A heat sink assembly comprises a heat sink and a retainer clip for attachment to an electronic package or semiconductor device so as to dissipate heat from such device. The heat sink may comprise a flat base with a plurality of upwardly extending fins. The fins will define at least one channel. The retainer clip includes two parts. One part is an elongated, resilient, metal strap that has holding means at each end for engaging a semiconductor socket, or a semiconductor module, so as to secure the retainer clip and heat sink to the device or module. The retainer clip also includes a cam-type latch which is pivotally positioned in the middle of the elongated strap and includes an arm and a cam. The cam has a bearing surface which is spaced from the axis of the elongated member a distance greater than the distance between the elongated member and the upper surface of the heat sink base when in the initially assembled position. When the arm is rotated, the bearing surface of the cam is forced against the upper surface of the heat sink which causes the strap to be displaced upwardly placing pressure on the strap and thereby forcing the heat sink into heat conducting engagement with the electronic device or module.
|
1. In a heat sink assembly providing cooling to an electronic semiconductor device wherein the device is mounted in a module, the module having means for engagement with a retainer clip, and the heat sink having a generally flat bottom surface and heat conducting engagement with the semiconductor device upper surface and a plurality of fins on the upper surface defining at least one channel, the improvement comprising a heat sink retainer clip including:
an elongated, resilient metal strap received in one of the channels of the heat sink having holding means at each end engaging the engagement means on the module, the center portion of the strap spaced a pre-determined distance above the upper surface of the heat sink base when the strap is not in tension; and a cam-type latch pivotally mounted in the center portion of the strap and including a cam with a bearing surface, the distance from the pivot access to the bearing surface of the cam being greater than the distance between the pivot access and the upper surface of the base of the heat sink when said strap is not in tension, and an arm fixedly mounted to said cam, said arm, when rotated, causing said bearing surface of said cam to be forced against the surface of the base of the heat sink placing the strap in tension so as to force the heat sink into heat conducting engagement with the module.
0. 12. In a heat sink assembly providing cooling to an electronic semiconductor device wherein the device is mounted in a module, the module having means for engagement with a retainer clip, and the heat sink having a generally flat bottom surface and heat conducting engagement with the semiconductor device upper surface and a plurality of fins on the upper surface defining at least one channel, the improvement comprising a heat sink retainer clip including:
an elongated, resilient strap received in one of the channels of the heat sink having holding means at each end for engaging the engagement means on the module, the center portion of the strap space a pre-determined distance above the upper surface of the heat sink base when the strap is not in tension; and a cam-type latch pivotally mounted in the center portion of the strap and including a cam with a bearing surface, the distance from the pivot access to the bearing surface of the cam being greater than the distance between the pivot access and the upper surface of the base of the heat sink when said strap is not in tension, and an arm fixedly mounted to said cam, said arm, when rotated, causing said bearing surface of said cam to be forced against the surface of the base of the heat sink placing the strap in tension so as to force the heat sink into heat conducting engagement with the module.
5. A heat sink assembly including a heat sink and a spring retainer clip providing cooling to an electronic integrated circuit device, the device being mounted in a housing, such as a socket or a module, the housing having engagement means for the spring retainer clip, said heat sink assembly comprising:
a heat sink including a metallic plate with a plurality of fins projecting upwardly from the top surface of the plate defining a series of channels; and such spring retainer clip comprising two members: an elongated, resilient metal strap received in one of said channels and holding means at each end of said strap engaging the engagement means on the housing, said strap having a length such that when it is in engagement with the housing, the center portion of the strap is spaced a pre-determined distance above the upper surface of the heat sink base when the strap is not in tension; and a cam-type latch pivotally mounted in the center portion of the strap and including a cam with a bearing surface, the distance from the pivot access to the bearing surface being greater than the distance between the pivot access and the upper surface of the base of the heat sink when said strap is not in tension, and an arm fixedly mounted to said cam, said arm when rotated causing said cam to bear against the surface of the base of the heat sink placing the strap in tension so as to force the heat sink into heat conducting engagement with the housing. 0. 16. A heat sink assembly including a heat sink and a spring retainer clip providing cooling to an electronic integrated circuit device, the device being mounted in a housing, such as a socket or a module, the housing having engagement means for the spring retainer clip, said heat sink assembly comprising:
