Measuring apparatus and measuring method

A measuring apparatus that simultaneously measures a phase shift amount and a transmittance of a phase shifter formed in a half-tone type phase shift mask, the measuring apparatus comprising:

• a lighting system that projects an illumination beam toward a monitor pattern, the monitor pattern being formed of a light-transmitting portion formed on a half-tone film, or being formed of the half-tone film formed on the light-transmitting portion;
• an objective lens that condenses light transmitted through the half-tone type phase shift mask;
• a shearing interferometer that forms first and second laterally-shifted shearing beams from the light condensed by the objective lens, and forms an interference beam by combining the first and second shearing beams;
• a two-dimensional imaging device that picks up laterally-shifted interference images including first to third interference images, the first and second interference images being formed by transmitted light transmitted through the monitor pattern and transmitted light transmitted through a peripheral area of the monitor pattern, the third interference image being formed by transmitted light beams transmitted through the peripheral area of the monitor pattern;
• and
• a processor that processes an output signal from the two-dimensional imaging device, wherein
• a phase modulation of one period is performed on the laterally-shifted interference images including the first to third interference images by adjusting a shearing amount of the shearing interferometer, and phase modulation data indicating a relationship between a phase modulation amount and a luminance value is obtained for each of the first to third interference images,
• the processor calculates, as the phase shift amount of the phase shifter, a phase shift amount between the first interference image and the second interference image by using the phase modulation data on the first and second interference images, and
• the processor calculates, as the transmittance of the phase shifter, a square of a ratio between an amplitude of the phase modulation data on the first interference image and an amplitude of the phase modulation data on the third interference image.