Factors that govern the performance of thermal interface materials

Finite element modeling is conducted to understand the factors that govern the performance of thermal interface pastes of controlled thickness between copper surfaces of controlled roughness. Carbon black paste is lower in thickness than metal particle paste, so it shows better performance. The performance of both pastes is more influenced by the paste-copper interfacial conductance than by the paste thermal conductivity. The effects of pressure, paste thickness, and copper surface roughness on performance are mainly due to the change in fractional filling of the valleys in the copper surface topography. Reasonable agreement is found between modeling and experimental results.