摘要 |
In the case of cutting streets on the rear surface of a wafer by laser beam irradiation, even if the wafer is variously doped or thermally-treated, the streets of a wafer front surface can accurately be detected and cut. Infrared light is emitted from an infrared light source to the front surface side of the wafer to penetrate the wafer. The penetrating image is captured by an infrared microscope disposed on the rear surface side of the wafer. The streets are detected by the image pattern of a wafer front surface captured. A laser beam is emitted from a laser head to the wafer rear surface along the streets detected, thus processing the streets for cutting.
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