Soft Chucking in One-by-one Automatic Mirror Polishing of Silicon Wafers

This paper deals with wafer chucking technology, a dominant factor in wafer flatness, in a one-by-one automatic mirror polishing process for large size silicon wafers. Rigid vacuum chucking generates wafer dimples from unexpected particles coming into the interface between wafer and chuck surfaces. Soft chucking with porous elastic film pads as chuck surfaces can prevent the generation of wafer dimples. Especially, controlling the moisture content distribution through the porous elastic film pads can achieve a good chucking accuracy to improve the wafer flatness in the chuck with a pressure detaching mechanism for automatic unloading.