| 摘要 |
PURPOSE:To improve element quality by a method wherein, at the time of etching, exposure of semiconductor and elimination of side wall material are not executed, thereby preventing the generation of cavities and the change of interface energy level. CONSTITUTION:Firstly, a first trench 5 is formed on a semiconductor substrate 1, and the following are deposited; a first protective film 2, a second protective film 3, a mask base film 15, and an insulating film 4 for a mask. By etching method of intense isotropy, the deposition layers are etched. At this time, the deposition layer is left only on the side surfaces of the trench 5; a first trench side wall material 7 is formed; the part where the substrate 1 is exposed is further etched, thereby forming a second trench 8. While the side wall material 7 is left as it is, burying material for the second trench 8 is deposited. In order that semiconductor material may not be exposed, the etching of the burying material for the trench 8 is interrupted in the midway of the trench 5. Thereby oxidation before the trench 5 is filled ie unnecessitated, adverse influence caused by stress can be avoided, the generation of cavities and the change of interface energy level can be prevented, so that element characteristics are improved. |
