WO2001009980A2

WO2001009980A2 - Controlled compliance fine pitch interconnect

Info

Publication number: WO2001009980A2
Application number: PCT/US2000/020748
Authority: WO
Inventors: James J. Rathburn
Original assignee: Gryphics, Inc.
Priority date: 1999-08-02
Filing date: 2000-07-31
Publication date: 2001-02-08
Also published as: WO2001009980A3; EP1204988A2; AU6750900A; JP2003506833A

Abstract

A method and apparatus for achieving a very fine pitch interconnect between a flexible circuit member and another circuit member with extremely co-planar electrical contacts that have a large range of compliance. An electrical interconnect assembly that can be used as a die-level test probe, a wafer probe, and a printed circuit probe is also disclosed. The second circuit member can be a printed circuit board, another flexible circuit, a bare-die device, an integrated circuit device, an organic or inorganic substrate, a rigid circuit and virtually any other type of electrical component. A plurality of electrical contacts are arranged in a housing. The electrical contacts may be arranged randomly or in a one or two-dimensional array. The housing acts as a receptacle to individually locate and generally align the electrical contacts, while preventing adjacent contacts from touching. The first ends of the electrical contacts are electrically coupled to a flexible circuit member. The electrical contacts are free to move along a central axis within the housing. The second ends of the electrical contacts are free to electrically couple with one or more second circuit members without the use of solder.

Description

CONTROLLED COMPLIANCE FINE PITCH INTERCONNECT

Field of the Invention

The present invention is directed to a method and apparatus for achieving a very fine pitch, solderless interconnect between a flexible circuit member and another circuit member, and to an electπcal interconnect assembly for forming a solderless interconnection with another circuit member.

Background of the Invention It is desirable to probe test each die or device under test (DUT) before the wafer is cut into individual integrated circuit die or before packaging. Die testing often needs to be performed at high speed or high frequency, for example 100 MHz data rate or higher. The probe cards that support a plurality of probe needles must provide reliable electπcal contact with the bonding pads of the DUT. The shank of the probe needle is typically 0.005 inches to 0.010 inches in diameter. One test probe technique is known as the Cobra system, m which the upper ends of the probe needles are guided through a πgid layer of an insulating mateπal. The upper ends of the individual probe needles are electπcally connected to suitable conductors of an interface assembly that is connected to an electπcal test system. Each of the needles is curved and the lower ends pass through a corresponding clearance hole m a lower πgid layer or template of insulating mateπal. The bottom ends of the needles contact the bonding pads on the wafer being tested. The length of the probe needles can result in undesirable levels of ground noise and power supply noise to the DUT Additionally, the epoxy or plastic πgid layers have large coefficients of thermal expansion and cause errors in the positioning of the needle probes. Another draw-back of current test probe technology is that it can often not accommodate fine pitches. For example, wafer probes typically require a target contact area of about 70 micrometers by 70 micrometers Flip- chip architecture has terminals on the order of 10 micrometers by 10 micrometers, and hence, can not effectively be tested using wafer probe technology. Consequently, integrated circuits in flip-chip architectures can generally be tested only after packaging is completed. The inability to wafer probe integrated circuits used in flip-chip architecture results m production time delays, poor yields and a resultant higher cost. Many of the problems encountered m testing electπcal devices also occur m connecting integrated circuit devices to larger circuit assemblies, such as pπnted circuit boards or multi-chip modules. The current trend in connector design for those connectors utilized m the computer field is to provide both high density and high reliability connectors between vaπous circuit devices. High reliability for such connections is essential due to potential system failure caused by misconnection of devices. Further, to assure effective repair, upgrade, testing and/or replacement of vaπous components, such as connectors, cards, chips, boards, and modules, it is highly desirable that such connections be separable and reconnectable in the final product. Pm-type connectors soldered into plated through holes or vias are among the most commonly used in the industry today. Pins on the connector body are inserted through plated holes or vias on a pπnted circuit board and soldered m place using conventional means. Another connector or a packaged semiconductor device is then inserted and retained by the connector body by mechanical interference or friction. The tm lead alloy solder and associated chemicals used throughout the process of soldering these connectors to the pπnted circuit board have come under increased scrutiny due to their environmental impact Additionally, the plastic housings of these connectors undergo a significant amount of thermal activity duπng the soldeπng process, which stresses the component and threatens reliability The soldered contacts on the connector body are typically the means of supporting the device being interfaced by the connector and are subject to fatigue, stress deformation, solder bπdgmg, and co-planaπty errors, potentially causing premature failure or loss of continuity. In particular, as the mating connector or semiconductor device is inserted and removed from the present connector, the elastic limit on the contacts soldered to the circuit board may be exceeded causing a loss of continuity. These connectors are typically not reliable for more than a few insertions and removals of devices. These devices also have a relatively long electπcal length that can degrade system performance, especially for high frequency or low power components. The pitch or separation between adjacent device leads that can be produced using these connectors is also limited due to the πsk of shorting.

Another electπcal interconnection method is known as wire bonding, which involves the mechanical or thermal compression of a soft metal wire, such as gold, from one circuit to another. Such bonding, however, does not lend itself readily to high-density connections because of possible wire breakage and accompanying mechanical difficulties m wire handling.

An alternate electπcal interconnection technique involves placement of solder balls or the like between respective circuit elements. The solder is reflown to form the electπcal interconnection. While this technique has proven successful in providing high-density interconnections for vaπous structures, this technique does not facilitate separation and subsequent reconnection of the circuit members.

An elastomer having a plurality of conductive paths has also been used as an interconnection device. The conductive elements embedded in the elastomeπc sheet provide an electπcal connection between two opposing terminals brought into contact with the elastomeπc sheet. The elastomeπc mateπal must be compressed to achieve and maintain an electπcal connection, requiπng a relatively high force per contact to achieve adequate electπcal connection, exacerbating non-planaπty between mating surfaces. Location of the conductive elements is generally not controllable. Elastomeπc connectors may also exhibit a relatively high electπcal resistance through the interconnection between the associated circuit elements The interconnection with the circuit elements can be sensitive to dust, debπs, oxidation, temperature fluctuations, vibration, and other environmental elements that may adversely affect the connection.

The problems associated with connector design are multiplied when multiple integrated circuit devices are packaged together m functional groups. The traditional way is to solder the components to a pπnted circuit board, flex circuit, or ceramic substrate in either a bare die silicon integrated circuit form or packaged form. Multi-chip modules, ball gπds, array packaging, and chip scale packaging have evolved to allow multiple integrated circuit devices to be interconnected in a group.

One of the major issues regarding these technologies is the difficulty m soldeπng the components, while ensuπng that reject conditions do not exist. Many of these devices rely on balls of solder attached to the underside of the integrated circuit device which is then reflown to connect with surface mount pads of the pπnted circuit board, flex circuit, or ceramic substrate. In some circumstances, these joints are generally not very reliable or easy to inspect for defects. The process to remove and repair a damaged or defective device is costly and many times results in unusable electronic components and damage to other components in the functional group.

