Patent ID: 7545520
Filing Date: 2009-06-09
Classification: G03F

Abstract:
1. A method for measuring a feature dimension in a patterned substrate, comprising; providing an experimental structure on a substrate, the experimental structure comprising a first array of features having a first pitch and a first duty cycle, and comprising a second array of features having a second pitch smaller than the first pitch; providing a first beam of radiation incident on the experimental structure, the first beam having a first wavelength larger than the second pitch and smaller than the first pitch; detecting an intensity of a non-zero order of light produced by diffraction of the first beam from the experimental structure; detecting an intensity of a non-zero order of light produced by diffraction from a reference structure of a second beam that is substantially the same as the first beam; and determining a critical dimension of the second array of features based upon the detected intensities and the first pitch.