| 摘要 |
PURPOSE:To simply measure the depth of the uneven pattern of an object to be inspected with high accuracy, by irradiating the object to be inspected with a plurality of coherent light beams having the same wavelength at mutually different angles and calculating the intensity ratio of the same degree of diffacted beams thereof. CONSTITUTION:An object 11 to be inspected comprising arranging and forming a predetermined uneven pattern corresponding to a recording signal is moved to the radius direction thereof by a stage moving mechanism 13 while receives rotary driving by a motor 12. Coherent light beams generated from a light source 14 are allowed to irradiate the same position of the object 11 to be inspected as two light beams different in an irradiation angle through a beam splitter 15 and a mirror 16. Light detectors 17, 18 detect the primary diffracted beams of two light beams to output electric signals correspondent to the intensity of light. These signals are taken in an operation control part 21 through preamplifiers 19, 20 a selector 20 and an A/D converter 22. The operation control part 21 calculates the depth of the uneven pattern from the intensity ratio of these signals and displayed on a display part 23. |
