Heat exchange – With retainer for removable article – Electrical component
Reexamination Certificate
1998-12-10
2001-01-30
Atkinson, Christopher (Department: 3743)
Heat exchange
With retainer for removable article
Electrical component
C165S185000, C361S702000, C257S719000, C257S718000
Reexamination Certificate
active
06179047
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to mechanical assemblies that regulate the temperature of an electronic device, such as an integrated circuit chip, by pressing a temperature controlled heat exchanger against the chip.
In the prior art, one assembly of the above type is described in U.S. Pat. No. 4,791,983 which is assigned to the assignee of the present invention. The assembly in patent '983 uses a coil spring 20 to press a planar surface of a liquid cooling jacket against a planar surface of an integrated circuit chip. More specifically, the coil spring 20 is compressed in a direction perpendicular to the planar surfaces of the liquid cooling jacket and the integrated circuit chip to squeeze those surfaces together and thereby lower the thermal resistance between them.
Due to various manufacturing tolerances, the planar surface of the integrated circuit chip (to which the cooling jacket mates) can be oriented at different angles and different heights relative to a nominal position. To accommodate these variances, the assembly in patent '983 includes a guidepost 18 which is attached to the cooling jacket, extends perpendicular to the mating faces of the cooling jacket and the integrated circuit chip, and is loosely held by a beam 14. This guidepost, together with the coil spring and the cooling jacket, can tilt at different angles and move to different heights to thereby accommodate the variations in the orientation of the integrated circuit chip.
With the assembly of patent '983, it is desirable for the coil spring to have a small spring constant. That is because when the planar surface on the cooling jacket initially contacts the planar surface on the integrated circuit chip, those two surfaces will be at different angles, so contact will initially occur at a single point on the corner of the chip. If the coil spring has a small spring constant, then the force that is exerted at the initial point of contact will be small and the chances of cracking the corner of the chip will be reduced.
On the other hand, to insure that the thermal resistance between the mating surfaces of the cooling jacket and the chip is sufficiently small, the final force with which those two surfaces are pressed together must be large. Thus to achieve this large final force with a small spring constant, the coil spring 20 must have a long length. However, increasing the length of the spring 20 inherently increases the minimal distance with which several of the assemblies can be placed side-by-side in a rack within an end-product.
Also, after initial contact occurs between the planar surface of the cooling jacket in patent '983 and one corner of the chip, the cooling jacket must pivot on the guidepost to make the cooling jacket lie flat against the chip. However, in order for the cooling jacket to pivot on the guidepost, its planar surface must slip on the chip at the initial point of contact. And, such slippage between the cooling jacket and the chip can damage the chip.
Further with the assembly of patent '983, the planar surface of the cooling jacket can become twisted and/or offset relative to the planar surface of the chip. To accommodate the above problem, the planar surface of the cooling jacket can be made substantially larger than the planar surface of the integrated circuit chip. But, such an increase in the size of the cooling jacket will be prohibited if the chip is held by a socket which the enlarged cooling jacket can hit, or another component lies next to the chip which the enlarged cooling jacket can hit.
Accordingly, a primary object of the present invention is to provide an improved mechanical assembly for regulating the temperature of an integrated circuit chip in which all of the above drawbacks with the prior art are overcome.
BRIEF SUMMARY OF THE INVENTION
In accordance with the present invention, a mechanical assembly for regulating the temperature of an integrated circuit chip is comprised of a frame which has at least two spaced-apart spring supports. Respective leaf springs extend from each of the spring supports towards each other. And, a heat exchanger lies in the space between the spring supports, attaches to all of the leaf springs, and has a face for mating with the chip.
With this assembly, the leaf springs deflect while the frame is moved such that the face of the heat exchanger presses against the chip. When the face of the heat exchanger initially contacts the chip, the leaf springs have a minimal deflection. Thus, the heat exchanger exerts a very small force at its initial point of contact with the chip.
Subsequently, when the face of the heat exchanger is pressed with a large final force against the chip, the leaf springs have a maximum deflection. But only the length of that deflection, and not the length of the leaf springs, adds to the profile of the assembly. Consequently, the minimal distance with which several of the assemblies can be placed side-by-side is small.
As the face of the heat exchanger moves from its initial point of contact with the chip to its final position where the large force is exerted on the chip, the leaf springs slip on the spring supports or the heat exchanger. No slippage occurs between the face of the heat exchanger and the chip.
Also, the leaf springs only deflect in one direction. Thus, the leaf springs prevent the face of the heat exchanger from twisting relative to the mating surface of the chip; and, the leaf springs also prevent the face of the heat exchanger from becoming offset relative to the mating surface of the chip.
REFERENCES:
patent: 4013337 (1977-03-01), Roger et al.
patent: 4498530 (1985-02-01), Lipschutz
patent: 4908695 (1990-03-01), Morihara et al.
patent: 5001548 (1991-03-01), Iversen
patent: 5036384 (1991-07-01), Umezawa
patent: 5052481 (1991-10-01), Horvath et al.
patent: 5132873 (1992-07-01), Nelson et al.
patent: 5159531 (1992-10-01), Horvath et al.
patent: 5842512 (1998-12-01), Guerrero
patent: 5875096 (1999-02-01), Gates
Beaulieu, Modular Thermal Clip IBM, pp. 4851-4852, Apr. 1981.
Self-Loaded Plates for Chip Cooling, IBM, p. 151, Jun. 1989.
Ostergren, Chip-Cooling Structure, IBM pp. 313-314, Jun. 1982.
Babcock James Wittman
Tustaniwskyj Jerry Ihor
Adornato Rocco L.
Atkinson Christopher
Fassbender Charles J.
Starr Mark T.
Unisys Corporation
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