Socket for electrical component

Abstract: A connector (10) for electrically connecting an electrical component (1) having a plurality of conductive elements (3) extending therefrom to a substrate (S). The connector comprises a first base (15) and a second base. The first base (15) has at least one aperture therein and a hinge assembly. The second base comprises a plurality of contacts (100) that correspond to the conductive elements in the electrical component and a hinge assembly. The hinge (27) assemblies of the first and second bases allow movement of the first base (15) relative to the second base. A method of securing the electrical component (1) to the substrate including the steps of: inserting the component into a cassette (11); mounting the housing to the substrate (S); connecting a portion of the conductive elements of the electrical component with a portion of the contacts; and connecting the remainder of the conductive elements of the electrical component (1) with the remainder of the contacts. A contact (100) having a retention portion, a tail portion and a pair of beams (101). The beams each have a first portion which displaces the beam from opposite sides of the plane of the retention portion and a second portion extending from, and canted relative to, the first portion. The second portions interact to receive a mating contact therebetween.

Description: Background of the Invention 1. Field of Invention The present invention relates to electrical connectors. More specifically, the present invention relates to a socket for an electrical component. 2. Description of Reported Developments Electrical components, such as integrated circuit (IC) chips, must be secured to a substrate. One example of an interconnection system for securing such pin grid array (PGA) components to a substrate is a zero insertion force (ZIF) system. In ZIF systems, pins of the PGA component enter an interconnect housing without engaging contacts of the interconnect mounted to the substrate. Only after the PGA component seats on the interconnect housing are the contacts and pins engaged. One method of engaging the contacts and PGA pins involves moving the PGA pins laterally and into engagement with the contacts. An actuating lever and a cam surface drive an interposer assembly laterally to propel the PGA pins. The interposer assembly moves the PGA pins towards, and into connection with, the contacts. The housing used with such ZIF interconnects encounters loading during, and after, lever actuation. The forces required to deflect the contacts in order to receive the PGA pins determines the amount of loading on the lousing. The greater number of contacts increases the peak, or maximum force required to mate the contacts and PGA pins. It is estimated that an interconnect with 500 contacts requires approximately twenty (20) pounds of force to mate the contacts and PGA pins successfully. Technological advances have increased the pin count and contact density of PGA components and have miniaturized computer components (requiring reduced profile sizes). While the improved speed may satisfy consumers, these technological advances burden conventional ZIF sockets. Often, a design that compensates for one of the above technological advances is mutually exclusive to a design that compensates for another technological advance. In one example of a modification, a designer may increase the number of holes in the socket and decrease the pitch between the holes to account for increased pin density and the pin count. However, this reduces the strength of the socket. In another example of a modification, a designer may shorten the contact to account for reduced profile size. A shorter contact exhibits greater stiffness, thus increasing the required insertion force to mate with the PGA pins. These two design objectives impose conflicting requirements, since a stiffer contact requires more actuation force on the lever. A larger actuation force increases the loading on the socket. But the reduced strength of the socket (due to the increased hole count and decreases pitch) renders the socket less likely to withstand the increased loading. The increased contact density has also taxed the capabilities of conventional contact forming methods. The typical method of forming opposed dual beam contacts is to stamp the contact from a sheet of material. However, the width of the sheet material required to form a single contact with conventional techniques will exceed the pitch requirements imposed by these technological advances. US-4 836 798 discloses a zero insertion socket with normally closed contacts which comprises an activating arm which upon activation rotates a cammed cylinder which pushes a plate laterally to open prongs of the contact for component lead insertion. This plate acts therefore as a kind of secondary locking