THICKNESS MEASURING DEVICE AND THICKNESS MEASURING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a thickness measuring device and a thickness measuring method with excellent practical utility for measuring the thickness of a measuring object put between interfaces of mediums differed in light diffractive index such as a thin film. SOLUTION: This device comprises a means emitting a part of light from a light source 1 to the measuring object 3 to form an inspection reflected light; a means reflecting another part of the light from the light source 1 to form a reference reflected light; a beam splitter 32 interfering a first luminous flux including at least a light signal of the inspection reflected light with a second luminous flux including at least a light signal of the reference reflected light to form an interference light; a first optical path length variable means changing the optical path length of the first luminous flux; a second optical path length variable means changing the optical path length of the second luminous flux; and light receivers 4 and 5 detecting the light intensity of the interference light. Either the first variable means or the second variable means comprises a stepping motor 41, and the other comprises a piezo-actuator 43. COPYRIGHT: (C)2006,JPO&NCIPI