219 Grinding of 300 mm Silicon Wafers : Finite Element Analysis of Waviness Removal

It is estimated that the transition from 200 mm to 300 mm wafers will bring a die cost saving of 30-40%. To meet customers' needs, silicon wafer manufacturers are actively searching for cost-effective ways to manufacture 300 mm wafers with high quality. Removal of wire-sawing induced waviness in one of the main purposes in grinding of silicon wafers. Various efforts have been directed to the improvement of waviness removal ability of grinding process, and several approaches have been explored, such as soft-pad grinding, wax-mounting grinding, and reduced-vacuum grinding. In this paper, waviness removal mechanisms in grinding of 300 mm silicon wafers are investigated by finite element method (FEM). Results show that waviness-removal ability of grinding depends strongly upon wafer thickness and waviness wavelength. Moreover, soft-pad grinding is found to be effective in removing waviness. The soft pad employed in grinding should possess adequate mechanical properties and thickness for effective waviness removal.