GB2262384A - Integrated circuit chip socket using elastomeric connectors - Google Patents

Abstract

An integrated circuit socket assembly includes elastomeric elements in slots 16 of a body 1 as electrical contact between the device and the printed circuit board 7. The socket assembly is designed to ensure that no insertion force is applied when the integrated circuit is inserted and no withdrawal force when the device is removed from the socket. The socket assembly is designed to receive lead less leaded as well as TAB Integrated Circuits during testing or other procedures. Guide rails 19 on a hinged lid 10 press upon the elastomeric elements when the lid is closed and locked by means of spring catch 12. An open cavity 18 allows cooling of the circuit, eg during a burn-in process. The assembly is positioned over the pcb footprint 8 by means of pins 11. In another embodiment the assembly can hold a plurality of integrated circuits in an array. <IMAGE>

Description

INTEGRATED CIRCUIT CHIP SOCKET USING ELASTOMERIC CONNECTORS This invention relates to an apparatus for mounting circuit components onto the surface of printed circuit boards while electrical connection is secured between leads of the electrical component and a printed wiring pattern on the printed circuit board. In particular it relates to an assembly for mounting an electrical component, such as an integrated circuit, onto a printed circuit board by using a socket mounting assembly involving a two-piece housing hinged together on one side and a spring locking lever on the other end. The electrical component is sandwiched between the two electrically insulated housings. The bottom housing member is fitted with an elastomeric element or elements to form electrical contact(s) between the component and the printed circuit board for testing, burn-in and other uses.

DESCRIPTION OF THE PRIOR ART Integrated Circuits are widely used in various industries such as medical equipment, computers, electronic instruments, military equipment, etc.

Typically, a chip or a chip which is mounted on a carrier is referred to as an integrated circuit. Electrical connections extend from the terminals provided on the edges of the component to the electrical circuitry of the chip. A common arrangement in the art has terminals or metal leads extending on two opposite sides of the component forming what is known as a dual-in-line package.

To connect to the circuitry of the printed circuit board, an integrated circuits may be soldered directly to the printed circuit board or it could be inserted on a dual-in-line socket which has been permanently soldered into place on the printed circuit board. See U.S. Patent No. 3,917,984 issued Nov. 4, 1975 to G.C. Song et. al., which describes a printed circuit board having a plurality of sockets mounted thereon. The socket is usually provided with spring loaded contact pins to make electrical connections between the integrated circuit and the printed circuit board when the integrated circuit component is inserted into the socket.

Presently, integrated circuits are progressively becoming miniaturized with more added functions. They are also produced in different shapes and sizes with terminals or leads extending from various sides of the chip carrier, fanning out and bent in different configurations. The leads of the chip carriers are also finer, narrower and packed in higher pin density. Further, to improve thermal dissipation of the chips during operation, heat sinks are additionally attached to the body of the integrated circuits.

With all of these complexities, a socket which has spring loaded contact pins to hold the leads of an integrated circuit has become quite difficult to manufacture. The width of the leads are thinner and the pitch of the leads are closer. Therefore, the spring loaded contacts are required to be very narrow and placed very closely to one another. With present technology, the width of the spring loaded contacts has reached the minimum possible and any attempt to make these contacts even narrower increases the cost of manufacturing a socket substantially. Moreover, with leads bent in different configurations, the spring loaded contacts must be made longer to take into considerations factors such as the insertion and withdrawal retention force of the spring, etc.With long spring loaded contacts, undesirable inductances and capacitances are introduced, limiting the switching times which are particularly critical for high frequency integrated circuits.

To overcome the problem associated with spring loaded contacts, conductive elastomeric elements have been found to be useful as effective replacements. For example, Baker, U.S. Patent 4,652,973 describes and illustrates an apparatus for mounting chip carrier devices onto printed circuit boards using elastomeric contacts.

Also Strange et al, U.S. Patent 4,955,818 suggests an apparatus using elastomeric elements as contacts. The Baker and Strange et al patents are examples of using elastomeric elements as effect electrical connections between the chip carrier and the printed circuit board.