and the activation arm movement is not intended to mate the leads and corresponding contacts directly. US-5 147 213 shows a zero insertion pressure test socket which transforms a hinge movement, activated by the rotation of a handle into a translational shift of a plate resulting in the opening or closing of an array of contacts. This resulting movement is not intended to mate contacts. Summary of the Invention It is an object of the present invention to provide a connector for connecting an electrical component to a substrate. It is a further object of the present invention to provide a connector for connecting an electrical component to a substrate that exhibits lower peak insertion force. It is a further object of the present invention to provide a connector for connecting an electrical component to a substrate that selectively mates only a portion of the contacts at a time. It is a further object of the present invention to provide a connector for connecting an electrical component to a substrate that sequentially mates contacts in columns. It is a further object of the present invention to provide a connector for connecting an electrical component to a substrate that accommodates larger pin counts. It is a further object of the present invention to provide a connector for connecting an electrical component to a substrate that precisely aligns the mating contacts during rotation. These and other objects of the present invention are achieved in one aspect by a connector for electrically connecting an electrical component having a plurality of conductive elements extending therefrom to a substrate. The connector comprises a first base and a second base. The first base has at least one aperture therein and a hinge assembly. The second base comprises a plurality of contacts that correspond to the conductive elements in the electrical component and a hinge assembly. The hinge assemblies of the first and second bases allow rotative movement of the first base relative to the second base. These and other objects of the present invention are achieved in another aspect by a cassette for interacting with a housing to secure an electrical component to a substrate. The cassette has a base, a hinge for rotative movement with a complementary hinge of the interacting housing and at least one aperture extending through the base for receiving at least a portion of the electrical component. These and other objects of the present invention are achieved in another aspect by a housing for interacting with a cassette for attaching an electronic component, having a plurality of conductive elements, to a substrate. The housing comprises: a base; a hinge for rotative movement with a complementary hinge of the interacting cassette and a plurality of contacts in the base forming an array of columns adapted to receive the conductive elements of the electrical component. Brief Description of the Drawings Other uses and advantages of the present invention will become apparent to those skilled in the art upon reference to the specification and the drawings, in which: Figure 1 a is a perspective view of one embodiment of a connector of the present invention in a mated condition; Figure 1 b is the connector shown in Figure 1 a, but in an unmated condition; Figure 2a is a perspective view of a portion of the connector shown in Figures 1 a and 1 b, but prior to receiving an electrical component; Figure 2b is another perspective view of the portiow of the connector shown in Figure 2a; Figure 3a is an enlarged view of the portion of the connector appearing within the dashed lines in Figure 2b; Figure 3b is a cross-sectional view of the portion of the connector shown in Figure 3a taken along line IIIB-IIIB; Figure 3c is an alternative arrangement of the portion of the connector shown in Figure 3a; Figure 3d is a cross-sectional view of the portion of the connector shown in Figure 3c taken along line IIID-IIID; Figure 4a is a perspective view of another portion of the connector shown in Figures 1 a and 1 b; Figure 4b is a cross-sectional view of the portion of the connector shown in Figure 4a taken along lines IVB-IVB; Figure 4c is the cross-sectional view of the portion of the connector in Figure 4b with contacts inserted therein; Figure 5 is a cross-sectional view of a portion of the connector taken along lines V-V in Figure 1b Detailed Description of the Preferred Embodiments Figures 1a, 1b, 2a, 2b, 3a, 3b, 4a-c and 5 display a first embodiment of the present invention. The present invention is an electrical connector 10 that secures an electrical component 1 to a substrate S (see Figure 5). As seen in Figure 2a, electrical component 1 can be a PGA component such as in IC chip, however other types of electrical components could be used, such as a multi-chip module (MCM). Component 1 has a plurality of conductive