US Patent 7220167 Gentle chemical mechanical polishing (CMP) liftoff process

A method for chemical mechanical polishing (CMP) wafers having high aspect ratio surface topography. A wafer is positioned on a plate. A polishing pad is coupled to a platen. A polishing solution (e.g., slurry) is added between the polishing pad and the wafer. CMP is performed on the wafer by creating a relative movement between the polishing pad and the wafer. The polishing pad removes substantially all residual material from the channels. To accomplish this, the polishing pad has a compressibility of at least 5% at a polishing pressure of about 4 psi.