Patent ID: 6194101
Filing Date: 2001-02-27
Classification: G01N,G03F

Abstract:
A process for determining whether a photomask is good or defective, comprising:providing a photomask comprising a glass substrate having a mask pattern made of an opaque film and formed on the substrate, said mask pattern including a circuit pattern and at least one detection mark that is separate from said circuit pattern;providing a photomask holder for holding the photomask, the holder having at least one hole formed therethrough at a position aligned substantially with the detection mark when the photomask is held on the holder;holding the photomask on the holder;radiating light toward the hole;receiving the light which has passed through both the hole and the photomask so as to generate an electric signal which corresponds to an amount of the received light; anddetermining whether the circuit pattern of said photomask is properly positioned on the photomask on the basis of a level of the electric signal.