Elastomeric elements and its applications are also discussed generally in Buchoff "Solving High Density Electronic Problems With Elastomeric Connectors" article published at the March 1990 Nepcon Technical Program Conference in Anaheim and in Lee et al. U.S. Patent 4,778,950. Elastomeric elements are made of flexible insulator material and conductors. The electrically insulated conductors can be aligned with the contact surface of the printed circuit board and the leads of the integrated circuit to form electrical connections. An advantage of an elastomeric element is that it is replaceable.

In the Strange et al patent, a housing with a recess is provided to receive the chip carrier. The electrical connection as well as the contact between the lead and chip carrier is maintained by inserting and retaining the chip carrier in the recess. However, without a lid or cover, there is no assurance that proper contact between the lead and the elastomeric elements is established or maintained. This is particularly important during environmental testing, when the various parts of a device must be held together with a high degree of stability, despite external vibration or large temperature changes. Further, as previously described, leads fanning out from the integrated circuits are typically fragile and thin.These integrated circuits cannot simply tbe fitted" to the printed circuit board without applying a force to hold the integrated circuits to the socket.

In the Baker patent, contact is made between the chip and the printed circuit board from the bottom side of the chip carrier However, the chip carrier described does not have protruding metal leads. Therefore, designing the mounting assembly becomes complex when chip carriers have protruding metal leads bent in various configurations and with attached heat sinks. Although Baker's design uses a cover to apply pressure, the cover is provided as a separate unit, introducing an extra step for mounting the assembly. Also, the cover provided in Baker restricts air flow to the integrated circuits, causing heat to be built up during the burn-in process.

Very recently, Elastomeric Technologies Inc., published a "Elastomeric Connector Catalog - ETI 114-2-90 SM" and proposed on page 64, an integrated circuit socket assembly (called Plastic Quad Flat Pack Socket) useful for testing, burn-in and the like. The proposed socket assembly has an electrically insulating housing comprising a body member and a lid member hinged on one side.

Elastomeric elements are disposed inside a center cavity in the body member for electrical connection with the metal leads protruding from an integrated circuit chip or carrier. Although this assembly provides a quick action lid for easy insertion, it has limited application. There is no element provided to exert force on the leads to force them into contact with the elastomeric elements. In this proposed socket, the pressure is exerted on the body of the integrated circuits, causing the leads to be potentially bent, so that some leads of the integrated circuits may not be entirely flat, causing poor contact or no contact in the worst case. In other words, without any guide member to force the leads on to the elastomeric elements, there is no assurance of an effective electrical connection between all the leads of the integrated circuit carrier and the elastomeric elements. As obvious to those skilled in the art, those potential issues would arise in applying stress on the body of the integrated circuit in the burn-in/testing process. Moreover, since the elastomeric elements are to be inserted inside the cavity in the body member of the housing, it is difficult to wipe off fine foreign particles or dust that settles on the elastomer causing "shorts" or poor contacts. Had the elastomer elements been designed to be flush with the surface of the body member, the condition of the elastomer would be observable during loading of the integrated circuits and cleaning or maintenance required can be easily performed to ensure effective electrical connections between the leads and the elastomer elements.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an improved assembly for mounting an electrical component such as integrated circuit chip onto a surface of a printed circuit board while electric connection is secured between leads of the electrical component and a printed wiring pattern (footprint) on the printed circuit board.

The present invention comprises two electrically insulating housing members, namely a body member and a cover lid member. The body and lid members are hinged on one side and a spring lock lever on the opposite end. The body member is precisely designed to allow the integrated circuit chip to rest on the elastomer elements with the leads facing correspondingly to the footprint of the printed circuit board. When the lid member is clamped, contact is made between the leads of the chip or chip carrier and the printed circuit board through the strips of elastomeric elements. Some of the features added to this apparatus are described below.

The lid member is attached to the body member by a mechanical spring hinge on one side. The lid member is held in an open or perpendicular position at all times to allow easy access for insertion and removal of the integrated circuits. The lid member has a cavity to allow the integrated circuits to be exposed to the environmental temperature. Around the perimeter of the cavity are guide rails that are precisely constructed to align with the base of the leads giving sufficient tolerance such that pressure is applied on the leads in contact with the strip of elastomeric elements when closed. More particularly, recessed slots are formed at the perimeter of an open cavity in the body member, which slots extend through the thickness of the body member for accommodation of the elastomeric elements.The top surface of the elastomer elements is flush with the surface of the body member.

