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Method for a universal retention fixture capable of applying a variable point load to any type of heatsink

IP.com Disclosure Number: IPCOM000009285D
Publication Date: 2002-Aug-14
Document File: 3 page(s) / 85K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for a universal retention fixture capable of applying a variable point load to any type of heatsink. Benefits include improved thermal performance, improved functionality, and an improved design environment.

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Method for a universal retention fixture capable of applying a variable point load to any type of heatsink

Disclosed is a method for a universal retention fixture capable of applying a variable point load to any type of heatsink. Benefits include improved thermal performance, improved functionality, and an improved design environment.

Background

              Poor thermal performance of a semiconductor package can result from the tilting of a thermal solution (for example, a heatsink). Tilting is caused by the application of an uneven load on a heatsink. The effects of heatsink tilt are more prevalent on bare-die semiconductor packages, which may be convex in shape. Tilting on a bare-die package generates hot spots that can affect the performance and life span of the package.

      Conventional retention devices apply a load on two or more sides of the heatsink (see Figure 1). If the load is not applied uniformly, the heatsink can become tilted impacting the thermal performance of the semiconductor package.

      Point load is applied on a plate directly over the heat source, such as a bare die or an integrated heat spreader (IHS). A heatsink must be placed on at least one side of the point load to remove heat (see Figure 2). This approach provides an effective point-load source but requires additional space, which may be unacceptable.

              Conventional heatsink design compromises performance to accommodate the retention mechanism. Some heatsink designs have open spaces to enable the engagement of a retention mechanism, reducing the performance of the heatsink.

General description

              The disclosed method is a universal retention fixture capable of applying a variable point load to any type of heatsink. A heatsink is placed directly over a heat source using a point-loaded fixture along the center of the heatsink over a range of loads.

      The key elements of the method include:

·        A cover over the heatsink top has a small depression in it where a point load is to be applied.

·        The top plate of the retention goes over the top of any type of heatsink and has a provision to apply a load to the depression in the center of the heatsink cover.

·        The top plate is secured to the surrounding area using two or more fasteners of any type that extend from the top plate down to the surrounding surface.

·        The amount of deflection of the top plate enables the load on the heatsink to be adjustab...