WO2006078664A1 - Connector system - Google Patents

Abstract

A connector system for providing electrical interconnection between a substrate (504) and a packaged integrated circuit (500) is provided. The connector system includes a first connector assembly (514) including (a) a first framework (512) , (b) a first plurality of resilient contacts supported by the first framework and configured to contact electrical connections of the packaged integrated circuit. The connector system also includes a second connector assembly (524) including (a) a second framework (522) , (b) a second plurality of resilient contacts supported by the second framework and configured to contact (1) the first plurality of resilient contacts, and (2) electrical connections of the substrate.

Description

CONNECTOR SYSTEM

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No.

60/645,895, filed January 21, 2005, the contents of which are incorporated herein by reference.

FIELD OF THE INVENTION

[0002] The present invention relates to connector systems for providing electrical interconnection in the testing of packaged integrated circuits, and more particularly, to stacking connector assemblies for use in testing packaged integrated circuits.

BACKGROUND OF THE INVENTION

[0003] In the testing of packaged integrated circuits, connector assemblies are often used to provide electrical interconnection between the testing system (e.g., through a substrate/printed circuit board such as a load board) and the packaged integrated circuit under test (e.g., through contacts or terminals of the packaged integrated circuit). For example, interposer connector assemblies housed by a socket are used to provide such electrical interconnection.

[0004] Unfortunately, such connector assemblies suffer from a number of deficiencies. For example, such connector assemblies may be configured to provide a desired deflection range in certain circuit configurations (e.g., land grid array configurations), but may not be configured to provide a desired deflection range in other circuit configurations (e.g., ball grid array configurations).

[0005] Thus, it would be desirable to provide a connector system configured to provide electrical interconnection between components in various circuit configurations.

SUMMARY OF THE INVENTION

[0006] According to an exemplary embodiment of the present invention, a connector system for providing electrical interconnection between a substrate and a packaged integrated circuit is provided. The connector system includes a first connector assembly including (a) a first framework, (b) a first plurality of resilient contacts supported by the first framework and configured to contact electrical connections of the packaged integrated circuit. The connector system also includes a second connector assembly including (a) a second framework, (b) a second plurality of resilient contacts supported by the second framework and configured to contact (1) the first plurality of resilient contacts, and (2) electrical connections of the substrate.

[0007] According to another exemplary embodiment of the present invention, a connector system for providing electrical interconnection between a substrate and a packaged integrated circuit is provided. The connector system includes a socket and a plurality of connector assemblies arranged in a stacked configuration at least partially within the socket. Each of the connector assemblies includes (a) a framework, and (b) a plurality of resilient contacts supported by the framework. The stacked connector assemblies provide electrical interconnection between the substrate and the packaged integrated circuit via stacked ones of the resilient contacts.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The invention is best understood from the following detailed description when read in connection with the accompanying drawing. It is emphasized that, according to common practice, the various features of the drawing are not to scale. On the contrary, the dimensions of the various features are arbitrarily expanded or reduced for clarity. Included in the drawing are the following figures:

Fig. IA is a side view of a portion of a connector system in accordance with an exemplary embodiment of the present invention;

Fig. IB is a perspective view of a portion of the connector system of Fig. IA;

Fig. 2A is a detailed perspective view of a portion of another connector system in accordance with an exemplary embodiment of the present invention;

Fig. 2B is a side view of a portion of the connector system of Fig. 2A; Fig. 2C is a perspective view of another portion of the connector system of Fig. 2A;

Fig. 2D is another perspective view of Fig. 2C;

Fig. 3A is a perspective view of a portion of another connector system in accordance with an exemplary embodiment of the present invention;

Fig. 3B is a side view of the portion of the connector system of Fig. 3A;

Fig. 4A is a perspective view of a portion of yet another connector system in accordance with an exemplary embodiment of the present invention;

Fig. 4B is a side view of the portion of the connector system of Fig. 4A;

Fig. 5A is a block diagram of a side view of a portion of a connector system providing electrical interconnection between an packaged integrated circuit device and a substrate in a free state according to an exemplary embodiment of the present invention;

Fig. 5B is a block diagram of a side view of the portion of the connector system of Fig. 5A in a compressed state; and

Fig. 5C is a block diagram illustrating an alignment structure for aligning the connector system of Fig. 5A.

DETAILED DESCRIPTION OF THE INVENTION

[0009] United States Patent Nos. 5,629,837; 6,042,387; and 6,890,185, as well as United States Patent Application Publication No. 2005/0159025, as well as United States Patent Application No. 11/198,995, relate to electrical interconnection technology, and are herein incorporated by reference in their entirety.

