Patent ID: 9163931
Filing Date: 2015-10-20
Classification: G01B,G01K,H01J,H01L

Abstract:
1. An apparatus for measuring at least a thickness of a ceramic member provided in a chamber maintained in a vacuum atmosphere, the apparatus comprising: a terahertz wave generating unit configured to output a terahertz wave; a terahertz wave analysis unit configured to analyze a terahertz wave; and an optical system configured to guide the terahertz wave output from the terahertz wave generating unit to the ceramic member and guide reflected waves of the terahertz wave reflected from the ceramic member to the terahertz wave analysis unit, wherein the terahertz wave analysis unit obtains an optical path difference between a first reflection wave reflected from a front surface of the ceramic member and a second reflection wave reflected from a rear surface of the ceramic member and measures a thickness of the ceramic member based on the optical path difference.