~octlonal~lo ~or Any pr~nt~d wirirlg ~oard ., !
.: ~ppl~ satiorls u~ing ~inger ~ontac:t~ or edge connec~ors .
The sur~a~e rou5~hrle~ wac 1.5-2~0 ym. Th~ formulation~ ;
~or~bed in Eslampla 1 wer~a modi~i~d by th~ addition 2~ 01~1 172~-40~3 o~ a v~nadium co~pound to impro~e tb~ ~ur~ce fln~eh ~nd th~ du~tlllty o~ the d~po~it. An ~l~ctroloc~
soppe~ platin~ bath wa~ operated with the followlng ~os~mulatlon:
~uSO~,~ 5H20 g~L 10 Na~,EDrA- 2H20 g~ll 41 NaO~ pH At 2 5 C~ 11 . 8 Formaldehyd~ (37~ ~olution) ml4I. 4 . 3 lo By-proauct N2~So,, mol/L 0. 25 ~y-product NaOOC~ ~nol~L Q . 5 Polyoxyethylen~ 7=1000) g/L
G~02 mg/~ 7 V~05 mg,~l 2 Air ~n~ec~ion ~la~ bubble~ n/L(~ath) O . 07 Ai~ ln~ac~ion ~fin~a ~ubb'~es) L~min~L(bath) 0.07 T~mperature ' C 7 ~h~ platln~ bath wa~ ope~a~ed with a losd o~
- 1.5 dm~ of ~ur~e being plated p~r lite~r. ~he s~'¢e of copper deposition wa~ ~.5-5.5 ~hr. ~h~ ~ur~ca flnl~h o~ the ~spper d~po~it wa~ o. 5-1. 0 ,um. Th~ 26 ,um ~opper ~oil depQsited on the ~tAinle66 61:~el ~ub~tr~tum wa~ drle~ for 1 hour at 160~. A teneile teat was ~S per$ormad on the fo~ 1. The teneil~ ~trongth w~ 345 ,, , . . . . ... I
1728~4093 2~g~ ~
MPa and the ~longstlon was 18~ (~o~ when normallzed to 30 ~m ~hic~ depo~it).
~h4 pla~ing bath ~l~o wa~ op~rated with wor~c loa~ 3f~ 1.2 ~nd 2.5 d~2 per liter, and ~uivaler~t re~ult~ wer~ obtaln~d.
Exa~pl~ 3 Pla~ing b~hs h~ving ~hR 6~me ~onnulation ~xampl~ 2 war~ op~r~ted on ~i~e dif ~r~nt ~ays ~o provlde ~ample~ for ~Qn~lle t2sting. A~t~r ~ach day, the aopp~r depo~ Q~ the st~inle6s ~t~el ~ub~tratum w~ ~rla~ ~or ~ hcur~ 0 t c~ . The reault~ arQ
repor~d ln ~ho ~ble 2. ~ha p~rc~n~ ~longation 1 repor~ed a~ eaeured At the ~epo~ hicknea~ arld a~
no2ma~ized to a thlGlcne~ o~ 30 ~m~
_~_ __ l~ Tuullc ~
~ ~ L-- ~C~ U~ ~ M ~ ~
26.1 ~ 0.3 3~6 t 4 1~ 1 2 20 36.8 ' 0,~ 31~ ~ 3 21 -' ~ ~8 ~ 2~.1 0,~ 3~ 1~ ;t 1 17 6 16,2 ~ ~,3 31~ 1 3 12 -' 2 17 ~ 24 1 1 0 3 306 + 3 15 ~ I 11 ____ .~ ___ 2101~1 Example 4 P~inted wirin~ board~ werQ propara~ by ths p~rtly-a~ditlve proce~. In the par~ly-~dditive I prooe~s, a 1.~ ~ thick, ~a~e ma~ria~, coppar-ala~ on both ~ides, ~ dxilled to provide through hole~ wlth 0.3~ mm di~metex: the hQle wall~ w~ro ~ctiv~t~d and eloc~rol~sly plat~ wl~h 1-2 ~m of ooppQr; a double-slded "da~sy-ohain" pa~ern w~ appli~ w~h a tenting rQsist whi~h covered the ~hrough holes: th~ conductlv~
patt~rn wa~ for~4~ by e~chlng, an~ th~ re~t was ~tr~pp~d~ A parm~n~nt ~e ist wa~ appli~d on both sldes over ~he c~nductiv~ pa~t~rn lsaving the through hol~
And th~ land~ ~xpos~d. Th~ l~nd~ ~nd the w~113 o~ the through hole~ wero el~ctrol~ly plat~d with ~opper usins an ~lec~rol~s oopper pla~lnq ~ath op~r~t~d w~th the lo~ pH formulation of Examp~e 1. A~t~r platins, the printed ~i~ing board~ w~re dried for 4 hour~ at l~iO'C.
. ~he platod-through hole in the pr~nted wlr~ng bo~ds we~e ~u~e~ed ~ the fluid sand thermal ~ycling ~eet ~eoorl~d h~r4in. ~ablQ 3 ~how~ ths ~hicXnea~ an~
t~n~ prop~rti4~ of ~he coppRr d~po~it with th~
result~ of the fluld san~ ~herm~l ~ycling t~
~ ~2 1728-4093 2~18~1 __ ,, .~ " ~
Pl~tln~ D~ T~U~ % Inpllon Cyol~-~biob~eu hr~o~th A~ Nom~ll~ 'rb !1 R~l M~ d lo _ Mh 30 ym F~ila~
` l-- . .. _ .... __ __ _ ~ _ ,1 l 51 273;t2 1~ 1 7 40 2 5~ 241~4 12 t2 7 34 __3 ~8 ~ 3 13~ I 8 4~
' __ _ _ _e .. . ,~ ~__ ~5x~ple 5 Example 4 wa~ rep~t~d ~xoept that the ho~
wall~ werQ pl~ted with An eleGtroles~ copper pl~t~ng ~ h opexating ~ith ths ~ormulation o~ Exa;apl~ 2. A
~ample o~ the ç:opper ~oll was anal~zed ~nd the iron cont~nt wa~ fsun~ to ~ 0.34 mg per mo~e coppQr. ~a~le 4 below ~hows ths th~ s~ and tona~ l~ p~op~rti~ o~
~ha ~opper depo~t and th~ ra~ult~ o~ ~he ~lu~a sand the~mal c:yçl ~ ng t~
~ __ Ihpodt ~n~llc ~ 3Ll~ n Cyclos l Pl~tlng _~ _ I
~lurl ~ Mh MUA~U~ Nl3mot~1~ T; ¦
_~ _._ _ _- ~ . . _ 2 ~32~0 t I10 1 1 ~3 63 _ ~ 30~15 ~: 31~ ~ 4 1~ 4 ___ ~ ___ _ Th~ e excellent re~ul~e Q~p6~1all~ fQr thin fo-l ls further illust~at~ th~ ~u~prisin~ tou~hne~ nd ductili~y o~ the ~alBCt~01~358 ~opp~r deposit~ when a - ~3 -172~-4093 2 1 ~
~nall e~foctlv~ amount o~ a Yanadlum co~pound 1~
di~oolved in the el~ctrole~ ~oppe~ pla~ing b~th.
, .' ~
Exar~pl~ 5 w~ repaated excep~ th~t th~
~1Q~rO1~8 copper pl~tinq ba~h hnd a hlgh tr~ ron ~ontent f~oJn ~pl~nl~hmQnt w~h copper ~u~fata ~olutlon cont~mlnat~ with 32 mg i~on per mole of coppe~
3ulfa~ h~ r~sult~ o~ ~en~ile t~tir~g o~ th2 çopp~r d~po~ited ~r~3 ~hown ln Tab~ 5.
