DIVOT DEFECT REPAIR ON A DEEP-ULTRAVIOLET SINX HALF-TONE MASK

Divot defect repair on deep ultraviolet SiNx halftone masks in the cas e of 0.275 mu m (on a wafer) line and space patterns was investigated experimentally. The problem regarding imaging is the difficulty of are a recognition due to low contrast of halftone masks without the focuse d ion beam (FIB) irradiation damage. It is overcome by means of limiti ng the total FIB dose for imaging and by means of image processing wit h an image filter. Opaque carbon (C) film deposition on a divot defect was found to improve the performance of a defective area. The degree of the improvement was not perfect but allowable for practical use. It was also found that there were other factors that make the performanc e of the repaired area worse than the nondefective area, except for mi ssing of the phase shift effect. (C) 1996 American Vacuum Society.