CLAMP RING FOR FIXING WAFER

摘要

PROBLEM TO BE SOLVED: To fix a wafer effectively, and to prevent excess etching of a wafer outer edge by mounting a clamp ring body having an inside diameter smaller than the outside diameter of the wafer and covering the wafer outer edge and a plurality of square-shaped projections disposed at the inner edge of the clamp ring body. SOLUTION: A distance d3 between the inner edge of a clamp ring body 320 fixing the wafer 300 and the outer edge of the wafer 300 is set in approximately 1 mm. Consequently, the outer edge of the wafer 300 is covered completely, but an effective device region on the wafer 300 is not covered. One or two square-shaped projections 322 are disposed to the upper and lower and left and right sections of the inner edge of the clamp ring body 320 respectively while a distance d4 among the inner edge of the clamp ring body 320 and the front ends of the square-shaped projections 322 is set in approximately 1 mm. When the wafer 300 is fixed, an effective device region 302 is not covered because the square-shaped projections 322 are placed in a blank region 304 on the side outer than the effective device region 302 of the wafer 300.