_ . . . ~ . " . _ __ _ I
D~c~k 'toncllo~ ~lonp~bn ~on I
l 5Plalln~ iblcl:ne~ jt~nglh A~ ~c~nal~dCcv~rr I
Run Llr M~ Me~nd 30 ~m ppm l ~ 455 ~ 7 ~ ~ I 7 20S
2 ~9 ~34 ~ I ~ ~ I 6 62 __ ~ ~ , I
Thi~ ~er~on~tra~e~ that ~,rhen ths é~ce iron ln the plating b~th i~ hlgh, eve~ oper~ting th~
electrole66 copp~r plating b~th a~ ~ pH b~twe~n 11 and 12 A O is not u~ici~n$ to ~intAin low lron in th~ .
~, deposi~ ~n~ the dep~s~ts obtain~ wlll h~ lower ductll ~ ty ~
.. . . ..
1728-40~3 2 1 0 ~ 8 ~ 1 Example ~
Exafflpl~ S 1B repeated uslng ~he copper ~ulfa~e repleniohmQn~ ~olutlon ~ontairing 32 m~ iron pe~ ~olo copper ~ulr~te, but the elRotrol~s copper : pla~ing bath i~ ~no~ ied ~y an lron ~o~plexinq addition R~ont. ~he comple~ing add~tlon ~ge~nt i8 b~cene. Flv~
gram~ o~ bicene is ~ad~d ~o eaoh llter o~ th~ coppe~
sulfate ~pl~nl~ nt ~olu~ion . ~oppç~
~lectrole~ly plAt3~ ~rom the bathJ the copp~r haP hlgh thermal ~hook rR~ ~ ~t~n~ and l~ss than 1. 5 ~ng iron per mol~ o~ oopp~r.
/
~
,. ~
~! 5
RiohA~d ~rthux~ Mayernlk ~cr IMPROYE~ ELæCTROLESS COPPEg D~POSITION
This ln~r~ntion ~Dncexns electroless copper ~positio~ and it~ uee in thQ manu~acturQ of ad~ive printad wiring boards. More ~p~cifio~lly, i~ oono~rn~
~n improvement in a method o~ manu~acturing an ~lec:trole~ coppar deposit and ~h~ el~ctrola~ly d~po~it~d aopp~r with ~mp~o~t~d ~moothnes3 and elongation.
~XGRO~Nl:) O~ ~IE ~ENTIQN
United ~tates Patent ~o . 4, 632 ~ 85a to Akaho~hi e~ al. des~ribRs Rn ~l~ctrole~ oOpp~ pl~ting p2oce~
~or addltive p~inted wirlng boarde. ThQ copper d~po~lt~
ob~ined are ~Lescri1~e~ ~æ havlng tan~ trangth~ o~
276 to 442 P~ and ~lon~tion on 30 ,~Lm th$ok te~ otripe ranging ~rom 3 . ~: to 11.1~6 . The el~o~rol~s~ ooppe~
plating ~o:Lution~ are operated a~ temperatures of 40-80'C, a ~odl~m hydroxide eonoentratlon whloh will giv~ ~ pH of 12.~ (mea~ured at ~5-C), an~ e~rR
.. ... .
1728-4~33 2 ~
cha~cteri~ed by ~he st~llizer~ comprlolng 1-1000 mg~L
of 3ilicon or germanlum in th~ 801ut~0n ~nd at lea~t .01 ~/mln per liter ot in~ct~d air per liter o~
platlng solution.
S 1, ~nited 8t~te~ Pa~ent No. 4,~65,888 to Akaho~hi et ~l. de~ribe6 an improv~m~nt ln the proce~ of United Statet Pat~nt No. 4,632,85~ wherei~ the ~$r 18 in~cted in flna bubbles wlth ~ bubble d~a~e~er of 1 mm or le8~.
The copper depo~lt~ formed by the proce~6es of ~nited Stat~a PatRnto Noo. 4,632,85~ and 4,865,~88 ha rough surface. BecAuse many ad~itive prlnte~ wlring applicatlQns r~quirQ a ~mooth ur~aoa, th~ sux~e rougbne~ o~ ~he copper llml~ u~e. ThR roughneao of th~ doposit6 1~ d~on6tr~t~ in unlt~ St~ta~ Patent No. 4r~70,l07 to ~aho~h~ e~ al. ~hiqh d~oribe~ A
pro~e~s whexein tha eleotroless c~pper depo~ition b~h de~oribed ln Uni~ed S~a~e~ Pa~on~ No. 4,632,85~
employed ~o plat~ o~er a ~moo~h.oopper ~ur~ace with an , 41~ctrolQs~ oopp~r ~posit ~o ~ th~ckn~s of 5 ~m. The ~urfac~ thu~ produoed has knl~ hap~ pro~octlon~ ~or lmproving tho bond when the Goppor ourf~aQ $~ l~mina~d ln ~ multilay~r pr~nt~d wirlng bosFd. An aaditive : oeleot~ ~rom oxoacid~ of ailicon, g~m~nium, v~nad~um !
2101~1 or ~ar~on ia employed in the electrole~s ba~h to pro~ote ~o~A~ion o~ the ~ni~e-~hAped pro~ections.
l Unlt~ Stata~ Patent No. 3,9Ss,~Sl to Schn~bl~
j at al. lndiaat~ that lron in QlQ~trolea~ aopper depo~ition ~olutions ~hould b~ below 2~ mg/l, p~e~3rabl~r below 10 ~/1 ln or~er to r~aduce extraneou oopp~r dQpos~t~ ~nd avold ~p`ontaneous ~composit~on of th~ plAting 801ution. TherB i8 no t~aohing ~n Un~t2d ~ta~e~ Patent No. 3195g,~51 that trace guantitiss o~
oodeposited iron ~e~t th~ physical properties o~ the el~ctrole~sly depos~ed copp~ he control o~ the iron cont~nt wa~ lmportan~ only for th~ ot~bllity o~ :
the electrole~Q copper b~th, not ~or the quality o~ the ~op~er depq~it.
Unl~ed 8tates Patent No. 3, 485, 643 to ZebliE~ky ~t al. a4~crtbe~ h~xa~yanoforrat~ a6 8t~iliz8rs in ela~trole~ aopper ~posl~ion ~olutlon~. Unitea State~
Pat~n~ No. 4,650,691 ~o Xinoshlta e~ al. rQports that the h0xacy~ 0~erxate~ decompose in the plat~ ng bath and that the dec~po~ltion product~ lnhiblt ~urther elactrol~e~ coppe~ plating And ~orm precipitAt~s ~n the b~h. X1no~hita 4t al~ lndlcat~ thAt th~ uj~ o~
trle~hAnolA~in~ at one to thre~ tlms~ the molar ~oncent~ation of ~h~ hQx~cyanof~rrate ln the ~5 ~l~ctrol~ bath will pre~nt de~truotion of the bath l72a-40~3 2101881 by lnhibition o~ the plating reactlon ~nd the ~o~m~tion o~ prec$pi~ate~. The use o~ ~riethanolamlne 1~ taught ~or preventing lron precipitatlon ln tho plstlng ~olutlon, and not ~or lmprovlng the quality of the ~I copper ~epo~
Unit~d 8tate~ Patent No. 3,31~,430 to ~hnable et al. deRribe~ elactroles~ ~opper baths containing A
vAnadiu~ ~4~pound as a hydro~en inclu~ion re~a~din~
agent. ~opper i3 depo3ited Re thln foil6 ~5-12 ~m thick) with ~u$flcl~nt duotllity to permit fold1ng th~
~O~lB in half, areasing th~m and unfol~ing the foil~ up to 5 tlm~s ~efo~e the ~4il bXR~k~ at the crease.
