POSITION MEASURING APPARATUS USING HOLOGRAM

摘要

PURPOSE: A position measuring apparatus is provided to exactly measure the position of a mask and a wafer by recording an alignment mark on the mask according to a hologram method and measuring a strength variation of an alignment signal. CONSTITUTION: The first mask has the first alignment mark, and a hologram forming part irradiates a laser on the first mask to form a hologram alignment mark. The hologram alignment mark is recorded on the second mask(2), and a circuit pattern to be projected is formed on the second mask(2). A reproduction part irradiates a laser on the second mask to reproduce the hologram alignment mark. A wafer(5) includes the second alignment mark(51) for generate a diffraction light by interaction with the reproduced alignment mark. A signal detecting part(6) detects an alignment signal corresponding to the generated diffraction light. A controller calculates the position of the second mask(2) and wafer(5) according to an output signal of the signal detecting part(6).