Multi-chip modules have had slow acceptance in the industry due to the lack of large scale known good die for integrated circuits that have been tested and burned-m at the silicon level. These dies are then mounted to a substrate which interconnect several components. As the number of devices increases, the probability of failure increases dramatically With the chance of one device failing m some way and effective means of repaiπng or replacing currently unavailable, yield rates have been low and the manufactuπng costs high Bπef Summary of the Invention The present invention is directed to a method and apparatus for achieving a very fine pitch interconnect between a flexible circuit member and another circuit member with extremely co-planar electπcal contacts that have a large range of compliance. The second circuit member can be a pπnted circuit board, another flexible circuit, a bare-die device, an integrated circuit device, an organic or inorganic substrate, a πgid circuit and virtually any other type of electncal component. The present invention is also directed to an electπcal interconnect assembly compnsmg a flexible circuit member electπcally coupled to an electπcal connector m accordance with the present invention. The present electπcal interconnect assembly can be used as a die-level test probe, a wafer probe, a pπnted circuit probe, a connector for a packaged or unpackaged circuit device, a conventional connector, a semiconductor socket, and the like.

The present method includes prepaπng a plurality of through holes extending between a first surface and a second surface of a housing. Each of the through holes defines a central axis. A plurality of elongated electπcal contacts are positioned in at least some of the through holes and oπented along the central axis. The electπcal contacts have first ends that extend beyond the first surface. The electπcal contacts are retained in the through holes by a vaπety of techniques. The first ends of the electπcal contacts are electπcally coupled to contact pads or terminals on a flexible circuit so that the second ends of the electπcal contacts extend beyond the second surface. The second ends of the electπcal contacts are then free to electπcally couple with a second circuit member. A resilient member controls movement of the electπcal contacts along their respective central axes withm the housing.

The step of retaining the electπcal contacts in the through holes can be achieved by interposing a compliant encapsulating mateπal between a portion of the through holes and a portion of the electπcal contacts, surrounding a portion of the electπcal contacts with an encapsulating mateπal along one of the surfaces of the housing, bonding the first end of the electncal contacts to the terminals on the flexible circuit, and/or positioning a compliant mateπal along a surface of the flexible circuit opposite the terminals. A back-up member may optionally be positioned behind the compliant mateπal. In one embodiment, the compliant encapsulant elastically bonds the electπcal contacts to the housing.

In one embodiment, the step of positioning the plurality of electπcal contacts includes applying a solder mask mateπal or comparable dissolvable/removable mateπal along the first surface. The solder mask mateπal and a portion of the electπcal contacts extending above the first surface are planaπzed. When the solder mask is removed, the electπcal contacts have precisely formed end surfaces that extends above the first surface of the housing. The resilient member can optionally be applied to the electncal contacts either before application of the solder mask or after removal of the solder mask.

The ends of the electπcal contacts can be modified by a vaπety of techniques, such as etching, gπnding, abrasion, ablation or the like. The ends of the electπcal contacts can also be modified to have a shape that facilitates engagement with vaπous structures on the flexible circuit member or the second circuit member. The second ends of the electπcal contacts can be configured to engage with another flexible circuit, a πbbon connector, a cable, a pπnted circuit board, a bare die device, a ball gπd array, a land gπd array, a plastic leaded chip earner, a pm gπd array, a small outline integrated circuit, a dual in-line package, a quad flat package, a flip chip, a leadless chip earner, and a chip scale package

The first ends of the electncal contacts are electπcally coupled to the flexible circuit bonding pads using a vaπety of techniques, such as a compressive force, solder, wedge bonding, conductive adhesives, solder paste, ultrasonic bonding, wire bonding, or a combination thereof In one embodiment, the flexible circuit is bonded to the first surface of the housing with an adhesive.

The electncal connector in accordance with the present invention includes a housing with a plurality of through holes extending between a first surface and a second surface. A plurality of elongated electncal contacts are positioned m the through holes and onented along the central axis. The first ends of the electπcal contacts are electπcally coupled to the terminals on the flexible circuit. The second ends extend beyond the second surface of the housing to couple electπcally with the second circuit member. A resilient member controls movement of the electncal contacts along their respective central axes. The resilient member can be an encapsulating mateπal interposed between a portion of the through hole and a portion of the electπcal contacts, an encapsulating mateπal surrounding a portion of the electπcal contacts along one of the surfaces of the housing, the flexible circuit bonded to the contacts, a smgulated terminal on the flexible circuit, and/or a compliant mateπal positioned along a surface of the flexible circuit opposite the terminals.

The electncal contacts can be a multi-layered construction or a homogenous mateπal. The electπcal contacts may have a cross-sectional shape of circular, oval, polygonal, or rectangular. The electπcal contacts can have a pitch of less than about 0.4 millimeters and preferably a pitch of less than about 0.2 millimeters.

The present invention is also directed to an electπcal interconnect assembly compnsing a flexible circuit bonded to the first ends of the electπcal contacts m the housing. A resilient member controls movement of the electπcal contacts along their respective axes. The second ends of the electπcal contacts are free to engage with a vaπety of second circuit members, or to operate as test probes for testing vaπous electπcal components Bnef Descπption of the Drawings Figure 1 is a side sectional view of an electncal interconnect m accordance with the present invention.

Figure 1 A is a side sectional view of an alternate electncal interconnect in accordance with the present invention.

Figure IB is a side sectional view of another alternate electncal interconnect m accordance with the present invention.

Figure 2 is a side sectional view of a method of modifying the electπcal interconnect of Figure 1. Figure 3 is a side sectional view of a method of modifying the electπcal interconnect of Figure 2.

Figure 4 is a side sectional view of an electπcal contact modified in accordance with the method of the present invention.

Figure 5 is a side sectional view of an electncal contact modified m accordance with an alternate method of the present invention.

Figure 6 is a side sectional view of an electncal contact bonded to a flexible circuit in accordance with the present invention.

Figure 7 is a side sectional view of an alternate method of bonding the flexible circuit to the electπcal contact in accordance with the present invention.

Figure 8 is a side sectional view of an alternate method of bonding the flexible circuit to the electncal contact in accordance with the present invention.

Figure 9 is a side sectional view of an electncal interconnect bonded to a flexible circuit in accordance with the present invention.

Figure 9A is a side sectional view of an alternate electπcal interconnect bonded to a flexible circuit m accordance with the present invention

Figure 10 is a perspective view of an flexible circuit member in accordance with the present invention Figure 1 1 is a side sectional view of a smgulated flexible circuit in accordance with the present invention.

Figure 1 1 A is a non- smgulated flexible circuit in accordance with the present invention. Figure 12 is side sectional view of an alternate electncal interconnect bonded to a flexible circuit member m accordance with the present invention.

Figure 13 is a side sectional view of a flexible circuit bonded to an electncal interconnect in accordance with the present invention. Figure 14 is a side sectional view of the electncal interconnect of

Figure 13 m an engaged state.

Figure 15 is a side sectional view of an alternate electπcal interconnect bonded to a smgulated flexible circuit in accordance with the present invention. Figure 15 A is side sectional view of an alternate electπcal interconnect in which the flexible circuit and encapsulating mateπal are smgulated m accordance with the present invention.

Figure 16 is a side sectional view of an electπcal interconnect assembly in accordance with the present invention engaged with a second circuit member.

Figure 17 is a side sectional schematic illustration of an electπcal interconnect assembly m which both surfaces of the flex circuit member are used for forming electπcal connections.

Figure 18 is a side sectional view of two electπcal interconnects in accordance with the present invention m a stacked configuration.

