Chip Drop After Silver Sintering ProcessM.H. Poech, M. Weiß, and K. Gruber
Fraunhofer Institute for Silicon Technology, Itzehoe, Germany
Since a couple of years, sintering becomes more and more important for power electronics. To press a semiconductor under high temperature in silver paste on a substrate promises benefits for durability. Tests with semiconductors of different thickness expose some problems. After the cool down, some of them fall slightly from the substrate. Stress in the boundary layer, caused by different expansion coefficients, is probably the reason for this effect. To describe the reasons and mechanisms of these phenomena, some simulations with different programs were started. The aim is to understand and specify the effects of different thermal expansion coefficients in such a thermal stack.