a heat sink including a metallic plate with a plurality of fins projecting upwardly from the top surface of the plate defining a series of channels; and such spring retainer clip comprising two members: an elongated, resilient strap received in one of said channels and holding means at each end of said strap for engaging the engagement means on the housing, said resilient strap having a length such that when it is in engagement with the housing, the center portion of said strap is good a pre-determined distance above the upper surface of the heat sink base when the strap is not in tension; and a cam-type latch pivotally mounted in the center portion of said strap and including a cam with a bearing surface, the distance from the pivot access to the bearing surface being greater than the distance between the pivot access and the upper surface of the base of the heat sink when said strap is not in tension, and an arm fixedly mounted to said cam, said arm when rotated causing said cam to bear against the surface of the base of the heat sink placing the strap in tension so as to force the heat sink into heat conducting engagement with the housing. 0. 18. A combination heat sink and heat sink retainer clip, for attachment to a rectangular electronic module wherein the rectangular electronic module contains a printed circuit board and at least one semiconductor device, has at least one major wall which is substantially flat and made of a heat conducting material, and includes at least two spaced apart openings each adjacent one of the longer edges of the wall,
said heat sink having a rectangular base substantially the same size as the electronic module major wall and a plurality of cooling fins defining at least one channel, said at least one channel aligned transversely between the at least two spaced apart openings in the electronic module wall; and said retainer clip comprising: an elongated, resilient strap received in said at least one channel and holding means at each end engaging one of the openings in the module wall, said resilient strap having a length such that with each end in engagement with one of the module wall openings, a center portion of said strap is spaced a predetermined distance above the upper surface of the heat sink base when the strap is not in tension; and a cam-type latch is pivotally mounted in the center portion of said strap and including a cam with a bearing surface, the distance from the pivot axis to the cam bearing surface being greater than the distance between the pivot axis and the upper surface of the base of the heat sink when said strap is not in tension, and an arm fixedly mounted to said cam, said arm when rotated causing said cam to bear against the surface of the base of the heat sink and placing the strap in tension so as to force the heat sink into heat conducting engagement with the module wall. 7. A combination heat sink and heat sink retainer clip, for attachment to a rectangular electronic module wherein the rectangular electronic module contains a printed circuit board and at least one semiconductor device, has at least one major wall which is substantially flat and made of a heat conducting material such as metal, and includes at least two spaced apart openings each adjacent one of the longer edges of the wall,
said heat sink having a rectangular base substantially the same size as the electronic module major wall and a plurality of cooling fins defining at least one channel, said at least one channel aligned transversely between the at least two spaced apart openings in the electronic module wall; and said retainer clip comprising: an elongated, resilient, metal strap received in said at least one channel and holding means at each end engaging one of the openings in the module wall, said strap having a length such that with each end in engagement with one of the module wall openings, the center portion of the strap is spaced a predetermined distance above the upper surface of the heat sink base when the strap is not in tension; and a cam-type latch is pivotally mounted in the center portion of the strap and including a cam with a bearing surface, the distance from the pivot axis to the cam bearing surface being greater than the distance between the pivot axis and the upper surface of the base of the heat sink when said strap is not in tension, and an arm fixedly mounted to said cam, said arm when rotated causing said cam to bear against the surface of the base of the heat sink and placing the strap in tension so as to force the heat sink into heat conducting engagement with the module wall. 2. The improved retainer clip set forth in
3. The improved retainer clip of
4. The improved retainer clip of
6. The heat sink assembly of
8. The assembly of
9. The heat sink assembly of
10. The heat sink assembly of
11. The heat sink assembly of
0. 13. The improved retainer clip set forth in
0. 14. The improved retainer clip of
0. 15. The improved retainer clip of
0. 17. The heat sink assembly of
0. 19. The assembly of
0. 20. The heat sink assembly of
0. 21. The heat sink assembly of
0. 22. The heat sink assembly of
|
1. Field of the Invention (Technical Field)
This invention relates to cooling of electronic assemblies.
Since the successful introduction of integrated circuits (ICs), there has been a steady progression toward larger IC devices to permit inclusion of a greater number of functions on the IC. The result is that the heat produced by these larger semiconductor devices is not adequately removed by either natural air convection nor by powered ventilation, such as a fan.
Convection cooling is performed by use of a heat sink that is directly applied to the semiconductor device. It is not desirable to use a bonding process, such as an adhesive, because of the permanent nature of such attachment; a semiconductor device may be discarded if malfunctioning and it is not desirable to throw away the heat sink too. It has therefore been found desirable to attach the heat sink to the chip or device by mechanical means such as a retainer clip. The typical heat sink currently in use comprises a flat plate generally the same size as the device, with a plurality of radiation tins extending upwardly. The heat sink is commonly fabricated from aluminum and is extruded and subsequently machined.