Unlted State~ Patent No. 4,563,217 to Kikuchi et al. do~o~ibes eleotroles~ coppe~ ba~hs oompri~ing a ca~lonla wett$ng ~gon~ an~ an inorg~nlc compound oont~in~ng ~ on, germ~n~um o~ v~n dium to ~mprove the stablllty of the pla~ing ~a~h and t~n~ile str~ngth and perc~nt elonga~ion o~ ~he. d~po~ited ~opper. The copper depo~ite repor~ad ha~ to~lloe ~trengths of 324-6S7 ~Pa and peraent elongati~n ~or 50 ~m th$o~
~oil~ oS 2~7~ the~e p~r~ent Qlonqatlons ar~ ~
~ or~all~ed to copper ~oll ~0 ~m thick, th~ ran~ woul~
!, be 2~5~.
... . . . .
1728-4093 21~8~1 ~h~s ln~rentlon comprlse~ an ~snp~oved ~nethod o~
; ~lectroles61y deposl~ing copper ~rom a platlng bath ~on~ninlng a aopper Gompound, EDTA ~ the oo~plexing ~nt ~or coppQr, 2 rQ~ucing ~g~nt ~or oopp~r, a pH-ad~u~ting agent, ~n additiv~ ~slect~d from ~ha group - consis~ng o~ ~zol~ble lnorganic ~llicon ownpound~ ~nd ~olubl~ ~norganlo g~rmanium compoundo, snd ln which method an oxy~on containing 9'elE ~ n~ ected lnto ~he plating bath. The lmprovement produc4e a coppQr depo~i~ on A prlnt~d wiring board h~Y~ng at ~aa~t one pl~ted-th~ough hol~ ~nd capable o~ with~nding 25 r~p&titivQ ~h~r~ai cycle~ without ~ailu~e~ or an lncr~a~ of more ~h~n 10% in the re~etance o~ the pla~ed-through hole. Each thermal ~ycl~ con~ o~
i~mer~ion $n w~ter At~ 25'~ followed ~y lram~r~ion ln A
~l~idi~d ~nd bed at a~ooc. The ~p~ovemen1; compri~e~
monltoring ~na ma~ntalnlng ~ho pH of the plat~ng bath ln the ~ang~ o~ 11.2 to 12 when ~a. ured a~ 25'C ~o that the P~nt~nt o~ trace iron in the depo~ited copper layer i~ ~ain~alned ~elow 1.5 ~g per ~nole copper.
Xn ono embodi~nt, the plating ~ath ~urther co~prl~as a &ompl~xing a~nt for iron ~n an amount su~icient to complex the irorl in the plating bath and ~728-4093 2~018~1 li~it codep~slte~ i~on in th~ copper lay~r to leEi~ thAn 1.5 mg per mol~l copp~r.
~n ~nother embodiment, tho lnYention ~omprlees ~! the ~ur~her lmp~o~eme~ o~ ln~r~2slng the ~moo~hn~s ` and~or ~ncr~a~ln~ th~ ~ue~lity of ~he ~ormQd coppex depo~t. Smoot~n~o~ incr~as~d by ~dding ~o tha plating ba~b ~ vana~iu~ oompound in ~n amount siu~ ient to r~du~ th~ roughn~ o~ th~ surrace of the d~posi~ad copper ~ayer to no greater than 1 micron~
~uc~ility of th~ ~orm~ coppex ~poslt i8 incr~ased by add~ng to the platlng bath ~ Y~nadium compound in an Amount ~ufflcient to increas~ the p~rcent ~l~ngation of the dep~t~d copper ~yer ~o 1.5 to Z tim~6 the p~rcent ~longation oP a ~opper depo~lt ~rom a comparAbl~ pl~tln~ bath without th~ ~ana~lum o~mpound and in an amount ~ufficient to w~hetand at 12a5t 30 of the r~p~it~a thermal ~ycles.
Thus, th~ plating bath i~ op4rat~d to depo~it CQ~pl31~ h}~Ylng a ~mooth ~urf~cR, high ductllity and a O trace iron oontent le~ than l.S ~g per m~le by ~Qntrolllng tb~ aonc~ntr~t~on of th~ p~-a~u~ting ~g~nt to ~lntain a E~ o~ o ~h~n ~ea~ur~d ~ 25 c, ~nd incr~a~lng th~ ~moothnes~ anfl duct41ity o~ the copper deposit ~y op~ra~ing the plat;~ng ~th wi$h an addi~ion a~nt comprielng ~ van~lum oo~pound.
172~-~093 21018~1 In anothQr ombod$~nt, th~ in~ehtion com~rie~e a ~ethod o~ m~nufaoturlng printed wlrlng boar~, wherein the pl~tlng ~Ath i~ operate~ ~o d~poRit copper Il ~or a pr~n~ed wlrin~ board. In p~rt~cul~ h~ platlny bs~h i~ u e~ to depo~i~ tha con~u~tive pattern o~ a p~i~ted wlr~ng ~oard i~ a ~ully-additlve proce~, or the aopper depos~t on th~ hol~ w~lls in a "partly-additive~ ~roçe~.
LO ~A~ED ~ESC~I~TION OF
~h~g lnv~ntlon 15 conoe~ned wl~h improvement~
in the products, pro~sse~ And electrole~ copper platlng ~ath~ de oxib~d in Unite~ S~te8 P~tent~ No~.
4,~32,85z 2nd 4,855,888, the ~clo~ure~ of whioh are in~o~porat~d her~in ~y ref~ren~e.
It has been found that l~miting th~
ao~epo~ited iron ~on~ent o~ el~ctrolQs~l~ depo~itæd copp~r ~o 1~ thAn 1.5 m~ lron per mole or copp~r sub~t~n~ially l~lpro~e~ th~ qu~lity of th~ deposited ~opper in duo~ility, and porcen~ elongatlon and the r~ no~ to th~rm~ t~e60 and ~hermal cycling o~
copper plated-throu~h hol~ re~erably, the tr~c~
iron ~onten~ ~f th~ d~po~ d aopper hould ~e 1~
: th~n 0.~ mg p~r ~o~e o~ dQpo~it~d copper. Appllcant h~ found that ~ollowing ~uch t~aching gubst~ntially ........
1728-4093 21~18~1 lmprov~t th~ ductility o~ the fo~m~d copp~r depo~lt a~
$nd~ cRted by a ~hree to four ~old incr~Rse in the Il peroRnt elon~a'cion as co~npar~d to ~ co~np~rablQ ~la'cing .I bath at a hi~her p~l. Further, it h~ been ~oun~ th~t l wh~n the iron ~ol~tent 1~ malntQined bal4w 1.5 Plg per mole aopp~r, ~oppex depo~t$ ~n print~ wlring bo~rds c~n wi~hstan~ the therm~l stre~ c~ ~our, 10 seoon~, ~old~r ~yoles at 288 n C ~
~h~ amoun~ of co~eposlte~ iron depend~ on the 0 ~t~angth o~ ~h~ ~ron compl~x pre~ent in th~ electrol3ss copper pl~t~ng bath. It ha~ ~e4r~ ~ound that ~or QlQatroles~ copper pl~t~n~ ~aths ~o~pri~ing ethylene~ls~ etet~a~etic acld ~ED~A) as th~
co~plexing a~e~lt ~or soppe~, tha optim~lm plating ~ox ~ln~mum iron in ~le~trol~a~ly depos~ted copper ~a obtalned wh~n the pl~ting bath ha~ a pX oae' 11.~ t~ 12 ~m~a~ur~ ~t 25-c).
