Patent ID: 7123414

Claim:
A method of measuring a sectional shape of a periodic pattern, said method comprising steps of: simulating a condition of reflected lights from a periodic pattern to be obtained with respect to a plurality of conditions of an incident light to the periodic pattern, the condition of the reflected lights being simulated with respect to each of a plurality of sectional shapes of the periodic pattern and each of a plurality of optical constants of a material that forms the periodic pattern; producing a library which relates the condition of the reflected lights to the sectional shape of the periodic pattern with respect to each of the plurality of optical constants; measuring the optical constant of a material that forms an actual periodic pattern; selecting a library corresponding to the measured optical constant from the produced plurality of libraries; detecting a condition of reflected lights from the actual periodic pattern with respect to the plurality of conditions of an incident light to the actual periodic pattern; and obtaining a sectional shape of the actual periodic pattern based on the selected library and the detected condition of reflected lights.