[0010] As used herein, the term "substrate" is intended to refer to any of a number of devices configured to be electrically connected to a packaged integrated circuit during the testing of the packaged integrated circuit. For example, an exemplary substrate is a printed circuit board which is coupled to a testing system, wherein terminals/pads/contacts of the printed circuit board are configured to be electrically connected to terminals/pads/contacts of the packaged integrated circuit device to be tested. According to the present invention, this electrical connection is provided via a connector system including stacked connector assemblies. A specific example of such a printed circuit board is a conventional load board used in package testing environments.

[0011] As used herein, the term "arm" is intended to refer to a portion of a resilient contact extending from a base portion of the resilient contact and is not limited to any particular shape or configuration.

[0012] As used herein, the terms "upwardly" and "downwardly" are relative in nature, and may be interchanged depending upon the orientation of a connector assembly. Thus, for a given connector assembly, a contact may extend upwardly in a first orientation of the connector assembly, and downwardly in a second orientation of the connector assembly.

[0013] According to certain exemplary embodiments of the present invention, a plurality of connector assemblies are stacked to provide an increased vertical deflection range and increased compliance between a packaged integrated circuit and a testing point for the packaged integrated circuit (e.g., a substrate such as a load board). For example, each of the connector assemblies may include a laminated structure (e.g., a dielectric/conductor structure) including a base dielectric layer and a conductive (or semiconductive) layer (e.g., a conductive layer selectively applied to the base layer). The base dielectric layer may be a processed to form a framework/grid by removing certain portions of the base dielectric layer (e.g., by laser ablation). The conductive layer may be selectively applied to form electrical contacts using, for example, electroplating, photolithography, x-ray lithography, e-beam lithography, and nano- imprint lithography. As will be explained in greater detail herein, in order to test a packaged integrated circuit, a force (e.g., a compressive force applied via a mechanical system such as a pneumatic chuck) is applied to the connector system (i.e., the stacked connector assemblies), thereby establishing the desired electrical contact between the stacked connector assemblies.

[0014] By stacking connector assemblies as disclosed herein, a larger vertical deflection range is provided. Such an increased vertical deflection range facilitates interconnection of packaged integrated circuits having various configurations, for example, land grid array (i.e., LGA) and ball grid array (i.e., BGA) configurations. In an LGA configuration, such a connector assembly may be used to compensate for inconsistencies in the packaged integrated circuit flatness and inconsistencies in the printed circuit board flatness. In BGA configurations, the connector system may also be used to compensate for inconsistencies in ball heights.

[0015] The connector system disclosed herein may be modular in nature in that any number of connector assemblies may be included in the connector system to provide a desired vertical deflection range. For example, in certain circuit configurations (e.g., LGA circuit configurations), a single layer connector assembly may provide the desired vertical deflection range. In other circuit configurations (e.g., BGA circuit configurations), two or more connector assemblies may be stacked to provide the desired vertical deflection range. Thus, although a different number of connector assemblies may be stacked depending on the circuit configuration, the same modular connector assembly may be used in each of the configurations. Through the use of such a modular connector assembly, cost savings are derived.

[0016] According to certain exemplary embodiments of the present invention, the framework (e.g., a grid) of each of the connector assemblies has a resilient property. Thus, at least a portion of the framework will flex (e.g., compliantly bend) upon a predetermined force being applied to at least a portion of resilient contacts supported by the framework.

[0017] Referring now to Figs. 1A-1B, side and perspective views of a portion of a connector system are shown. Note that Fig. IA is arbitrarily rotated vertically with respect to Fig. IB. The connector system includes two stacked connector assemblies, that is, connector assemblies 110 and 120. Connector assembly 110 includes framework 112 and a plurality of resilient contacts 114 disposed thereon, and connector assembly 120 includes framework 122 and a plurality of resilient contacts 124 disposed thereon.

[0018] Connector assembly 110 includes framework 112 (e.g., a polyimide sheet patterned to define apertures therethrough, using, for example, laser ablation). Connector system also includes a plurality of resilient contacts 114 made of, for example, a nickel alloy such as NiMn. Such a nickel alloy may desirably be plated with a noble metal (e.g., gold) to provide improved conductivity, etc. Material used to define each of the contacts 114 is deposited (e.g., electroplating NiMn on a lithographically defined pattern) onto the polyimide sheet, for example, with a seed layer of copper or the like disposed therebetween (NiMn plates well to copper). After processing, the remainder of the seed layer (e.g., the portion of the seed layer not provided between the polyimide sheet and a respective one of contacts 114) may be removed, for example, using an etchant. After deposition of the material for contacts 114, apertures are formed in the polyimide sheet to define framework 112, after which contacts 114 are processed (e.g., using a mandrel, an automated tool, etc) to have the shape shown in Figs. 1A-1B. More specifically, contacts 114 are shaped to such that arms of the contacts 114 extend through the apertures defined in framework 112.

