Adhesion of Continuous and Homogeneous Electrodeposited Copper Layers on Silicon

Abstract:
In this work, the influence of different silicon crystal orientations and doping types on the adhesion of electrochemically deposited copper layers is discussed. The analysis has mainly considered the crystal matching and copper diffusion in silicon. Quantitative tensile tests have shown adhesion higher than 48 N cm^-2 for copper layers on n-Si(110), n-Si(111) and p-Si(100). Bonding forces between Cu and n-Si(100) were not measured because continuous layers of Cu were not obtained on such samples. The difference between n- and p-Si(100) is discussed as function of Cu diffusion into the substrate. For the other two orientations, a better crystal matching can be used to explain the higher adhesion.