The recessed slots and the elastomeric elements received therein are in precise alignment with the guide rails on the lid member. When the lid member is closed, the guide rails presses the elastomeric elements in the recessed slots into contact with the wiring pattern on the printed circuit board, while sandwiching the integrated circuits between the lid member and the printed circuit board. In addition, the guide posts on the body member provides self alignment of the integrated circuits on the elastomeric element. The integrated circuits are precisely guided, not forced, snapped or pressed to rest on the socket. The apparatus is attached to the printed circuit board with, for example, four pins which are soldered to the printed circuit board or an appropriate number of screws for easy replacement.

In particular, the present invention achieves the primary object by providing an electrical component mounting assembly with a new and novel combination of the guide rails formed on the inside of the lid member for pressing both the leads of the integrated circuits and the elastomeric elements and forcing the elastomeric elements into contact with the wiring pattern on the printed circuit board and the clamping device for applying clamping force not only for clamping the lid member into the body member of the housing assembly but also for pressing the elastomeric elements into electrical contact with the wiring pattern on the printed circuit board.

In accordance with one aspect of the present invention, there is provided an assembly for mounting an electrical component onto a surface of a printed circuit board while electrical connection is secured between leads of said electrical component and a printed wiring pattern on said printed circuit board, comprising:: (a) an electrically insulating housing assembly comprising a body member and a lid member, said lid member being hinged on one side of said body member and being held in an open position to allow easy access for insertion and removal of the electrical component; (b) an open cavity formed in said body member; (c) at least one recessed slot disposed at the periphery of said cavity in said body member to extend the thickness of said lid member; (d) an elastomeric element positioned within said slot to form electrical contact between the leads of said electric component and the printed wiring pattern on said printed circuit board;; (e) at least one protruding guide rail disposed on an inside surface of said lid member for alignment with said slot in said body member and for pressing both the electrical component and said elastomeric element and forcing the elastomeric element into contact with the wiring pattern on said printed circuit board;; (f) a clamping device for said lid member on said body member and applying clamping force on the leads of said electric component through said guide rail to secure electric contact between the leads of said electric component and the printed wiring patterns on said printed circuit board via said elastomeric element, while the elastomeric element is pressed into contact with the wiring pattern on said printed circuit board with the aid of lid action, wherein the thickness of said guide rail is predetermined to prevent excessive pressure on the leads of said electric components when said lid member is clamped on said body member.

In a preferred embodiment of the present invention, the body member and the lid member are spring hinged on one side so that clamping force is applied on the leads of the integrated circuit chip through the guide rail to secure electrical contact between the leads of the integrated circuit chip and the; printed wiring patterns on the printed circuit board via the elastomeric element.

The spring hinge device serves as advantageous features to secure that: (a) the lid member is lifted up to allow easy access for the chip entry and removal; (b) the positioning of said guide rail to the leads is fixed and accurately targeted each time when said lid member is clamped down; - (c) the thickness of said guide rail can be predetermined to prevent excessive pressure on the leads; (d) the alignment between the leads of said integrated chip to the metallic pads of the printed circuit board is guided by said guide posts; and (e) said body member houses said elastomeric elements and is positioned between the leads of said integrated circuit chip and said printed circuit board for electrical connection.

As is clear from the foregoing, a desired number of slots and elastomeric elements may be used, depending the number of sides the integrated circuit is to be connected to the printed wiring pattern on the printed circuit board. In the case of the square chip carrier (Plastic Quad Flat Pack), four sides may be used for electrical connection in a mounted assembly. It is also noted that the socket assembly of the present invention applies whether the leads of the integrated circuit chip are metal leads fanning out in desired directions or bonded to a film for TAB (Tape Automated Bonding) integrated circuits.In the socket according to the present invention, spring force of the leads of the integrated circuit chip is not required to maintain contact since electrical connection between the integrated circuit chip and the printed circuit board is secured by a combination of the clamping device, the recessed slot in the housing body for receiving the elastomeric element and the protruding guide rails formed on the housing lid member.