elements, such as pins 3 extending therefrom. Pins 3 are arranged in an array of columns and rows. Although the conductive elements are shown as being round pins, other types of conductive elements, including blades (not shown), could be used. Connector 10 has two matable pieces, a cassette 11 and a housing 13. Figure 1a displays cassette 11 and housing 13 in a mated condition, while Figure 1b displays an unmated condition. Cassette 11 and housing 13 will now be individually described. Figures 2a and 2b display cassette 11, preferably manufactured from a suitable plastic, such as a liquid crystal polymer (LCP). Cassette 11 can have a base 15, described throughout as a plate, that receives component 1. However, other arrangements are possible to accommodate different types of electrical components 1. At least one aperture 17 extends through base 15. In the embodiment shown in Figures 2a and 2b, base 15 has a plurality of apertures 17. Apertures 17 are arranged on base plate 15 so as to receive corresponding pins 3 of electrical component 1. Thus, the arrangement of apertures 17 on base 15 is determined by the location of pins 3 on electrical component 1. As seen in Figures 3a and 3b, apertures 17 could have beveled lead-ins to assist in the insertion of pins 3. With electrical component 1 properly positioned on cassette 11, pins 3 extend past the lower surface of base plate 15 as seen in Figure 1b. Base plate 15 could include a wall 19 along its outer perimeter. As seen in the embodiment of Figure 2b, wall 19 extends below the lower surface of base plate 15, for example, to protect pins 3 from damage. Latches 21 extend from base plate 15, preferably along the sides. Latches 21 include a flange portion (see Figure 2a) projecting generally perpendicular from base plate 15. The distal ends of the flange portions include a retaining portion 23 extending from the flange portion. The area between retaining portion 23 and the upper surface of base plate 15 receives electrical component 1. As pins 3 of electrical component 1 enter apertures 17, electrical component 1 deflects resilient latches 21 outwardly. When electrical component 1 is fully seated on cassette 11, retaining portions 23 return to their original, non-deflected position to engage the upper surface of electrical component 1 as seen in Figure 1b. Retaining portions 23 prevent electrical component 1 from inadvertently dislodging from cassette 11. Electrical component 1 may be removed from cassette 11 by disengaging retaining portions 23 from the upper surface of electrical component 1. When properly seated within cassette 11, electrical component 1 can be mated with contacts 100. Cassette 11 rotates relative to housing 13 so that only a limited number of pins 3 mate with contacts 100 at one time. Cassette 11 rotates relative to housing 13 so that consecutive columns of pins 3 mate with consecutive columns of contacts 100. Wall 19 includes a tab 25 on a leading edge of base plate 15 to assist the installer in rotating cassette 11. The mating of pins 3 with contacts 100 will be described in greater detail below. Wall 19 also includes a hinge assembly 27 at a trailing edge of base plate 15. Hinge assembly 27, in conjunction with the hinge assembly on housing 13, allows rotation of cassette 11 relative to housing 13 and ensures the proper alignment of pins 3 of electrical component 1 with contacts 100 of housing 13 during the mating process. Hinge assembly 27 extends generally parallel to the plane of cassette 11. A description of the components of hinge assembly 27 follows. Extensions 29 project outwardly from the trailing edge of cassette 11, preferably at opposite sides of the trailing edge. Each extension 29 has a curved element 31 flanked by a pair of arms 33. Curved elements 31 have a first surface 67 shaped to engage a hinge pin on housing 13 and a second surface 69 opposite first surface 67 shaped to interact with a block 65 on housing 13. Each outermost arm 33 includes an outwardly facing, or exterior surface 35 that interacts with corresponding surfaces on the hinge assembly of housing 13 to ensure proper lateral alignment of pins 3 on electrical component 1 and the contacts on housing 13 during mating. Another extension 39 projects outwardly from the trailing edge of housing 13. Extension 39 preferably extends from a central location along the trailing edge of housing 13 between extensions 29, but extends in a direction opposite of extensions 29. Central extension 39 has a curved element 71 flanked by a pair of arms 73. Curved elements 71 have a first surface 75 shaped to engage a hinge pin on housing 13 and a second surface 77 opposite first surface 75 and shaped to interact with block 65 on housing 13. Figures 3a and 3b display a portion of the lower surface of base plate 15. With this arrangement, pins 3 of electrical