WO2005048410A1

WO2005048410A1 - Land grid socket connector

Info

Publication number: WO2005048410A1
Application number: PCT/US2004/037239
Authority: WO
Inventors: Kathleen A. Sweeney; Samuel C. Ramey; Thomas B. Schoder
Original assignee: Molex Incorporated
Priority date: 2003-11-06
Filing date: 2004-11-05
Publication date: 2005-05-26
Also published as: TWI249882B; TW200531364A

Abstract

A socket connector includes a dielectric carrier and at least one conductive terminal. The conductive terminal is mounted through an aperture in the carrier, and includes a connecting portion extending through the aperture, a first beam extending from the connecting portion and provided on a first side of the carrier, and a second beam extending from the connecting portion and provided on a second opposite side of the carrier. The first and second beams are angled relative to the carrier. The connecting portion is formed as a separate member to the first and second beams and is subsequently attached to the first and second beams to forra a mechanical attachment between the first and second beams.

Description

LAND GRID ARRAYSOCKET CONNECTOR

Background of the Invention: Socket connectors are commonly used in a land grid array (LGA) for use in an electronic device, such as a computer server or a router. The socket connector provides a connection between a chip package or other appropriate electronic component and a printed circuit board or other appropriate electronic component. Terminals in the socket connector provide for a secure connection to the electronic components. As electronic devices become smaller, more and more connections for passing signals must be provided in a smaller space. There is a need for a socket connector which can provide for a high array count, while being inexpensive to manufacture. In addition, the inductance of the socket connector must be low.

Objects and Summary of the Invention: A general object of the present invention is to provide a socket connector for a land grid array that is low cost to form and easily manufactured. An object of the of the present invention is to provide a socket connector which has a small pitch such that a low inductance is provided. Another object of the present invention is to provide a socket connector which has a low profile. Yet another object of the present invention is to provide a socket connector which has terminals that can be provided in an array, as a single terminal or as a strip. Briefly, and in accordance with the foregoing, the present invention discloses a socket connector for use in a land grid array. The socket connector includes a dielectric carrier and at least one conductive terminal. The conductive terminal is mounted through an aperture in the carrier, and includes a connecting portion extending through the aperture, a first beam extending from the connecting portion and provided on a first side of the carrier, and a second beam extending from the connecting portion and provided on a second opposite side of the carrier. The first and second beams are angled relative to the carrier. The connecting portion is formed as a separate member to the first and second beams and is subsequently attached to the first and second beams to form a mechanical attachment between the first and second beams. Brief Description of the Drawings: The organization and manner of the structure and operation of the invention, together with further objects and advantages thereof, may best be understood by reference to the following description, taken in connection with the accompanying drawings, wherein like reference numerals identify like elements in which: FIG. 1 is a perspective view of a first embodiment of a terminal prior to assembly to a carrier; FIG. 2 is a perspective view of a second embodiment of a terminal prior to assembly to a carrier; FIG. 3 is an alternate embodiment of the terminal formed in accordance with the embodiment shown in FIG. 1; FIG. 4 is a side elevational view of a socket connector which incorporates features of the present invention shown with electronic components in side elevation; FIG. 5 is a top perspective view of the socket connector; FIG. 6 is a cross-sectional view, shown in perspective, of the carrier and portions of the terminals of FIG. 1 attached thereto, some of the terminals shown in cross-section and others shown in perspective; FIG. 7 is a cross-sectional view, shown in perspective, of the socket connector shown in FIG. 5 being shown during the assembly process; FIG. 8 is a cross-sectional view, shown in perspective, of a socket connector in accordance with an alternate embodiment being formed; FIG. 9 is a cross-sectional view, shown in perspective, of the partially formed socket connector in accordance with the alternate embodiment; FIG. 10 is a top perspective view of the socket connector including a single terminal shown in FIG. 1; FIG. 11 is a perspective view of the socket connector showing a framework which can be used during assembly of the socket connector; FIG. 12 is a top elevational view of a strip of beams used in forming the socket connector; FIG. 13 is a top elevational view of a socket connector; FIG. 14 is a perspective view of the socket connector and including coverlays provided on a side of the carrier; FIG. 15 is a cross-sectional view, shown in perspective, of the socket connector and including the coverlays shown in FIG. 14; and FIG. 16 is a perspective view of the socket connector surrounded by a framework.

