WO2006081119A1

WO2006081119A1 - Connector system

Info

Publication number: WO2006081119A1
Application number: PCT/US2006/001808
Authority: WO
Inventors: David T. Beatson; James L. Jaquette; Gene E. Tokraks; Steven Fahrner
Original assignee: K & S Interconnect, Inc.
Priority date: 2005-01-24
Filing date: 2006-01-19
Publication date: 2006-08-03

Abstract

A connector system (100) for providing electrical interconnection between a testing system and a packaged integrated circuit device. The connector system includes a substrate (102) configured to be engaged with the testing system, the substrate including a plurality of conductive contacts (104) disposed adjacent a surface thereof. The connector system also includes a connector assembly (106), the connector assembly including a framework (108) and a plurality of resilient contacts (110) supported by the framework. The resilient contacts are configured to provide electrical interconnection between the packaged integrated circuit device and the conductive contacts (104) of the substrate (102). Each of the resilient contacts includes (a) a first arm (110b) including a first contact region mechanically bonded to at least one of the conductive contacts (104) of the substrate, and (b) a second arm (110a) including a second contact region configured to be in electrical contact with at least one electrical contact of the packaged integrated circuit device during testing thereof .

Description

CONNECTOR SYSTEM

CROSS-REFERENCE TO RELATED APPLICATIONS

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

60/646,927, filed January 24, 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 connector systems having increased deflection and reduced contact resistance.

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 or printed circuit board) and the packaged integrated circuit under test. For example, socket-based interposer connector assemblies are used to provide such electrical interconnection.

[0004] Unfortunately, such connector assemblies suffer from a number of deficiencies. For example, the deflection range provided by such connector assemblies is often lower than a desired deflection range. Further, the resistance associated with such connector assemblies (e.g., the contact resistance between the connector assembly and a substrate, the contact resistance between the connector assembly and a packaged integrated circuit under test, etc.) is often higher than is desired.

[0005] Thus, it would be desirable to provide a connector assembly configured to provide an increased deflection range while reducing the associated contact resistance. SUMMARY OF THE INVENTION

[0006] According to an exemplary embodiment of the present invention, a connector system for providing electrical interconnection between a testing system and a packaged integrated circuit device is provided. The connector system includes a substrate configured to be engaged with the testing system, the substrate including a plurality of conductive contacts disposed adjacent a surface thereof. The connector system also includes a connector assembly, the connector assembly including a framework and a plurality of resilient contacts supported by the framework. The resilient contacts are configured to provide electrical interconnection between the packaged integrated circuit device and the conductive contacts of the substrate. Each of the resilient contacts includes (a) a first arm including a first contact region mechanically bonded to at least one of the conductive contacts of the substrate, and (b) a second arm including a second contact region configured to be in electrical contact with at least one electrical contact of the packaged integrated circuit device during testing thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] 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 perspective view of a portion of a connector system in :> accordance with an exemplary embodiment of the present invention;

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

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

Fig. 2B is a side perspective view of a portion of the connector system of Fig. 2A; Fig. 3 is a perspective view of a portion of yet another connector system in accordance with an exemplary embodiment of the present invention;

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

Fig. 5A is a side view of a portion of a connector system aligned with a packaged integrated circuit device in accordance with an exemplary embodiment of the present invention;

Fig. 5B is a perspective view of a portion of the connector system aligned with the packaged integrated circuit device of Fig. 5A; and

Fig. 5C is a front view of a portion of the connector system aligned with the packaged integrated circuit device of Fig. 5A.

DETAILED DESCRIPTION OF THE INVENTION

[0008] 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.

[0009] 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 device during the testing of the packaged integrated circuit device. For example, an exemplary substrate is a printed circuit board which is coupled to a testing system,, wherein terminals/pads/contacts (i.e., conductive contacts) of the printed circuit board are configured to be electrically connected to terminals/pads/contacts/leads of the packaged integrated circuit device to be tested. A specific example of such a printed circuit board is a conventional load board used in package testing environments.

[0010] 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. [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] According to certain exemplary embodiments of the present invention, resilient electrical contacts (also described herein as "resilient contacts") of a connector assembly (e.g., a torsion style planar interconnect such as that disclosed in United States Patent Application Publication No. 2005/0159025) are mechanically bonded to conductive contacts of a substrate (e.g., a printed circuit board such as a load board, a multilayer ceramic substrate, etc.). The connector assembly is configured to provide electrical interconnection between the substrate and a packaged integrated circuit device (e.g., a packaged integrated circuit device under test). Thus, while one end of each of the resilient contacts is mechanically bonded to a respective conductive contact of the substrate, the other end of each of the resilient contacts is configured to be electrically connected to a corresponding electrical contact of the packaged integrated circuit device (e.g., a device land of the packaged integrated circuit) during testing thereof. By mechanically bonding the resilient contacts to the conductive contacts of the substrate the contact resistance between the conductive contacts of the substrate and the packaged integrated circuit device to be tested is desirably decreased. Further, the vertical deflection of the connector assembly may be desirably increased concurrent with the decrease in the contact resistance.

