ball grid array devices are mounted in a burn-in and test socket which has a top surface sockets which have top surfaces with windows for the ball terminals terminal balls depending from the ball grad grid array device. contact fingers mounted on the base of the socket extend through a bending plate and into the windows from the opposite side of the top surface. When the bending plate is moved laterally with respect to the top surface, the ends of the contact members are moved into contact with the ball terminals terminal balls. The ends of the contact members are urged into contact with the ball terminals terminal balls between the center of the ball terminal ball and the surface of the ball grid array device, thus retaining the device in the socket.

Patent
   RE39418
Priority
Jun 10 1994
Filed
Nov 17 2000
Issued
Dec 05 2006
Expiry
Jun 10 2014

TERM.DISCL.
Assg.orig
Entity
Small
2
4
all paid
22. Apparatus for mounting a ball grid array device comprising:
(a) a support member having a support face with a plurality of windows therein arranged in a pattern to correspond with and receive ball terminals terminal balls depending from the face of a ball grid array device when said ball grid array device is positioned on the support face of said support member;
(b) a base member;
(c) biasing means having apertures therein substantially corresponding with said windows positioned between said base member and said support member;
(d) a plurality of elongated contact members anchored in said base member, each having an interconnection end and a free end portion disposed on opposite sides of a central section with said central section projecting through an aperture in said biasing means and said free end portion having an extreme end portion thereon positioned in a window in said support member; and
(c) (e) means for moving said free end portions with respect to said window.
0. 34. The combination comprising:
(a) a ball grid array device having a first face and a plurality of terminal balls depending from said first face in a predetermined pattern, each of said terminal balls defining a geometric center spaced from said first face; and
(b) mounting apparatus comprising:
(i) a support member adjacent to which said ball grid array device is located;
(ii) a base member;
(iii) a bending plate having apertures therein substantially corresponding with said terminal balls positioned between said base member and said support member; and
(iv) a plurality of elongated contact members, each having an interconnection end and a free end portion disposed on opposite sides of a central section with said central section projecting through an aperture in said bending plate and said free end portion positioned adjacent to a respective one of said terminal balls and terminating between said first face of said ball grid array and the geometric center of said respective one of said terminal balls.
0. 43. Apparatus for mounting a ball grid array device, the ball grid array device having terminal balls depending from one face of the ball grid array device, and said apparatus comprising:
(a) a base member;
(b) a support member having a support face against which the ball grid array device is located, with said terminal balls extending toward said base member;
(c) biasing means having apertures therein substantially corresponding with said terminal balls, said biasing means positioned between said base member and said support face of said support member;
(d) a plurality of elongated contact members anchored in said base member, each having an interconnection end and a free end portion disposed on opposite sides of a central section with said central section projecting through an aperture in said biasing means and said free end portion having an extreme end portion thereof positioned adjacent respective ones of the terminal balls; and
(e) means for moving said free end portions with respect to said terminal balls.
0. 31. Apparatus for mounting a ball grid array device, the ball grid array device having terminal balls depending from one face of the ball grid array device, and said apparatus comprising:
(a) a support member having a support face on which said ball grid array device is located relative to said support member;
(b) a base member;
(c) biasing means having apertures therein substantially corresponding with the locations of said terminal balls;
(d) a plurality of elongated contact members anchored in said base member, each having an interconnection end and a free end portion disposed on opposite sides of a central section with said central section projecting through an aperture in said biasing means and said free end portion defining a generally central axis with the extreme end portion of said free end portion deviated from said central axis and positioned adjacent a respective one of said terminal balls of said ball grid array device; and
(e) means for moving said free end portions with respect to said support member.
10. Apparatus for mounting a ball grid array device comprising:
(a) a support member having a support face with a plurality of windows therein arranged in a pattern to correspond with and receive ball terminals terminal balls depending from the face of a ball grid array device when said ball grid array device is positioned on the support face of said support member;
(b) a base member;
(c) biasing means having apertures therein substantially corresponding with said windows positioned between said base member and said support member;
(d) a plurality of elongated contact members anchored in said base member, each having an interconnection end and a free end portion disposed on opposite sides of a central section with said central section projecting through an aperture in said biasing means and said free end portion defining a generally central axis with the extreme end portion of said free end portion deviated from said central axis and positioned in a window in said support member; and
(c) (e) means for moving said free end portions with respect to said window.
21. Apparatus for mounting a ball grid array device comprising:
(a) a support member having a support face with a plurality of windows therein arranged in a pattern to correspond with and receive terminal balls depending from one face of a ball grid array device when said ball grid array device is positioned on the support face of said support member;
(b) a base member;
(c) a bending plate having apertures therein substantially corresponding with said windows positioned between said base member and said support member and adapted for lateral movement with respect to said support member;
(d) a plurality of elongated contact member members anchored in said base member, each having an interconnection end and a free end portion disposed on opposite sides of a central section with said central section projecting through an aperture in said bending plate and said free end portion positioned in a window in said support member; and
(c) (e) a cam adapted to move the position of said bending plate laterally with respect to said support member and thereby move said free end portions within said windows.
13. The combination comprising:
(a) a ball grid array device having a first face and a plurality of terminal balls depending from said first face in a predetermined pattern, each of said ball terminals terminal balls defining a geometric center spaced from said first face; and
(b) mounting apparatus comprising:
(i) a support member having a support face with a plurality of windows therein arranged in a pattern to correspond with and receiving said terminal balls depending from said first face of said ball array device;
(ii) a base member;
(iii) a bending plate having apertures therein substantially corresponding with said windows positioned between said base member and said support member; and
(iv) a plurality of elongated contact members, each having an interconnection end and a free end portion disposed on opposite sides of a central section with said central section projecting through an aperture in said bending plate and said free end portion positioned in one of said windows in said support member and terminating between said first face of said ball grid array and the geometric center of a terminal ball.
0. 50. Apparatus for use with a ball grid array device of the type having an array of terminal balls extending therefrom, said apparatus comprising:
a support member having a support face for supporting thereon the ball grid array device, said support member having a stop for engaging the ball grid array device to locate the ball grid array device with respect to said support member;
a bending member having a plurality of apertures generally registered with the terminal balls when the ball grid array device is located with respect to said support member;
a base member;
a plurality of elongated contact members secured in said base member and extending from said base member, through respective ones of said apertures in said bending member and toward the ball grid array device, said elongated contact members each having contact ends extending so as to be positioned to a side of a respective terminal ball of said ball grid array device; and
a cam adapted for moving at least one of said bending member and said support member to thereby move the contact ends of said elongated contact members sideways into contact with respective terminal balls.
0. 23. Apparatus for mounting a ball grid array device, the ball grid array device having terminal balls depending from the ball grid array device, and the apparatus comprising:
(a) a support member having a support face, wherein the ball grid array device is positioned on said support face of said support member;
(b) a base member;
(c) a bending plate having apertures therein substantially corresponding with the terminal balls, said bending plate positioned between said base member and said support face of said support member and adapted for lateral movement with respect to said support member;
(d) a plurality of elongated contact members anchored in said base member, each having an interconnection end and a face end portion disposed on opposite sides of a central section with said central section projecting through an aperture in said bending plate, and said free end portion positioned to extend adjacent to a respective one of the terminal balls of the ball grid array device; and
(e) a cam adapted to move the position of said bending plate laterally with respect to said support member and thereby urge said free end portions into contact with the terminal balls.
1. Apparatus for mounting a ball grid array device comprising:
(a) a support member having a support face with a plurality of windows therein arranged in a pattern to correspond with and receive terminal balls depending from one face of a ball grid array device when said ball grid array device is positioned on the support face of said support member;
(b) a base member;
(c) a bending plate having apertures therein substantially corresponding with said windows positioned between said base member and said support member and adapted for lateral movement with respect to said support member;
(d) a plurality of elongated contact members anchored in said base member, each having an interconnection end and a free end portion disposed on opposite sides of a central section with said central section projecting through an aperture in said bending plate and said free end portion positioned in a window in said support member; and
(e) a cam adapted to move the position of said bending plate laterally with respect to said support member and thereby urge said free end portions into contact with said terminal balls between the centerline thereof and the face from which they depend.
0. 42. Apparatus for mounting a ball grid array device, the ball grid array device having terminal balls depending from the ball grid array device, and said apparatus comprising:
(a) a support member having at least one support surface against which the ball grid array device is disposed to locate the ball grid array device in a desired position relative to said support member;
(b) a base member;
