| 摘要 |
PURPOSE:To obtain the oxide film having no irregularity in film thickness as well as to enable to perform a selective diffusion for the titled integrated circuit by a method wherein, using a buffer hydrofluoric acid solution, a boron-silicate glass film is removed by dissolution in the state wherein the oxide film is masked with a tetranitride tri-silicone film. CONSTITUTION:A tetranitride trisilicon film 7 is formed on an SiO2 film 6, and a BSG film 8 is formed thereon. Then, under that condition, boron is thermally diffused off the BSG film 8, and then the BSG film 8 is removed using a BHF solution. In this case, the SiO2 film 6 is not damaged by an BHF solution, because it is masked with the tetranitride trisilicon film 7. Also, an epitaxial layer 9 is not spoiled by the BHF solution, because it is hardly affected by the BHF solution. Then, the tetranitride trisilicon film 7 located on the SiO2 film 6 is removed. As a result, there remains an entirely undamaged SiO2 film 6 whereon no etching is performed. |
