MEASURING APPARATUS AND MEASURING METHOD

Provided is a phase shift amount measuring apparatus and method capable of measuring a phase shift amount and a transmittance of a phase shift mask in one measurement step by using a miniaturized monitor pattern. The phase shift amount and transmittance of the monitor pattern are simultaneously measured using a shearing interferometer. The phase shift amount is obtained from a phase difference of interference light between light passing through the monitor pattern and light passing through a non-pattern area. The transmittance of the monitor pattern is obtained using an amplitude of interference light between light passing through the monitor pattern and light passing through the non-pattern area and an amplitude of interference light between light beams passing through the non-pattern area. The use of common interference images in measuring the phase shift amount and transmittance enables measurement of both the phase shift amount and the transmittance in one measurement operation.