component 1 can freely project from apertures 17 and extend beyond the bottom surface of base plate 15. Base plate 15 provides lateral support to the portions of pins 3 residing within base plate 15. However, the distal ends of pins 3 (i.e. the portions of pins extending beyond the lower surface of base plate 15) are not laterally supported. Figures 3c and 3d demonstrate an alternative arrangement in which base plate 15' laterally supports a greater length of pins 3' than the earlier alternative embodiment. Specifically, Figures 3c and 3d demonstrate an alternative arrangement of the lower surface of base plate 15', which includes bridges 79' positioned between each aperture 17'. Bridge 79' may include arcuate sides 81' and recessed ends 83'. Recessed ends 83' correspond to the shape of pins 3'. As seen in Figure 3c, if electrical component 1 uses round pins 3', recessed ends 83' have a rounded, concave shape to receive a portion of pin 3'. Bridges 79' are located on base plate 15' so as not to interfere with contacts 100'. As shown in Figure 3c, beams 101' of each contact 100' are arranged in a column, while bridges 79' are arranged in rows. Thus, the presence of bridges 79' do not affect the flexure of beams 101'. Bridges 79' may be molded unitarily with base plate 15'. Figures 4a-4c display housing 13, which is preferably manufactured from a suitable plastic. Housing 13 includes a base 41 with a plurality of apertures 43 extending therethrough. As with base 15, base 41 can have a generally planar configuration, although other orientations are possible. Each aperture 43 preferably includes three portions. First portion 45 is a relatively wide opening so as to accommodate the flexure of dual beams 101 of contact 100 during mating. Second portion 47 accommodates tail portion 103 of contact 100 and, as described below, a portion of a fusible element 105. Finally, third portion 49 retains intermediate portion 107 of contact 100 within aperture 43. As shown in Figure 4b, beam accommodating portion 45 resides at the mating end of housing 13 and has tapered side walls 51 forming a lead-in. Tapered side walls 51 allow for the easy insertion of contact 100 within aperture 43 and allow the flexure of beams 101 by pins 3 without restriction. Tail accommodating portion 47 resides at the mounting end of housing 13. Since housing 13 can surface mount to substrate S, preferably using Ball Grid Array (BGA) technology, tail accommodating portion 47 can have a suitable shape to accommodate the BGA features. In one example of BGA technology, a fusible element, such as a solder ball 105, secures to tail portion 103 of contact 100. At least a portion of solder ball 105 secured to tail portion 103 of contact 100 can seat within tail accommodating portion 47 of aperture 43. International Publication number WO 98/15989 (International Application number PCT/US97/ 18066), herein incorporated by reference, describes methods of securing a solder ball to a contact and of securing a solder ball to a substrate. Intermediate portion 49 extends between beam accommodating portion 45 and tail accommodating portion 47. Opposed walls of intermediate portion 49 each include a protuberance 53 extending towards each other. As seen in Figure 4b, protuberance 53 can be a rib extending axially along a length of aperture 43. The distance between opposed walls of intermediate portion 49 exceeds the width of contact 100 to allow contact 100 to pass through aperture 43. However, the width of contact 100 exceeds the distance between the opposed protuberances 53. As a result, contact 100 interference fits between protuberance 53 for retention in aperture 43. Base plate 41 can also have a wall 55 along its outer perimeter. Similar to wall 19 of cassette 11, wall 55 extends from plate 41 and protects contacts 100 from damage. When cassette 11 and housing 13 mate, wall 19 of cassette 11 resides between wall 55 and contacts 100. As seen in Figure 4a, the leading edge of wall 15 includes a notch 57 to receive tab 25 from cassette 11 when connector 10 is in a mated condition. This allows complete rotation of cassette 11 relative to housing 13 for mating all pins 3 and contacts 100. To avoid interference with hinge assemblies 27, 59, wall 55 is discontinuous in the trailing edge region of base 41. The trailing edge of base plate 41 includes a hinge assembly 59 that interacts with hinge assembly 27 of cassette 11 to allow rotation of cassette 11 relative to housing 13. Hinge assembly 59 extends generally parallel to the plane of housing 13 and includes a hinge pin 61 braced by a series of supports 63 along the trailing edge of housing 13. A series of cams, or blocks 65 extend from the trailing edge between adjacent supports 63. Blocks 65 have curved surfaces 75 that correspond to second surfaces 69, 77 of extensions 33 and central extension 