Figure 19 is a replaceable chip module coupled to a flexible circuit member using the controlled compliance interconnect of the present invention. Figure 20 is a pair of replaceable chip modules m a stacked configuration coupled by a flexible circuit member using the controlled compliance interconnect of the present invention.

Figure 21 is a side sectional view of an electπcal interconnect bonded to a two-sided flexible circuit m accordance with the present invention.

Figure 22 is a side sectional view of an electncal interconnect assembly m accordance with the present invention.

Figure 23 is a perspective view of an electncal interconnect coupled to a display in accordance with the present invention. Figure 24 is a schematic illustration of an electπcal interconnect used as a test probe in accordance with the present invention.

Figure 25 is a perspective view of electπcal interconnect used as a test probe for wafer level devices in accordance with the present invention.

Figure 26 is a side sectional view of a two-sided electncal interconnect m accordance with the present invention

Figure 27A is a side sectional view of an electncal interconnect assembly m a disengaged configuration in accordance with the present invention.

Figure 27B is a side sectional view of the electncal interconnect assembly of Figure 27A m an engaged configuration m accordance with the present invention.

Figure 28A is a side sectional view of an alternate electπcal interconnect assembly in a disengaged configuration in accordance with the present invention Figure 28B is a side sectional view of the electπcal interconnect assembly of Figure 28B in an engaged configuration in accordance with the present invention Detailed Descnption of the Invention Figure 1 is a side sectional view illustrating a step m the method of making an electπcal interconnect 30 m accordance with the present invention. Housing 32 has a plurality of through holes 34 that extend from a first surface 36 to a second surface 38. Each of the holes 34 defines a central axis 40. Housing or mterposer 32 may be constructed from a dielectπc matenal, such as plastic, ceramic, metal with a non-conductive coating. The holes can be formed by a vaπety of techniques, such as molding, laser dπlhng, or mechanical dπllmg. The holes 34 can be arranged m a vaπety of configuration, including one or two-dimensional arrays. The housing 32 may optionally include a tooling hole 42 to facilitate handling and alignment with other components.

A plurality of ngid or semi-πgid electncal contacts 44 are positioned in some or all of the holes 34. The electncal contacts 44 may be positioned in the holes 34 by a vaπety of techniques, such as manual assembly, vibratory assembly, or robotic assembly. In the illustrated embodiment, the electncal contacts 44 are maintained in their desired location by a height fixture 46. Upper ends 62 of the electncal contacts 44 may exhibit height differences based upon the manufactuπng tolerances and constancy of the manufactunng process.

The electncal contacts may be a vanety of mateπals, such as wire, rod, formed stπps, or turned or machined members. The electncal contacts can have a cross-sectional shape that is circular, oval, polygonal, or the like. The electncal contacts can be made from a vaπety of mateπals, such as gold, copper, copper alloy, palanae, or nickel. The electncal contacts 44 are typically cut or formed into a general length, which reduces cost and handling difficulties. The electπcal contacts are modified duπng subsequent processing steps to achieve the necessary precision, such as planaπty and tip shape In order to achieve a fine pitch without shorting, the electrical contact must typically be straight to withm about 0.25 millimeters and be πgid or semi-πgid in construction. The electncal contacts 44, however, may have a different cross section at vanous locations along their entire length (see Figure 1 A). In the embodiment illustrated in Figure 1 , a compliant encapsulating matenal 50 is applied to the first surface 36. The compliant encapsulating matenal 50 surrounds the electncal contacts 44 and bonds to the first surface 36. In the illustrated embodiment, the complaint encapsulating mateπal penetrates at least part way into the holes 34. In an alternate embodiment, the encapsulating mateπal 50 remains generally on the surface 36. The compliant encapsulating matenal 50 permits the electπcal contacts 44 to move elastically along the central axis 40, while retaining them in the housing 32. Suitable compliant encapsulating matenals include Sylgard® available from Dow Corning Sihcone of Midland, Michigan, and MasterSyl 713, available from Master Bond Sihcone of Hackensack, New Jersey.

Figure 2 illustrates another step in the method of forming the electπcal interconnect 30 m accordance with the present invention. The first surface 36 and/or the second surface 38 are flooded with one or more retention mateπals 60 that will assist in the further processing steps. The retention mateπal 60 can be a compliant encapsulant or a mateπal that cures solid, such as a solder mask. Once the retention mateπal 60 has cured, the electncal contacts 44 are ngidly held to the housing 32 so that the fixture 46 can be removed. The mateπal retention 60 can optionally be applied to the second surface 38. In an alternate embodiment, the compliant encapsulatmg mateπal 50 is omitted and the retention matenal 60 is applied directly to the first surface 36 Figure 3 is a side sectional view showing a subsequent step in the processing of the electπcal interconnect 30 in accordance with the present invention The retention mateπal 60 retains the electπcal contacts 44 m the housing 32 so that ends 62, 64 can be processed without flexural displacement or damage The assembly is subjected to a precision gnnding operation, which results in very flat ends 62, 64 on the electπcal contacts 44. typically withm about 0.0005 inches. The gnndmg operation can be performed on both sides at the same time using a lapping or double grinding process. In an alternate embodiment, only one surface 36, 38 of the electπcal interconnect 30 is subject to the planaπzation operation. The retention matenal 60 is then dissolved from the electncal interconnect 30 to expose the first and second ends 62, 64, of the electncal contacts 44 (see Figure 9). In an alternate embodiment, the first and/or second ends 62, 64 of the electncal contacts are subject to further processing pnor to removal of the mateπal 60.

Figure 1 A illustrates an alternate embodiment method of making an electπcal interconnect 30' in accordance with the present invention. Upper ends 62' of the electπcal contacts 44' have a cross sectional portion 61' that is larger than the cross sectional area of the holes 34' that engages with the first surface 36'. Consequently, the electπcal contacts 44' are always onented m the same direction in the housing 32', even when positioned using automated processes such as vibratory assembly. The cross sectional portion 61' also makes the fixture 46 of Figure 1 unnecessary. The electncal interconnect 30' may subsequently processed as discussed herein, such as application of a compliant encapsulating matenal 50'. Alternatively, the upper ends 62' can be deformed dunng a subsequent processing step. Figure IB illustrates another alternate embodiment method of making an electncal interconnect 30" in accordance with the present invention. In the illustrated embodiment the electπcal contacts 44" are generally of the same length. Fixture 46" has support surfaces at vanous levels relative to second surface 38" of housing 32". Consequently, the electπcal contacts 44" are maintained m the holes 34" in a step configuration. The electπcal interconnect 30" may be subsequently processed as discussed herein, such as application of a compliant encapsulatmg mateπal 50" In one embodiment, a retention mateπal 60 (see Figure 2) is applied to the first surface 36". The ends 62" of the electπcal contacts 44" are plananzed, such as is illustrated in Figure 3. The ends 64" extending beyond the surface 38", however, are not plananzed and retain the step configuration.

Depending on the mateπal of the electπcal contacts 44 and the desired function, the planar ends 62, 64 may exhibit different properties. If the electπcal contacts are made of a copper base metal or alloy and plated with a barner layer and a gold layer, the gnndmg process will remove the nickel and gold from the tips, exposing base metal that will oxidize. If the electπcal contact 44 is a matenal such as gold or palanae, corrosion is minimized. The ends 62, 64 can be tailored for specific applications, such that the first end 62 may have a different structure or shape than the second end 64.