A new development in the electronic assembly art particularly for microprocessor semiconductor devices, utilizes a cartridge which contains a printed circuit board on which the microprocessor is mounted. The cartridge may be formed of plastic except for one major surface which may be constructed of metal so as to provide a thermal interface or plate for attachment of a heat sink. At least one major microprocessor supplier, Intel, has established a specification for the cartridge including the thermal plate. To facilitate the proper attachment of the heat sink to the cartridge thermal plate, the thermal plate is provided with multiple openings to permit the engagement of a heat sink retaining clip, or multiple clips.
The present invention will be described in its preferred embodiment in connection with the above-described microprocessor cartridge. However, it should be understood that the heat sink assembly, i.e. the heat sink and retainer clip, may also be used directly with a semiconductor device mounted directly on a printed circuit board or a socket.
2. Background and Prior Art
A wide variety of heat sink assemblies and retainer clips are available in the prior art. For example, the applicant's earlier U.S. Pat. No. 5,600,540 shows a heat sink and retainer for electronic integrated circuits comprising a two-piece retainer clip particularly adapted for use in connection with a semiconductor device mounted directly on a socket which in turn is attached to a printed circuit board. Another device is shown in applicant's earlier U.S. Pat. No. 5,208,731 which is a single-piece retainer clip for a similar chip, socket, and heat sink assembly. Other devices are shown in Bright U.S. Pat. Nos. 5,448,449 and 4,716,494 the former showing both one or two piece retainer clips for securing a heat sink to a semiconductor chip which is mounted in a socket and the latter showing a similar assembly with a different type of heat sink. Other prior art includes Clemens U.S. Pat. No. 5,371,652 which shows several types of retainer clips for attaching a heat sink directly to a semiconductor chip.
In all of the above-described devices, a common problem is the cost of the retainer clip and, much more importantly, the labor required to properly attach the retainer clip to secure the heat sink to the semiconductor chip and/or socket. It must be understood that when a semiconductor device such as a microprocessor is used in a personal computer, literally millions of chips, sockets, heat sinks, and retainer clips are used in these ubiquitous products. Thus, the time in which it takes to properly secure the heat sink in position and to attach it to the semiconductor device or socket becomes a critical consideration in the cost-effectiveness of a retainer clip. Other problems include design of a retainer clip so that there is a positive and easily recognized proper engagement of the retainer clip. If the means for attaching the retainer clip to the socket and/or chip is not positive in a sense that a retainer clip can only be attached or detached, with no middle ground, the assembly may not be attached yet that may not be noticeable to the technician or assembler performing that operation. The result is that when the computer or other electronic device is shipped, and is subjected to various forces, shaking, vibration, and other environmental shipping conditions the retainer clip may be unloosed with the result that the heat sink becomes disengaged and can ruin other components within the electronic device as the device is continued to be roughly handled in shipping. Even if other components are not damaged, with the heat sink dislodged, there being little likelihood that the user will be aware of such problem, the semiconductor device can be easily overheated and damaged or destroyed.
Still another problem with prior art devices is the cost of the retainer clip itself. Many proposed prior art devices require complex machining operations which greatly increase the price of the clip. It is highly desirable to make the clip using only the simplest metal forming devices such as a stamping machine. Wires are particularly unsuitable for the construction of retainer clips; although they are simple in appearance, the bending and forming of wire is a more complex and expensive forming operation than simple stamping. Other prior art devices use molded plastic and/or metal parts that must be cast or forged which again are more expensive metal forming operations.
Another problem with prior art retainer clips again relates to the rough handling that occurs during shipping of electronic devices which contain a semiconductor device, heat sink and retainer clip. It is of course desirable in all retainer clips that a relatively uniform and large pressure be applied to the heat sink so that the lower flat base surface is in intimate heat-conducting engagement with the upper surface of the chip, or with the module plate (see above). This pressure creates a frictional engagement between these two surfaces. However, with a sharp blow in the plane of the surfaces, such as the acceleration that may be experienced during some sudden starting or stopping of the electronic device in which this assembly is contained, the heat sink may slide relative to the chip and then strike the retainer clip holding means so as to dislodge the clip and again allowing the heat sink to be separated from the chip and heat sink assembly. Even partial movement of the heat sink base relative to the semiconductor device so that the heat sink is still in engagement with the semiconductor device but is displaced will affect the efficiency of the heat transfer from the device to the heat sink.
