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Direct Contact Thermal Interface Materials with Single Layer Solder Coated Metal Spheres

IP.com Disclosure Number: IPCOM000010220D
Publication Date: 2002-Nov-06
Document File: 3 page(s) / 116K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for a single layer of a thermal interface material (TIM), composed of copper or silver spheres with a solder coating. Benefits include better bonding, lower thermal resistance, and a polymer matrix that provides mechanical flexibility.

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Direct Contact Thermal Interface Materials with Single Layer Solder Coated Metal Spheres

Disclosed is a method for a single layer of a thermal interface material (TIM), composed of copper or silver spheres with a solder coating. Benefits include better bonding, lower thermal resistance, and a polymer matrix that provides mechanical flexibility.

Background

The thermal resistance of TIMs between the die and Integrated Heat Spreader (IHS) contributes to about 30% to 40% of total thermal resistance, which limits the total power and performance of a microprocessor. Polymeric materials have very poor intrinsic thermal conductivity, and many two phase PSHs (Polymer solder hybrids) have limited thermal performance because of the poor interconnect of solder phase and the poor wetting of solder on the die and IHS.

Currently, polymer-based TIMs have an effective thermal conductivity of approximately 1 to 2 W/m K. This conductivity might be improved to approximately 3 W/m K. With current state of the art, better thermal performance will likely sacrifice the mechanical properties by increasing solder doping levels. The typical dimension of solder phase in PSH is much smaller than the TIM thickness.

General Description

The TIM of the disclosed method consists of copper or silver spheres coated with a layer of soft solder (such as Indium), and a polymeric matrix (such as epoxy). The TIM can be a pre-fabricated B-stage thin film which contains only a layer of spheres, or a paste of the sphe...