(c) a bending plate having apertures therein substantially corresponding with the terminal balls, said bending plate positioned between said base member and said support member and adapted for lateral movement with respect to said support member;
(d) a plurality of elongated contact members anchored in said base member, each having an interconnection end and a free end portion disposed on opposite sides of a central section with said central section projecting through an aperture in said bending plate and said free end portion positioned adjacent to a respective one of the terminal balls; and
(e) a cam adapted to move the position of said bending plate laterally with respect to said support member and thereby move said free end portions against respective ones of the terminal balls.
0. 46. Apparatus for mounting a ball grid array device, the ball grid array device having an array of terminal balls depending from the ball grid array device, and said apparatus comprising:
(a) a support member having a support face, wherein the ball grid array device is positioned on said support face such that at least a portion of said support face supportingly engages the ball grid array device;
(b) a base member;
(c) a bending plate having apertures therein substantially corresponding in relative relation with the terminal balls depending from the ball grid array device and adapted for lateral movement with respect to said support member;
(d) a plurality of elongated contact members anchored in said base member, each having an interconnection end and a free end portion disposed on opposite sides of a central section, with said central section projecting through a respective one of said apertures in said bending plate and said free end portion positioned to extend adjacent to a respective one of the terminal balls of the ball grid array device; and
(e) a cam adapted to move the position of said bending plate laterally with respect to said support member and thereby urge said free end portions of said elongated contact members into contact with the respective ones of the terminal balls.
2. Apparatus as defined in claim 1 wherein said free end portion of each of said contact members has a generally central axis and the extreme end of said end portion is deviated from said generally central axis.
3. Apparatus as defined in claim 2 wherein each said extreme end portion extends into a window in the support member but does not extend through said window.
4. Apparatus as defined in claim 1 wherein said cam contacts and moves said bending plate.
0. 5. Apparatus as defined in claim 1 wherein said cam contacts and moves said support member.
6. Apparatus as defined in claim 4 further comprising spring means to urge said bending plate laterally with respect to said support member.
7. Apparatus as defined in claim 5 1 further comprising spring means to urge said support member laterally with respect to said bending plate.
8. Apparatus as defined in claim 2 wherein the extreme end of said free end portion of each of said contact members extends into a window in said support member a sufficient distance to contact a ball terminal ball positioned in said window between the center of the ball terminal ball and the face of the device from which such ball terminal ball depends.
9. Apparatus as defined in claim 1 further comprising spacers removeably removably affixed adjacent said support face to at least partially define the periphery of a ball grid array device to be positioned on said support face.
11. Apparatus as defined in claim 10 wherein each said extreme end portion extends into a window in the support member but does not extend through said window.
12. Apparatus as defined in claim 10 further comprising spacers removeably removably affixed adjacent said support face to at least partially define the periphery of ball grid array devices to be positioned on said support face.
14. The combination defined in claim 13 wherein said free end portion of each of said contact members has a generally central axis and the extreme end of said end portion is deviated from said generally central axis.
15. The combination defined in claim 14 wherein each said extreme end portion extends into a window in the support member but does not extend through said window.
16. The combination defined in claim 13 including means for moving said free end portions with respect to said windows.
17. The combination defined in claim 16 wherein said means for moving comprises a rotatable cam adjacent said bending plate which, when rotated, coacts with said bending plate to move said plate laterally with respect to said support member.
18. The combination defined in claim 17 wherein said means for moving includes a spring positioned to urge said bending plate laterally with respect to said support member.
19. The combination defined in claim 16 wherein said means for moving comprises a rotatable cam adjacent said support member which, when rotated, coacts with said support member to move said support member laterally with respect to said bending plate.
20. The combination defined in claim 19 wherein said means for moving includes a spring positioned to urge said support means laterally with respect to said bending plate.
0. 24. Apparatus as defined in claim 23 wherein said free end portion of each of said contact members has a generally central axis and the extreme end of said end portion is deviated from said generally central axis.
0. 25. Apparatus as defined in claim 24 wherein each said extreme end portion extends into an open space in said support member but does not extend through said open space in said support member.
0. 26. Apparatus as defined in claim 23 wherein said cam contacts and moves said bending plate.
0. 27. Apparatus as defined in claim 26 further comprising spring means to urge said bending plate laterally with respect to said support member.
0. 28. Apparatus as defined in claim 23 further comprising spring means to urge said support member laterally with respect to said bending plate.
0. 29. Apparatus as defined in claim 24 wherein the extreme end of said free end portion of each of said contact members extends beneath a face of the ball grid array device from which said terminal balls depend a sufficient distance to contact a terminal ball between the center of the terminal ball and the face of the device from which such terminal ball depends.
