Fluid Analysis of air Spindle for Wafer Grinding

Wafer grinding is a key process for integrated circuit chip packaging. The air spindle, the core component of thinning equipment, directly affects the TTV and roughness of wafer grinding. In view of the requirement of large and stable wafer grinding force, this paper proposes a new type of air spindle structure with large bearing capacity and high stiffness. The working principle of the new type of air spindle is introduced, and the analytical formulas of the bearing characteristics of the radial bearing and the thrust bearing are deduced by using the volume flow method. relationship between parameters. Based on the Reynolds equation and the NS equation, a numerical model of the orifice hydrodynamics was established, and the air pressure distribution of the air film under the no-load condition of the main shaft was obtained by the finite element method. Through the comparison of the bearing capacity, the analytical method and the finite element method are in good agreement, and the bearing capacity and stiffness of the designed air-floating spindle can meet the requirements of wafer grinding.