Addi~elonal oomplex~ng ag~nts ~h~t ~quQster iron prQf~re~ltially can be a~ded to th~ plat~ng bath a~ ~
ad~itlon agen~ to ext~nd the operntin~ range. ~uah compl~xing ad~lition agorlt~ 6hould f o~ a ~oluble com~lex with iron (III) at the operatlng ~e~p~r~'cur~
and p~ ~f t)~e plating b~th. Th~ çomplexing addition I, a~en~ ~hould ee~ r ~ron (III~ more ~trongly than coppea~. Su~t~ble complexing addltion R~ents lnclude - R -.. . . .... . . .
l72~-40g3 21~1881 ~lcine ~N,N-bl~2-hydroxyothyl)gl~cinel which pr~erentially o~ ter5 iron (III) but not copper Con~pl~x~ ng A~d.ltlon Ag~nt~ th~t ~t~ongly ~e~ue~ter col?por (~ ay be utlli~ad in p~tlng b~th~
whQr~ ~h~ mbin c:omploxing 3gent ~or copp~r form~
~ronger c:Dmpl~x w~th copper than th~ compl~xing Aædl~ion ager~t, ~o that the c:omplex~ng A~lt~on ag~nt ~emains fr~ ~o ~eque~ter iron ~III).
It now ha~ b~on ~oun~ th~t additi-re printRd wirin~ board~ w~th pla~ed-th~ough hsle5 in which ~he 21ectrolas~ ~opper depo~lt~ con~Ain tr~o~ irOh in exc~s OI 1. 5 mg pe~ ~nGle Co~?er ~eil in therhlal ~hock and~or ther~al ~ycling test~, Fu~her it h~ ~een found th~t th~3 ~ddition o~
lS small amount~ of van~d~um c:~mpound~ to c~rtaln platlng bath forr~ulatlon~ following applic:~n~ ' ~ invention ~urther i~prove~ the duGtility o~ the copper depoalt ~o th~ the p~ro~r~ olorl~a~clon of th~ copper ~5epo~it i8 lnor~a~ad to 1.~ to 2 t~m~ ~he percent elongatlon of a ao copper produc~d by ~ oo~parabl~ pla~cing b~th wi~hout ~he vanAd~um oo~pourld.
Applioant al~ ha~ ~ound that the ~ddit~ on o~
sma~ 1 a~nounts o~ vana~lum c:~pound tG the~ electroless coppe~ pla~lng hath ~urpr~ B~ ngly eliminates the characteri~t~ ~ s-ar~a~ ro~ghnesR of tho c~ppar ~po~
_ g _ 1728-~093 ~1~1881 ~orm~ ln ele~trole~s plating bath~ s~ab$1ized ~y german1um or ~ lic~te aompound~ an~ a poly~thylena glycol. ~hQ sur~ace roughne~ r~du~d to nc~ gre~ter than 1 ,~-~. The~e s~ooth doposlts, ~ro~n the u~e of a ~ van~dium addition agent combined with a g~rmanlum or ~ilica~e a~lt~on agent, ~re p~rtlculArly unQxpa~t~d, in vl~w of the te~ohing o~ A~al~o~hi et al., United ~tate~ P~tant No. 4,970,107/ th~t ~tan~dlum additiorl ;
agent~ produca lcn$f~-~haped pro~eotions ln th~ copper d~pos ~ t .
In the electr~less copper pla~ing ba~h~
d~ribad in ~1} o~ the a~oremen~lon~ AXahoshl 0t al.
patents, ~he ~tan~ar~ ~o~u~ hydrox$d~ concentr~on i~
ad~u~t~ to provide a p~ o~ 12.S-12.8 at 25~C
(0.03-0.~ mole o~ ~ee hydroxl~). It n~w ha~ ~en di~overed th~t depoeit~ from ~lect~oless coppe~
plating ba~h~ operat~d ~ low~r hydroxide conoRntration~, to g~ve ~ p~ o~ 11.2-~2.0 ~t 25~C
~ 0 . ~02-0 . ~10 fflol~ of fra~ hydroxids), p~e~era~ly a pH
. o~ 11.7-11.9 ~t 25-C (~ee hyd~oxid~ conc~ntrstion ~f O.OOS-0.008 ~nolE p~r liter), ~uxp~isingly hav~ a tr~ca iron content an ord~x of m~gnl~u~ ~asa than th~t o~
depo~ from the ~m~ ~opp~r p~at~hq ~aths operated ~he ~ndard hyd~oxide aonc~n~r~tlons o~ the prior art (0.03-0.06 M or a pH Q~ 1~.5-12.8 ~ 25~).
.... . . .
: 17~8-40~3 21~1881 ~orr~pondingly, thQ copper depo~it~ from th plating bQths wlth the low hydro~cide aor.c~ntra~ion ha~ e 1nlgher ~en~ etrength and p~r~nt ~longation~
Aaditive prlnted wi~lng boards wlth pl~ted-through hol~ plAted by ~he el~c~role~ aopp~r pl~t~ng ~athl3 wi~h l~wer ~oalum hydroxi~e cont~nt wlth~tan~ ~herm~l ~ho~k t~3s~ and tharmal ~ycl~ng bett~r than ~h~
additive printed ~irlng board~ wi~h plat~d-~hrou~h hola~ ple.~ed in the ~onv~ntion~l platln~ bat~
~6sGr~b~d ~y Akahoshl ~t al.
A ~ouroe o~ tr~e iron ~n the eleotr~ 3 coppe~ plat~ng bath ~ the Gopp~r salt us~d BC a 60ur~e o~ cQppe~ ln l:h~ pl~ting ~ath, ~nd us~d to replen1~h tha plating bath and rgpl~o~ thel Gopl?er sl~c~roles~ly depo~it~. eopp~r ~ul~ ommonly ~eleot~ for repleni~hment o~ el~c~rol~s~ copper plat~ng ba~s in manU~a~tUring ~aC~ e~ aB ~ th~ PUre~t COPPer ~1t COmmeraia11Y ~V~ b1e~ MO~t e1eqtrO1eO~ COPPer P1a~ing ~;he arR OPeratæd in a "bai1-OUt" m~ 1n Wh1Ch bY-PrOdUCt ~ulfa'ce 1n the P1~ting bath 1B
C~ntrO11~ bY di~Gard1n~ ~ P~rt1On O~ th~ P1ati-~ bath an~ replacin~ the di~car~ed portlon with an ~qual volumQ of î~e3h, ~3y-product frae plating b~th. Th~
~-onaent~ti~ of tha iron in the ele~trol~ opp~r plAting bath w~ll deE~na on th~ lrcn C~n~n~ratiOn~ ~g 1728-40~3 2 ~
F~/mol Cu, $n the copper sul~at~ replen~hment n~lutlon, and will b~ approximately equal to the mg Fa~mol S0$~ ln ~h4 eleotrol~ss plating bath. I~ the by-product ~ulfa~ con~entratlon i~ malntained ~ 0.25 . ~ol~ he copper ~ul~a~ us~d to ~epleni3h the ~le~01~8 plating b~th ~hould ha~e an iron concen~ration no higher th~n 10 ~ iron per ~ole ~opp~r an~ preferably no highQr than 5 mg per mO16 copper.
Th~ oopp~r con~*n~ratlon ln th~ otrol~
plating b~h i~ 0.02-0.08 mol/L, pr~fRra~ly 0sO3~0~0 ~ol/L, and most p~e~e~ably 0.036-0~04~ mol/~ ~he Qopper concen~r~tion in th~ plating bath i6 repleni~hed to matnta~n t~3 aopp~r oonc~ntra~lon a~ copp4r iB
depo~itsd ~om the pla~ing bath. If ~he copp~r ¢ompound ~n ~he repleni~hment ~olu~lon oont~in~ mor~
~h~n 10 mg of ~ron p~r mol~ of copper, An lron complaxing ad~ition sg~nt may b~ n~ad~d. Pr~ferably, the copper replenlsh~ent solu~on will con~ain le~3 th~n ~0 mg of lron p~r mole of copper An~ more pre~er~ly, leas than S mg of lron per mola of aopp~r.
When an i~on co~plexing ~gent i~ requ~red, ~h~
~oncentra~on of th~ lron compl~xing agQnt ~hould b~
1~10 ~ill~m~leY psr ~illimol~ ~ iron~ When biaine iB
u~d ~ th~ iron com~lexing agent ~ulta~le 1728-40~ 2 ~
concentrati;ms are Q . 5-1 g/L ln the copp~r ~posltlon bath .