0. 30. Apparatus as defined in claim 23 further comprising spacers removeably affixed adjacent said support face to at least partially locate the periphery of a ball grid array device relative to said support member.
0. 32. Apparatus as defined in claim 31 wherein each said extreme end portion extends into an open space in said support member but does not extend through said open space in said support member.
0. 33. Apparatus as defined in claim 31 further comprising spacers removably affixed adjacent said support face to at least partially locate the periphery of ball grid array devices relative to said support face.
0. 35. The combination defined in claim 34 wherein said free end portion of each of said contact members has a generally central axis and the extreme end of said end portion is deviated from said generally central axis.
0. 36. The combination defined in claim 35, wherein each said extreme end portion extends into an open space in said support member but does not extend through said open space in said support member.
0. 37. The combination defined in claim 34 including means for moving said free end portion with respect to the terminal balls depending from the face of the ball grid array device.
0. 38. The combination defined in claim 37 wherein said means for moving comprises a rotatable cam adjacent said bending plate which, when rotated, coacts with said bending plate to move said plate laterally with respect to said support member.
0. 39. The combination defined in claim 38 wherein said means for moving includes a spring positioned to urge said bending plate laterally with respect to said support member.
0. 40. The combination defined in claim 37 wherein said means for moving comprises a rotatable cam adjacent said support member which, when rotated, coacts with said support member to move said support member laterally with respect to said bending plate.
0. 41. The combination defined in claim 40 wherein said means for moving includes a spring positioned to urge said support means laterally with respect to said bending plate.
0. 44. Apparatus as defined in claim 43, wherein said terminal balls extend downward from said support face, and said base member is disposed beneath said support face.
0. 45. Apparatus as defined in claim 43 wherein each said extreme end portion extends into an open space in said support member but does not extend through said open space in said support member.
0. 47. Apparatus as defined in claim 46 wherein said free end portion of each of said contact members has a generally central axis and the extreme end of said end portion is deviated from said generally central axis.
0. 48. Apparatus as defined in claim 46 wherein the extreme end of said free end portion of each of said contact members extends a sufficient distance to contact a respective terminal ball between the center of the terminal ball and the face of the device from which such terminal ball depends.
0. 49. Apparatus as defined in claim 46 further comprising spacers disposed adjacent said support face to at least partially locate a periphery of the ball grid array device in a lateral position relative to said on said support face.
0. 51. The apparatus of claim 50, wherein said support member is positioned over said bending member, and said bending member is positioned over said base member, and said contact ends of said elongated contact members extend into an area occupied by said support member, whereby when the ball grid array device rests on said support face and is engaged with said stop, said contact ends of said elongated contact members are adjacent respective terminal balls of the ball grid array device.
0. 52. The apparatus of claim 51, wherein said support member includes in said area occupied by said support member, an array of windows, and each contact end of said contact members extends into a respective one of said windows.
0. 53. Apparatus as defined in claim 50 wherein said free end portion of each of said contact members has a generally central axis and the extreme end of said end portion is deviated from said generally central axis.
0. 54. Apparatus as defined in claim 50 wherein said cam contacts and moves only one of said bending member and said support member, and said apparatus further comprising spring means to urge said one of said bending plate and said support plate laterally with respect to the other of said bending plate and said support member.
0. 55. Apparatus as defined in claim 50 herein the extreme end of said free end portion of each of said contact members extends a sufficient distance to contact a respective terminal ball between the center of the terminal ball and the face of the device from which such terminal ball depends.
0. 56. Apparatus as defined in claim 50, wherein said stop comprises a spacer disposed adjacent said support face to at least partially locate a periphery of the ball grid array device laterally relative to with respect to said support face.
(see FIG. 1A). The As shown in FIG. 1A the windows 23 are arranged in a grid pattern matching the grid pattern of the ball terminals terminal balls 12. As shown in FIGS. 2, 3, 6 and 7 top support member 22 defines a single window into which all the terminal balls depend and into which the contact fingers extend with their ends arranged in a grid pattern matching the grid pattern of the terminal balls 12. To accommodate ball grid array devices of different dimensions, the top face 24 of support member 22 may be provided with removeable spacers 35 of various sizes. The spacers 35 define the periphery of each particular ball grid array device and position the ball grid array device to prevent movement thereof laterally with respect to top face 24. Spacers 35 therefore assure that each ball grid array is aligned with the ball terminals terminal balls 12 depending from the lower face 11 thereof in proper registry and orientation with windows 23 and may be changed as required for each size and shape of ball grid array device package.

