IC package assembly with retention mechanism

• US 6,449,157 B1
• Filed: 10/03/2001
• Issued: 09/10/2002
• Est. Priority Date: 10/03/2001
• Status: Expired due to Fees

• Current Assignee: Ho Kang Chu
• Original Assignee: Ho Kang Chu
• Inventors: Chu, Ho Kang
• Primary Examiner(s): CHERVINSKY, BORIS LEO
• Application Number:
  US09/970,662
• Time in Patent Office: 342 Days
• Field of Search: 361/702-704, 361/707, 361/709, 361/717-719, 165/80.3, 165/185, 257/706, 257/717-719, 257/722, 257/727, 174/16.3, 248/316.7, 248/510, 244/57, 245/20, 411/516, 411/522, 411/523
• US Class Current: 361/704
• CPC Class Codes: H01L 23/4093 Snap-on arrangements, e.g. clips
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: Y10T 24/44026 for cooperating with aperture in supporting structure or structure-to-be-secured
• CPC Class Codes: Y10T 24/44556 Resilient gripping member

Abstract

A retention mechanism (6, 6′) for an LGA package assembly (1, 1′) consists of a spring clip (60, 60′) and a lever (62, 62′) both attached to a heat sink (5, 5′). The spring clip has a biasing strip (612, 612′) and a pair of opposite engaging legs (610, 610′). The lever includes an arcuate section (680, 680′) positioned beneath the biasing strip, whereby the lever is rotatable from a vertical position where the arcuate section is contained in a plane parallel with the biasing strip to a horizontal position where the arcuate section is contained in a plane perpendicular to the biasing strip and engages with the biasing strip. When the lever is rotated to the horizontal position, the biasing strip is biased upwardly to cause the engaging legs to abut against a bottom surface (22) of a PCB (2), whereby the components of the LGA package assembly are mechanically and electrically connected to one another.

Claims

1. An IC (Integrated Circuit) package assembly comprising:

a PCB (Printed Circuit Board) having a plurality of contact pads on a top surface thereof;

a socket mounted on the PCB, the socket receiving a plurality of contacts each having oppositely projecting contact portions;

an IC package coupled to the socket and having a plurality of contact pads on a bottom surface thereof;

a heat sink positioned on the IC package, the heat sink including a planar substrate and a plurality of heat dissipating fins upwardly extending from the substrate; and

a retention mechanism for mechanically and electrically assembling the PCB, the socket, the IC package and the heat sink together, the retention mechanism comprising;

a spring clip attached to a top surface of the substrate of the heat sink and disengaged from the heat dissipating fins, the spring clip having a pair of engaging legs and a biasing strip between the pair of engaging legs substantially parallel with the substrate of the heat sink; and

a lever having an actuation beam retentively seated on the top surface of the substrate of the heat sink, the actuation beam having an arcuate section located beneath the biasing strip of the spring clip, the lever being rotatable from a first position where the arcuate section is contained in a plane parallel with the biasing strip of the spring clip to a second position where the arcuate section is contained in a plane perpendicular to the biasing strip of the spring clip and engages with the biasing strip of the spring clip;

wherein, when the lever is rotated to the second position to engage with the biasing strip of the spring clip, the biasing strip is biased upwardly to engage the engaging legs of the spring clip with a bottom surface of the PCB, whereby a reliable electrical connection is established between the contact portions of the contacts of the socket and corresponding contact pads of the IC package and the PCB.

2. The IC package assembly as described in claim 1, wherein the first and second positions of the lever are, respectively, vertical and horizontal positions relative to the substrate of the heat sink.

3. The IC package assembly as described in claim 1, wherein the PCB defines a pair of holes therein for extension of corresponding engaging legs of the spring clip therethrough, and wherein the pair of engaging legs of the spring clip forms a pair of respective horizontally extending engaging toes for abutting against the bottom surface of the PCB.

4. The IC package assembly as described in claim 1, wherein the actuation beam of the lever extends in a direction perpendicular to that of the biasing strip of the spring clip.

5. The IC package assembly as described in claim 1, wherein the biasing strip of the spring clip has opposite ends thereof connected with corresponding engaging legs via a pair of bent portions having a reversed U-shape.

6. The IC package assembly as described in claim 1, wherein the substrate of the heat sink forms a first pair and a second pair of spaced protrusions on a top surface thereof, the first and second pairs of spaced protrusions defining a space therebetween for accommodating the arcuate section of the actuation beam of the lever while opposite ends of the actuation beam of the lever are received within the respective first and second pairs of spaced protrusions.

7. The IC package assembly as described in claim 6, wherein the spring clip has a downwardly extending yoke loosely received in an engaging aperture defined in the substrate of the heat sink proximate one of the first and second pairs of the protrusions, and wherein a free end section of the actuation beam of the lever extends through the yoke.

8. The IC package assembly as described in claim 1, wherein the substrate of the heat sink forms a pair of protrusions defining a groove therebetween for receiving the actuation beam of the lever while the arcuate section of the lever is located beside the protrusions.

9. The IC package assembly as described in claim 8, wherein each protrusion of the heat sink defines an upwardly exposed slot proximate the groove, and wherein the biasing strip of the spring clip forms a pair of projected fingers for being received in corresponding slots.

10. The IC package assembly as described in claim 1, wherein the lever comprises a handling beam opposite to the actuation beam for facilitating handling by a user, and wherein the spring clip forms a catch for receiving the handling beam of the lever when the lever is retained in the second position.