Detailed Description of the Illustrated Embodiment: While the invention may be susceptible to embodiment in different forms, there is shown in the drawings, and herein will be described in detail, a specific embodiment with the understanding that the present disclosure is to be considered an exemplification of the principles of the invention, and is not intended to limit the invention to that as illustrated and described herein. The present invention provides a socket connector 20 for a land grid array (LGA) for use in an electronic device, such as a computer server or a router. The socket connector 20 includes a carrier 22 onto which at least one terminal 24; 25 is mounted. The carrier 22 is formed of a flexible sheet of dielectric material, such as plastic or a film. The carrier 22 has a first side 26 and a second side 27 and includes a plurality of spaced apart apertures 28 provided therethrough in a predetermined pattern. Each terminal 24; 25 is formed from a pair of beams 30, 32; 34, 36 and a connecting portion 38. The terminal 24; 25 is formed from a conductive material. The beams 30, 32; 34, 36 may be stamped and formed by means known in the art. Two embodiments of the terminal 24; 25 are provided; a dual beam terminal 24 and a single beam terminal 25. Either terminal 24; 25 can be used with the carrier 22. As is best shown in FIG. 1, the dual beam terminal 24 includes the first beam 30 which connects with the second beam 32 by the connecting portion 38. One of the dual beam terminals 24 is described with the understanding that the other dual beam terminals 24 are formed in an identical manner. The connecting portion 38 may be formed as a rivet as shown in FIG. 1, or as a solder mass 40 that is melted to form the connecting portion 38 as shown in FIGS. 8 and 9. The first beam 30 is formed from a base 42 and a pair of fingers 44a, 44b which extend therefrom. The base 42 has an aperture 46 therethrough. Each finger 44a, 44b is elongated and extends from the base 42 such that the opposite end of the respective finger 44a, 44b is free. The free end may be rounded as shown in the drawings. The fingers 44a, 44b are spaced apart from each other on the base 42 such that a slot 48 is formed between the fingers 44a, 44b. The fingers 44a, 44b are angled relative to the base 42 at a predetermined angle. As shown in the drawings, the fingers 44a, 44b are angled outwardly and upwardly from the base 42. The fingers 44a, 44b are small and have a small pitch, for example 1mm grid. The second beam 32 has a base 50 and a pair of fingers 52a, 52b which extend therefrom. The base 50 has an aperture 54 therethrough. Each finger 52a, 52b is elongated and extends from the base 50 such that the opposite end of the respective finger 52a, 52b is free. The free end may be rounded as shown in the drawings. The fingers 52a, 52b are spaced apart from each other on the base 50 such that a slot 56 is formed between the fingers 52a, 52b. The fingers 52a, 52b are angled relative to the base 50 at a predetermined angle. As shown in the drawings, the fingers 52a, 52b are angled outwardly and downwardly from the base 50. The fingers 52a, 52b are small and have a small pitch, for example 1mm grid. Each aperture 28 provided through the carrier 22 is dimensioned such that the connecting portion 38 is accommodated therein. The height of each aperture 28 is less than the height of the connecting portion 38. Assembly of the dual beam terminal 24 with the carrier 22 is now described. The first beam 30 is placed on the first side 26 of the carrier 22 and the aperture 46 through the base 42 of the first beam 30 is aligned with the aperture 28 through the carrier 22. The second beam 32 is placed on the second side 27 of the carrier 22 and the aperture 54 through the base 50 of the second beam 32 is aligned with the aperture 28 through the carrier 22. As a result, a "V" shape is generally formed by the first and second beams 30, 32. The connecting member 38 is thereafter inserted into the apertures 46, 28, 54 and secured to the first and second beams 30, 32. If the connecting member 38 is a rivet, the rivet is riveted to the first and second beams 30, 32 by deforming the ends of the rivet by suitable means, thereby forming blooms 55 (only one of which is shown in the drawings) on the opposite ends of the rivet to secure the first and second beams 30, 32 to the rivet. If the connecting member 38 is a solder mass, the solder mass 40 is inserted into the apertures 46, 28 through the first beam 30 (although the solder mass 40 could