[0013] In operation (e.g., during the testing of a packaged integrated circuit), a compressive force may be applied to the connector assembly, for example, using a pneumatic device to apply the compressive force through the packaged integrated circuit device. This compressive force establishes the desired electrical connections between the packaged integrated circuit device and the resilient contacts of the connector assembly. In certain configurations of the present invention, physical contact may exist between conductive contacts of the packaged integrated circuit device and a corresponding portion of the resilient contacts prior to a compressive force being applied; however, such physical contact may not result in the desired electrical connection therebetween (i.e., the physical contact may result in an electrical connection of a high resistance).

[0014] 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.

[0015] 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.

[0016] According to certain exemplary embodiments of the present invention, a portion (e.g., a tip portion of an arm) of each of resilient contacts is mechanically bonded (e.g., thermosonically bonded, soldered, reflow soldered, ultrasonically bonded, etc.) to a corresponding conductive contact of a substrate. The other end of each of resilient contacts remains "free" and is configured to be in electrical communication with an electrical contact/terminal/lead/pad of a packaged integrated circuit device during testing of the packaged integrated circuit device.

[0017] Referring now to Figs. 1A-1B, side and top perspective views of a portion of connector system 100 are shown. Connector system 100 includes substrate 102 (e.g., printed circuit board 102 such as a load board), where substrate 102 includes a plurality of conductive contacts 104 disposed adjacent a surface of substrate 102. Connector system 100 also includes connector assembly 106. Connector assembly 106 includes framework 108 and a plurality of resilient contacts 110 disposed thereon.

[0018] As provided above, connector assembly 106 includes framework 108

(e.g., a polyimide sheet patterned to define apertures therethrough, using, for example, laser ablation). Connector assembly 106 also includes a plurality of resilient contacts 110 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 resilient contacts 110 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 resilient contacts 110) may be removed, for example, using an etchant. After deposition of the material for resilient contacts 110, apertures are formed (e.g., using laser ablation techniques) in the polyimide sheet to define framework 108, after which resilient contacts 110 are processed (e.g., using a mandrel, an automated tool, etc) to have the shape shown in Figs. 1A-1B. More specifically, resilient contacts 110 are shaped such that arms of resilient contacts 110 extend through the apertures defined in framework 108.

[0019] In the exemplary configuration shown in Figs. 1A-1B, each resilient contact 110 includes (a) base portion 110c that is substantially planar with framework 108 (note that base portion 110c is not clearly visible in Figs. 1A-1B, and a representative base portion is more clearly shown in Fig. 5A as element 510c), (b) upwardly extending arm 110a terminating in a contact region (e.g., a tip) configured to contact a contact/pad/terminal/lead of a packaged integrated circuit device to be tested, and (c) downwardly extending arm 110b terminating in a contact region (e.g., a tip) that is mechanically bonded to a respective conductive contact 104 of substrate 102.

[0020] As shown in Figs. 1A-1B, at the interface between downwardly extending arm 110b and a corresponding conductive contact 104 (i.e., the interface where downwardly extending arm 110b is mechanically bonded to a corresponding conductive contact 104), the contact region of each downwardly extending arm 110b is shaped to have flat surface llOf configured to provide a relatively large contact area for desirable mechanically bonding (in comparison to a point contact region). In certain applications, it may also be desirable to provide such a shape to the contact region of upwardly extending arm 110a which is configured to contact the packaged integrated circuit device to be tested. Further, in certain applications, neither of the contact regions will be shaped to have such a flat surface. Thus, it is clear that the contact regions of the arms of the resilient contacts may be shaped as desired in a given application.

[0021] Each of upwardly extending arm 110a and downwardly extending arm

110b defines a slot therethrough. For example, slots 11Od and llOe are illustrated in Fig. IA. Such a slot favorably distributes the stresses in framework 108 caused by loads applied to resilient contacts 110 (e.g., a compressive load applied during testing of a packaged integrated circuit). Additionally, such a slot may be used to divide a signal transmitted through the respective resilient contact. [0022] As with each of the illustrations provided herein, Figs. 1A-1B illustrate a portion of a connector system. The complete connector system will typically include many resilient contacts, and will also typically include (amongst other features) a housing (e.g., a socket) and an alignment mechanism to align a connector assembly with the substrate, and/or an alignment mechanism to align the connector system with a packaged integrated circuit device to be tested.

