Repair technique for phase shifting masks using silicon-containing resist

Abstract

Each mask repair technique discussed consists of spin-coating the silicon-containing resist, electron beam exposure around the defects, development, and hard-bake. The difference among the three techniques (type A,B,C) is the thickness of the spin-coated resist; the thicknesses are below 30 degrees phase angle (type A), 360 degrees (type B), and 180 degrees (type C) at the defect point. The thickness must be selected according to the defect type. The type A repair is used for isolated hole and dot defects and hole defects in fine patterns. The type B repair is used for isolated dot defects in fine patterns or large clear areas. The type C sequence is used for the repair of a missing shifter in which a desired shifter pattern is absent. The missing shifter patterns are restored through electron beam lithography. >