Thermal contact resistance: effect of elastic deformation [microelectronics packaging]

Existing models over-predict the thermal contact resistance of conforming rough joints at low contact pressures. However, the applicable pressure range in the microelectronics industry is low due to load constraints. In this paper, a new model is presented which is more suitable for low pressures. The present model assumes plastic deformation at microcontacts. The effect of elastic deformations beneath the microcontacts is determined by superimposing normal deformations in an elastic half-space due to adjacent microcontacts. The model also accounts for the variation of the effective microhardness. A parametric study is conducted to investigate the effects of main contact input parameters on the elastic effect. The study reveals that the elastic deformation effect is an important phenomenon especially in low contact pressures. The present model is compared with experimental data and good agreement is observed at low contact pressures.