Depending on the type of terminal the electncal contact 44 is intended to interface with, it may be desirable to abrasively process the tips such that the ends 62, 64 are still essentially planar but have a surface which is more irregular than that left by the gnnding process. This abrasive processing can also be of a cleaning nature to remove any oxides formed between process steps. Figure 4 illustrates one embodiment of an ends 62, 64 of an electπcal contact 44 that has been subject to an abrasive blast operation to provide a correspondingly rough surface.

Figure 5 illustrates an alternate ends 62, 64 of an electncal contact 44 that has been subject to an etching process. In the illustrated embodiment, the electncal contact 44 is constructed from a copper alloy core 70, an intermediate nickel layer 72 and an outer gold layer 74. When subjected to an etching solution, only the copper alloy 70 is removed. In the illustrated embodiment, the ends 62, 64 has a generally concave tip shape, where the outer walls 72, 74 extend beyond the post-processed base metal 70 The ends 62, 64 can then be processed to deposit another barner to prevent contamination by oxides, such as a gold layer (see Figure 6). In some instances, it may be acceptable to leave the base metal 70 untreated.

The generally concave shape of the ends 62, 64 can provide several desired functional properties, such as contacting a solder, gold, or other deposits m a generally mating fashion, without excessively deforming the deposits. Additionally, the protruding outer wall 72, 74 provides a slight wiping action duπng mating with the coπespondmg component. The outer walls 72, 74 form a tubular structure that increases the pressure per unit area when compressively engaged with a mating electπcal circuit member. Finally, the concave shape of the ends 62, 64 provides a reservoir for contamination on the terminal of the mating circuit member, while the relatively hard outer layer 72, 74 minimize deformation of the tip 62, 64. The etching process may be performed either before or after removal of the matenal 60. Figure 6 is a side sectional view of a flexible circuit member 80 being bonded to a electncal contact 82 in accordance with the present invention. The electncal contact 82 includes a barner layer 84 along the ends 62, 64. In the illustrated embodiment, the terminals 86 on the flexible circuit member 80 include a ball structure 88 having a shape corresponding to the ends 62, 64 of the electncal contact 82. The ball structure 88 can be constructed from gold, solder, or a conductive adhesive. The ball structure 88 is aligned to each corresponding electncal contact ends 62, 64 and ultrasomcally bonded. Alternatively, the ball structure 88 can be a solder ball or deposit, which can then be reflown to attach each electncal contact member 82. Several lso-tropic and amsotropic conductive adhesives are available to achieve similar results. In another embodiment, the ball structure 88 can be electrically coupled to the ends 62, 64 by a compressive force.

Figure 7 is a side sectional view of an alternate electncal contact 90 m accordance with the present invention. A barner layer 92, such as gold, is deposited on the generally planar ends 62, 64 of the electπcal contact 90. The ball structure 88 of the flexible circuit member 80 is then bonded to the barner layer 92. Figure 8 is a side sectional view of a high density, flexible circuit member 100 being bonded to the electncal contact 90 using a wire bonding technique. Figure 9 is a side sectional view of an electπcal interconnect 110 electπcally coupled to bonding pads 113 on a flexible circuit member 1 12 m accordance with the present invention. In the illustrated embodiment, the resilient encapsulating mateπal 114 retains the electπcal contacts 116 withm the housing 118, but permits movement along the central axes. The first ends 120 of the electπcal contacts 116 may be electncally coupled with the flexible circuit 112 using a vanety of techniques discussed herein, such as applying a compressive force, solder, wedge bonding, conductive adhesives, ultrasonic bonding and wire bonding. The second ends 122 of the electπcal contacts 116 extend beyond the second surface 124 of the housing 118 to couple electncally with a second circuit member (see Figure 16).

Figure 9A illustrates an alternate embodiment of an electncal interconnect 110' electncally coupled a flexible circuit member 112' in accordance with the present invention. The flexible circuit member 112' has a senes of pass through openings. The flexible circuit member 112' is aligned to the electncal contacts 116' such that the pass though openings are located directly on each electncal contact end 120' m the array. A gold ball bonder can then be used to bond the flexible circuit member 112' to the ends 120' of the electncal contacts 116', where the gold balls 115' extend to an exposed conductive layer in the flexible circuit member 112'.

Once the flexible circuit member 112 is attached, several options can be employed to increase the function of the electncal interconnect 110. These features, discussed in detail below, provide a relatively large range of compliance of the electncal contacts 116, complimented by the extreme co- planaπty of the electπcal contact ends 122. The nature of the flexible circuit 112 allows fine pitch interconnect and signal escape routing, but also inherently provides a mechanism for compliance. One option is to allow the flexing nature of the flexible circuit member 112 to provide compliance as the lower ends 122 are compressed The semi-πgid or πgid nature of the electπcal contacts 116 will transmit the incident force to the flexible circuit member 112 and cause flexure at the area around the bond sites 113 The flexible circuit member 112 can be left separate from the housing 118 to allow a free range of movement or the flexible circuit 1 12 can be selectively bonded to the housing 118 to restnct movement if desired. Figure 10 is a perspective view of a flexible circuit member 140 m accordance with the present invention. The flexible circuit member 140 includes a senes of electncal traces 142 deposited on a polymenc sheet 144 and terminating at a plurality of terminals or terminals 146. As used herein terminal refers to an electncal contact location or contact pad. In the illustrated embodiment, the terminals 146 include a singulation 148. Singulation refers to a partial separation of the terminal from the sheet that does not disrupt the electπcal integπty of the conductive trace. The partial separation can be a perforation in the polymenc sheet 144. Alternatively, singulation may include a thinning or point of weakness of the sheet matenal along the edge of, or directly behind, the terminal. In the illustrated embodiment, smgulating the flexible circuit member 140 near or around the terminals 146 releases or separates the terminal from the sheeting 144, while maintaining the interconnecting circuit traces 142. The singulations can be formed at the time of manufacture or the sheeting 144 can be subsequently patterned by stamping, cutting or a vanety of other techniques. In one embodiment, a laser system, such as Excimer, CO2, or YAG, creates the singulation 148. This structure is advantageous in several ways, where the force of movement is greatly reduced since the flexible circuit member 140 is no longer a continuous membrane, but a senes of flaps or bond sites with a living hmge and bonded contact In the illustrated embodiment, the singulation 148 is a slit surrounding a portion of the terminal 146 The slit may be located adjacent to the peπmeter of the terminal 146 or offset therefrom The singulation 148 may be formed to serve as the resilient member for controlling movement of the electπcal contacts along their respective central axes The smgulated terminal 146 can be left free from the housing or it can be selectively bonded such that the hinged portion is allowed to move freely withm a given range The smgulated flexible circuit member 140 can also be encapsulated or mated with a compliant sheet to control the amount of force, the range of motion, or assist with creating a more evenly distnbuted force vs deflection profile across the array (see Figure 11)