The present invention comprises a heat sink assembly including a heat sink and a heat sink retainer clip. The heat sink assembly is mounted to a semiconductor device or module or housing containing the device used in electronic equipment, such as a computer, so as to provide cooling of the device. The heat sink comprises a base which may be approximately the same size as the upper surface of the semiconductor device or, in the case of a module, the metal plate forming the upper surface of the module. On the base of the heat sink there is provided a plurality of cooling fins which may be integral with the base plate of the heat sink and which define at least one channel for receiving the retainer clip. The retainer clip includes two parts one of which is an elongated, resilient, metal strap that is positioned in the channel of the heat sink and which includes at each end holding means engaging lugs on a socket or openings in a module. The strap has a length so that when initially placed in the channel so that each of the holding means is in approximate position to the corresponding means (lug, opening, etc.) on the socket or module, the center portion of the strap is spaced a predetermined distance above the upper surface of the base. The strap is not in tension. The retainer clip also includes a cam-type latch pivotally mounted in the center portion of the strap and including a cam with a bearing surface at the outer end and an arm fixedly mounted to the cam. The distance from the pivot axis to the bearing surface of the cam is greater than the distance between the pivot axis and the upper surface of the base of the heat sink when the strap is initially placed in the channel and is not in tension. When the arm is rotated it causes the cam to bear against the surface of the base of the heat sink placing the strap in tension so as to force the heat sink into heat conducting engagement with the module or semiconductor device.
It is an object of the present invention to overcome the above stated difficulties of the prior art devices so as to provide a retainer clip and heat sink assembly which is low in cost, easy to assemble, has substantial assembly integrity, is relatively impervious to adverse environmental conditions affecting the electronic device in which the heat sink assembly is used, and is inexpensive to fabricate.
The first embodiment of the present invention will be shown and described in conjunction with a semiconductor module 10 which has a case 11 including a wall 12 defining the upper surface of case 11. The module is merely representative of a housing that contains at least one semiconductor device; the term "housing" includes modules, cartridges, the semiconductor device itself, or the semiconductor device mounted in a socket. Within the module is mounted a printed circuit board 13 which may include one or more semiconductor devices (not shown). A portion of the upper major wall 12 is made of metal or other high heat-conducting material and is intended to engage or interface with a heat sink for dissipating heat from the semiconductor devices and the module as a whole. To assist in the engagement of a heat sink to the wall 12, the major wall 12 is provided with a plurality of openings shown at 14 and 15. In the particular module configuration shown, two holes 14A, 15a are adjacent one longitudinal edge and two holes 14b, 15b are adjacent a second longitudinal edge of the module.
As seen in
The retainer clips are shown at 30 and 31, one of which will be described in detail, since both are identical in construction, function and operation. As will be seen in
The retainer clip will now be described in more detail, in this first embodiment, and reference may be made to
The elongated strap 40 is made of a resilient metal such as stainless steel although other resilient materials may be suitable for the strap. Each strap has a relatively flat center portion 41 and is bent at each end to form two legs or depending members, 42 and 43. The lower ends of the legs 42 and 43 are each provided with holding means such as hook portions 44 and 45 for engaging the holes 14, 15 in the module 10. In this first embodiment, the engaging, holding or attaching means each comprise a bent tip or hook adapted to engage the underside of the module wall after extending through the openings 14, 15 in a manner described below.
As seen best in
The cam-type latch 60 is pivotally mounted in the center portion of the strap 40 on pivot arms or stub axles 47, 48 which may be integrally formed as part of the center portion 41 of strap 40. The latch body is formed by stamping so as to form a channel cross-section including a pair of legs 61, 62 defining a cam which has bearing edge 64.
Cam-type latch 60 also includes an arm 65 which is integrally formed with the cam, 61, 62. Arm 65 as seen in
The dimensions of the retainer clip 30, relative to the thickness of the base 24, and module wall 12, including the length of the legs 42, 43 of strap 40, as well as the resiliency of the material used to form the strap, are all important in achieving the objective of the invention. As will be seen in
Referring now to FIG. 10. it will be seen that the cam-type retainer clip of the present invention may be made to cooperate with other types of semiconductor devices, modules, sockets, or other housings used in the industry for mounting a semiconductor device. In the configuration shown in
Other embodiments of the invention described above will be apparent to those having ordinary skill in the art and the above-described invention is limited not by the embodiments described but only by the appended claims.
