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Method for a heat-spreader design to minimize warpage for improved case-to-heatsink transfer

IP.com Disclosure Number: IPCOM000006891D
Publication Date: 2002-Feb-08
Document File: 3 page(s) / 60K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for a heat-spreader design to minimize warpage for improved case-to-heatsink transfer. Benefits include improved thermal performance and improved yield.

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Method for a heat-spreader design to minimize warpage for improved case-to-heatsink transfer

Disclosed is a method for a heat-spreader design to minimize warpage for improved case-to-heatsink transfer. Benefits include improved thermal performance and improved yield.

Background

      The conventional heat-spreader design is comprised of an integrated heat spreader (IHS), a thermal interface material (TIM) layer, a die, and sealant (see Figure 1). IHS warpage is caused by a load applied to the heat spreader that bends the substrate. Warpage causes increased thermal resistance. No conventional solution exists for this problem.

Description

              The disclosed method optimizes the heat-spreader design to reduce thermal resistance by subjecting the IHS to bending that results in a flat heat spreader after assembly is complete. 

              During the assembly process, the heat spreader is subjected to 3-point bending that results in a concave warpage (see Figure 2) caused by the heat spreader material, size, thickness, and spring-clip force. This warpage results in increased case-to-heatsink thermal resistance due to increased bond line thickness (BLT) of the thermal grease or phase-change material applied to the base of the heatsink. Manufacturing the heat spreader with reversed (convex) warpage results in a flat heat spreader post assembly (see Figure 3).

              Analytical calculations of the heat spreader warpage are determined from Equation 1 (see Figure 4). Analytical results (see Figure 5) matched empiric...