be inserted into the aperture 54 of the second beam 32 if desired) and the carrier 22, and thereafter melted to form the connecting portion 38 between the first and second beams 30, 32. The aperture 38 through the carrier 22 is smaller than the width of the bases 42, 50 to prevent either base 42, 50 from being able to pass therethrough. As a result, the first beam 30 is on the first side 26 of the carrier 22 and the second beam 32 is on the second side 27 of the carrier 22. The assembled dual beam terminal 24 allows for small pitch and provides for a low cost array. In addition, because the first and second beams 30, 32 are small and have a small pitch, a low inductance is provided by the terminal 24. The use of the carrier 22 provides for a low cost and provides for a low profile for the socket connector 20. The socket connector 20 is easily manufactured as a result of the uncomplicated steps for assembling same. The single beam terminal 25 includes a first beam 34 which connects with a second beam 36 by the connecting portion 28. One of the single beam terminals 25 is described with the understanding that the other single beam terminals 25 are formed in an identical manner. The connecting portion 38 may be formed as a rivet as shown in FIG. 2, or as a solder mass that is melted to fonn the connecting portion 38 similar to that shown in FIGS. 8 and 9. The first beam 34 has a base 60 and a finger 62 which extends therefrom. The base 60 has an aperture 64 therethrough. The finger 62 is elongated and extends from the base 60 such that the opposite end of the finger 62 is free. The free end may be rounded as shown in the drawings. The finger 62 is angled relative to the base 60 at a predetermined angle. As shown in the drawings, the finger 62 is angled outwardly and upwardly from the base 60. The finger 62 is small and has a small pitch, for example 1mm grid. The second beam 36 has a base 66 and a finger 68 which extends therefrom. The base 66 has an aperture 70 therethrough. The finger 68 is elongated and extends from the base 66 such that the opposite end of the finger 68 is free. The free end may be rounded as shown in the drawings. The finger 68 is angled relative to the base 66 at a predetermined angle. As shown in the drawings, the finger 68 is angled outwardly and downwardly from the base 66. The finger 68 is small and has a small pitch, for example 1mm grid. The carrier used with the single beam terminal 25 is identical to the carrier 22 provided for the dual beam terminal 24. Assembly of the single beam terminal 25 with the carrier 22 is now described. The first beam 34 is placed on the first side 26 of the carrier 22 and the aperture 64 through the base 50 of the first beam 32 is aligned with the aperture 28 through the carrier 22. The second beam 36 is placed on the second side 27 of the carrier 22 and the aperture 70 through the base 66 of the second beam 36 is aligned with the aperture 28 through the carrier 22. As a result, a "V" shape is generally formed by the first and second beams 34, 36. The connecting member 38 is thereafter inserted into the apertures 64, 28, 70 and secured to the first and second beams 34, 36. If the connecting member 38 is a rivet, the rivet is riveted to the first and second beams 34, 36 by deforming the ends of the rivet by suitable means, thereby forming blooms on the ends of the rivet to secure the first and second beams 34, 36 to the rivet. If the connecting member 38 is a solder mass, the solder mass 40 is inserted into the apertures 64, 28 through the first beam 34 (although the solder mass 40 could be inserted into the aperture 70 of the second beam 36 if desired) and the carrier 22, and thereafter melted to form the connecting portion 38 between the first and second beams 34, 36. The aperture 38 through the carrier 22 is smaller than the width of the bases 60, 66 to prevent either base 60, 66 from being able to pass therethrough. As a result, the first beam 34 is on the first side 26 of the carrier 22 and the second beam 36 is on the second side 27 of the carrier 22. The assembled single beam terminal 25 allows for small pitch and provides for a low cost array. In addition, because the first and second beams 34, 36 are small and have a small pitch, a low inductance is provided by the single beam terminal 25. The use of the carrier 22 is low cost and provides for a low profile for the socket connector 20. The socket connector 20 is easily manufactured as a result of the uncomplicated steps for assembling same. As shown in FIG. 4, the first beam 