It is further understood that the present invention is not limited to use for mounting and connection of integrated circuit chips or carriers with leads but may also be applied to integrated circuit without leads, e.g. LCC (Leadless Chip Carrier) which has flat (non-protruding) metal pad on their bottom side.

This present invention may also be applied to other electrical components requiring precise and high density connection such as high density matrix display panels. In another application, the housing assembly may be designed to receive a plurality of integrated circuit chips. In some cases, it is preferable that integrated circuit chips have leads (either protruding metal leads or flat metal pads) to be connected with elastomeric elements in vertical directions (instead of horizontal directions in the single-chip mounting assembly). In other wcrds, the leads of the integrated circuits and the elastomeric elements are held side-to-side in electrical contact condition. It is also obvious that a larger sized housing assembly permits a plurality of the integrated circuit chips to be electrically connected in horizontal directions with the printed circuit board.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings illustrate the invention: Fig. 1 is an exploded view of a square chip carrier (Plastic Quad Flat Pack) mounting apparatus according to a preferred embodiment of the present invention, showing a printed circuit board, a device footprint on a printed circuit board, a body member, a lid member and an integrated circuit chip carrier and screws; Fig. 1A is an enlarged view of the metal leads of the integrated circuit chip carrier in Fig. 1; Fig. 2 is an exploded view of a square chip carrier mounting apparatus according to another preferred embodiment of present invention; Fig. 2A is an enlarged view of vertical grooves in the embodiment of Fig. 2; Fig. 3 is a sectional view of a square chip carrier (Plastic Quad Flat Pack) in the mounting assembly of Fig. 1;; Fig. 3a is a partial sectional view of a square chip carrier in a mounting assembly of another embodiment of the invention; Fig. 4 is an exploded view of a rectangular chip carrier (vertical surface mount package) mounting apparatus according to still another embodiment of the present invention, showing a printed circuit board, a body member, a lid member, an integrated circuit chip carrier and screws; Fig. 4A is an enlarged view of the metal leads of the integrated circuit chip carrier in Fig. 4; and Fig. 5-is a sectional view of the rectangular chip carrier (vertical surface mount package) in the mounting assembly of Fig. 4.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Fig. 1, illustrates in an exploded view a preferred embodiment of an integrated circuit chip socket assembly of the present invention. The socket comprises a two-piece housing assembly having a body member 1 and a lid member 10 made of electrically insulating material by a plastic molding process. In another embodiment, the housing assembly may also be molded in one-piece so that the body member 1 is integral with the lid member 10 with a hinge mechanism through known plastic molding techniques. The body member 1 is solid and provided with four recessed slots 16 which are aligned with the a printed wiring circuit pattern of metallic pads (the footprint) 8, of a printed circuit board (PCB) 7 by means of two guiding pins 11.It is well known in the art that the spacing of the electric connections (pitch) on the footprint of the printed circuit board 7 is selected to be equal to or larger than the spacing of conductive members of elastomeric elements as discussed hereinafter. As an alternative shown in Figs. 2 and 2A, the body member 1 may also have vertical grooves 20 in the vicinity of the slots 16 to provide space for slight expansion of elastomeric elements to be described below when pressure is applied.

The guiding pins 11 pass through holes of the body member 1 and through the plated through-holes 5 of the printed circuit board. To locate the socket assembly to the footprint 8, two guide pins 11 are mounted or soldered to the printed circuit board 7 and four screws 14 are used to fasten the socket assembly to the board 7. Of course, other fastening techniques may be used. In the illustrated embodiment, an integrated circuit chip 9 is the well-known square chip carrier (Plastic Quad Flat Pack). The chip carrier 9 has metal leads (leaded) fanned out in an orderly direction as shown in an elarged view of Fig. 1A. Four pieces of elastomeric elements 6 are fitted into the four recessed slots 16 in the body member 1.In the case of an integrated circuit carrier with only a single side connection, one elastomeric element is enough for electrical connection with the printed circuit board 7.

