Process monitor and process monitoring method
A process monitor includes a photodetector that separately measures intensities of radiant light from a semiconductor member being annealed, in a plurality of wavelength ranges that are different from each other, and a processing device that obtains a physical quantity related to the semiconductor member that changes due to annealing, based on the intensities in the plurality of wavelength ranges measured by the photodetector.
1. A process monitor comprising:
a photodetector includes a plurality of light receiving units configured to separately measure intensities of radiant light from a semiconductor member being annealed, in a plurality of wavelength ranges that are different from each other; and
a processing device configured to obtain a physical quantity related to the semiconductor member that changes due to annealing by a laser beam, based on the intensities in the plurality of wavelength ranges measured by the photodetector;
a beam spot of the laser beam on a surface of the semiconductor member has a long shape that is elongated in one direction,
an imaging optical system including two lenses that forms an image of the beam spot;
the plurality of light receiving units are disposed at different positions in a longitudinal direction of the image of the beam spot; and
one light receiving unit of the plurality of light receiving units detects the radiant light emitted from a region shallower than a depth D 1 and another light receiving unit of the plurality of light receiving units detects the radiant light emitted from a region shallower than a depth D 2 wherein D 2 <D 1 .
2. The process monitor according to claim 1 , wherein
the photodetector is further configured to detect the radiant light from the semiconductor member whose outer layer portion is heated by input of the laser beam, and
the processing device is further configured to obtain a reached temperature of an outermost surface of the semiconductor member, as the physical quantity related to the semiconductor member that changes due to annealing.
3. The process monitor according to claim 2 , wherein
the photodetector includes the plurality of light receiving units that separately measure the intensities of radiant light in the plurality of wavelength ranges.
4. The process monitor according to claim 3 , wherein
each of the plurality of light receiving units includes an optical sensor having a different peak sensitivity wavelength.
5. The process monitor according to claim 3 , wherein
each of the plurality of light receiving units includes an optical sensor having a same spectral sensitivity characteristic, and a bandpass filter having a different passing wavelength range, and wherein radiant light transmitted through the bandpass filter is incident on the optical sensor.