Apparatus for real-time semiconductor wafer temperature measurement based on a surface roughness characteristic of the wafer

摘要

A sensor (100) for measuring semiconductor wafer (10) temperature in semiconductor processing equipment (30), comprising a first laser (104) to provide a first laser beam at a first wavelength and a second laser (106) to provide a second laser beam at a second wavelength. The sensor also includes a laser driver (108) and an oscillator (110) to modulate the wavelength of the first and second laser beams as the laser beams are directed to and reflected from the wafer (10), and a detector module (130) to measure the change in specular reflectance of the wafer (10) resulting from the modulation of the wavelength of the first and second laser beams. The sensor system also includes signal processing circuitry (138) to determine rms surface roughness of the wafer (10) at a known reference temperature from the change in reflectance of wafer (10) resulting from modulation of the wavelengths of the first and second laser beams, and to determine the temperature of wafer (10) from the change in specular reflectance of wafer (10) resulting from modulation of the wavelengths of the first and second laser beams while wafer (10) is at an unknown temperature and the surface roughness of the wafer at the known temperature.