In the preferred embodiment illustrated in FIG. 1 the socket of the invention is formed of a plurality of plate-like components (described in detail hereinafter) contained within a unitary box-like housing 100 having an open top and open bottom. As illustrated in the embodiment of FIGS. 2, 3 and 4 the housing contains a base member 21 which has a plurality of apertures 30 therein positioned substantially in registry with windows 23 in support member 22. Each aperture 30 has an internal shoulder 31 (see FIG. 4). An elongated contact finger 40 is positioned in each aperture 30. In the preferred embodiment, each elongated contact finger defines an axially elongated body of resilient electrically conductive material such as nickel-coated steel or the like. The mid-section 43 of each contact finger 40 is substantially widened to form shoulders 45 and 46 on opposite ends thereof. Accordingly, when contact fingers 40 are inserted in the base member 21, tail portions 41 project through apertures 30 and shoulders 46 rest on shoulders 31. Trap plate 25 having apertures 32 and shoulders 33 in registry with and corresponding to apertures 30 is secured to base member 21 and shoulders 33. The upper portion 44 of each contact finger 40 extends through an aperture 32 and the shoulders 33 on aperture 32 contact shoulders 45 on the expanded mid-sections 44 of the contact fingers. Accordingly, the contact fingers 40 are securely entrapped and held in place in the base member 21 by trap plate 25.

