| 摘要 |
PURPOSE:To facilitate formation of a minute U shape groove in a semiconductor device by a method wherein polycrystalline semiconductor layer provided on a semiconductor substrate interposing an insulating film between them is patternized, and the substrate is etched making the polycrystalline layer and the insulating film thereof as the mask. CONSTITUTION:The polycrystalline Si layer 3 is provided on the Si substrate 1 interposing the SiO2 film 2 between them, an N<+> layer is formed by diffusion making an Si3N4 film formed along the necessitated U shape groove as the mask, and after the surface thereof is oxidized thermally, the Si3N4 film is removed, minute breath of the exposed N<+> region only is etched to be removed by selective etching according to difference of concentration of impurities, the insulating film 2 is patternized making the polycrystalline Si layer thereof as the mask, the U shape groove is formed in the substrate 1 making the insulating film thereof as the mask, and the U shape groove is buried up with an SiO2 layer by thermall oxidation. Accordingly the minute U shape groove can be formed extremely precisely without according to the photoetching treatment technique. |