~he ~oncent~ion o th~ oopp~r compl~ g il agent ln th~ ~oppor a~poo~ion bath ~hould be 0.06-0.15 mol/IJ, ~nd pr~farably 0. 08~0.12 m~ . When th~
conoentration of tho ~omp~xing agent i~ ~oo low, the bath ~pooi~ copper out~de o~ ~e conau~or pa~rr~:
when it i8 toc high, t~Q pl~lng rate 810W8 down.
The formaldehydQ cono~ntration ~ B 0 . 04-0. g mol/L: prege2~bly 0.045-0.0~7 ~ol/L, An~ ~ore pre~erably 0. 053-o. 060 ~ol/L. The formaldehyde repl~nish~ t eolutiPn ~hould ¢ontain le~ than 0 . 2 mg af i~on p~r ~ole formalsl~21yde, ~n~ pre~erably la~ than 0.1 ~g per moll3 formald~hy~
The hydroxid~ repl~nl~hm~n~ ~olutlon should ~ont~in le~ than 0.3 mg of iron per mol~ hydroxia~, ~nd pref~ra~ly le~s thAn 0.15 mg o~ iron per r~ole hydrox~de ~
The el~ctrol~ aopper plating bath may ~0 contain as ~abil~zer~ '~rom lO-lO00 mg/L o~ ~ ~oluble ~no~gan~o ~ on oompQund in ~erm~ of silicon Atom or lO-1000 ~g~ of An inorg nio ger~nium ço~po~nd ~n t~rm~ of g~ niu~ a~om in oon~un~tlon w~th a polyoxyet~ylene ~ompound. P~efer2bly, th~ ~lectrole~
~5 copper plating b~h will cont2in ~ ~tabillz~r6 ~ro~
... . .. . .. .
l72s-4og3 21 Q 18 ~ i ~5-loo ~ng/l, o~ gen~anium or ln ~oh~unction wlth a !~ polyoxyetb~lene oompound. Platlng hath~ with le~s thAn 25 mg~II g~rmanlum 4re ~ignlf ~ aantly 11~8S ~table .
~: Platlng baths oper~od wlth ger~ iu~ ~oncentration~ up ~o 250 mg~ y produc:e deposlt~ w$th a ~llght impro~ra~ent in par~n~ elongation, bu~ the platin~ ra~e ~eoreA~ when the germanium ~on~entratlon 1~ ~bove loo mg/I"
Ths Gon~entr~tion o~ compo~lnd~ Gont~ning lo pQlyoxy~thylene ln the pla~lng solution ~hould be v~lent to 5-50 ~thyl~n~ oxl~ unit~ per litar.
Pre~rably, ~he polyoxye~hyl~ oo~pound i~ ~elected ~x3m the group o~ ~thylen2 ~lycol poly~re w~th a mo~cula~ weigh~ bQtw~en ~50 and 250,000 daltona. MorQ
pref~r~bly, t:h~ pol~nnor ha~ a mol~ular wel~ht be~w~n 600 and ~00 daltsns, an~ mo~t preferably ~e~w~en 800 and 1400 dalton~. Ethyl~ne glycol polym4r~ are u6ed a~
conaentr~ti.on o~ 0.1-lo g/L~ pref~rabl~r 0~ 5-4 g/L, ~nd more prefer~bly 1-2 g/~, 2~ Th~ e~entra~lor. o~ ~nadium in the plA~lng bath ~hould be 0.5-~.S ~ h~r6 i9 no ~ignifinant ~n~re~se ~n tho ~oothnasæ or ~e~a~nt elon~ation o~ th~
qopp~r depo~it~d from plating ba~h~ containing 1~B
th~n 0.5 mg~L v~na~ium. ~pooit~ ~rom pl~tlng b~h~
2~ oontaining groate~ thæn 2.5 ~g~ a~adium exhibit a .. . . ~ . . . . . .
1728-40~3 2 1 ~ ~ 8 ~ 1 p~rcent elongation oomparable ~o depo~its ~rom pl~ting b~th~ cont2~ning lowor vanadium c~ncentr~tion~, but thQ
pl~ting ra~ pproxlmately 60~ ~lower.
Finq alr bubble~ ~houl~ ~ lntroduced lnto the ~10ctrol~s ooppar pl~ting bath at a r~t~ of ~.04-3 liters o~ ~lr p~r m~nute p~r li~er of plating bath; and pre~r~bly at ~ rat~ o~ 0.06-o.l liters o~ ai~ p~r mlnute per litar o~ plating bath.
The prR~ent inven~l~n i~ further il~ustr~ted ~n the Qxa~ple~ balow. In ths ~xam~ , th~ copper deposit~ varied in thickne~3. The ~andard ten3ile ~trengt~ c~loula~ion lncluda~ a ~orr~ction for the ~hi~ o~ he depo it, b~lt ~he a~An~Ar~ percent elongation did not. In th~ ~xampl~, the p~3rcent ~longatlon o~ deE~o~lt w~th varylng thlcknes~e~ wa~
compare~ by normalizing th~ thiakne~ses to 30 ~m.
Al~o, ln ~he exampl~, thQ pE~, ~ormaldRhyde ~nd copper conc~ntrQtlon and alr in~ection and the plsting bath t~mper~t~lr~ w~r~ monitor~d and tnaint~ned at the oetate~ vAlues.
1728-~093 ~18~
Examp'~ ~ 1 A~ o~p~rieon to appl$oant'~ lnventlon, ~n ;l eleotrolRse ~opper platlng ba~h Wa~ operat~d wlth the ~ollowing ~ormulation ~cording to the procedures o~
U.S. Patent No~. 4,632,~52and 4,g70,l07s ;
Cu~o"~ 5HzO ~f~ 10 N~,EDTA~ 2H20 g~ 41 NaOH pH at 25~C12.5 ~orm~ldehyde (37% oolu~lon) mL/~ ~ . 2 By-p~oduot NA2~04 ~ool/L 0 . 2 5 By-produc:t NaOOC~ mol/L O ~ 5 P31yoxyethylene (~W=1000) ~;QO~ ~g~L 7 0 A$2 in~e~tlon (l~rg~ buJ~bl~s) L/~(b~th) O. 07 Air in~ctlon (fin~ bubbla~ 1/min~ bath) 0.14 Temperatur~ ~ ~ 7 2 I~r~e ~i~ bu~le~ ~me ~ro~ a plpq wl~h 0.6 mm d~amet~r hole~. ~ine ~lir bubbles cams from a porous w~ plp~. :
Tho platlng hath wa~ ope~t2d with A load o~
1. 5 dm2 of curface b~ing pl~te~ par l~t~ opper w~
~Qpoaitad on printad wi~in~ board~ ~nd ~l~o on a ~talnle~ ste01 ~ub~t~tu~ ~o ob~ain a ~oll suit~ble ... , . . . ~
17~8-4093 ~ 1 3 ~
~or ten~ e~t~ ng. The ratQ of copper d~po~ltlon we~5 6-7 ~m/hr.
i Th~ p1R~ad-through ho1e~ ~n the pr~nt~ wlrin~
~oard~ wer~ je~tea to the ~1uid ~and therm~l ~yclin~
. te~t deseri~ad lrl IPC ~E~H~tICA~ R~CPORT, IP~-TR-~79, ROUND ROBTN RE:~IABII,~TY EVALUATIO~I ~F SMALI. DIAMETER
P~ATE~ THROUGH ~OLE:S IN PRINl ED WI~:tNG; ~OARD5 .