30 of the dual beam terminal 24 is suited for engagement with a chip package or other appropriate electronic component 72 and the second beam 32 of the dual beam terminal 24 is suited for engagement with a printed circuit board or other appropriate electronic component 74. The elongation and the angling of the fingers 44a, 44b; 52a, 52b allows for the flexure of the beams 30, 32 to provide for a secure connection to the electronic components 72, 74. The provision of the dual fingers 44a, 44b; 52a, 52b provides for a redundancy for the electrical connection to the electronic components 72, 74 in the even that one of the fingers fails. In a like manner (which is not shown), the first beam 34 of the single beam terminal 25 engages with a chip package or other appropriate electronic component and the second beam 36 of the single beam terminal 25 engages with a printed circuit board or other appropriate electronic component. The elongation and the angling of the fingers 62, 68 allows for the flexure of the beams 34, 36 to provide for a secure connection to the electrical components. As shown in FIGS. 10-13, the terminals 24 can be inserted individually into the carrier 22 (FIG. 10), inserted as an array 76 into the carrier 22 (FIG. 11) or inserted as a strip (FIG. 12) into the carrier 22. If the terminals 24 are inserted into the carrier 22 in an array 76 or a strip 78, framework 80, 82 which mates the terminals 24 together are removed by suitable means, such as by cutting the framework 80, 82 away or etching, to remove the electrical connection between the terminals 24. It is to be understood that the terminals 25 can be inserted in a like manner to that shown in FIGS. 10-13. As shown in FIGS. 14 and 15, a coverlay 84 can be provided on one or both of the exposed surfaces 26, 27 of the carrier 22 between the terminals 24 to prevent the electrical engagement of adjacent beams when the beams are deflected upon engagement with the electrical component 70. As shown in FIGS. 14 and 15, the coverlay 84 is only illustrated on surface 26, but it is to be understood that the coverlay 84 can also be provided on surface 27. The coverlay 84 is formed from a dielectric material and is secured to the exposed surface 26 of the carrier 22 by suitable means, such as adhesive. The coverlay 84 extends outwardly from the first surface 36 of the carrier 22 a predetermined distance and is engaged by the fingers 44a, 44b when the terminals 24 are in the fully deflected condition such that the coverlay 84 prevent the engagement of a finger or fingers 44a, 44b with an adjacent terminal 24 when fully deflected condition. Alternatively, a dielectric material can be dispensed onto portions of the exposed surfaces of the carrier 22 to perform the same function. The coverlay 84 can be a conformal coating, or a solder mask. The coverlay 84 can also be used with the single beam terminal 25. If desired, a solder ball 86 can be provided on the end of one of the beams 32; 36 to provide for a ball grid array attachment to the printed circuit board 72. The beam 32; 36 preferably includes a portion 87 which is angled to the remainder of the fingers 46a, 46b or I finger 68 such that it is parallel to the electronic component 72 for attachment of the solder ball 86 thereto. Electrical traces (not shown) may be provided on the carrier 22 between desired ones of the terminals 24; 25 to electrically connect same. In addition, because the carrier 22 is flexible, a stiffening framework 88 can be provided around the perimeter of the carrier 22 as shown for example in FIG. 16. The stiffening framework 88 can be made of plastic or the like. It is to be understood that while a rivet and a solder mass are described herein as the means for providing the connecting portion 38 between the beams 30, 32; 34, 36, other connecting means are within the scope of the present invention provided the connecting means provides an electrical connection between the beams 30, 32; 34, 36 and can be formed a separate member that is subsequently attached to the beams 30, 32; 34, 36 to form mechanical attachment. For example, the aperture 28 through the carrier 22 can be plated with a conductive material to provide the connecting portion 38 and the beams 30, 32; 34, 36 attached by suitable means to the plating. While preferred embodiments of the present invention are shown and described, it is envisioned that those skilled in the art may devise various modifications of the present invention without departing from the spirit and scope of the appended claims.

