To restrain the generation of dust due to evaporation of a molten member and to obtain the mark having excellent visibility by heating the background part around a pattern marking part at the lower temperature than the temperature reaching when a pulse laser beam transmitted a pattern mask is irradiated.
The laser beam oscillating command to Nb:YAG laser oscillator 1 (pulse laser oscillator) from a controller 10 and a pattern displaying signal from a liquid mask controller 11 are sent. The laser beam 2 of a linear polarized light having about uniform intensity distribution is emitted from the pulse laser beam oscillator 1. The laser beam 2 is made incident on a liquid crystal mask 4 via a magnifying optical system 3. The laser beam 2' transmitted the liquid crystal mask 4 is irradiated on a Si water to mark the pattern 9A after being separated with a beam splitter 6. The laser beam is irradiated under the state heating the Si wafer, whereby energy poured into the pattern marking part 9A is restrained to diffuse into the background part 9B, and moreover the generation of dust due to partial evaporation is prevented.
SASAKI HIROHARU
YOSHIKAWA TOSHIMITSU
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