I.inoo1nwood, II.: Institute ~or In~rconneqtin~ and Packagin~ Electroni~ ~iraui~, 19~8, p25. In one cycle ~ th~ te6t, printed wirlng board~ ar~ lmm~sed ln wa'car at ~5'C, withdr~wn arld the ~xc~s water remov~, and immer~ed in a fluidiz~d s~nd bath ~t 260 ' C . ~he boar~e are cy~le~ to ~ai1ure, whi~h ~s an open o~rcuil: -or a 10~ in~roaoe in th~ r~ tarle~ of the ch~in of plat~3d-through ho1a. . Thi~ty cycl~ without fAi1ure i~
con~ide~d ~quivalen~ ~o ~a~sing 400 cycles o~ MIL-8TD-2Q2 the~n~l cy~le t~t.
The prin~çd wir$ng boards prepared in electroles~ oopp~r plating ~th~ ~coording to th~
~4r~ulat~sn ~ailed a~er lg rep6titive thermal cycl~, on av~ra~e.
Th~ pla~ng ~h (prepared ~ccor~ ng to th~ pro~e~ures ~ U . S . Peit~n~ No6 . 4, 632, 8S2 ~n~
4,~70,107) w~ modi~ie~ ~wo:~ding ~o thi~ inven'cion.
~5 The pH of the ~1ec~ro1e~s copper pl~ting b ~h was .
~01~
17~40g3 lowe~d to 11. B and the pl~lng ~ath w~a op~rate~ with the ~ollowing ~xmul~ n:
;
~USO"~ ~2 g/~ 10 Na6 ~rA~ ~H20 ~ 41 ` I NaOH PH ~ 2 5 ~ C 11 . 8 FOrma1d~hYde ~37 I; 001Ut1 On) m~/L 3 .
BY-PrOdU~t NA2604 mol/L O . 2 ~y-product NaOO~H ~ol/~ 0~5 Polyoxy~hyl~na (MW~1000~ g~
2 m~/L 7 Air inje~tion (lar~e bubble~) I4~in~L~ath~ 0. 07 Air in~Q~tlon (fin~ ~ubble~) ~/m~n/~(bath) 0.07 ~rempe~tur~ ~ C 72 The plating ba~h ~ras operated wil;h a l~ad ~f 1.5 dm~ o~ 6urfacQ being plated per ~iter. Coppar al~o was ~posited on a ~inles~ ~teal ~ubstratu~ to ebt~n A l~oll sui~abl~ for tQneil~ t~o~ing. The rat~ o~
' aoppe~ dep~s$tion w~ 7 ~n~/hr.
The plating bath wa~ oper~t~d for ~wo mor~
d~y~ at pH 11 . s ~msa~u~ t 25 ~] .
A~t~3r each day, th~ copper ~epoel~l on ~he ~ta~nle~ 3'ceel ~b~trat~m ~aE dri~d ~or 1 hour at 160DC. AftQr ~rylng, ~ copper ~oil W218 removed from 1~ ~
..
1728-4093 21~ ~gl the etainles~ ste~l. A portion o~ the fo~l w~ u~ed ~or ten~ esting, an~ ~ portion wae analyzed ror th~ j ~rac~ lron aontent~ The result~ ~omp~ring the sa~e plA~lng bath operA~ed at A p~ 0~ 12 . f!!i ~U. ~it . Patent No3 .
4,632,B52 ~n~ 4,970,107) ~nd a platlng ~ath operhtQ~ ~t ~ pH o~ ll.B (a b~h pH wlthln ~pplioantlh in~ention) are reportR~ ln Table 1. Th~3 paroent elong~t~ on 1Y
reported as Pleasured ~t th~ depo~t thicknes6 and A6 normali~ed ~o a thickness o~ 30 ,u~, TABL~ 1 ~_ ~ ~. ~., ., B-thIron Cono.Ton ileP~po~i~ S ~Jon~60n pHIn tho r~lc~Dou _. . ..
~lCcppor S~n~h h~ 1~ 1iz~
25'~ h~ro~ to . . . .
n~/mol MP~ . ~lm 30 ~m __ _ __~ ___ 12.5 3.50 331 ~9~5 2 2 11 ,B 0,~3 413 N,Z 6 7 11 .B 0.5~ 400 ~.2 ~ J
11~0.~3 ~55 3~.5 9 9 ' ....................... .,_.... __ Examplo 2 ThQ ooppRr d~po~it~ pro~u~d in th~ platin~
bath formulations of Example 1 had a rough surfa~e, 2S whieh 1~ ob~octlonal~lo ~or Any pr~nt~d wirirlg ~oard ., !
.: ~ppl~ satiorls u~ing ~inger ~ontac:t~ or edge connec~ors .
The sur~a~e rou5~hrle~ wac 1.5-2~0 ym. Th~ formulation~ ;
~or~bed in Eslampla 1 wer~a modi~i~d by th~ addition 2~ 01~1 172~-40~3 o~ a v~nadium co~pound to impro~e tb~ ~ur~ce fln~eh ~nd th~ du~tlllty o~ the d~po~it. An ~l~ctroloc~
soppe~ platin~ bath wa~ operated with the followlng ~os~mulatlon:
~uSO~,~ 5H20 g~L 10 Na~,EDrA- 2H20 g~ll 41 NaO~ pH At 2 5 C~ 11 . 8 Formaldehyd~ (37~ ~olution) ml4I. 4 . 3 lo By-proauct N2~So,, mol/L 0. 25 ~y-product NaOOC~ ~nol~L Q . 5 Polyoxyethylen~ 7=1000) g/L
G~02 mg/~ 7 V~05 mg,~l 2 Air ~n~ec~ion ~la~ bubble~ n/L(~ath) O . 07 Ai~ ln~ac~ion ~fin~a ~ubb'~es) L~min~L(bath) 0.07 T~mperature ' C 7 ~h~ platln~ bath wa~ ope~a~ed with a losd o~
- 1.5 dm~ of ~ur~e being plated p~r lite~r. ~he s~'¢e of copper deposition wa~ ~.5-5.5 ~hr. ~h~ ~ur~ca flnl~h o~ the ~spper d~po~it wa~ o. 5-1. 0 ,um. Th~ 26 ,um ~opper ~oil depQsited on the ~tAinle66 61:~el ~ub~tr~tum wa~ drle~ for 1 hour at 160~. A teneile teat was ~S per$ormad on the fo~ 1. The teneil~ ~trongth w~ 345 ,, , . . . . ... I
1728~4093 2~g~ ~
MPa and the ~longstlon was 18~ (~o~ when normallzed to 30 ~m ~hic~ depo~it).
~h4 pla~ing bath ~l~o wa~ op~rated with wor~c loa~ 3f~ 1.2 ~nd 2.5 d~2 per liter, and ~uivaler~t re~ult~ wer~ obtaln~d.
Exa~pl~ 3 Pla~ing b~hs h~ving ~hR 6~me ~onnulation ~xampl~ 2 war~ op~r~ted on ~i~e dif ~r~nt ~ays ~o provlde ~ample~ for ~Qn~lle t2sting. A~t~r ~ach day, the aopp~r depo~ Q~ the st~inle6s ~t~el ~ub~tratum w~ ~rla~ ~or ~ hcur~ 0 t c~ . The reault~ arQ
repor~d ln ~ho ~ble 2. ~ha p~rc~n~ ~longation 1 repor~ed a~ eaeured At the ~epo~ hicknea~ arld a~
no2ma~ized to a thlGlcne~ o~ 30 ~m~
_~_ __ l~ Tuullc ~
~ ~ L-- ~C~ U~ ~ M ~ ~
26.1 ~ 0.3 3~6 t 4 1~ 1 2 20 36.8 ' 0,~ 31~ ~ 3 21 -' ~ ~8 ~ 2~.1 0,~ 3~ 1~ ;t 1 17 6 16,2 ~ ~,3 31~ 1 3 12 -' 2 17 ~ 24 1 1 0 3 306 + 3 15 ~ I 11 ____ .~ ___ 2101~1 Example 4 P~inted wirin~ board~ werQ propara~ by ths p~rtly-a~ditlve proce~. In the par~ly-~dditive I prooe~s, a 1.~ ~ thick, ~a~e ma~ria~, coppar-ala~ on both ~ides, ~ dxilled to provide through hole~ wlth 0.3~ mm di~metex: the hQle wall~ w~ro ~ctiv~t~d and eloc~rol~sly plat~ wl~h 1-2 ~m of ooppQr; a double-slded "da~sy-ohain" pa~ern w~ appli~ w~h a tenting rQsist whi~h covered the ~hrough holes: th~ conductlv~
patt~rn wa~ for~4~ by e~chlng, an~ th~ re~t was ~tr~pp~d~ A parm~n~nt ~e ist wa~ appli~d on both sldes over ~he c~nductiv~ pa~t~rn lsaving the through hol~
And th~ land~ ~xpos~d. Th~ l~nd~ ~nd the w~113 o~ the through hole~ wero el~ctrol~ly plat~d with ~opper usins an ~lec~rol~s oopper pla~lnq ~ath op~r~t~d w~th the lo~ pH formulation of Examp~e 1. A~t~r platins, the printed ~i~ing board~ w~re dried for 4 hour~ at l~iO'C.