Figure 11 is a side sectional view of an electncal contact 150 electncally coupled to a flexible circuit member 152. The terminal 154 of the flexible circuit member 152 has been smgulated at a location 156. A compliant encapsulatmg mateπal 158 has been deposited on the surface of the flexible circuit member 152 opposite the electπcal contact 150. Alternatively, the flexible circuit member 152 can be mated with a compliant sheet of mateπal to provide controlled force and compliance. The additional layer of compliant encapsulant or sheeting can also be precision ground to provide uniform thickness and compliance across the array. In the illustrated embodiment, movement of the electπcal contact 150 along the central axis 162 is controlled by the compliant encapsulant 166 deposited around the electncal contact 150, the resiliency of the flexible circuit member 152, and the resiliency of the compliant encapsulant 158. These components are engineered to provide a desired level of compliance to the electncal contact 150 withm the housing 166. In the illustrated embodiment, a portion of the compliant encapsulating matenal 160 has seeped through the singulation 156 The liquid nature of the uncured encapsulant can be taken advantage of by applying or injecting it into the singulation gap 157 under a slight vacuum condition in the region 159 between the flexible circuit member 152 and the encapsulant 166 The matenal 158 is drawn into the singulation gap 157 The encapsulated gap 157 supports and controls the motion of the terminal 154 This control can minimize the flexural stress and fatigue of the smgulated terminal 154. increasing mechanical performance and life In an alternate embodiment, the compliant sheet or encapsulant 158 can be applied pnor to singulation of the flexible circuit member 152, such that the living hmge mechanism is a laminate or composite of the compliant encapsulant 158 and the flexible circuit member 152.

Figure 11A is a side sectional view of an electπcal contact 150A electπcally coupled to a flexible circuit member 152 A, without singulation of the terminals 154A. A vacuum is applied m the region 159A between the flexible circuit member 152A and the encapsulant 166A pnor to applying the complaint encapsulating mateπal 168A. The vacuum draws the flexible circuit member 152A down at the bond sites 154A and forms a dimple 155 A over the first end 157A of the electπcal contact 150A. Application of the complaint encapsulant 168A fills the dimples 155A, and when the vacuum is removed, the flexible circuit member 152 A will have a different shape and a preload caused by the mateπal 168A in the dimple 155 A biasing the electπcal contact 150A downward. A layer of compliant mateπal 158A may optionally be applied to the outer surface of the flexible circuit member 152 A. Figure 12 is a side sectional view of an alternate electπcal interconnect 170 in accordance with the present invention. The electπcal contacts 172 have been prepared using the techniques discussed above, but no compliant encapsulating mateπal was applied. Height fixture 174 retains the electncal contacts 172 at the desired position withm the housing 176. A flexible circuit member 178 is bonded to the first ends 180 of the electπcal contacts 172, using any of the techniques discussed above. Once the electncal contacts 172 are bonded to the flexible circuit member 178, the fixture 174 can be removed. The electncal contacts 172 are then suspended withm the housing 176 by the flexible circuit member 178. Compliance is provided by the resiliency of the flexible circuit member 178. In one embodiment, the flexible circuit member is bonded to the housing 176. Other compliant members may optionally be added to the electncal interconnect 170.

Figure 13 is a side sectional view showing one embodiment of an electncal interconnect 190 m an disengaged configuration The flexible circuit member 192 is bonded to the electπcal contact 194 as discussed herein. No encapsulating mateπal is provided between the electncal contact 194 and housing 196. The electπcal contact is suspended in the housing 196 by the flexible circuit member 192. The flexible circuit member 192 is optionally bonded to housing 196 with an adhesive layer 202. The flexible circuit member 192 is optionally smgulated at the location 198 to provide a flexure point 200. Figure 14 is a side sectional view of the electπcal interconnect 190 of Figure 13 in an engaged configuration. The electπcal contact 194 has been displaced in the direction 204, causing the flexible circuit member 192 to flex at the flexure point 200. In the embodiment illustrated in Figures 13 and 14, the sole resilient member is the flexible circuit 192. In alternate embodiments, a compliant encapsulating mateπal may be positioned along the rear surface 206 of the flexible circuit member 192 (see Figures 11A, 1 IB and 15).

Figure 15 is a side sectional view of an electncal interconnect 210 m which the resiliency of a smgulated, flexible circuit member 192 is supplemented by a compliant encapsulatmg mateπal 212 positioned along the rear surface 214 of the flexible circuit 192 and a compliant encapsulating mateπal 222 deposited between the flexible circuit 192 and the housing 196. The compliant encapsulating matenal 212 may be deposited as a liquid or positioned in sheet form, as discussed above. An adhesive layer 216 may optionally be provided for retaining the flexible circuit member 192 to the housing 196.

Figure 15 A is a side sectional view of an electπcal interconnect 210A in which both the flexible circuit member 192 A and the compliant encapsulating matenal 212A are smgulated at a location 218A. The compliant encapsulating mateπal 212A may be deposited in liquid form or positioned as a sheet form, as discussed above. An adhesive layer 216A may optionally be provided for retaining the flexible circuit member 192 A to the housing 196A The flexible circuit member 192A may be smgulated prior to application of the encapsulating matenal 212A, or simultaneously therewith. A back-up member 220A may optionally be located behind the compliant matenal 192 A to provide additional support. The back-up member 220A may be part of a larger assembly using the present electncal interconnect 210A

Figure 16 is a side sectional view of an electπcal interconnect assembly 230 in accordance with the present invention. First ends 232 of the electπcal contacts 234 are electπcally coupled to a flexible circuit 236, using any of the techniques descnbed herein. A compliant encapsulant or sheet mateπal 238 is deposited on the rear surface of the flexible circuit 236. The second ends 240 of the electπcal contacts 234 extend beyond the second surface 242 of the housing 244 to couple electncally with terminals 246 on a second circuit member 248. The terminals 246 may be a vaπety of structures such as, for example, a ball gnd array, a land gnd array, a pm gnd array, contact points on a bare die device, etc. Similarly, the second ends 240 of the electncal contacts 234 can be a vanety of shapes as discussed herein. The second circuit member 248 can be a pnnted circuit board, another flexible circuit, a nbbon cable, a bare die device, an integrated circuit device, organic or inorganic substrates, a πgid circuit or a vanety of other electncal components.

In the illustrated embodiment, the electncal interconnect assembly 230 is releasably coupled to the second circuit member 248 by a compressive force 249. The compliance of the flexible circuit member 236, complaint matenal 238 and encapsulating matenal between the electncal contacts 234 and the housing 244, if any, provides the electncal contacts 234 with a large range of compliance along the central axes 247. Consequently, a stable electncal connection can be formed without permanently bonding the second ends 240 to the terminals 246. The electπcal interconnect assembly 230 can serve as a die level test probe, a wafer probe, a pπnted circuit probe, or a vaπety of other test circuits The vaπous complaint members in the assembly 230 permit it to be onented m any direction without mterfenng with its functionality The nature of the flexible circuit member 236 allows for a high density routing to external circuitry or electronics. The present electncal interconnection methodology can be extended to the distal end of the flexible circuit member 236 as well, to achieve a high performance connection where previous methods relied on cabling, spnng probes, or masses of bundled wires. Figure 17 is a side sectional schematic illustration of an electπcal interconnect assembly 280 m which both surfaces of the flex circuit member 282 can be used for forming electπcal connections. The flex circuit member 282 is bonded to housing 284 by an adhesive 286. Singulation 288 is formed m the flex circuit members 282 around trace 290. Electncal contact 292 is positioned to be compressively engaged with the trace 290 between circuit member 294 and controlled compliance layer 296 (see generally Figures 15 A and 15). Solder balls 298 electncally coupled with one or more traces are located on the opposite side of the flex circuit member 282 for engagement with circuit members or other electncal interconnect assemblies.