The lower ends of the contact fingers 40 extend from the lower face of base support 22 to define input/output tails 41. Tails 41 may be secured in a suitable circuit board, burn-in board or the like. Alternatively, other means for making electrical contact to the circuitry of the supporting medium may be used.

The upper portion 44 of each contact finger 40 which extends above the mid-section 43 projects through an aperture 54 in bending plate 28 with its free end 42 terminating in window 23. In the preferred embodiment, the free end portion 42 of each finger 40 is sufficiently elongated to define a generally central axis which is substantially perpendicular to the support surface 24 and extends into a window 23. The extreme end 42a, however, is bent or curved to deviate from the central axis and extends into the window 23 toward the support surface 24 but does not extend through the window 23 or surface 24. For best results, the extreme end 42a should extend as near the surface 24 as possible without extending therethrough. It is only necessary, however, that the extreme end 42a be above the centerline of the ball terminal which it contacts.

In the preferred embodiment of FIG. 1A each window 23 has a small recess 23a which accommodates the end portion 42 of contact finger 40. As illustrated in FIGS. 2, 3 and 4 bending plate 28 is positioned between trap plate 25 and support member 22 but is free for reciprocal movement laterally with respect to the housing. Since mid-sections 43 of contact fingers 40 are securely anchored between the base member 21 and trap plate 25, lateral movement of bending plate 28 causes corresponding lateral movement of the free end portions 42 of contact fingers 40.

Rotatable cam 50 extends horizontally through the mounting housing adjacent one end surface 29 of the bending plate. The cam 50 is secured in housing 100 on one end by retainer 53. The opposite end of the cam 50 is controlled by lever 52. A lobe 51 extending from cam 50 is moved into contact with end surface 29 of plate 28 when lever 52 is moved in a first direction. Thus, rotation of a cam 50 (counter-clockwise as shown in FIG. 2) cams bending plate 28 in the same direction (to the left as shown in FIG. 2). Movement of bending plate 22 thus forces the free end portions 42 in the same direction, withdrawing them from recesses 23a and causing them to laterally traverse the window 23. It should be recognized that a rotating cam 50 is the presently preferred means for moving plate 28. Other means such as wedge plates, ratchets, plungers and rack-and-pinion arrangements, to name a few, may be designed to perform the relative movement function of the cam. Thus the terms “cam” and “cam plate” are used herein to describe any mechanical arrangement which moves the upper portion 44 of the contact fingers laterally with respect to the support member 22.

The position of the upper portions 44 of contact fingers 42 in the housing in the open condition is illustrated in FIG. 2. In this position the contact fingers 40 are either relaxed or forced into the open position by bending plate 28. If desired, a spring (not shown) may be positioned between the housing 100 and the end of the plate 28 opposite end 29 to ensure that the free end portions 42 are withdrawn into recesses 23a. Accordingly, a ball grid array device may be positioned with the ball terminals terminal balls 12 depending into windows 23 by simply positioning the ball grid array in the proper position. Since the free end portions 42 are withdrawn into recesses 23a, the ball terminals terminal balls 12 simply depend into windows 23. Thus, no pressure of any sort is applied to any portion of the ball grid array device 10 or the depending ball terminals terminal balls 12. Furthermore, no force is applied (other than gravitational) to any portion of the socket by the electronic device package or the ball terminals terminal balls. When the ball grid array device is securely in place, lever 52 is moved to rotate cam 50 and urge lobe 51 into contact with the end surface 29 of bending plate 28. As plate 28 is moved (to the left as shown in FIG. 2) by lobe 51, the free end portions 42 of the contact fingers 40 uniformly and simultaneously move toward and into contact with the ball terminals terminal balls 12 depending into the windows 23.

