| 摘要 |
PURPOSE:To remove the generation of voids, and to obtain the device having high dielectric strength by a method wherein a mask used for forming a mesa groove is taken away from a Si substrate the inside of the mesa groove is coated with a glass film and a silica film is anew shaped on the whole surface of the substrate containing the glass film at a temperature lower than a softening temperature of glass. CONSTITUTION:The P<+> type layer side of the N type Si substrate 1, to the surface thereof a P<+> type layer is formed and to the back thereof an N<+> type layer is shaped, is coated with a thermal oxide film, windows are formed to mesa shaping sections and etched, and a plurality of mesa grooves 4 intruding into the substrate 1 are bored to the P<+> type layer. The thermal oxide film used as the mask is removed, and a glass material is applied onto the inner surfaces of the mesa grooves 4 and baked and the glass films 5 are formed, but the voids are not generated because the thermal oxide film is removed previously at that time. Ethyl alcohol containing 5% silanol is applied rotatively on the whole surface containing the films 5, and baked for thirty min-one hr at a temperature of 360-450 deg.C in dried air. Accordingly, the silica film is anew shaped on the whole surface of the substrate. |
