Patent ID: 6463184
Filing Date: 2002-10-08
Classification: G03F

Abstract:
A method for measuring an alignment between a first pattern and a second pattern, comprising the steps of:forming the first pattern on a first surface and forming the second pattern on a second surface; forming a first picture of at least a portion of the second pattern; projecting an image of the first pattern onto the second surface; forming a composite picture comprising at least a portion of the second pattern and at least a portion of the image of the first pattern projected thereon; digitizing the first picture to generate a first digitized image, and digitizing the composite picture to generate a composite digitized image; subtracting the first digitized image from the composite digitized image to generate a second digitized image, the second digitized image comprising at least a portion of the first pattern; and comparing the first digitized image and the second digitized image to calculate the alignment between the first pattern and the second pattern.