[0023] Figs. 2A-2B illustrate portion of connector system 200. Connector system 200 includes substrate 202 having conductive contacts 204 disposed adjacent a surface of substrate 202. Connector system 200 also includes connector assembly 206. Connector assembly 206 includes framework 208 and a plurality of resilient contacts 210 supported by framework 208. A downwardly extending arm of resilient contact 210 is mechanically bonded to a corresponding conductive contact 204, and the opposing upwardly extending arm of resilient contact 210 is configured to contact a packaged integrated circuit device during testing thereof.

[0024] The exemplary embodiment of the present invention illustrated in Figs.

2A-2B is very similar to that illustrated and described above with respect to Figs. IA- IB; however, in Figs. 2A-2B, a tip portion of the downwardly extending arm has not been shaped to have a flat surface as with the embodiment illustrated in Figs. 1A-1B.

[0025] Fig. 3 illustrates a portion of another exemplary connector system 300.

Connector system 300 includes substrate 302 having conductive contacts 304 disposed adjacent a surface of substrate 302. Connector system 300 also includes connector assembly 306. Connector assembly 306 includes framework 308 and a plurality of resilient contacts 310 supported by framework 308.

[0026] Each resilient contact 310 includes (a) base portion 310c that is substantially planar with framework 308 (note that base portion 310c is not clearly visible in Fig. 3, and a representative base portion is more clearly shown in Fig. 5A as element 510c), (b) upwardly extending arm 310a terminating in a contact region (e.g., a tip) configured to contact a contact/pad/terminal/lead of a packaged integrated circuit device to be tested, and (c) downwardly extending arm 310b terminating in a contact region (e.g., a tip) that is mechanically bonded to a respective conductive contact 304 of substrate 302. [0027] Upwardly extending arm 310a defines aperture 31Od, and downwardly extending arm 310b defines aperture 31Oe. Such an aperture favorably distributes the stresses in framework 308 caused by loads applied to contacts 310 (e.g., a compressive load applied during testing of a packaged integrated circuit).

[0028] Fig. 4 illustrates a portion of another exemplary connector system 400.

Connector system 400 includes substrate 402 having conductive contacts 404 disposed adjacent a surface of substrate 402. Connector system 400 also includes connector assembly 406. Connector assembly 406 includes framework 408 and a plurality of resilient contacts 410 supported by framework 408.

[0029] Each resilient contact 410 includes (a) base portion 410c that is substantially planar with framework 408 (note that base portion 410c is not clearly visible in Fig. 4, and a representative base portion is more clearly shown in Fig. 5A as element 510c), (b) upwardly extending arms 410a terminating in a contact region (e.g., a tip) configured to contact a contact/pad/terminal/iead of a packaged integrated circuit to be tested, and (c) downwardly extending arms 410b terminating in a contact region (e.g., a tip) that are mechanically bonded to a respective conductive contact 404 of substrate 402.

[0030] Upwardly extending arms 410a are separated by a slot 41Od, and downwardly extending arms 410b are separated by a slot 41Oe. Such slots favorably distribute the stresses in framework 408 caused by loads applied to contacts 410 (e.g., a compressive load applied during testing of a packaged integrated circuit).

[0031] Figs. 5A-5C illustrates a portion of another exemplary connector system

500 engaged with a packaged integrated circuit device 512. Connector system 500 includes substrate 502 having conductive contacts 504 disposed adjacent a surface of substrate 502. Connector system 500 also includes connector assembly 506. Connector assembly 506 includes framework 508 and a plurality of resilient contacts 510 supported by framework 508.

[0032] Each resilient contact 510 includes (a) base portion 510c that is substantially planar with framework 508, (b) upwardly extending arm 510a terminating in a contact region (e.g., a tip) configured to contact contact/pad/terminal/lead 514 of packaged integrated circuit device 512, and (c) downwardly extending arm 510b terminating in a contact region (e.g., a tip) that is mechanically bonded to a respective conductive contact 504 of substrate 502. Note that in the configuration illustrated in Fig. 5A, upwardly extending arm 510a is illustrated as being below base portion 510c (and downwardly extending arm 510b is illustrated as being above base portion 510c). As provided above, the terms "upwardly" and "downwardly" are relative in nature, and may be interchanged depending upon the orientation of a connector assembly.