[0019] In the exemplary configuration shown in Figs. 1A-1B, each contact 114 includes (a) a base portion 114c that is substantially planar with framework 112, (b) an upwardly extending arm 114a terminating in a tip configured to contact a contact/pad/terminal/lead of a packaged integrated circuit to be tested, (c) a downwardly extending arm 114b terminating in a tip configured to contact the upwardly extending contact arm of contact 124 of connector assembly 120. Upwardly extending arm 114a defines aperture 114d, and downwardly extending arm 114b defines aperture 114e. Lower extending arm 124b of contact 124 terminates in a tip configured to contact a contact/pad/terminal/lead of a substrate (e.g., a substrate such as a load board).

[0020] As described above, upwardly extending arm 114a defines aperture

114d, and downwardly extending arm 114b defines aperture 114e. Such an aperture favorably distributes the stresses in framework 112 caused by loads applied to contacts 114/124 (e.g., a compressive load applied during testing of a packaged integrated circuit).

[0021] As shown in Figs. 1A-1B, at the interface of contacts 114 and 124 (i.e., the interface of the tip portion of downwardly extending arm 114b and the tip portion of the upwardly extending arm of contact 124), each of contacts 114 and 124 is shaped to have a flat surface configured to provide a relatively large contact area therebetween. Likewise, the tip of downwardly extending arm 124b is shaped to have a flat surface to contact a contact/pad/terminal/lead of a substrate (e.g., a substrate such as a load board). Thus, it is clear that certain of the tip portions of the arms of the contacts may be shaped as desired in a given application. [0022] As with each of the illustrations provided herein, Figs. 1A-1B illustrate a portion of the connector system. The complete connector system will typically include many contacts 114/124, and will also typically include (amongst other features) a housing (e.g., a socket) and an alignment mechanism to align the connector assemblies with one another.

[0023] Referring now to Figs. 2A-2D, various views of portions of a connector system are shown. The connector system includes three stacked connector assemblies, that is, connector assemblies 210, 220 and 230. Connector assembly 210 includes framework 212 and a plurality of resilient contacts 214 disposed thereon; connector assembly 220 includes framework 222 and a plurality of resilient contacts 224 disposed thereon; and connector assembly 230 includes framework 232 and a plurality of resilient contacts 234 disposed thereon.

[0024] Referring specifically to Fig. 2A, a detailed view of three stacked contacts

214, 224, and 234 (supported by respective frameworks 212, 222, and 232) are shown. As with contacts 114 and 124 described above with respect to Figs. 1A-1B, contact 214 (and contacts 224 and 234) includes: (a) base portion 214c substantially planar with framework 212, (b) upwardly extending arm 214a terminating in a tip configured to contact a packaged integrated circuit device to be tested, (c) downwardly extending arm 214b, (d) aperture 214d defined in upwardly extending arm 214a, and (e) aperture 214e defined in downwardly extending arm 214b. Downwardly extending arm 234b of contact 234 is configured to contact a substrate (e.g., a printed circuit board such as a load board).

[0025] Referring specifically to Fig. 2B, a side view of contacts 214, 224, and

234 is provided. In this exemplary configuration, neither of contact arm 214a (configured to contact a packaged device to be tested) and contact arm 234b (configured to contact a substrate such as a load board) has been shaped to have a substantially flat length at a tip thereof. If desired, both tips could be so shaped. In contrast, the tip portion of downwardly extending arm 214b of contact 214 and the tip portion of upwardly extending arm 224a of contact 224, have been shaped to have substantially flat lengths providing an interface region 250.

[0026] Figs. 3A-3B are perspective and side views of a portion of another connector system having a different configuration. The connector system includes two stacked connector assemblies, that is, connector assembly 310 and connector assembly 320. Connector assembly 310 includes a framework 312 and a plurality of resilient contacts 314. Connector assembly 320 includes a framework 322 and a plurality of resilient contacts 324. In the illustrated configuration, contacts 314 have been deposited on framework 312 such that channels 316 are defined between respect contacts 314, thereby providing electrical isolation. Each contact 314 includes two upwardly extending contacts 314al and 314a2, as well as two downwardly extending contacts 314bl and 314b2. Likewise, each contact 324 includes two upwardly extending contacts 324al and 324a2, as well as two downwardly extending contacts 324bl and 324b2.

