Patent ID: 6731787
Filing Date: 2004-05-04
Classification: G01N

Abstract:
A computer program stored on a computer readable medium for determining the presence of a defect on a reticle or photomask, said computer program comprising:instructions for creating a pixel grid image of a first portion of said reticle or photomask, said pixel grid image having a plurality of associated individual pixel images of said reticle or photomask; instructions for determining a coarse center pixel of said pixel grid image; instructions for determining a region of physical extent of said pixel grid image; instructions for assigning a gray scale value to each of said associated individual pixel images of said pixel grid image; instructions for summing together said gray scale values of all of said pixels included within said pixel grid image to determine a first summed energy level of said pixel grid image; instructions for selecting a similar region adjacent to said pixel grid image wherein said adjacent region is defect free; instructions for summing together gray scale values of all pixels included within said adjacent region to determine a second summed energy level; instructions for subtracting said second summed energy level from said first summed energy level; and instructions for determining if said pixel grid image contains a defect.