| 摘要 |
PURPOSE:To eliminate a source of transposition while reducing the width of etching by means of selective etching and utilization of laser beams. CONSTITUTION:A silicon substrate 4 placed on a quartz-made base 5 is inserted into a quartz-made reaction tube 3. 1l/min of hydrochloric anhydride and 40l/ min of hydrogen as carrier gas are introduced from a gas introducing channel 6 and laser beams from a laser emitter 1 irradiates the semiconductor device 4 through a focussing lens 2. At this time, if the laser beams are focussed on the surface of said semiconductor device 4, a hole perforated by melting and evaporating the silicon of said device 4 may become a source of transposition easily. Therefore, the energy concentration of the laser beams is controlled either by separating the focus from the substrate 4 or by focussing on a position inside the substrate 4 so as to heat the irradiated part only without melting and evaporating silicon making hydrochloric acid in the atmosphere and silicon react to each other for etching process. Through these procedures, an etching without lateral extension may be performed since the source of transposition at groove sides is eliminated and the etching can be limited to the part only irradiated by the laser beam. |