35. Curved surfaces 75 of blocks 65 can be circular and preferably have substantially the same radius of curvature as second curved surfaces 69, 77 of extensions 33 and central extension 35. This can ensure proper longitudinal and Z-axis (i.e. normal to the plane of housing 13) alignment of pins 3 of electrical component 1 and contacts 100 in housing 13 for mating. Each outermost support 63 includes an inwardly facing, or interior surface 85 that interact with surfaces 35 of hinge assembly 27 to ensure proper alignment of pins 3 of electrical component E and contacts 100 during mating. Specifically, surfaces 35 of cassette 11 abut surfaces 85 of housing 13 for precisely aligning cassette 11 and housing 13 laterally for mating pins 3 and contacts 100. The mating of cassette 11 and housing 13 will now be described. Initially, cassette 11 and housing 13 are separate, or unmated. In this condition, housing 13 should be secured to substrate S. As discussed above, housing 13 can be surface mounted to substrate S, preferably using BGA technology. However, other methods could be used. Next, electrical component 1 secures to cassette 11. In the embodiment described above, pins 3 of electrical component 1 enter apertures 17 until latch 21 retains electrical component 1 against cassette 11. To interface cassette 11 and housing 13, hinge assemblies 27, 59 must mesh as shown in Figures 1b and 5. The features of hinge assemblies 27, 59, cassette 11 and housing 13 enhance the ease of blind mating cassette 11 and housing 13. Describing the mating in particular, extensions 29 and central extension 39 enter the openings formed between hinge pin 61, supports 63 and the trailing edge of housing 13. Insertion occurs in the direction designated by arrow A in Figure 5. Arms 33, 73 of hinge assembly 27 enter the areas flanking blocks 65 of hinge assembly 59. Outer surfaces 35 of arms 33 abut surfaces 85 of support 63. The interaction of outer surfaces 35 with inner surfaces 85 laterally align pins 3 and contacts 100 along an axis parallel to the trailing edges of cassette 11 and housing 13. In the mated, open condition shown in Figure 1b, surfaces 75 of blocks 65 begin to abut second surfaces 69, 77 of extensions 29 and central extension 39 as cassette 11 rotates along the direction of arrow B in Figure 5. Surfaces 69, 75, 77 help align cassette 11 and receptacle 13 along an axis parallel to the sides of cassette 11 and housing 13. Preferably, the other adjacent surfaces of arms 33, supports 63 and blocks 65 have a clearance therebetween to reduce the amount of force required to rotate cassette 11. Extensions 29 and central extension 39 provide a retaining force on opposite sides of hinge pin 61 as seen in Figure 5 due to the opposite orientation of central element 39 relative to extensions 29. The retaining forces, along with the placing of extensions 29 and central extension 39 between hinge pin 61 and housing 13 prevents separation of cassette 11 from housing 13. In other words, cassette 11 can only separate from housing 13 by reversing the mating process (i.e. rotating cassette 11 away from housing 13). Rotation of cassette 11 relative to housing 13 begins the mating of pins 3 of electrical component 1 and contacts 100 in housing 13. As seen in Figure 5, the column of pins 3 and contacts 100 closest to the trailing edges of cassette 11 and housing 13 mate first. Mating progresses with each subsequent column away from the trailing edges of cassette 11 and housing 13. Sequential mating of pins 3 and contacts 100 reduces the peak insertion force when compared to ZIF sockets. The column of pins 3 and contacts 100 closest to the trailing edges of cassette 11 and housing 13 mate first. Mating progresses with each subsequent column away from the trailing edges of cassette 11 and housing 13. The rotation of cassette 11 begins the mating of pins 3 and contacts 100. Each pin 3 progressively enters the space between the opposite arms of the dual beam contacts during rotation. The dual beams retain pin 3. The area between the dual beams is oriented generally parallel to the mating axis of cassette 11 and housing 13. Figure 1a shows connector 10 in a fully mated and closed condition. While mated, wall 55 of housing 13 surrounds cassette 11 and tab 25 can enter recess 57 in the leading edge of housing 13. While the present invention has been described in connection with the preferred embodiments of the various figures, it is to be understood that other similar embodiments may be used or modifications and additions may be made to the described embodiment for performing the same function of the present invention without deviating therefrom. Therefore, the present invention should not be limited to any single embodiment, but rather construed in breadth and scope in accordance with the recitation of the appended claims.

