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Method for an anisotropic heat spreader/conductor for efficient remote cooling

IP.com Disclosure Number: IPCOM000020302D
Publication Date: 2003-Nov-12
Document File: 5 page(s) / 138K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for an anisotropic heat spreader/conductor for efficient remote cooling. Benefits include improved performance.

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Method for an anisotropic heat spreader/conductor for efficient remote cooling

Disclosed is a method for an anisotropic heat spreader/conductor for efficient remote cooling. Benefits include improved performance.

Background

         The heat generated from a microprocessor must be transported to a remote place where a more efficient cooling method can be incorporated. Because the power dissipation of small form-factor products (like portable devices) keeps increasing, a very efficient thermal solution is required to maintain the products under the acceptable maximum operation temperature. The location of the thermal solution at the microprocessor might not be possible. As a result, efficient methods for transporting the heat are required to conduct the heat to a remote location where the thermal solution can be placed.

         The most predominant conventional solution is the use of heat pipes. The heat is transported by conduction through a conducting device to a remote location where it is dissipated by an efficient thermal solution such as a heatsink. The conducting device most widely employed is a thin copper bar. In more expensive products like laptop computers, a heat pipe is used. For other small form factor products, the cost and weight can become prohibitive. The alternative is a highly conductive copper or aluminum bar (see Figure 1).

         Even for mobile, in cases where the characterization of the heat pipe is not critical (such as when testing TIM performance), the heat pipe is usually replaced by a copper block due to cost issues. However, this replacement may not be an accurate representation because in a heat pipe, the equivalent in-plane conductivity is much higher than its lateral counterpart.

General description

The disclosed method uses a composite bar made of an anisotropic material to conduct heat to a remote place. The material’s conductivity in the direction of its fibers is more than twice that of copper, resulting in very low thermal resistance. The bar is bonded with copper wedges, which reduces the thermal resistance in the lateral direction. Additionally, the material is light weight.

The disclosed method enables heat conduction with minimal thermal resistance from a localized hot spot to a remote place where a cooling solution can be placed. This design is simple, light weight, and cost effective compared to more elaborate solutions, such as heat pipes.

         The key elements of the method include:

•         Anisotropic composite bar with very high in-plane thermal conductivity

•         Die

•         Heatsink

•         Small copper or aluminum prisms

Advantages

         The disclosed method provides advantages, including:

•         Improved performance due to better thermal performance than copper

•         Improved performance due to lower height compared to copper

•         Improved performance due to lighter weight

•         Improved performance due to higher reliability compared to heat pipes

•         Improved performance due to a simpler construction compared to heat pipes

Detailed description

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