Figure 18 is a schematic illustration of two electπcal interconnect assemblies 250, 252 arranged in a stacked configuration in accordance with the present invention. First ends 254 of the electπcal contacts 256 are electπcally coupled with a flexible circuit member 258. The flexible circuit member 258 is folded around a compliant layer 260 so that first ends 262 of electncal contacts 264 m the electncal interconnect assembly 252 are also electncally coupled to the flexible circuit member 258. Second ends 266 of the electπcal contacts 256 are electncally coupled with a second circuit member 268. Second ends 270 of the electπcal contacts 264 are electπcally coupled with circuit member 272. An alignment member 274 is optional provided on the interconnect assembly 252 to position the circuit member 272 relative to the electπcal contacts 264 The electπcal interconnect assemblies 250, 252 of Figure 17 permit two circuit devices 268, 272 to be arranged m a stacked configuration

Figure 19 illustrates a replaceable chip module 310 coupled to a flexible circuit member 312 using the controlled compliance interconnect of the present invention. Housing 314 has a plurality of device sites 316, 318 for receiving circuit members, such as an array of integrated circuit devices The device sites 316, 318 are recesses that each contain an array of electrical contacts, such as discussed herein. The housing 314 is retained against the flexible circuit member 312 using any of the methods discussed herein, such as mechanical fasteners, adhesives, secondary fixtures, etc. A controlled compliance layer 320 is optionally located behind the flexible circuit member 312. A stiffener 322 is optionally located behind the controlled compliance layer 320. The flexible circuit member 312 can be formed with or without singulation. In the illustrated embodiment, the flexible circuit member has a senes of terminals 326 for electπcally coupling the replaceable chip module 310 with another circuit member. Alignment holes 324 are optionally provided on the housing 314 for receiving a cover (not shown) that retains circuit members m the device sites 316, 318 and provides a compressive force The housing 314 allows for a great deal of configuration flexibility, such that it can be populated, upgraded, enhanced, or modified simply by removing, replacing, or adding individual circuit members or devices. The replaceable chip module 310 of Figure 19 is suited as a test fixture for evaluating circuit members. Conventional test or load boards used as the interface for testing electncal devices can be greatly simplified or in some cases completely eliminated along with the supporting mechanical and electncal support or interface structure. The replaceable chip module technology disclosed in U.S. Patent Senal No. 08/955,563, entitled Replaceable Chip Module, is suitable for use m the present invention Figure 20 is a side sectional schematic illustration of a pair of replaceable chip module 330, 332 using the controlled compliance interconnect of the present invention m a stacked configuration, coupled together by a flexible circuit member 334 The flexible circuit member 334 is folded around a compliant layer 336, such as is illustrated m Figure 18 The assembly 338 of the folded flexible circuit member 334 and compliant layer 336 is retained m a cavity 340 formed between the first replaceable chip module 330 and the second replaceable chip module 332. The vaπous interfaces 341 between the flexible circuit member 334 and the electπcal contacts 342, 344 of the respective replaceable chip modules 330, 332 can be formed using any of the techniques disclosed herein. For example, the electπcal contacts 342 are illustrated as coupling with a ball gπd array on circuit member 346. Electπcal contacts 344 can couple with another replaceable chip module, another flexible circuit members or vanous circuit members. An alignment structure 346 may optionally be located on the second replaceable chip module 332 for positionmg circuit members.

Figure 21 is a side sectional view of an electncal interconnect 400 in accordance with the present invention. Housing 402 includes an array of holes 404 each having a step 406. Electπcal contacts 408 include a shoulder 410 adapted to engage with the step 406. Consequently, the electπcal contacts 408 can move in the holes 404 along the central access 412 until the shoulders 410 engage with the steps 406. First ends 414 of the electπcal contacts 408 extend above surface 416 of housing 402.

Second ends 418 of the electπcal contacts 408 are electπcally coupled to contact pads on flexible circuit member 420 using any of the methods discussed herein. The flexible circuit member optional includes singulations 422 adjacent to one or more of the electπcal contacts 408. A compliant mateπal 424 is positioned on the opposite side of the flexible circuit member 420 behind the second ends 418 of each of the electncal contacts 408. The compliant matenal 424 biases the electncal contacts 408 in the direction 426

The second surface 430 of the flexible circuit member 420 optionally includes a senes of solder balls 432 electπcally coupled to traces on the flexible circuit member 430. Solder paste 434 may optionally be applied to the solder balls 432 Figure 22 illustrates an electπcal interconnect assembly 440 utilizing the electncal interconnect 400 of Figure 21 The electncal interconnect 400 is located in an alignment device 442 positioned on a first circuit member 444 Flexible circuit member 420 (see Figure 21) extends beyond the alignment device 442 to connect with another circuit member The solder balls 432 (see Figure 21) electncally couple the flexible circuit member 420 with contact pads on the circuit member 444 In the illustrated embodiment, the circuit member 444 is a pnnted circuit board or adapter. The circuit member 444 will typically include an additional connector, such as an edge card connector or the socket 7 compatible BGA adapter 446 illustrated m Figure 22.

A second circuit member 450 is compressively engaged with the electncal interconnect 400. Alignment device 442 ensures that the contact pads on the second circuit member 450 align with the electncal contacts 408 on the electπcal interconnect 400. Compliant mateπal 424 biases the electncal contacts 408 into engagement with the contact pads on the second circuit member 450. In the illustrated embodiment, the second circuit member 450 is a land gπd array (LGA) device. A heat sink 452 is optionally provided to retain the second circuit member 450 m compressive engagement with the electπcal interconnect 400.

Figure 23 illustrates an alternate electncal interconnect 460 in accordance with the present invention. Flexible circuit member 462 is electπcally coupled to an array of pms (see generally Figure 21) retained in housing 464. The flexible circuit member 462 may optionally include an edge card connector 466 The pms in the electπcal interconnect 460 are compressively engaged with a land gπd array device 468 on circuit member 470 In the illustrated embodiment, circuit member 470 is a display device The embodiment illustrated in Figure 23 is particularly suited for use m lap top computers where the flexible circuit member 462 permits the display 470 to be hinged to the chassis of the computer Figure 24 is a schematic illustration of an electπcal interconnect 480 used as a probe module 482 in accordance with the present invention. Electπcal contacts 484 are electπcally coupled to flexible circuit 486 Compliant matenal 488 supported by back-up member 494 biases the electncal contacts 484 withm the probe housing 490 towards a first circuit member 492. The first circuit member 492 can be a vanety of electncal devices or a wafer containing a plurality of electncal devices (see Figure 25).

The flexible circuit 486 can extend to one or more circuit members. In the illustrated embodiment, the flexible circuit member 486 includes a first branch 496. The branch 496 includes a senes of edge card pads (not shown) and a stiffening member 498 to form an edge card connector 500.

Second branch 502 extends to another electncal interconnect 504 that includes a compliant matenal 506, a backup member 508, and a senes of electncal contacts 510 in a housing 512. The electncal interconnect 504 can be used to interface the probe module 482 to another circuit member 514, such as a pnnted circuit board.

