Patent ID: 6100987
Filing Date: 2000-08-08
Classification: G03F

Abstract:
A position detecting apparatus for detecting an alignment mark formed on a substrate which is covered with a film having a wavelength selective feature, comprising:an alignment optical system which detects said alignment mark on the substrate by directing position detecting light through said film having the wavelength-selective feature;a wavelength changing device which is disposed in a path of said position detecting light and adjusts a wavelength of the position detecting light in accordance with the wavelength-selective feature of said film;a correction device which corrects an optical error of said alignment optical system which is created when the wavelength of said position detecting light is set in accordance with said film having the wavelength-selective feature, anda control system, connected to said wavelength changing device and said correction device, which controls said correction device based on the wavelength of said position detecting light set by said wavelength changing device,wherein said alignment mark is detected by said alignment optical system of which said optical error has been corrected.