Position sensor having a reflective projecting system and device fabrication method using the sensor

摘要

A position detecting apparatus for detecting the position of a substrate in an interval direction in which the substrate is spaced by an interval form a pattern-printing projection optical system for printing pattern on the substrate includes first and second luminous flux projecting and receiving systems and a detector. The first luminous flux projecting system projects a first luminous flux to the substrate form a direction oblique to the interval direction. The first luminous flux receiving system receives a first luminous flux after the first luminous flux is reflected form the substrate. The second luminous flux projecting system projects a second luminous flux to a reflection member secured to the bottom end of the pattern-printing projection optical system. The second luminous flux receiving system receives the second luminous flux after the second luminous flux is reflected by the reflection member. The detection detects the position of the substrate in the interval direction by detecting the position at which the first luminous flux receiving system receives the first luminous flux and by detecting the position at which the second luminous flux receiving system receives the second luminous flux.