As best shown in FIG. 1A and graphically illustrated in FIG. 5, the free end portions 42 of contact fingers 40 are positioned to extend into windows 23 near surface 24 but do not extend above surface 24. Furthermore, the free end portions 42 are bent so that the extreme end 42a deviates from the vertical axis of the pin 40 toward the ball terminal ball 12 to form a cup or hook at the extreme end 42a of the contact finger 40. As illustrated in FIG. 5, the extreme end 42a of free end portion 42 must extend above the centerline of the ball terminal ball 12. For representative purposes, FIG. 5 illustrates the relative position of extreme end 42a in contact with a ball terminal ball when the nominal ball size is 0.030 inch. Nominal ball sizes of 0.030 inch may vary from about 0.035 to about 0.024 inch in diameter. Thus the point of contact on the ball may vary slightly with variations in ball size. However, as shown in FIG. 5, where the extreme end 42a of free end portion 42 extends at least 0.001 to about 0.002 inch above the extended centerline (the horizontal line passing through the center of the ball terminal ball 12), the point of contact between the extreme end 42a of contact finger 40 will be approximately five degrees (5°) above the extended centerline of the ball terminal ball 12. Thus, since the ball grid array device 10 is trapped and prevented from horizontal movement by spacers 35, pressure exerted against the ball terminals terminal balls 12 by extreme ends 42a of the contact fingers 40 have both a lateral force component and a small downward force component. The ball grid array device 10 is thus trapped and secured against the top face 24 of the support member 22 by the lateral and downward pressure exerted on the ball terminals terminal balls 12 by contact fingers 40.

The relative positions of the Components components of the mounting housing and the ball grid array device when the housing is in the closed condition is illustrated in FIG. 3. Note that lobe 51 on cam 50 has forced plate 28 to the left as shown in FIG. 3. The extreme ends 42a of contact fingers 40 have moved in the same direction until they contact the surface of ball terminals terminal balls 12. As the bending plate 28 moves further to the left, the mid-section 44 of each contact finger 40 is bowed until a contact pressure of approximately thirty-five (35) grams is applied to each ball terminal ball. Since the extreme end 42a of the contact finger 40 is above the centerline of each of ball terminal ball 12, this pressure securely locks the entire ball grid array device adjacent the top surface 24 of the mounting housing and each contact finger 40 is in electrical contact with a ball terminal ball 12 for electrical function testing, etc. However, a pressure in the range of about thirty-five (35) grams is insufficient to damage or dislodge the ball terminals 12.

After testing, burn-in or other procedures have been applied to the ball grid array device 10, the device is released by merely moving lever 52 in the opposite direction, permitting the contact fingers 40 (and springs, if included) to urge plate 28 in the opposite direction and permitting the extreme ends 42a to withdraw into recesses 23. The apparatus of the invention therefore provides a totally zero insertion force socket for mounting ball grid array devices for testing and burn-in. The test device may be simply positioned on the top face of the mounting housing by gravity. No force of any sort is applied to the device package or the ball terminals terminal balls 12 during insertion or removal.

In the embodiment discussed in detail hereinabove, the bending plate 28 is cammed laterally to cause the free ends 42 of the contact fingers 40 to move into contact with the terminal balls 12. It will be recognized, however, that other arrangements may be employed to move the terminal balls 12 with respect to free ends 42 of the contact fingers.

In the embodiment illustrated in FIGS. 6 and 7 the bending plate 28 is maintained in a fixed position and the top support member 22 moved laterally to simultaneously bring the ball terminals 12 into physical contact with the free ends 42 of the contact fingers. In this embodiment, the upper portion 44 of each contact finger 40 extends through an aperture 54 in bending plate 28. The apertures 54 are positioned with respect to the apertures 32 to bias the free ends 42 of the contact finger in a direction which is offset with respect to apertures 32. In the embodiment shown in FIGS. 6 and 7, the contact fingers are reverse-curved in the section which passes through the bending plate 28 and the apertures 54 in the bending plate 28 are positioned to bias the ends 42 in the direction of curvature.

It will be observed that the free ends 42 rest in the recesses 23a in windows 23 when the socket is in the open position. However, when the top support member 22 is moved (to the right as shown in FIG. 7), the ball terminals are simultaneously brought into contact with the free ends 42a of the contact fingers 42 as described hereinabove in connection with the embodiment wherein the bending plate 28 is cammed to move the contact fingers. Other arrangements for effecting the desired relative movement will become apparent to those skilled in the art in view of the foregoing.