[0027] Figs. 4A-4B are perspective and side views of a portion of another connector system having a different configuration. The connector system includes two stacked connector assemblies, that is, connector assembly 410 and connector assembly 420. Connector assembly 410 includes framework 412 and a plurality of resilient contacts 414. Connector assembly 420 includes framework 422 and a plurality of resilient contacts 424. Each contact 414 includes upwardly extending contact 414a, downwardly extending contact 414b, and base portion 414c substantially planar with framework 412. Likewise, each contact 424 includes upwardly extending contact 424a, downwardly extending contact 424b, and base portion 424c substantially planar with framework 422.

[0028] As shown in Fig. 4A, contacts 414 and 424 defines slots/apertures therethrough. Such a slot/aperture tends to distribute stress applied to the electrical contacts (e.g., from a compressive load applied during testing of a packaged integrated circuit). Additionally, such a slot or aperture may be used to divide a signal transmitted through the respective electrical contact.

[0029] As is clear from the various exemplary shapes/configurations in Figs. IA-

IB, 2A-2D, 3A-3B, and 4A-4B, the present invention is applicable to resilient contacts (as well as other elements of the connector system) having many different shapes and configurations.

[0030] Figs. 5A-5B are block diagrams of a side view of a portion of a connector system providing electrical interconnection between packaged integrated semiconductor device 500 and substrate 504 in a free state, and a compressed state, respectively, according to an exemplary embodiment of the present invention. The connector system includes arrays of stacked resilient contacts 514 and 524, supported by frameworks 512 and 522 respectively. Note that Fig. 5A (and Fig. 5C) is arbitrarily rotated vertically with respect to Fig. 5B.

[0031] Referring specifically to Fig. 5A, in a free (uncompressed) state, a tip portion of the upwardly extending arm of contact 514 is configured to contact terminal (or the like) 502 of packaged semiconductor device 500. Likewise, a tip portion of the downwardly extending arm of contact 524 is configured to contact terminal (or the like) 504 of load board 504. The uncompressed height of the stacked connector system is 0.040 inches, and the spacing between frameworks 512 and 522 is a substantially constant 0.018 inches.

[0032] As shown in Fig. 5A, in certain configurations of the present invention, physical contact may exist between (a) terminal 502 of packaged semiconductor device 500 and an upwardly extending arm of contacts 514, (b) a downwardly extending portion of contact 514 and an upwardly extending portion of contacts 524, and/or (c) a downwardly extending portion of contact 524 and terminal 506 of load board 504 prior to a compressive force being applied to such contacts; however, such physical contact (without the compressive force) may not result in the desired electrical connection therebetween (i.e., the physical contact may result in an electrical connection of a high resistance).

[0033] As shown in Fig. 5B, during compression (i.e., during testing of device

500), the height of the stacked connector system is 0.030 inches, and the spacing between frameworks 512 and 522 is no longer substantially constant. More specifically, during compression, the frameworks of the connector system tend to "flex" thereby providing a portion of the force between the 514/524 contacts and packaged semiconductor device 500 and load board 504, respectively. Such compression may be applied, for example, using a pneumatic device to apply a compressive force through the packaged semiconductor device in order to establish the desired electrical connections between packaged integrated circuit device 500, the first connector assembly, the second connector assembly, and load board 504.

[0034] Also illustrated in Fig. 5B is the interface between (a) a tip portion of downwardly extending arm 514b and (b) a tip portion of upwardly extending portion 524a. As shown, during compression, relative motion between these tip portions occurs as one of the tip portions may "ride along" the other while maintaining the desired electrical contact therebetween. [0035] Fig. 5C illustrates that packaged semiconductor device 500, load board

504, and the connector system extends lengthwise (shown in dashed lines) as desired based on the given application. Also represented in Fig. 5C is alignment structure 508 (e.g., an alignment pin or the like) which is provided to align the respective contact arrays. More specifically, one or more alignment structures 508 may be provided (e.g., on a periphery of the connector system) to align respective connector assemblies of the connector system. In the exemplary embodiment illustrated in Fig. 5C, each of frameworks 512 and 522 define respective apertures to receive alignment structure 508 to ensure proper alignment. Further, the one or more alignment structures may be configured as part of a socket-type device (not shown) for housing the connector system.

[0036] Thus, according to the present invention, a plurality of connector assemblies (e.g., contactor arrays) are located relative to each other (e.g., stacked) and allowed to float in the Z direction. A desired electrical path between resilient contacts of the connector assemblies is provided when the connector system (including the connector assemblies) is compressed, thereby forcing adjacent resilient contacts to connect.

