CTE-matched heat pipe

Abstract

Heat sinks having a mounting surface with a coefficient of thermal expansion matching that of silicon are disclosed. Heat pipes having layered composite or integral composite low coefficient of expansion heat sinks are disclosed that can be mounted directly to silicon semiconductor devices.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a continuation-in-part of copending U.S. patent application Ser. No. 10 / 924,586, filed Aug. 24, 2004, which is itself a continuation application of U.S. patent application Ser. No. 10 / 458,168, filed Jun. 10, 2003, now issued as U.S. Pat. No. 6,793,009, and is also related to U.S. Provisional Patent Applications Nos. 60 / 561,436, filed Apr. 12, 2004, and 60 / 574,158, filed May 25, 2004.FIELD OF THE INVENTION [0002] The present invention relates to heat sinks having mounting surfaces for semiconductors, and more particularly to such heat sinks which include one or more mounting surfaces having a coefficient of thermal expansion that matches or nearly matches silicon. BACKGROUND OF THE INVENTION [0003] It is known that certain classes of semiconductor devices consume substantial amounts of power, which results in excess thermal energy that then must be transferred to the ambient environment. This waste heat is typically c...

AI Technical Summary

Benefits of technology

[0011] In a further embodiment, a heat pipe is provided that includes a tubular body having a central passageway with a wick disposed on at least an evaporator portion of the central passageway. The wick is at least partially saturated with a working fluid. A layered composite low CTE base seals off the evaporator portion of the central passag

Problems solved by technology

It is known that certain classes of semiconductor devices consume substantial amounts of power, which results in excess thermal energy that then must be transferred to the ambient environment.

Since heat is often dissipated to room temperature air, and the silicon constructed semiconductor has a finite upper bound on its operating temperature, package-related thermal resistance is becoming a limiting factor in the ability to dissipate the waste heat.

Some disadvantages of the alloy substrate include expense, unfavorable machining and stamping characteristics, and a fairly low thermal conductivity.

Some disadvantages of the ductile braze alloy include a limited fatigue life, which eventually results in failure due to delamination of the joint.

Such devices almost always operate under conditions of periodic fluctuating electrical load, which leads to periodic fluctuations in thermal load and mechanical stresses in the joint.

None of the foregoing techniques have been found to be completely satisfactory or have been successfully applied to heat pipe cooling devices.

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