[0033] Upwardly extending arm 510a defines aperture 51Od, and downwardly extending arm 510b defines aperture 51Oe. Such an aperture favorably distributes the stresses in framework 508 caused by loads applied to contacts 510 (e.g., a compressive load applied during testing of a packaged integrated circuit).

[0034] During the development of the present invention, certain potential issues related to mechanically bonding a resilient contact to a conductive contact/pad of a substrate using solder were observed. For example, because of the temperature applied to the connector assembly during the solder reflow procedure, the framework may realize a decrease in rigidity which may reduce its effective utilization as a contributing factor to the deflection range of the connector assembly. This issue is at least partially related to the materials used as the framework. For example, a polyester laminate having a relatively low operating temperature may realize such a decrease in rigidity. By using materials having a higher operating temperature (e.g., polyimide based materials), such an undesirable decrease in rigidity of the framework may be avoided or at least substantially reduced.

[0035] Further, if a solder reflow process is used to mechanically bond the resilient contacts of a conector assembly to corresponding conductive contacts of a substrate, solder wicking may occur during the reflow process. For example, these problems may occur as a result of too much heat being applied to the framework supporting the resilient contacts, too much flux being utilized, etc. According to the present invention, a modified soldering iron tip may be used for solder reflow. The modified soldering iron tip is smaller than a conventional tip, thereby allowing for a tighter focus of heat. Thus, the area of the connector assembly affected by the heat is reduced.

[0036] According to various exemplary embodiments of the present invention, the vertical deflection of the connector assembly (e.g., the deflection range used in testing a packaged integrated circuit device) may be increased in comparison to conventional connector assemblies. For example, because the resilient contacts of the connector assembly are mechanically bonded to the conductive contacts of the substrate, the compressive force applied does not need to overcome friction therebetween. In conventional connector systems, the contact tips move (e.g., scrub) as the compressive force is applied, thereby resulting in a loss of deflection; however, according to the present invention, the deflection range is increased because of the mechanically bonded connection. Further, the deflection range may be further increased by increasing the applied force, which is also practical because of the mechanically bonded connection.

[0037] According to the present invention, it has been determined that a number of factors may contribute to the failure of the mechanical bonds between the resilient contact of the connector assembly and the conductive contact of the substrate. For example, such factors include: (1) surface differences between the contacts (e.g., plating surface differences such as different gold platings) and/or thickness differences between the contacts, (2) inconsistent flat forming of the resilient contacts at the mechanical bond contact region, and (3) surface roughness of the mechanical bond contact region.

[0038] Regarding the contact surface differences, according to an exemplary embodiment of the present invention, both of the contact surfaces to be mechanically bonded to one another (i.e., the resilient contact surface and the conductive contact surface of the substrate) are plated (or formed) with similar metals. For example, the similar metals are noble metals such as gold. In connection with the present invention, it has been determined that when the contacts surfaces are formed of dissimilar metals (e.g., the resilient contact is plated with a hard gold and the electrical contact of the substrate is plated with a soft or bondable gold) the mechanical bond is not as secure. More specifically, the bondable or soft gold tends to separate or shear from the surface of the hard gold. Because hard gold platings are desirable for applications where the contact "scrubs" against another surface, according to an exemplary embodiment of the present invention, both of the contact surfaces are plated with a similar hard gold material.

[0039] Regarding the inconsistent flat forming factor, it has been determined that if each of the flat surfaces of the resilient contacts (e.g., flat surface llOf illustrated in Fig. IA) are flattened to have a consistent and predictable shape (e.g., by manual manipulation or the like) a more consistent and secure mechanical bond results. [0040] Regarding the surface roughness factor, it has been determined that the smoother the surface of the contact region of the resilient contact, the more secure the resultant mechanical bond.

[0041] Thus, according to the various exemplary embodiments of the present invention disclosed herein, by mechanically bonding a first end of each of the resilient contacts of a connector assembly to a corresponding conductive contact of a substrate, a number of benefits are derived. For example, the vertical deflection of the connector assembly (at the same level of applied force) is increased. Further, the contact resistance across the connector assembly is decreased because of the mechanical bonding of the resilient contacts to the conductive contacts of the substrate.

[0042] As described above, the resilient contacts described herein with respect to the present invention may be plated with a noble metal (e.g., a gold plating, a palladium plating) or a noble metal alloy (e.g., a palladium alloy plating) according to certain exemplary embodiments. Such a plating may be applied after the contacts are formed (e.g., through electroplating, plasma deposition, vapor deposition, etc.), or may be applied during construction of a laminated structure prior to the formation of the contacts.