. ~he platod-through hole in the pr~nted wlr~ng bo~ds we~e ~u~e~ed ~ the fluid sand thermal ~ycling ~eet ~eoorl~d h~r4in. ~ablQ 3 ~how~ ths ~hicXnea~ an~
t~n~ prop~rti4~ of ~he coppRr d~po~it with th~
result~ of the fluld san~ ~herm~l ~ycling t~
~ ~2 1728-4093 2~18~1 __ ,, .~ " ~
Pl~tln~ D~ T~U~ % Inpllon Cyol~-~biob~eu hr~o~th A~ Nom~ll~ 'rb !1 R~l M~ d lo _ Mh 30 ym F~ila~
` l-- . .. _ .... __ __ _ ~ _ ,1 l 51 273;t2 1~ 1 7 40 2 5~ 241~4 12 t2 7 34 __3 ~8 ~ 3 13~ I 8 4~
' __ _ _ _e .. . ,~ ~__ ~5x~ple 5 Example 4 wa~ rep~t~d ~xoept that the ho~
wall~ werQ pl~ted with An eleGtroles~ copper pl~t~ng ~ h opexating ~ith ths ~ormulation o~ Exa;apl~ 2. A
~ample o~ the ç:opper ~oll was anal~zed ~nd the iron cont~nt wa~ fsun~ to ~ 0.34 mg per mo~e coppQr. ~a~le 4 below ~hows ths th~ s~ and tona~ l~ p~op~rti~ o~
~ha ~opper depo~t and th~ ra~ult~ o~ ~he ~lu~a sand the~mal c:yçl ~ ng t~
~ __ Ihpodt ~n~llc ~ 3Ll~ n Cyclos l Pl~tlng _~ _ I
~lurl ~ Mh MUA~U~ Nl3mot~1~ T; ¦
_~ _._ _ _- ~ . . _ 2 ~32~0 t I10 1 1 ~3 63 _ ~ 30~15 ~: 31~ ~ 4 1~ 4 ___ ~ ___ _ Th~ e excellent re~ul~e Q~p6~1all~ fQr thin fo-l ls further illust~at~ th~ ~u~prisin~ tou~hne~ nd ductili~y o~ the ~alBCt~01~358 ~opp~r deposit~ when a - ~3 -172~-4093 2 1 ~
~nall e~foctlv~ amount o~ a Yanadlum co~pound 1~
di~oolved in the el~ctrole~ ~oppe~ pla~ing b~th.
, .' ~
Exar~pl~ 5 w~ repaated excep~ th~t th~
~1Q~rO1~8 copper pl~tinq ba~h hnd a hlgh tr~ ron ~ontent f~oJn ~pl~nl~hmQnt w~h copper ~u~fata ~olutlon cont~mlnat~ with 32 mg i~on per mole of coppe~
3ulfa~ h~ r~sult~ o~ ~en~ile t~tir~g o~ th2 çopp~r d~po~ited ~r~3 ~hown ln Tab~ 5.
_ . . . ~ . " . _ __ _ I
D~c~k 'toncllo~ ~lonp~bn ~on I
l 5Plalln~ iblcl:ne~ jt~nglh A~ ~c~nal~dCcv~rr I
Run Llr M~ Me~nd 30 ~m ppm l ~ 455 ~ 7 ~ ~ I 7 20S
2 ~9 ~34 ~ I ~ ~ I 6 62 __ ~ ~ , I
Thi~ ~er~on~tra~e~ that ~,rhen ths é~ce iron ln the plating b~th i~ hlgh, eve~ oper~ting th~
electrole66 copp~r plating b~th a~ ~ pH b~twe~n 11 and 12 A O is not u~ici~n$ to ~intAin low lron in th~ .
~, deposi~ ~n~ the dep~s~ts obtain~ wlll h~ lower ductll ~ ty ~
.. . . ..
1728-40~3 2 1 0 ~ 8 ~ 1 Example ~
Exafflpl~ S 1B repeated uslng ~he copper ~ulfa~e repleniohmQn~ ~olutlon ~ontairing 32 m~ iron pe~ ~olo copper ~ulr~te, but the elRotrol~s copper : pla~ing bath i~ ~no~ ied ~y an lron ~o~plexinq addition R~ont. ~he comple~ing add~tlon ~ge~nt i8 b~cene. Flv~
gram~ o~ bicene is ~ad~d ~o eaoh llter o~ th~ coppe~
sulfate ~pl~nl~ nt ~olu~ion . ~oppç~
~lectrole~ly plAt3~ ~rom the bathJ the copp~r haP hlgh thermal ~hook rR~ ~ ~t~n~ and l~ss than 1. 5 ~ng iron per mol~ o~ oopp~r.
/
~
,. ~
~! 5
Claims (19)
1. In a method of manufacturing an electroless copper deposit from a plating bath containing a copper compound, ehtylenediamine-tetraacetic acid as the complexing agent for copper, a reducing agent for copper, a pH-adjusting agent, an additive selected from the group consisting of soluble inorganic silicon compounds and soluble inorganic germanium compounds, and in which method an oxygen containing gas is injected into the plating bath; the improvement for producing a copper deposit on a printed writing board having at least one plated-through hole, said copper deposit being capable of withstanding 25 repetitive thermal cycles of immersion in water at 25°C
followed by immersion in a fluidized sand bed at 260°C
without failure or an increase of more than 10% in the resistance of the plated-through hole, comprising monitoring and maintaining the pH of the plating bath in the range of 11.2 to 12 when measured at 25°C so that the content of trace iron in the deposited copper layer is maintained below 1.5 mg per mole of copper.
followed by immersion in a fluidized sand bed at 260°C
without failure or an increase of more than 10% in the resistance of the plated-through hole, comprising monitoring and maintaining the pH of the plating bath in the range of 11.2 to 12 when measured at 25°C so that the content of trace iron in the deposited copper layer is maintained below 1.5 mg per mole of copper.
2. The method of claim 1 wherein the pH is maintained in the range of 11.5 to 11.9 when measured at 25°C.
3. The method of claim 1 wherein the copper compound in the plating bath is replenished by a copper compound containing less than 10 mg of iron per mols copper.
4. The method of claim 3 wherein the copper compound in the plating bath is replenished by a copper compound containing less than 5 mg of iron per mole copper.
5. The method of claim 1 wherein the improvement further comprises increasing the smoothness of the formed copper deposit by adding to the plating bath a vanadium compound in an amount sufficient to reduce the roughness of the surface of the deposited copper layer to no greater than 1 micron.
6. The method of claim 1 wherein the improvement further comprises increasing the ductility of the formed copper deposit by adding to the plating bath a vanadium compound in an amount sufficient to produce a copper deposit capable of withstanding at least 30 of said repetitive thermal cycles.