Claims: A connector (10) for electrically connecting an electrical component (1), having a plurality of conductive elements (3) extending therefrom, to a substrate (S), comprising: a first base (15) adapted to engage the electrical component (1) and comprising: at least one aperture (17) extending therethrough and adapted to receive at least a portion of the electrical component (1) therein; and a hinge assembly (27); and a second base (41) adapted to mount to the substrate and comprising: a plurality of contacts (100) corresponding to the conductive elements (3) in the electrical component (1); and a hinge assembly (39) engageable with said hinge assembly (27) of said first base (15) to allow a rotative movement of said first base relative to said second base for mating or dismating said conducting elements (3). The connector as recited in claim 1, wherein said at least one aperture (17) comprises a plurality of apertures, and said first base (15) further comprises a surface facing said second base (41) and having a plurality of bridges spanning between adjacent apertures (17). The connector as recited in claim 1, wherein said first base (15) includes a structure (21) for securing the electrical component (1) to said first base. The connector as recited in claim 3, wherein said structure comprises a latch (21). The connector as recited in claim 4, wherein said latch (21) extends from a wall (19) extending at least partially around said perimeter of said first base (15). The connector as recited in claim 1, wherein said at least one aperture (17) comprises a plurality of apertures, each adapted to receive a corresponding one of the conductive elements (3) of the electrical component (1). The connector as recited in claim 1, wherein said plurality of contacts (100) form an array of columns extending generally parallel to said hinge assembly (39) of said second base; (41) and said hinge assemblies (27, 39) are adapted to mate successive columns of contacts (100) with the conductive elements (3) of the electrical component (1). The connector as recited in claim 1, wherein said plurality of contacts (100) comprise dual beam contacts having a contact space extending between said dual beams and parallel to said hinge assemblies (27,39). The connector as recited in claim 1, further comprising a plurality of fusible elements (105), each secured to a respective one of said plurality of contacts (100) for securing said second base (41) to the substrate. The connector as recited in claim 9, wherein said plurality of fusible elements (105) are solder balls. The connector as recited in claim 1, in combination with an electrical component (1) having a plurality of conductive elements (3) extending therefrom, said electrical component (1) removably seatable within said aperture (17) in said first base (15) and engageable with said plurality of contacts (100) in said second base (41). The connector as recited in claim 11, wherein said electrical component (1) is one of a pin grid array component and a multi-chip module. The connector as recited in claim 12, wherein said electrical component (1) includes an IC chip. A cassette (11) adapted to interact with a housing (13) to secure an electrical component to a substrate, comprising: a base (15); a hinge (27) for rotative movement with a complementary hinge of the interacting housing; and at least one aperture (17) extending through said base (15) and adapted to receive at least a portion of the electrical component (1). The cassette as recited in claim 14, wherein said at least one aperture (17) comprises a plurality of apertures (17), each adapted to receive a corresponding one of said conductive elements (3) of said electrical component (1). The cassette as recited in claim 15, wherein said base further comprises a plurality of bridges spanning between adjacent apertures (17). The cassette as recited in claim 14, further comprising a structure for securing said electrical component to said cassette (11). The cassette (11) as recited in claim 17, wherein said structure comprises a latch (21). The cassette as recited in claim 14, in combination with an electrical component (1) having a plurality of conductive elements (3) extending therefrom and engageable with a plurality of contacts (100) in the second base. The cassette as recited in claim 19, wherein said electrical component (1) is one of a pin grid array component and a multi-chip module. The cassette as recited in claim 20, wherein said electrical component (1) includes an IC chip. A housing (13) adapted to interact with a cassette (11) for attaching an electrical component (1), having a plurality of conductive elements (3) extending therefrom, to a substrate, comprising: a base: a hinge (27) for rotative movement with a complementary hinge of the interacting cassette; and a plurality of contacts in said base and forming an array of columns adapted to receive the conductive elements (3) of the electrical component (1). The housing (13) as recited in claim 22, wherein said plurality of contacts are dual beam contacts having a contact space extending between said dual beams and parallel to said hinge. The housing (13) as recited in claim 22, further comprising a plurality of fusible elements, each secured to a respective one of said plurality of contacts (100) for securing said housing to the substrate. The housing as recited in claim 24, wherein said plurality of fusible elements are solder balls.

Inventors: HOUTZ TIMOTHY W, JOHNSON LEWIS R, LEMKE TIMOTHY A, OLSON STANLEY W, HOUTZ, TIMOTHY W., JOHNSON, LEWIS R., LEMKE, TIMOTHY A., OLSON, STANLEY W.
Applicants: FRAMATONE CONNECTORS INT, FCI
Application year: 1999
Main classification: H01R12
IPC codes: H01R33, H01R13, H05K7