Patent ID: 6129259
Filing Date: 2000-10-10
Classification: H01J,Y10T

Abstract:
A method of evaluating the alignment of a pair of substrates, at least one of said pair of substrates being transparent, the method comprising:providing a first set of alignment indicators on one of said substrates;providing a second set of alignment indicators on the other of said substrates;positioning at least one of said substrates on a transporter;advancing said transporter to move said one substrate to a first predetermined location;at said first location positioning the other of said substrates in position relative to said one substrate;advancing said transporter to move said one and said other substrates to a second predetermined location;at said second predetermined location observing said first set and said second set through said transparent one of said substrates;determining an extent of an overlap of the first and second sets; andevaluating said alignment of said substrates based on the extent of the overlap of the first and second sets.