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Method for the direct growth of a CNT thermal interface material

IP.com Disclosure Number: IPCOM000132634D
Publication Date: 2005-Dec-28
Document File: 3 page(s) / 130K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for the direct growth of a carbon nanotube (CNT) thermal interface material (TIM). Benefits include improved functionality, improved thermal performance, and improved reliability.

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Method for the direct growth of a CNT thermal interface material

Disclosed is a method for the direct growth of a carbon nanotube (CNT) thermal interface material (TIM). Benefits include improved functionality, improved thermal performance, and improved reliability.

Background

      Thermal management of high power density products of the future requires innovative materials and design solutions. Conventionally, silicon dice are bonded to copper heatsinks by appropriate solders. The coefficient of thermal expansion (CTE) mismatch between the silicon and the copper can introduce stress in the die, especially when the die is thinned to <100 microns to improve thermal properties (see Figure 1).

Description

      The disclosed method is a thermal interface connection between a die and an integrated heatsink (IHS). CNTs are grown in densely aligned arrays between the die backside and the IHS copper (Cu) surface. The carbon nanotubes are highly thermally conductive. They connect with minimal contact resistance, functioning as a TIM. Additionally, the nanotubes are flexible and can accommodate any assembly-related stresses.

              Aligned carbon nanotubes grow on a variety of substrates by using a catalyst, such as nickel (Ni) and plasma enhanced chemical vapor deposition (PECVD) processes. Contact resistance can be minimized by directly growing CNTs on the die backside and adding a catalyst, such as iron (Fe) or Ni, when they approach the IHS Cu surface. A thin silicon dioxide layer on the metal surface encourages contact to the surface.

      CNT growth by PECVD is a low temperature (~120°C) process.

      Direct CNT growth eliminates the requirement for a solder TIM for better th...