7. The method of claim 1 wherein the improvement further comprises increasing the ductility of the formed copper deposit by adding to the plating bath a vanadium compound in an amount sufficient to increase the percent elongation of the deposited copper layer to 1.5 to 2 times the percent elongation of a copper deposit from a comparable plating bath without said vanadium compound.
8. The method of claim 5 wherein the plating bath contains 0.036-0.048 mol/L copper compound, 0.086-0.106 mol/L EDTA, 0.053-0.060 mol/L formaldehyde, 0.1-10 g/L polyoxyethylene compound, 25-100 mg/L
germanium, and 0.5-2.5 mg/L of vanadium.
germanium, and 0.5-2.5 mg/L of vanadium.
9. The method of claim 6 wherein the plating bath contains 0.036-0.048 mol/L copper compound, 0.086-0.106 mol/L EDTA, 0.053-0.060 mol/L formaldehyde, 0.1-10 g/L polyoxyethylene compound, 25-100 mg/L
germanium, and 0.5-2.5 mg/L of vanadium.
germanium, and 0.5-2.5 mg/L of vanadium.
10. The method of claim 1 wherein the plating bath further comprises a complexing agent for iron in an amount sufficient to complex the iron in the plating bath and limit codeposited iron in the copper layer to less than 1.5 mg per mole copper.
11. The method of claim 10 wherein the plating bath pH is 11.2-12 (measured at 25°C), and the plating bath contains 0.036-0.048 mol/L copper compound, 0.086-0.106 mol/L EDTA, 0.053-0.060 mol/L
formaldehyde, 0.1-10 g/L polyoxyethylene compound, 25-100 mg/L germanium, and 0.5-1.0 g/L
N,N-bis(2-hydroxyethyl)- glycine as the complexing agent for iron.
formaldehyde, 0.1-10 g/L polyoxyethylene compound, 25-100 mg/L germanium, and 0.5-1.0 g/L
N,N-bis(2-hydroxyethyl)- glycine as the complexing agent for iron.
12. A method of manufacturing according to claim 1, wherein the plating bath is operated to deposit copper for a printed wiring board.
13. A printed wiring board produced by the method of claim 12.
14. A method of manufacturing according to claim 5, wherein the plating bath is operated to deposit copper for a printed circuit board.
15. A method of manufacturing according to claim 6, wherein the plating bath is operated to deposit copper for a printed wiring board.
16. A printed wiring board produced by the method of claim 14.
17. A printed wiring board produced by the method of claim 15.
18. A method of manufacturing according to claim 8, wherein the plating bath is operated to deposit copper for a printed wiring board.
19. A printed wiring board produced by the method of claim 18.
17. A printed wiring board produced by the method of claim 15.
17. A printed wiring board produced by the method of claim 15.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US07/924,842 US5258200A (en) | 1992-08-04 | 1992-08-04 | Electroless copper deposition |
| US924,842 | 1992-08-04 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2101881A1 true CA2101881A1 (en) | 1994-02-05 |
Family
ID=25450813
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002101881A Abandoned CA2101881A1 (en) | 1992-08-04 | 1993-08-04 | Electroless copper deposition |
Country Status (5)
| Country | Link |
|---|---|
| US (2) | US5258200A (en) |
| EP (1) | EP0582336B1 (en) |
| JP (1) | JPH06173018A (en) |
| CA (1) | CA2101881A1 (en) |
| DE (1) | DE69306189T2 (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5258200A (en) * | 1992-08-04 | 1993-11-02 | Amp-Akzo Corporation | Electroless copper deposition |
| US5633047A (en) * | 1994-02-22 | 1997-05-27 | International Business Machines Corporation | Electronic devices having metallurgies containing copper-semiconductor compounds |
| US5683568A (en) * | 1996-03-29 | 1997-11-04 | University Of Tulsa | Electroplating bath for nickel-iron alloys and method |
| US8354046B2 (en) * | 2004-07-08 | 2013-01-15 | Los Alamos National Security, Llc | Germanium films by polymer-assisted deposition |
| KR101011913B1 (en) * | 2002-09-09 | 2011-02-01 | 스미토모덴키고교가부시키가이샤 | Plated polyester resin article and method for production thereof |
| US7029529B2 (en) | 2002-09-19 | 2006-04-18 | Applied Materials, Inc. | Method and apparatus for metallization of large area substrates |
| JP4990966B2 (en) * | 2006-04-13 | 2012-08-01 | コーロン インダストリーズ インク | Method for manufacturing metal electrode |
| US8172627B2 (en) * | 2008-12-03 | 2012-05-08 | Tyco Electronics Corporation | Electrical connector with plated plug and receptacle |
| US20170073815A1 (en) * | 2015-09-10 | 2017-03-16 | Lam Research Corporation | Method for a non-aqueous electroless polyol deposition of metal or metal alloy in features of a substrate |
Family Cites Families (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3310430A (en) * | 1965-06-30 | 1967-03-21 | Day Company | Electroless copper plating |
| US3485643A (en) * | 1966-05-06 | 1969-12-23 | Photocircuits Corp | Electroless copper plating |
| US3615735A (en) * | 1968-08-13 | 1971-10-26 | Shipley Co | Electroless copper plating |
| US3615732A (en) * | 1968-08-13 | 1971-10-26 | Shipley Co | Electroless copper plating |
| US3959351A (en) * | 1972-07-24 | 1976-05-25 | Research Corporation | Haloalkylbenzoyl esters of di-lower alkylamino alkanols and quaternary lower alkyl salts thereof |
| GB2083080A (en) * | 1981-09-01 | 1982-03-17 | Philips Nv | Electroless deposition of copper alloy layers |
| DE3473890D1 (en) * | 1983-07-25 | 1988-10-13 | Hitachi Ltd | Electroless copper plating solution |
| JPS6070183A (en) * | 1983-09-28 | 1985-04-20 | C Uyemura & Co Ltd | Chemical copper plating method |
| KR920002710B1 (en) * | 1984-06-18 | 1992-03-31 | 가부시기가이샤 히다찌세이사꾸쇼 | Chemical copper plating method |
| US4695505A (en) * | 1985-10-25 | 1987-09-22 | Shipley Company Inc. | Ductile electroless copper |
| US4666683A (en) * | 1985-11-21 | 1987-05-19 | Eco-Tec Limited | Process for removal of copper from solutions of chelating agent and copper |
| JPS63312983A (en) * | 1987-06-16 | 1988-12-21 | Hitachi Ltd | Electroless copper plating method and equipment therefor |
| JPH0634448B2 (en) * | 1988-07-25 | 1994-05-02 | 株式会社日立製作所 | Multilayer printed wiring board and manufacturing method thereof |
| US5258200A (en) * | 1992-08-04 | 1993-11-02 | Amp-Akzo Corporation | Electroless copper deposition |
| US5256441A (en) * | 1992-08-04 | 1993-10-26 | Amp-Akzo Corporation | Ductile copper |
-
1992
- 1992-08-04 US US07/924,842 patent/US5258200A/en not_active Expired - Lifetime
-
1993
- 1993-07-23 EP EP93202178A patent/EP0582336B1/en not_active Expired - Lifetime
- 1993-07-23 DE DE69306189T patent/DE69306189T2/en not_active Expired - Lifetime
- 1993-08-04 JP JP5211114A patent/JPH06173018A/en active Pending
- 1993-08-04 CA CA002101881A patent/CA2101881A1/en not_active Abandoned
- 1993-10-28 US US08/144,823 patent/US5429861A/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH06173018A (en) | 1994-06-21 |
| DE69306189T2 (en) | 1997-05-28 |
| DE69306189D1 (en) | 1997-01-09 |
| EP0582336A2 (en) | 1994-02-09 |
| US5258200A (en) | 1993-11-02 |
| EP0582336B1 (en) | 1996-11-27 |
| US5429861A (en) | 1995-07-04 |
| EP0582336A3 (en) | 1995-02-01 |
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