Patent ID: 7738090
Filing Date: 2010-06-15
Classification: G01N,G02B,G03F

Abstract:
1. A method for fabricating a Fourier filter, wherein the method comprises: generating an image of light in a Fourier plane of an inspection system, wherein the image comprises light reflected and diffracted from structures on a specimen being inspected by the inspection system; and fabricating a Fourier filter based on the generated image, wherein the step of fabricating comprises forming an array of patterned features within an optically opaque layer, wherein the array of patterned features is configured to block the light reflected and diffracted from the structures on the specimen and to allow light scattered from defects on the specimen to pass through the filter, and wherein the array of patterned features is formed by removing portions of the optically opaque layer with laser light to create transmissive regions, which only allow the light scattered from the defects to pass through.