Thermal diffusion sheet and method for mounting the same

摘要

A thermal diffusion sheet of the present invention includes a graphite sheet and thermally conductive adhesive layers attached to both principal surfaces of the graphite sheet. The thermally conductive adhesive layer on a first surface is substantially the same in size as the graphite sheet. The thermally conductive adhesive layer on a second surface is relatively larger in size than the thermally conductive adhesive layer on the first surface, and the entire periphery of the thermally conductive adhesive layer on the second surface lies outside the graphite sheet. The adhesive strength of the thermally conductive adhesive layers on the first and second surfaces after exposure to 40° C. for 168 hours is reduced by no more than 20% relative to the initial adhesive strength. A hardened material of a polymer component of the thermally conductive adhesive layers on the first and second surfaces has a thermal conductivity of 0.6 W/m·K or more. With this configuration, the thermal diffusion sheet has a structure in which the graphite sheet is sealed by attaching the thermally conductive adhesive layer that is larger than the graphite sheet and has a good thermal conductivity in the plane direction to a radiator plate, and can transfer heat to the radiator plate reliably at a low cost.