When the socket is in the closed position, the extreme ends 42a of the contact fingers 40 each exert a lateral and downward force on the ball terminal at approximately five degrees (5°) above its centerline. The pressure exerted by each individual finger is limited so that there is no risk of damage to the ball terminals 12. Likewise, when the contact fingers 40 are withdrawn (or the top plate moved) to the open position, the ball grid array device 10 may be removed simply by gravity or with a vacuum pencil or the like. It is particularly noteworthy that the invention not only permits total zero insertion force and withdrawal force, no pressure whatsoever is ever applied to the ball grid array device except to the terminal balls 12. In fact, the entire top surface of the ball grid array device is exposed since no lid or cover is employed. Cooling air may be circulated thereover or a heat sink may be applied thereto. Furthermore, since test devices may be loaded simply by vertical movement by gravity, the test apparatus of the invention may be easily loaded and unloaded by automated equipment.

It should be particularly noted that in all configurations of the invention, all reactive forces caused by engagement between the device and the socket are contained within the body of the socket housing and not transmitted to the burn-in board. Note that opening (or closing) the socket by moving the ends 42 of the contact fingers with respect to the ball terminal balls 12 can involve substantial force. For example, a typical contact force requirement is approximately one (1) ounce of force exerted on each terminal ball 12 by each finger 42. In device packages having one thousand terminal balls or more, the cumulative contact force applied is greater than sixty-two (62) pounds. This constitutes a substantial force with which to reckon since a burn-in board or the like may include a multitude of sockets and each socket is repeatedly loaded and unloaded. However, since the contact fingers are moved simultaneously with respect to the ball terminals by rotation of a cam, all opening and closing forces (and their opposing reactive forces) are contained within the socket. Furthermore, the fingers each individually contact only one ball terminal. Thus only about one ounce of force is applied to any one terminal. No substantial force is ever applied to the device package or the supporting burn-in board. Instead, all forces (and reactive forces) applied are contained within the socket housing.

It will be readily recognized that the materials used for manufacture of the mounting housing of the invention may be varied as desired, depending upon the application. Similarly, the physical size and shape of the components may be arranged to accommodate any particular ball grid array device. For example, the contact fingers 40 are shown as axially elongated metal strips as may be cut or stamped from flat ribbon stock. However, the fingers 40 could be formed from wire stock and may be formed into various configurations without departing from the principles of the invention. Likewise, the fingers may be anchored in the socket as desired by any suitable means. If the socket is to be used for burn-in purposes, heat resistant materials, of course, should be employed. The design is particularly attractive for use in hostile environments since, in its preferred embodiment, very few moving parts are employed and the opening and closing functions can be readily automated. Thus the preferred structure is extremely reliable and functional in extended repetitive use.

From the foregoing it will be recognized that the principles of the invention may be employed in various arrangements to obtain the benefit of the many advantages and features disclosed. It is to be understood, therefore, that even though numerous characteristics and advantages of the invention have been set forth together with details of the structure and function of the invention, this disclosure is to be considered illustrative only. Various changes and modifications may be made in detail, especially in matters of size, shape and arrangements of parts, without departing from the spirit and scope of the invention as defined by the appended claims.

Pfaff, Wayne K.

Patent Priority Assignee Title
7972159, Aug 26 2008 Hon Hai Precision Ind. Co., Ltd. Electrical connector for test socket
9244487, Feb 09 2011 Intel Corporation Integrated translational land-grid array sockets and loading mechanisms for semiconductive devices
Patent Priority Assignee Title
4420205, Sep 14 1981 Augat Inc. Low insertion force electronic component socket
4739257, Jun 06 1985 Automated Electronic Technology, Inc. Testsite system
5073117, Mar 30 1989 Texas Instruments Incorporated Flip-chip test socket adaptor and method
5281160, Nov 07 1991 Burndy Corporation Zero disengagement force connector with wiping insertion
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Sep 10 2009PFAFF, WAYNE K PLASTRONICS SOCKET COMPANY, INC ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS 0232340442 pdf
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