| 摘要 |
PURPOSE: To stop laser beam machining immediately before a recessed section is penetrated, and to improve the productivity of laser beam machining by estimating the thickness of a semiconductor substrate in the bottom of the recessed section by the intensity of transmitted beams where second beams overlapped to the optical path of laser beams for machining are transmitted through the substrate. CONSTITUTION:When a groove or a recessed section is formed from the surface of a semiconductor substrate 101 by irradiating the semiconductor substrate 101 with laser beams 102, second beams 105 different from said laser beams 102 are overlapped to the optical path of laser beams 102, and the thickness of the substrate in the bottom of the recessed section 103 is estimated by the intensity of transmitted beams where second beams 105 are transmitted through the semiconductor substrate 101. A semi- insulating GaAs substrate is used as the semiconductor substrate 101, pulse beams having a wavelength of 280nm by an excimer laser as laser beams 102 for machining, an infrared laser as the second beams 105 and a photomultiplier as a detector 106. Laser beams for machining are stopped when an output from the detector reaches a fixed value, thus stopping etching immediately before the recessed section for a viahole is penetrated. |
