Study of Electro-Chemical Mechanical Polishing for Copper Damascene Process (2nd report)

Electro-CMP(Electro-Chemical Mechanical Polishing) was studied to reduce surface damage on copper and low-K dielectric for copper damascene process. It is indispensable to understand both copper surface oxidation and copper removal mechanism for accurate removal rate control. This study deals with the observation results of the polished copper surface by XPS (X-ray Photoelectron Spectroscopy) and AES(Auger Electron Spectroscopy). In particular, copper samples are measured immediately after polishing to estimate surface oxidation precisely. In addition, the depth profile of oxygen penetration into copper surface was evaluated to measure copper oxide layer thickness. As a result, the surface dipped in slurry for 30 min was oxidized 20A in depth. The formation of CuO on copper surface in Electro-CMP was less than that of conventional CMP. The oxygen penetration in Electro-CMP was loA in depth, less than 15A in conventional CMP