1983 Volume 49 Issue 11 Pages 1549-1554
Decreasing the bow in a silicon wafer by lapping is discussed. In simultaneous doubleside lapping, the bow in a silicon wafer was investigated theoretically as well as experimentally. Regarding the bow decreasing mechanism, the lapping rate and lapping plate rotation speed effects are discussed. The lapping rate depends on the pressure. Inequality between the lapping rate in the wafer center and that at the edge is brought about by the difference between the pressure applied at the wafer center and that at the edge. Bow can be decreased by such inequalities. Bow after lapping is expressed as exponential functions of initial thickness, plates rotation speed, wafer diameter and lapping rate. The obtained results are as follow: (1) With a decrease in the lapping rate, bow is decreased. (2) With an increase in the initial thickness, bow is decreased. (3) A convex wafer surface should be lapped with the plate which turns faster than the other with respect to the relative speed between wafer and plate.