The tester 516 illustrated m Figure 24 is completely modular. Any of the components can be easily replaced to facilitate testing of a wide vaπety of circuit members 492. For example, a different probe module 482 can be supplied so that the array of electπcal contacts 482 correspond with the contact pads on the circuit member 492. Alternatively, the electπcal interconnect 504 can be easily attached to a different circuit member 514 for performing different tests.

Figure 25 illustrates a system 520 for conducting full function testing at the wafer level. Electπcal interconnect 522 includes a module holder 524 with a plurality of recesses 526. Each recess 526 is adapted to receive a probe module, such as illustrated in Figure 24. Each of the probe modules 528 includes a flexible circuit 530 that can be electπcally coupled with one or more other circuit members for purposes of performing the testing Wafer 532 includes a plurality of electncal devices 534 The array of recesses on the module holder 524 correspond to the array of electncal devices 534 on the wafer 532. The electπcal interconnect 522 is placed over the wafer 532 so that the electπcal contacts (see Figure 24) of the probe modules 528 electπcally couple with contact pads on the electπcal devices 534. In one embodiment, the system 520 permits full speed testing of the electπcal devices 534 at the wafer level.

Figure 26 is a schematic illustration of an alternate electncal interconnect 550 m accordance with the present invention. Flexible circuit member 552 electncally couples upper electπcal contacts 554 and lower electπcal contacts 556. Elastomer 558 is positioned to bias electncal contacts 554 upward in the direction 560. Upper housing 562 includes a recess 564 for receiving a vanety of circuit members. Elastomer 566 biases lower electncal contacts 556 retained in the lower housing 568 m the direction 570 for coupling with another circuit member. In the embodiment illustrated m Figure 26, the upper housing 562 is a separate component from the lower housing 568. Figure 27A is a schematic illustration of another electncal interconnect 580 m the disengaged configuration m accordance with the present invention. Substrate 582 supports a flexible circuit member 584 having a plurality of BGA contact pads 586. Electncal contacts 588 are electncally coupled to the opposite side of the flexible circuit member 584. Compliant member 590 is located behind each of the electncal contacts 588. Gaps 592 in the compliant member 590 permit solder balls 594 of a BGA device 596 to electncally couple with the BGA contact pads 586 on the flexible circuit member 584.

Figure 27B illustrates the electπcal interconnect 580 of Figure 27A in the engaged configuration. The electncal interconnect 580 is compressed between the BGA device 596 and a second circuit member, such as a pnnted circuit board 598 The contact pads 600 on the pπnted circuit board 598 bias the electπcal contacts 588 toward the BGA device 596 The compliant matenal counteracts this bias on the electncal contacts 588. Singulations 602 in the flexible circuit member 584 facilitate movement of the electncal contacts 588 withm the substrate 582. Solder balls 594 electncally couple with BGA contact pads 586 on the flexible circuit member 584. Figure 28A illustrates an electπcal interconnect 620 substantially as shown in Figures 27 A, except that the compliant mateπal 622 includes a clearance opening or recess 624 immediately behind the electncal contact 626.

In the engaged configuration illustrated in Figure 27B, the electncal contacts 626 are biased toward the pnnted circuit board 628 only by the elastomenc properties of the flexible circuit member 628. In an alternate embodiment, the clearance opening 624 has a size that permits the electπcal contact 626 to be supported substantially by the flexible circuit member 628 only for a portion of their travel. After an initial amount of travel by the electπcal contact 626, the flexible circuit member 628 engages with the compliant mateπal 622. Thereafter, further displacement of the electπcal contact 626 is biased towards the pπnted circuit board 628 by a combination of the elastomeπc properties of the flexible circuit member 628 and the compliant mateπal 622.

Patents and patent applications disclosed herein, including those cited in the background of the invention, are hereby incorporated by reference. Other embodiments of the invention are possible. It is to be understood that the above descnption is intended to be illustrative, and not restrictive. Many other embodiments will be apparent to those of skill in the art upon reviewing the above descnption. The scope of the invention should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.

Claims

What Is Claimed Is-

1. An electπcal connector for electπcally interconnecting terminals on a flexible circuit member with terminals on a second circuit member, the electncal connector compnsmg: a housing having a plurality of through holes extending between a first surface and a second surface, each of the through holes defining a central axis; a plurality of elongated electπcal contacts positioned in at least a portion of the through holes and onented along the central axes, the electπcal contacts having first ends extending above the first surface adapted to couple electπcally with the terminals on the flexible circuit member, and second ends extending above the second surface to couple electncally with the second circuit member; and a resilient member controlling movement of the electncal contacts along their respective central axes.

2. The electncal connector of claim 1 wherein the resilient member compπses a compliant encapsulating mateπal interposed between a portion of the through hole and a portion of the electncal contacts.

3. The electncal connector of claim 1 wherein the resilient member compnses a compliant encapsulating mateπal surrounding a portion of the electπcal contacts along the first surface of the housing.

4. The electπcal connector of claim 1 wherein the resilient member compnses the flexible circuit member.

5 The electπcal connector of claim 1 wherein the resilient member compπses smgulated terminals on the flexible circuit member

6. The electπcal connector of claim 1 wherein the resilient member compπses a complaint matenal positioned along a surface of the flexible circuit member opposite the terminals of the flexible circuit member.

7. The electπcal connector of claim 6 further including a back-up member supporting the complaint mateπal.

8. The electπcal connector of claim 1 wherein the second surface of the housing includes at least one device site corresponding to the second circuit member.

9. The electπcal connector of claim 1 wherein the second ends of the electncal contacts have a shape that corresponds to a shape of the terminals on the second circuit member.

10. The electπcal connector of claim 1 wherein the second ends of the electπcal contacts are capable of engaging with a connector member selected from the group consisting of a flexible circuit, a nbbon connector, a cable, a pnnted circuit board, a ball gnd array (BGA), a land gnd array (LGA), a plastic leaded chip earner (PLCC), a pin gπd array (PGA), a small outline integrated circuit (SOIC), a dual in-line package (DIP), a quad flat package (QFP), a leadless chip earner (LCC), a chip scale package (CSP), or packaged or unpackaged integrated circuits.

11 The electncal connector of claim 1 wherein the electncal contacts are one of a homogeneous material or a multi-layered construction

12 The electncal connector of claim 1 wherein the electπcal contacts have a cross-sectional shape selected from one of circular, oval, polygonal, and rectangular.

13. The electncal connector of claim 1 wherein a portion of the flexible circuit member is bonded to the first surface of the housing with an adhesive.

14 The electπcal connector of claim 1 wherein the electπcal contacts are electncally coupled to the flex circuit using one or more of compressive force, solder, wedge bonding, conductive adhesives, ultrasonic bonding and wire bonding.

15 The electncal connector of claim 1 wherein the second ends of at least two of the electncal contacts extend beyond the second surface of the housing by a different amount.

16. The electπcal connector of claim 1 wherein electπcal contacts have a larger cross section proximate the first end than at the second end.

17 The electncal connector of claim 1 wherein the plurality of through holes are arranged in a two-dimensional array.

18. The electncal connector of claim 1 wherein the resilient member compnses a compliant encapsulating member elastically bonding the electπcal contacts to the housing

19. An electncal connector for electncally interconnecting terminals on a flexible circuit member with terminals on a second circuit member, the electncal connector compnsmg: a housing having a plurality of through holes extending between a first surface and a second surface, each of the through holes defining a central axis; a plurality of elongated electπcal contacts positioned in at least some of the through holes and onented along the central axes, the electncal contacts having first ends extending above the first surface and coupling electncally with the terminals on the flexible circuit member, and second ends extending above the second surface to couple electncally with the second circuit member; and a resilient member controlling movement of the electncal contacts along their respective central axes.

