公开(公告)号：US12209853B2

公开(公告)日：2025-01-28

申请号：US17604553

申请日：2020-04-09

Applicant: Fujikoshi Machinery Corp.

Inventor： Chihiro Miyagawa ,  Kazutaka Shibuya ,  Kiyohito Aoki

IPC: G01B11/06 ,  G01N21/95 ,  H01L21/304 ,  H01L21/66

Abstract: A non-contact apparatus for measuring wafer thickness includes a monolithic wavelength sweeping semiconductor laser light source having a laser source, a laser control unit that controls the laser source, and a processor to control the laser source to oscillate laser light having a wavelength that changes with a setting profile relative to time; an optical system that guides and emits the laser light onto a wafer; a detection unit that detects an interference light signal of reflected light; an A/D converter that converts the interference light signal detected by the detection unit into a digital signal; and a calculation unit that calculates a thickness of the wafer by analyzing the digital signal from the A/D converter. The processor causes the laser control unit to operate with a clock signal, and to oscillate laser light that performs wavelength-sweeping with the setting profile relative to the time, from the laser source. The A/D converts the interference light signal by generating a sampling clock in synchronization with the clock signal or directly using the clock signal as a sampling clock.