Liquid metal thermal interface for an electronic module
AssigneeInternational Business Machines Corporation
InventorsVaraprasad V. Calmidi, Eric A. Johnson, Randall J. Stutzman
Life of this patent
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Abstract
A heat dissipating system utilizes a thin layer of a high conductivity liquid metal to provide cooling for electronic sub-assemblies, such as semiconductor chips. The liquid metal preferably is gallium or its alloy which transfers heat from the chip to a heat sink or heat spreader. The system includes one or more vents that allow for filling and venting of the space occupied by the liquid. It also utilizes a flexible seal, such as an O-ring or a membrane held in place with a retainer ring, or a plug that seals the filling vent. The seal flexes to accommodate expansion and contraction of the liquid, as well as phase changes from the liquid phase to the solid phase.
Claims22
A thermal coupling device for facilitating heat transfer between generally parallel surfaces spaced from one another and having a temperature differential therebetween, the two surfaces forming a confined space comprising:
- a) a metal that is liquid over substantially the entire range of temperatures that comprise the temperature differential, occupying the confined space between the two surfaces;
- and
- b) a seal to contain the liquid metal between the two surfaces, said seal including means for accommodating changes in the distance between the two surfaces, and volumetric changes of the metal, and for eliminating air from the space.
A thermal coupling device for facilitating heat transfer between generally parallel surfaces spaced from one another and having a temperature differential therebetween and an annular opening in one of the surfaces, the two surfaces forming a confined space comprising:
- a) a metal that is liquid over substantially the entire range of temperatures that comprise the temperature differential, occupying the confined space between the two surfaces;
- and
- b) a seal to contain the liquid metal between the two surfaces, said seal including means for accommodating changes in the distance between the two surfaces and volumetric changes of the metal, and for eliminating air from the space, wherein the seal comprises a flexible elastomeric or polymeric plug composed of a flexible membrane, and a retaining ring used to retain the membrane in said annular opening of one of the surfaces.
An electronic structure comprising an integrated circuit associated with a semiconductor chip wherein the chip generates thermal heat when being used, and means for removing the generated heat from an exposed surface of the chip, the heat removing means comprising:
- a) a heat absorber comprising a heat sink or a heat spreader adjacent but spaced a small distance from said exposed surface of the chip;
- b) a non-toxic metal that is liquid over substantially the entire range of temperatures comprising the temperature differential;
- and
- c) a seal to contain the liquid metal between the two surfaces, said seal including means for accommodating changes in the spacing between the two surfaces and volumetric changes of the metal.
A method of transferring heat between two substrates having a ΔT and having generally parallel, opposing, spaced apart surfaces comprising the steps of
- a) confining the space between the two surfaces;
- b) introducing a non-toxic liquid metal into the space between the surfaces and displacing all of the air in the space;
- and
- c) providing a flexible seal to contain the liquid metal and to permit expansion and contraction of the metal without affecting the spaced relationship of the two substrates.
A thermal coupling device for facilitating heat transfer between generally parallel surfaces spaced from one another and having a temperature differential therebetween, the two surfaces forming a confined space, the coupling device comprising:
- a) a metal that is liquid over substantially the entire range of temperatures that comprise the temperature differential, occupying the confined space between the two surfaces;
- and
- b) a seal to contain the liquid metal between the two surfaces, said seal including means for accommodating changes in the distance between the two surfaces and volumetric changes of the metal, said seal comprising a flexible elastomeric or polymeric plug containing at least one vent hole for eliminating air from the space.
An electronic structure comprising an integrated circuit associated with a semiconductor chip wherein the chip generates thermal heat when in use, and means for removing the generated heat from an exposed surface of the chip, the heat removing means comprising:
- a) a heat absorber comprising a heat sink or a heat spreader adjacent to, but spaced a distance of about 0.9 mm from, said exposed surface of the chip;
- b) a metal that is liquid over substantially the entire range of temperatures comprising a temperature differential between the heat generator and the heat remover;
- and
- c) a seal to contain the liquid metal between the two surfaces, said seal comprising a flexible membrane and a retaining ring used to retain the membrane in an annular opening of one of the surfaces, said seal including means for accommodating changes in the spacing between the two surfaces and volumetric changes of the metal.
A method of transferring heat between two substrates having a ΔT therebetween and having generally parallel, opposing, spaced apart surfaces comprising the steps of
- a) confining the space between the two surfaces;
- b) introducing a liquid metal into the space between the surfaces and displacing all of the air in the space;
- and
- c) providing a flexible seal to contain the liquid metal and to permit expansion and contraction of said liquid metal without affecting the spaced relationship of the two substrates, wherein the seal comprises a flexible elastomeric or polymeric membrane, and a retaining ring to hold the membrane in an annular opening of one of the surfaces.
Dependencies are inferred from the claim text.