Patent | Priority | Assignee | Title |
6912765, | Dec 14 2001 | Hewlett-Packard Development Company, L.P. | Easily removed heatsink clip |
7072183, | Nov 21 2003 | Hon Hai Precision Industry Co., LTD | Locking device for heat dissipating device |
7167369, | Dec 08 2003 | Cisco Technology, Inc. | Methods and apparatus for installing a heat sink using surface mount technology |
7327573, | Dec 31 2002 | FU ZHUN PRECISION INDUSTRY SHEN ZHEN CO , LTD ; FOXCONN TECHNOLOGY CO , LTD | Heat sink clip with cammed handle |
7349217, | Apr 30 2003 | TYCO ELECTRONICS JAPAN G K | IC socket assembly |
7477527, | Mar 21 2005 | SAMSUNG ELECTRONICS CO , LTD | Apparatus for attaching a cooling structure to an integrated circuit |
7538422, | Aug 25 2003 | SAMSUNG ELECTRONICS CO , LTD | Integrated circuit micro-cooler having multi-layers of tubes of a CNT array |
7732918, | Aug 25 2003 | SAMSUNG ELECTRONICS CO , LTD | Vapor chamber heat sink having a carbon nanotube fluid interface |
8039953, | Aug 25 2003 | SAMSUNG ELECTRONICS CO , LTD | System and method using self-assembled nano structures in the design and fabrication of an integrated circuit micro-cooler |
Patent | Priority | Assignee | Title |
4716494, | Nov 07 1986 | AMP Incorporated | Retention system for removable heat sink |
5208731, | Jan 17 1992 | International Electronic Research Corporation | Heat dissipating assembly |
5371652, | Nov 15 1993 | ANTARES CAPITAL LP, AS SUCCESSOR AGENT | Spring clamp assembly with electrically insulating shoe |
5396402, | May 24 1993 | Burndy Corporation | Appliance for attaching heat sink to pin grid array and socket |
5448449, | Dec 20 1993 | The Whitaker Corporation | Retainer for securing a heat sink to a socket |
5521439, | Apr 05 1993 | SGS-THOMSON MICROELECTRONICS, S R L | Combination and method for coupling a heat sink to a semiconductor device |
5542468, | Jun 28 1995 | ASIA VITAL COMPONENTS CO , LTD | CPU heat dissipator hook-up apparatus |
5600540, | May 15 1995 | PSC COMPUTER PRODUCTS, INC | Heat sink and retainer for electronic integrated circuits |
5602719, | Nov 13 1995 | Micron Technology, Inc | No handle zip socket |
5671118, | May 15 1995 | Heat sink and retainer for electronic integrated circuits | |
5818695, | Feb 25 1997 | Apple Computer, Inc.; Apple Computer, Inc | Heat sink and spring clip assembly |
6061239, | May 16 1997 | PSC Computer Products | Cam-type retainer clip for heat sinks for electronic integrated circuits |
6082440, | Feb 06 1997 | LASALLE BUSINESS CREDIT, INC , AS AGENT | Heat dissipation system having releasable attachment assembly |
6199625, | Jun 11 1999 | PSC COMPUTER PRODUCTS, INC | Stackable heat sink for electronic components |
6301113, | May 07 1999 | PSC COMPUTER PRODUCTS, INC | Retainer clip for heat sink for electronic components |
6356446, | Sep 13 1999 | PSC COMPUTER PRODUCTS, INC | Slotted rail heat sink retainer clip |
WO9636996, |
Executed on | Assignor | Assignee | Conveyance | Frame | Reel | Doc |
May 09 2002 | PSC Computer Products, Inc. | (assignment on the face of the patent) | / |
Date | Maintenance Fee Events |
Nov 19 2007 | REM: Maintenance Fee Reminder Mailed. |
May 11 2008 | EXP: Patent Expired for Failure to Pay Maintenance Fees. |
Date | Maintenance Schedule |
Dec 28 2007 | 4 years fee payment window open |
Jun 28 2008 | 6 months grace period start (w surcharge) |
Dec 28 2008 | patent expiry (for year 4) |
Dec 28 2010 | 2 years to revive unintentionally abandoned end. (for year 4) |
Dec 28 2011 | 8 years fee payment window open |
Jun 28 2012 | 6 months grace period start (w surcharge) |
Dec 28 2012 | patent expiry (for year 8) |
Dec 28 2014 | 2 years to revive unintentionally abandoned end. (for year 8) |
Dec 28 2015 | 12 years fee payment window open |
Jun 28 2016 | 6 months grace period start (w surcharge) |
Dec 28 2016 | patent expiry (for year 12) |
Dec 28 2018 | 2 years to revive unintentionally abandoned end. (for year 12) |