Study of Electro-Chemical Mechanical Polishing for Copper Damascene Process

Electro-Chemical Mechanical Polishing is newly developed for Cu damascene process. In the Electro-CMP, not only mechanical and chemical effect, but also Electro-chemical effect acts on Cu surface. It is expected that the surface roughness will be reduced by relative reduction of mechanical effect. In the first place, fundamental polishing characteristics are evaluated. Then it is clarified that the Electro-CMP reduces surface roughness compared with ordinary CMP. Finally polishing mechanisms on the Electro-CMP are elucidated by observing XPS (X-ray photoelectron spectroscopy) and AES (Auger electron spectroscopy) on Cu surface after CMP. As a result, the amount of brittle layer creation composed of copper oxide was lower in the Electro-CMP than in ordinary CMP