As discussed in the above cited article "SOLVING HIGH DENSITY ELECTRONIC PROBLEMS WITH ELASTOMERIC CONNECTORS," there are two basic types of elastomeric conducting elements 6. One type, the layered elastomeric element consists of alternating conductive and nonconductive layers of silicone rubber. The other type of elastomeric element, elastomeric metal-on-elastomer has metal traces on the surface of a silicone core or traces that traverse the core. Either type of elastomeric elements may be used in the present invention. The four corner guiding posts 4, on the body member, guides the bumps of the four corners of the square chip carrier 9.

Although the guiding posts 4 serve to guide the alignment of the leads of the chip carrier 9 with the footprint 8 (metallic pads of the printed circuit board), a combination of the guide rails 19 and the recessed slots 16 further improves such alignment of the leads of the chip carrier 9 with the footprint 8. The leads of the integrated circuit (in the illustrated embodiment, the bottom surface of the chip carrier 9) will correspondingly be aligned with a printed wiring pattern or a footprint of the printed circuit board 7. Therefore, as is seen from Fig. 3, electrical connection is secured in horizontal directions between the chip carrier 9 and the footprint 8 of the printed circuit board. The mechanical spring hinge 17, allows the lid member 10 to be held upward such that it remains in a perpendicular standing position at all times unless it is pushed down to lock the chip carrier. Opposite the mechanical spring hinge 17, is a spring locking lever 12. A bevel catch 3, on the body member 1 is aligned to receive the spring locking lever 12. At the center of the lid member 10 is an open cavity 18. Similarly, the body member has a cavity 15. These cavities allow the chip carrier to be exposed to the environment and is particularly necessary when used in a burn-in environment. Around the perimeter of the square cavity of the lid member 10 is a protruding guide rail 19.

The guide rail 19 is intended to provide the pressure on the leads of the chip carrier 9 when the spring locking lever 12 is pressed into the catch bevel 3. The thickness or height of the guide rail protrusion 19 is determined depending largely by the amount of pressure desired to avoid excessive depression on the elastomeric element 6 and to avoid denting the leads. At the center of the cavity 18, lies a strip with a spring construction 21 to hold the device in place to assure there is no movement of the integrated circuit before the guide rail presses the leads. Although the guide rails are disposed on the lid member side in the above illustrated embodiment, they may be eliminated from the lid member side and the elastomeric elements may protrude into recessed slots formed on the lid member side.

Such an embodiment is illustrated in Fig. 3A.

In this embodiment the elastomeric conducting elements 6 protrude from the slot 16 so that they extend above the upper surface of the body member 1. The re-entrant edges of the cavity 18 in the lid member 10 are removed to define a series of recesses 50 into which the elastomeric conducting elements extend on closure of the lid member 10. The recesses 50 thus act as guide parts which, in combination with the elastomeric conducting elements 6, provide pressure on the leads of the chip carrier 9, in a similar way to the protruding guide rails 19 of the previously-described embodiment In another preferred embodiment of the present invention, Figs. 4 and 5 illustrate how the body members are designed to hold multiple integrated circuits.In the illustrated embodiments of Figs. 4 and 5, a housing assembly 30 including a body member 31 and a lid member 32 is designed to accommodate six integrated circuit carriers 33. At least one side of each of those integrated circuit carriers has metal leads to be connected to a printed circuit board 34 via an elastomeric element 35. The elastomeric elements 35 are received within individual slots 38 which are formed in the body member 31 to extend the thickness of the body member 31. There are disposed three guide rails 36 for alignment between the integrated circuit carriers 33 and a footprint 37 on the printed circuit board 34.With the combination of the slots 38, the guide rails 36 and a spring lock lever 40 which applies clamping force to the integrated circuit carriers 33 and then the elastomeric elements 35, a good contact is maintained between the leads 39 of the integrated circuit carriers 33 and the footprint 37 on the printed circuit board 34.