20. The electncal connector of claim 19 wherein the compliant encapsulating member elastically bonds the electπcal contacts to the housing.

21. An electπcal interconnect assembly for electπcally coupling with a second circuit member, compnsmg: a flexible circuit member having terminals along a first surface; a housing having a plurality of through holes extending between a first surface and a second surface, each of the through holes defining a central axis; a plurality of elongated electπcal contacts positioned in at least some of the through holes and oriented along the central axes, the electncal contacts having first ends extending above the first surface and electπcally coupled with the terminals on the flexible circuit member, and second ends extending above the second surface to couple electπcally with the second circuit member; and a resilient member controlling movement of the electπcal contacts along their respective central axes.

22. The electπcal interconnect assembly of claim 21 wherein the second surface of the housing includes at least one device site.

23. The electπcal interconnect assembly of claim 21 wherein the second circuit member is one of a pπnted circuit board, a flexible circuit, a bare-die device, an integrated circuit device, an organic or inorganic substrate, a πgid circuit, or a wafer containing a plurality of integrated circuit devices.

24. The electπcal interconnect assembly of claim 21 wherein the second ends of the electπcal contacts compnses one or more of die level test probes, wafer probes, and pnnted circuit board probes.

25. The electπcal interconnect assembly of claim 21 wherein the resilient member compπses one of a compliant encapsulating mateπal interposed between a portion of the through hole and a portion of the electπcal contacts, a compliant encapsulating mateπal surrounding a portion of the electπcal contacts along the first surface of the housing, the flexible circuit member, smgulated terminals on the flexible circuit member, or a complaint mateπal positioned along a surface of the flexible circuit member opposite the terminals.

26. The electπcal interconnect assembly of claim 21 wherein a portion of the flexible circuit member is bonded to the first surface of the housing with an adhesive

27. The electπcal interconnect assembly of claim 21 wherein the electncal contacts are electncally coupled to the flex circuit using one or more of compressive force, solder, wedge bonding, conductive adhesives, ultrasonic bonding and wire bonding.

28. The electπcal interconnect assembly of claim 21 wherein the first end of at least one of the electπcal contacts extends through the flexible circuit member.

29. The electπcal interconnect assembly of claim 21 wherein the flexible circuit member is folded over a resilient member to electπcally couple two electπcal interconnect assemblies in a stacked configuration.

30. The electπcal interconnect assembly of claim 21 wherein the flexible circuit member comprises electncal contact pads along a second surface thereof.

31. An electncal interconnect assembly for electncally coupling with a second and a third circuit member, compnsmg: a flexible circuit member having a plurality of terminals; a first housing having a plurality of through holes extending between a first surface and a second surface, each of the through holes defining a central axis, a plurality of elongated electncal contacts positioned m at least some of the through holes and onented along the central axes, the electπcal contacts having first ends extending above the first surface and electπcally coupled to terminals on the flexible circuit member, and second ends extending above the second surface to couple electπcally with the second circuit member, a second housing having a plurality of through holes extending between a first surface and a second surface, each of the through holes defining a central axis, a plurality of elongated electπcal contacts positioned in at least some of the through holes and onented along the central axes, the electrical contacts having first ends extending above the first surface and electπcally coupled to terminals on the flexible circuit member, and second ends extending above the second surface to couple electπcally with the third circuit member, the first surface of the first housing being positioned opposite the first surface of the second housing; and a resilient member controlling movement of the electπcal contacts along their respective central axes.

32. A method of making an electπcal interconnect compnsmg the steps of: providing a housing with a plurality of through holes extending between a first surface and a second surface, each of the through holes defining a central axis; positioning a plurality of elongated electncal contacts in at least some the through holes onented along the central axes, the electncal contacts having first ends extending above the first surface; retaining the electncal contacts in the through holes; and electncally coupling the first ends with the terminals on a flexible circuit member so that the second ends extending above the second surface.

33. The method of claim 32 compnsmg the step of applying a resilient member to control movement of the electncal contacts along their respective central axes.

34. The method of claim 32 compnsmg the step of singulatmg the terminals on the flexible circuit member.

35. The method of claim 32 wherein the step of positioning a plurality of electπcal contacts in the through holes compπses the steps of applying a soldermask matenal along the first surface; plananzmg the soldermask mateπal and a portion of the electncal contacts extending above the first surface; and removing the soldermask.

36. The method of claim 35 compnsmg the step of applying a resilient member to control movement of the electπcal contacts along their respective central axes before applying the soldermask.

37. The method of claim 35 compnsmg the step modifying the shape of the first or second ends of the electncal contacts by etching, gnnding, abratmg, ablating before removing the solder mask.

38 The method of claim 32 wherein the step of retaining the electncal contacts in the through holes compnses interposing a compliant encapsulating matenal between a portion of the through hole and a portion of the electncal contacts.

39. The method of claim 32 wherein the step of retaining the electncal contacts in the through holes compnses surrounding a portion of the electncal contacts with a compliant encapsulating matenal along the first surface of the housing.

40 The method of claim 32 wherein the step of retaining the electπcal contacts in the through holes compπses bonding the electπcal contacts to the terminals on the flexible circuit member

41 The method of claim 40 wherein the step of retaining the electπcal contacts in the through holes comprises positioning a complaint mateπal along a surface of the flexible circuit member opposite the terminals

42. The method of claim 32 wherein the step of retaining the electncal contacts in the through holes compnses bonding the electncal contacts to the terminals on the flexible circuit member and smgulatmg one or more of the terminals.

43. The method of claim 42 further compnsmg positioning a back-up member behind the compliant matenal.

44. The method of claim 32 wherein the second ends of the electncal contacts are modified to have a shape capable of engaging with a second circuit member selected from the group consisting of a flexible circuit, a ribbon connector, a cable, a pnnted circuit board, a ball gnd array (BGA), a land gnd array (LGA), a plastic leaded chip earner (PLCC), a pm gnd array (PGA), a small outline integrated circuit (SOIC), a dual m-lme package (DIP), a quad flat package (QFP), a leadless chip earner (LCC), a chip scale package (CSP), packaged and unpackaged integrated circuits.

45. The method of claim 32 wherein the electncal contacts are electncally coupled to the flex circuit using one or more of compressive forces, solder, wedge bonding, conductive adhesives, ultrasonic bonding and wire bonding.

46. The method of claim 32 compnsmg the step of engaging the second ends of the electπcal contacts with a second circuit member.

47 The method of claim 32 compnsmg the step of prepanng at least one device site on the second surface of the housing.

48. A method of making an electncal interconnect for electπcally coupling terminals on a flexible circuit member with terminals on a second circuit member, compnsmg the steps of: providing a housing having a plurality of through holes extending between a first surface and a second surface, each of the through holes defining a central axis; positioning a plurality of elongated electπcal contacts in at least some of the through holes onented along the central axes, the electncal contacts having first ends extending above the first surface; and elastically bonding the electncal contacts in the through holes.