[0043] According to the present invention, the resilient contacts of the connector assembly may be mechanically bonded to the conductive contacts of the substrate at a number of points in time during the manufacturing/assembly process. For example, the resilient contacts may be mechanically bonded after the resilient contacts of the connector assembly have been shaped.

[0044] Alternatively, the resilient contacts may be mechanically bonded before

(or contemporaneous with) shaping of the resilient contacts of the connector assembly, whereby it may be desirable to mechanically bond the resilient contacts in conjunction with the shaping operation.

[0045] Although the present invention has been described primarily with respect to providing interconnection between components (e.g., a packaged integrated circuit and a substrate) for testing packaged integrated circuits, it is not limited thereto. Rather, the present invention is applicable to any of a number of applications which desire an electrical connector assembly with increased deflection and decreased contact resistance. [0046] Although the present invention has been described primarily with respect to certain mechanically bonding techniques (e.g., thermosonic bonding, soldering, ultrasonic bonding, etc.), it is not limited thereto. Any of a number of mechanical bonding techniques may be used, for example, bonding using an electrical adhesive or electrically conductive epoxy.

[0047] Although the invention is illustrated and described herein with reference to specific embodiments, the invention is not intended to be limited to the details shown. 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 testing system and a packaged integrated circuit device, the connector system comprising:

a substrate having a plurality of conductive contacts disposed adjacent a surface thereof, the substrate being configured to be engaged with the testing system; and

a connector assembly, the connector assembly including: (a) a framework, and (b) a plurality of resilient contacts supported by the framework and configured to provide electrical interconnection between the packaged integrated circuit device and the conductive contacts of the substrate,

each of the resilient contacts including (1) a first arm including a first contact region mechanically bonded to at least one of the conductive contacts of the substrate, and (2) a second arm including a second contact region configured to be in electrical contact with at least one electrical contact of the packaged integrated circuit device during testing thereof.

2. The connector system of claim 1 wherein a mechanical bond between the first contact region and a corresponding conductive contact of the substrate includes solder.

3. The connector system of claim 1 wherein a mechanical bond between the first contact region and a corresponding conductive contact of the substrate includes a thermosonic bond.

4. The connector system of claim 1 wherein a mechanical bond between the first contact region and a corresponding conductive contact of the substrate includes a ultrasonic bond.

5. The connector system of claim 1 wherein at least one of the first arm or the second arm of each of the plurality of resilient contacts defines a slot extending therethrough.

6. The connector system of claim 1 wherein at least one of the first arm or the second arm of each of the plurality of resilient contacts defines an aperture extending therethrough.

7. The connector system of claim 1 wherein the first contact region of each of the plurality of resilient contacts is substantially flat.

8. The connector system of claim 1 wherein the first contact region of each of the plurality of resilient contacts and a corresponding contact surface of each of the conductive contacts of the substrate are plated with a plating including a noble metal.

9. The connector system of claim 8 wherein said noble metal is gold.

10. The connector system of claim 1 wherein the first contact region of each of the plurality of resilient contacts and a corresponding contact surface of each of the conductive contacts of the substrate are plated with a substantially similar noble metal.

11. The connector system of claim 1 wherein the framework and the plurality of resilient contacts are formed from a unitary laminated structure.

12. The connector system of claim 1 wherein the framework comprises polyimide.

13. The connector system of claim 1 wherein each of the resilient contacts includes a base portion between the first arm and the second arm, the base portion being substantially planar with the framework.

14. The connector system of claim 1 wherein at least one of the plurality of resilient contacts comprises a nickel alloy.

15. The connector system of claim 1 wherein at least one of the plurality of resilient contacts comprises NiMn.

16. The connector system of claim 1 wherein the framework is configured to flex during compression of the connector assembly, thereby providing contact force between the connector system and the electrical contacts of the packaged integrated circuit device.

17. A method of assembling a connector system, the method comprising the steps of:

selectively depositing a conductive material on an insulative sheet such that the conductive material is planar with the insulative sheet;

shaping the conductive material to define a plurality of resilient contacts supported by the insulative sheet such that each of the resilient contacts includes a first arm extending above the insulative sheet and a second arm extending below the insulative sheet; and

mechanically bonding a contact region of each of the first arms to a corresponding conductive contact of a substrate.

18. The method of claim 17 wherein the mechanically bonding step includes thermosonically bonding the contact region of each of the first arms to the corresponding conductive contact of the substrate.

19. The method of claim 17 wherein the mechanically bonding step includes ultrasonically bonding the contact region of each of the first arms to the corresponding conductive contact of the substrate.

20. The method of claim 17 wherein the mechanically bonding step includes soldering the contact region of each of the first arms to the corresponding conductive contact of the substrate.