The above embodiments of the invention offer several advantages in effecting electrical interconnections between circuitry of printed circuit boards and chip carriers through the use of elastomeric elements. Those skilled in the art will immediately recognize the utility of the present invention in other areas of electrical connectors, such as display panel connectors. While preferred embodiments have been described, various modifications and substitutions may be made without departing from the spirit and scope of the invention. Accordingly, it is understood that the present invention has been described by way of illustration and not limitation.

Claims (25)

Claims:

1. An assembly for mounting an electrical component onto a surface of a printed circuit board while electrical connection is secured between leads of said electrical component and a printed wiring pattern on said printed circuit board, comprising: (a) an electrically insulating housing assembly comprising a body member and a lid member, said lid member being hinged on one side of said body member and being held in an open position to allow easy access for insertion and removal of the electrical component; (b) an open cavity formed in said body member; (c) at least one recessed slot disposed at the periphery of said cavity in said body member to extend the thickness of said lid member; (d) an elastomeric element positioned within said slot to form electrical contact between the leads of said electric component and the printed wiring pattern on said printed circuit board;; (e) at least one protruding guide rail disposed on an inside surface of said lid member for alignment with said slot in said body member and for pressing both the electrical component and said elastomeric element and forcing the elastomeric element into contact with the wiring pattern on said printed circuit board;; (f) a clamping device for said lid member on said body member and applying clamping force on the leads of said electric component through said guide rail to secure electric contact between the leads of said electric component and the printed wiring patterns on said printed circuit board via said elastomeric element, while the elastomeric element is pressed into contact with the wiring pattern on said printed circuit board with the aid of lid action, wherein the thickness of said guide rail is predetermined to prevent excessive pressure on the leads of said electric components when said lid member is clamped on said body member.

2. An assembly for mounting an electric component onto a surface of a printed circuit board, as defined Claim 1 wherein said lid member is spring hinged on one side of said body member through the use of a spring member secured between said lid member and said body member to hold the lid member in an open position to allow ease access for insertion and removal of said electrical component, and wherein said lid member has a spring locking lever on a non-hinging side of said lid member and said body member has bevel catch for holding said spring locking lever when said lid member is clamped down.

3. An assembly for mounting an electric component onto a surface of a printed circuit board, according to Claim 1 further comprising: (g) guide posts disposed around the periphery of said cavity for holding said electric component for precise alignment between the leads of said electric component and the printed wiring pattern of said printed circuit board.

4. An assembly for mounting an electric component onto a surface of a printed circuit board, according to Claim 1 wherein said elastomeric element comprises conductive material and non-conductive material

5. An integrated circuit socket assembly for mounting an integrated circuit chip onto a surface of a printed circuit board while electrical connection is secured between leads of said integrated circuit chip and a printed wiring pattern on said printed circuit board, comprising:: (a) an electrically insulating housing assembly comprising a body member and a lid member, said lid member being hinged on one side of said body member and being held in an open position to allow easy access for insertion and removal of the integrated circuit chip; (b) an open cavity formed in said body member; (c) at least one recessed slot disposed at the periphery of said cavity in said body member to extend the thickness of said lid member; (d) at least one elastomeric element positioned within said slot to form electrical contact between the leads of said integrated circuit chip and the printed wiring pattern on said printed circuit board;; (e) at least one protruding guide rail disposed on an inside surface of said lid member for alignment with said slot in said body member and for pressing both the leads of the integrated circuit chip and said elastomeric element and forcing the elastomeric element into contact with the wiring pattern on said printed circuit board;; (f) a clamping device for said lid member on said body member and applying clamping force on the leads of said integrated circuit chip through said guide rail to secure electric contact between the leads of said integrated circuit chip and the printed wiring patterns on said printed circuit board via said elastomeric element, while the elastomeric element is pressed into contact with the wiring pattern on said printed circuit board with the aid of lid action, wherein the thickness of said guide rail is predetermined to prevent excessive pressure on the leads of said integrated circuit chip when said lid member is clamped on said body member.

6. An integrated circuit socket assembly according to claim 5 wherein the leads of said integrated circuit chip comprise metal leads fanned out in desired direction or metal pad.

