Synopsys, Inc.
LITHOGRAPHY IMPROVEMENT BASED ON DEFECT PROBABILITY DISTRIBUTIONS AND CRITICAL DIMENSION VARIATIONS

Abstract:

Certain aspects relate to a method for improving a lithography configuration. In the lithography configuration, a source illuminates a mask to expose resist on a wafer. A processor determines a defect-based focus exposure window (FEW). The defect-based FEW is an area of depth of focus and exposure latitude for the lithography configuration with an acceptable level of defects on the wafer. The defect-based FEW is determined based on a predicted probability distribution for occurrence of defects on the wafer. A processor also determines a critical dimension (CD)-based FEW. The CD-based FEW is an area of depth of focus and exposure latitude for the lithography configuration with an acceptable level of CD variation on the wafer. It is determined based on predicted CDs on the wafer. The lithography configuration is modified based on increasing an area of overlap between the defect-based FEW and the CD-based FEW.