Patent ID: 7027635
Filing Date: 2006-04-11
Classification: G03F,G06T

Abstract:
1. A method for inspecting an advanced phase shift mask comprising: receiving a first database file and rendering a first image of a first photoresist layer; conditioning the first image according to a first set of transformation functions to generate a first critical layer model image; conditioning the first image according to a second set of transformation functions to generate a second critical layer model image; receiving a second database file and rendering a second image of a second photoresist layer; aligning the first critical layer model image, the second critical layer model image, and the second image with an optical image of the advanced phase shift mask; determining a first differential value between the first critical layer model image and the optical image; determining a second differential value between the second critical layer model image and the optical image; according a respective weight to the first and second differential values, and generating a weighted differential value; and comparing the weighted differential value against a threshold value to determine if a defect exists.