Claims

CLAIMS: What is claimed is: 1. A connector comprising: a flexible, dielectric carrier having first and second opposite sides and an aperture provided therethrough extending from the first side to the second side; and a conductive terminal mounted through the aperture in the carrier, the terminal having a connecting portion extending through the aperture, a first beam extending from the connecting portion and provided on the first side of the carrier, the first beam being angled relative to the first side of carrier, and a second beam extending from the connecting portion and provided on the second side of the carrier, the second beam being angled relative to the second side of the carrier, the connecting portion being formed as a separate member to the first and second beams which is subsequently attached to the first and second beams to form a mechanical attachment between the first and second beams.

2. The connector of claim 1, wherein the first beam is formed of two spaced apart fingers extending from the connecting portion and the second beam is formed of two spaced apart fingers extending from the connecting portion.

3. The connector of claim 1, wherein the first beam is formed of a single finger extending from the connecting portion and the second beam is formed of a single finger extending from the connecting portion.

4. The connector of claim 1, wherein the connecting member is a rivet which is attached to the first and second beams.

5. The connector of claim 4, wherein the first beam includes an aperture therethrough through which a first end of the rivet is inserted, the first end of the rivet thereafter being deformed to form a first bloom to connect the rivet to the first beam, and the second beam includes an aperture therethrough through which a second end of the rivet is inserted, the second end of the rivet being thereafter deformed to form a second bloom to connect the rivet to the second beam.

6. The connector of claim 1, wherein the connecting member is a solder mass which is melted to connect the first and second beams together.

7. The connector of claim 6, wherein the first beam includes an aperture therethrough and the second beam includes an aperture therethrough, the solder mass, when melted, flowing into the apertures in the first and second beams.

8. The connector of claim 1, wherein the first beam has a predetermined width and the second beam has a predetermined width, the aperture having a predetermined width which is less than the predetermined width defined by the first beam and less than the predetermined width defined by the second beam.

9. The connector of claim 1, further including a coverlay formed of a dielectric material over at least one of the sides of the carrier.

10. The connector of claim 1, further including a stiffening framework around a perimeter of the carrier.

11. The connector of claim 1, further including a solder ball provided on an end of one of the beams.

12. The connector of claim 1, wherein the second beam includes a first portion extending at an angle from the connecting portion and a second portion extending from the first section, the second section being generally parallel to the carrier, and a solder ball mounted on the second portion.

13. The connector of claim 1, wherein a plurality of terminals are mounted on the carrier through associated apertures.

14. The connector of claim 13, wherein the terminals are laid out in an array.

15. The connector of claim 13, wherein the terminals are laid out in a strip.

16. The connector of claim 1, wherein a plurality of first beams are provided, a plurality of second beams are provided, and a plurality of connecting portions are provided, the plurality of first beams being connected together by a framework that is removed once the respective connecting portions are attached to the first beams and the plurality of second beams being connected together by a framework that is removed once the respective connecting portions are attached to the second beams.

17. A method of assembling a socket connector comprising the steps of: providing an aperture through a flexible, dielectric carrier, the carrier having first and second opposite sides; providing a first conductive beam and a conductive second beam; positioning the first beam proximate the aperture on the first side of the carrier; positioning the second beam proximate the aperture on the second side of the carrier; providing a conductive connecting portion, the connecting portion being formed as a separate member to the first and second beams; using the connecting portion to mechanically attach the first and second beams together.

18. The method of claim 17, wherein the connecting portion is a rivet, and further including the steps of: inserting the rivet into the aperture in the carrier; attaching a first end of the rivet with the first beam; and attaching a second end of the rivet with second first beam.

19. The method of claim 17, wherein the connecting portion is a rivet, and wherein the first beam includes an aperture therethrough and the second beam includes an aperture therethrough, and further including the steps of: inserting the rivet into the aperture in the carrier; inserting a first end of the rivet through the aperture in the first beam; deforming the first end of the rivet to form a first bloom to connect the rivet to the first beam; inserting a second end of the rivet through the aperture in the second beam; and deforming the second end of the rivet to form a second bloom to connect the rivet to the second beam.

20. The method of claim 17, wherein the connecting portion is a separately formed solder mass, and further including the steps of: inserting the solder mass into the aperture in the carrier; melting the solder mass to thereby attach the first and second beams together.

21. The method of claim 17, wherein the connecting portion is a solder mass, and wherein the first beam includes an aperture therethrough and the second beam includes an aperture therethrough, and further including the steps of: inserting the solder mass into the aperture in the carrier; melting the solder mass such that the solder mass flows into the apertures in the first and second beams to thereby attach the first and second beams together.

22. The method of claim 17, further including the step of providing a coverlay over at least one of the sides of the carrier.

23. The method of claim 17, further including the step of providing a stiffening framework around a perimeter of the carrier.

24. The method of claim 17, further including the steps of providing a plurality of the apertures and providing a plurality of the terminals.

25. The method of claim 24, wherein the plurality of terminals are connected by a framework and the framework is removed after the terminals are inserted into the apertures.