7. An integrated circuit socket assembly according to Claim 6 wherein said integrated circuit chip is an LCC (Leadless Chip Carrier) or TAB IC (Tape Automated Bonding) and, when said integrated circuit chip is an LCC without any leads but having metal pads on the bottom of the chip, said guide rail holds the integrated circuit chip to ensure electrical connection between the metal pads and printed wiring pattern through the elastomer elements.

8. An integrated circuit socket assembly for mounting an integrated circuit chip onto a surface of a printed circuit board while electrical connection is secured between leads of said integrated circuit chip and a printed wiring pattern on said printed circuit board, comprising: (a) an electrically insulating housing assembly comprising a body member and a lid member, said lid member being hinged on one side of said body member and being held in an open position to allow easy access for insertion and removal of the integrated circuit chip; (b) at least one recessed slot disposed at the periphery of said body member to extend the thickness of said lid member; (c) at least one elastomeric element positioned within said slot to form electrical contact between the leads of said integrated circuit chip and the printed wiring pattern on said printed circuit board;; (d) at least one protruding guide rail disposed on an inside surface of said lid member for alignment with said slot in said body member and for pressing both the integrated circuit chip and said elastomeric element and forcing the elastomeric element into contact with the wiring pattern on said printed circuit board;; (e) a spring lock lever for said lid member on said body member and applying clamping force on the leads of said integrated circuit chip through said guide rail to secure electric contact between the leads of said integrated circuit chip and the printed wiring patterns on said printed circuit board via said elastomeric element, while the elastomeric element is pressed into contact with the wiring pattern on said printed circuit board with the aid of lid action, wherein the thickness of said guide rail is predetermined to prevent excessive pressure on the leads of said integrated circuit chip when said lid member is clamped on said body member.

9. An integrated circuit socket assembly for mounting an integrated circuit chip onto a surface of a printed circuit board while electrical connection is secured between leads of said integrated circuit chip and a printed wiring pattern on said printed circuit board, comprising: (a) an electrically insulating housing assembly comprising a body member and a lid member, said lid member being hinged on one side of said body member and being held in an open position to allow easy access for insertion and removal of the integrated circuit chip; (b) at least one recessed slot disposed at the periphery of said body member to extend the thickness of said lid member; (c) at least one elastomeric element positioned within said slot to form electrical contact between the leads of said integrated circuit chip and the printed wiring pattern on said printed circuit board; ; (d) at least one protruding guide rail disposed on an inside surface of said lid member for alignment with said slot in said body member and for pressing both the integrated circuit chip and said elastomeric element and forcing the elastomeric element into contact with the wiring pattern on said printed circuit board; (e) a clamping device for said lid member on said body member and applying clamping force on the leads of said integrated circuit chip through said guide rail to secure electric contact between the leads of said integrated circuit chip and the printed wiring patterns on said printed circuit board via said elastomeric element, wherein the clamping device serves to allow said integrated circuit chip to rest, on said body member with no insertion force or withdrawal force.

10. An integrated circuit socket assembly for mounting an integrated circuit chip onto a surface of a printed circuit board while electrical connection is secured between leads of said integrated circuit chip and a printed wiring pattern on said printed circuit board, comprising: (a) an electrically insulating housing assembly comprising a body member and a lid member, said lid member being hinged on one side of said body member and being held in an open position to allow easy access for insertion and removal of the integrated circuit chip; (b) four recessed slots disposed at the periphery of either of said two housing members to extend the thickness of either of said two housing members;; (c) four elastomeric elements each positioned within each of said four recessed slots to form electrical contact between the leads of said integrated circuit chip and the printed wiring pattern on said printed circuit board; (d) four protruding guide rails disposed on an inside surface of the other of said two housing members for alignment with said slots in the one of said two housing members and for pressing both said integrated circuit chip and said elastomeric elements and forcing said elastomeric elements into contact with the wiring pattern on said printed circuit board;; (e) a spring hinge device for said lid member on said body member and applying clamping force on the leads of said integrated circuit chip through said guide rails to secure electric contact between the leads of said integrated circuit chip and the printed wiring patterns on said printed circuit board via said elastomeric elements, wherein the spring hinge device serves to allow said integrated circuit chip to rest on said body member with no insertion force or withdrawal force.