[0037] Although the present invention has been described primarily with respect to providing interconnection between a packaged integrated circuit and a printed circuit board such as a load board, it is not limited thereto. Likewise, the present invention is not limited to providing interconnection between components for testing packaged integrated circuits. Rather, the present invention is applicable to any of a number of applications which desire a modular and versatile electrical connector system. For example, stacking connector assemblies may also be utilized in the testing of wafer based semiconductor devices (e.g., as an interposer of a probe card assembly).

[0038] Although the invention is illustrated and described herein with reference to specific embodiments, the invention is not intended to be limited to the details show/i. Rather, various modifications may be made in the details within the scope and range of equivalents of the claims and without departing from the invention.

Claims

What is Claimed:

1. A connector system for providing electrical interconnection between a substrate and a packaged integrated circuit, the connector system comprising:

a first connector assembly including (a) a first framework, (b) a first plurality of resilient contacts supported by the first framework and configured to contact electrical connections of the packaged integrated circuit; and

a second connector assembly including (a) a second framework, (b) a second plurality of resilient contacts supported by the second framework and configured to contact (1) the first plurality of resilient contacts, and (2) electrical connections of the substrate.

2. The connector system of claim 1 wherein the first framework defines a first plurality of apertures, and the second framework defines a second plurality of apertures, and each of the first plurality of resilient contacts includes a first arm extending through a respective one of the first plurality of apertures, and each of the second plurality of resilient contacts includes a second arm extending through a respective one of the second plurality of apertures.

3. The connector system of claim 1 wherein each of the first plurality of resilient contacts includes (a) a first base portion substantially planar with the framework, (b) a first upwardly extending arm extending away from the base portion, and (c) a first downwardly extending arm extending away from the base portion.

4. The connector system of claim 3 wherein each of the second plurality of resilient contacts includes (a) a second base portion substantially planar with the framework, (b) a second upwardly extending arm extending away from the base portion, and (c) a second downwardly extending arm extending away from the base portion.

5. The connector system of claim 4 wherein (a) each of the first upwardly extending arms is configured to contact one of the electrical connections of the packaged integrated circuit, (b) each of the second downwardly extending arms is configured to contact one of the electrical connections of the substrate, and (c) each of the first downwardly extending arms is configured to contact a respective one of the second upwardly extending arms.

6. The connector system of claim 1 wherein at least one of the first plurality of resilient contacts and the second plurality of resilient contacts define apertures extending therethrough.

7 The connector system of claim 1 wherein at least one of the first plurality of resilient contacts and the second plurality of resilient contacts define slots extending therethrough.

8. The connector system of claim 1 wherein at least one of the first framework and the second framework comprises polyimide.

9. The connector system of claim 1 wherein at least one of said first plurality of resilient contacts and said second plurality of resilient contacts comprises a nickel alloy.

10. The connector system of claim 1 wherein at least one of said first plurality of resilient contacts and said second plurality of resilient contacts comprises NiMn.

11. The connector system of claim 1 further comprising at least one alignment pin for aligning the first connector assembly and the second connector assembly in a stacked configuration.

12. The connector system of claim 11 further comprising a socket, the alignment pin being connected to the socket, and each of the connector assemblies defining respective apertures for receiving the alignment pin.

13. The connector system of claim 12 wherein the apertures are provided at peripheral areas of each of the connector assemblies.

14. The connector system of claim 1 wherein (a) a portion of each of the first plurality of resilient contacts is configured to move along (b) a portion of a respective one of the second plurality of resilient contacts during compression of the connector system while maintaining contact therebetween.

15. The connector system of claim 1 wherein the first framework and the second framework are configured to flex during compression of the connector system, thereby providing contact force between the connector system, the electrical connections of the packaged circuit device, and the electrical connections of the substrate.

16. A connector system for providing electrical interconnection between a substrate and a packaged integrated circuit, the connector system comprising:

a socket; and

a plurality of connector assemblies arranged in a stacked configuration at least partially within the socket, each of the connector assemblies including (a) a framework, (b) a plurality of resilient contacts supported by the first framework,

the stacked connector assemblies providing electrical interconnection between the substrate and the packaged integrated circuit via stacked ones of the resilient contacts.

17. The connector system of claim 16 wherein the plurality of connector assemblies consists of two of the connector assemblies.

18. The connector system of claim 16 wherein the plurality of connector assemblies consists of three of the connector assemblies.

19. The connector system of claim 16 wherein each of the plurality of resilient contacts includes (a) a base portion substantially planar with a respective one the frameworks, (b) an upwardly extending arm extending away from the base portion, and (c) a downwardly extending arm extending away from the base portion.

20. The connector system of claim 16 further comprising at least one alignment pin for aligning the plurality of connector assemblies in the stacked configuration.