11. The IC package assembly as described in claim 1, further comprising a metal support plate attached to the bottom surface of the PCB for strengthening the PCB, the support plate defining holes aligned with corresponding holes of the PCB for extension of the engaging legs of the spring clip therethrough.

12. The IC package assembly as described in claim 11, further comprising an elastomer sandwiched between the PCB and the support plate and also between the IC package and the heat sink.

13. An IC (Integrated Circuit) package assembly comprising:

a PCB (Printed Circuit Board) having a plurality of contact pads on a top surface thereof;

a socket mounted on the PCB, the socket receiving a plurality of contacts each having oppositely projecting contact portions;

an IC package coupled to the socket and having a plurality of contact pads on a bottom surface thereof;

a heat sink positioned on the IC package, the heat sink including a planar substrate and a plurality of heat dissipating fins upwardly extending from the substrate; and

a retention mechanism for mechanically and electrically assembling the PCB, the socket, the IC package and the heat sink together, the retention mechanism comprising;

a spring clip attached to a top surface of the substrate of the heat sink and disengaged from the heat dissipating fins, the spring clip having a pair of engaging legs and a biasing strip between the engaging legs substantially parallel with the substrate of the heat sink; and

a lever having an actuation beam retentively seated on the top surface of the substrate of the heat sink beneath the biasing strip of the spring clip, the lever being rotatable from a vertical position where the actuation beam is disengaged from the biasing strip of the spring clip to a horizontal position where the actuation beam is engaged with the biasing strip of the spring clip;

wherein, when the lever is rotated to the horizontal position to engage the actuation beam thereof with the biasing strip of the spring clip, the engaging legs of the spring clip are actuated to press against a bottom surface of the PCB, whereby a reliable electrical connection is established between the opposite contact portions of the contacts of the socket and corresponding contact pads of the IC package and the PCB.

14. The IC package assembly as described in claim 13, wherein the actuation beam of the lever includes an arcuate section, the arcuate section being contained in a plane parallel with the biasing strip of the spring clip when the lever is in the vertical position and being contained in a plane perpendicular to the biasing strip of the spring clip when the lever is in the horizontal position.

15. The IC package assembly as described in claim 13, wherein the PCB defines a pair of holes therein for extension of corresponding engaging legs of the spring clip therethrough, and wherein the pair of engaging legs of the spring clip forms a pair of respective horizontally extending engaging toes for abutting against the bottom surface of the PCB.

16. The IC package assembly as described in claim 13, wherein the actuation beam of the lever extends in a direction perpendicular to that of the biasing strip of the spring clip.

17. The IC package assembly as described in claim 13, wherein the biasing strip of the spring clip has opposite ends thereof connected with corresponding engaging legs via a pair of bent portions having a reversed U-shape.

18. The IC package assembly as described in claim 13, wherein the lever comprises a handling beam opposite to the actuation beam for facilitating handling by a user, and wherein the spring clip forms a catch for receiving the handling beam of the lever when the lever is retained in the horizontal position.

19. A retention mechanism for mechanically and electrically assembling a PCB (Printed Circuit Board), a socket, an IC (Integrated Circuit) package and a heat sink which are arranged in order, the retention mechanism comprising:

a spring clip for being attached to the heat sink, the spring clip having a pair of engaging legs and a biasing strip between the engaging legs, the biasing strip having a downwardly extending yoke and being connected with the engaging legs by a pair of bent portions; and

a lever having an actuation beam adapted for being attached to the heat sink, the actuation beam having an arcuate section located beneath the biasing strip of the spring clip and a free end section extending through and vertically movable in the yoke of the spring clip, the lever being rotatable from a first position where the arcuate section is contained in a plane parallel with the biasing strip of the spring clip to a second position where the arcuate section is contained in a plane perpendicular to the biasing strip of the spring clip and engages with the biasing strip of the spring clip;

wherein, when the lever is rotated to the second position to engage with the biasing strip of the spring clip, the biasing strip is biased upwardly to engage the engaging legs of the spring clip with a bottom surface of the PCB, whereby the heat sink, the IC package, the socket and the PCB are securely attached together and a reliable electrical connection is established between the IC package and the PCB via the socket.

20. A retention mechanism assembly comprising:

a spring clip defining a pair of downwardly extending engaging legs with engaging toes thereof and a biasing strip between the engaging legs;

a PCB (Printed Circuit Board) positioned under said spring clip with means for latchable engagement with said engaging toes of said engaging legs;

a heat sink positioned between said PCB and the biasing strip, said heat sink having a substrate facing said PCB; and

a lever moveably located around said spring clip and said heat sink, said lever including an actuation beam retained to and seated upon a top face of the substrate of said heat sink, and an actuation section which, when said lever is operated at a first position, said actuation section is spaced from a bottom face of said biasing strip so as to form a non-tension condition of the assembly with the engaging toes not latchably engaging the means of the PCB, and when said lever is operated at a second position, said actuation section is engaged with the bottom face of said biasing strip so as to form a tension condition of the assembly with the engaging toes latchably engaging the means of said PCB;

wherein a latch of the lever rests on a catch of the spring clip when said lever is operated at the second position.

21. The assembly as described in claim 20, wherein said lever is rotatable between said first position and said second position around a central axis of the actuation beam.

22. The assembly as described in claim 21, wherein said spring clip and said heat sink are restrained not to move relative to each other in a front-to-back direction parallel to a direction between said first and second positions, by means of either direct engagement between the clip and the heat sink or through said lever being retained to both the clip and the heat sink.

23. The assembly as described in claim 20, wherein said spring clip provides at least one flange abutting against the top face of said heat sink when said clip is in a non-tension condition.