11. An integrated circuit socket assembly for mounting an integrated circuit chip onto a surface of a printed circuit board while electrical connection is secured between leads of said integrated circuit chip and a printed wiring pattern on said printed circuit board, comprising: (a) an electrically insulating housing assembly comprising a body member and a lid member, said lid member being hinged on one side of said body member and being held in an open position to allow easy access for insertion and removal of the integrated circuit chip; (b) at least one recessed slot disposed at the periphery of said body member to extend the thickness of said lid member; (c) at least one elastomeric element positioned within said slot to form electrical contact between the leads of said integrated circuit chip and the printed wiring pattern on said printed circuit board;; (d) at least one protruding guide rail disposed on an inside surface of said lid member for alignment with said slot in said body member and for pressing both the integrated circuit chip and said elastomeric element and forcing the elastomeric element into contact with the wiring pattern on said printed circuit board; (e) a spring hinge device for said lid member on said body member and applying clamping force on the leads of said integrated circuit chip through said guide rail to secure electric contact between the leads of said integrated circuit chip and the printed wiring patterns on said printed circuit board via said elastomeric element, wherein said spring hinge device serves to secure:: (a) the lid is lifted up to allow easy access for the chip entry and removal; (b) the positioning of said guide rail to the leads is fixed and accurately targeted each time when said lid member is clamped down; (c) the thickness of said guide rail can be predetermined to prevent excessive pressure on the leads; (d) the alignment between the leads of said integrated chip to the metallic pads of the printed circuit board is guided by said guide posts; and (e) said body member houses said elastomeric elements and is positioned between the leads of said integrated circuit chip and said printed circuit board for electrical connection.

12. An integrated circuit socket assembly according to Claim 11 wherein said integrated circuits is allowed by said spring hinge device to rest on said body member with no insertion force or withdrawal force.

13. An integrated circuit socket assembly according to Claim 9 wherein clamping force is focussed on the leads of said integrated circuit chip through said guide rails to achieve a good electrical conductivity on said elastomeric element and said printed circuit board.

14. An integrated circuit socket assembly according Claim 9 wherein said body member comprises a plurality of open cavities to accommodate a plurality of integrated circuit chips.

15. An integrated circuit socket assembly according to Claim 11 said spring hinge device on the lid member provides a grip on said body member to prevent said integrated circuit chip from moving while the guide rail presses down the leads of said integrated circuit chip.

16. An integrated circuit socket assembly according to claim 11 wherein electrical connection is secured in a horizontal direction between leads of said integrated circuit chip and said elastomeric elements.

17. An integrated circuit socket assembly according to claim 11 wherein electrical connection is secured in a vertical direction between leads of said integrated circuit chip and said elastomeric elements.

18. An integrated circuit socket assembly according to claim 11 wherein said body member and said lid member each have an open cavity to expose said integrated circuit chip to the environmental temperature for burn-in purposes.

19. An integrated circuit socket assembly according to claim 11 wherein there is further provided a vertical groove in the vicinity of said slot to provide space for slight expansion of said elastomeric elements when pressure is applied.

20. An integrated circuit socket assembly according to claim ll wherein the top surface of the elastomeric elements is flush so that the condition of the elastomer can be easily seen and allow easy maintenance.

21. An assembly for making an electrical connection between an electrical component and a wiring pattern on a printed circuit board, comprising:.

(a) an electrically insulating body member having at least one slot extending therethrough in which a conductive elastomeric member is positioned for making an electrical connection between the electrical contacts of said component placed on said body and said printed circuit board; and (b) an electrically insulating lid member having at least one guide part formed therein for guiding the electrical contacts of said component towards said elastomeric component at a desired orientation on connection of said lid to said body.

22. An assembly according to claim 21, wherein said guide part comprises a rail protruding from said lid member.

23. An assembly according to claim 21, wherein said guide part comprises a recess formed in said lid member into which said elastomeric member extends on connection of said lid to said body.

24. An assembly according to claim 23, wherein said recess is formed by removing an edge portion of a cavity in said lid member in which said electrical body is at least partially housed on connection of said lid to said body.

25. An assembly substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.