| 摘要 |
PROBLEM TO BE SOLVED: To prevent a background silicon nitride film from being excessively etched, in the case of forming a contact hole for a bit wire contact or the like in a DRAM. SOLUTION: For example, a gate electrode 13 is formed on a surface of a silicon substrate 11 via a gate insulation film 12 to coat the surface and the side wall of the gate electrode 13 with a silicon nitride film 14. After a silicon oxide film 16 is formed to an upper layer of the silicon nitride film 14, the silicon oxide film 16 is etched by using a resist pattern 17 as a mask to form a contact hole 18 in a self-alignment way with respect to the gate electrode 13. In this case, first of all a mixture gas of C4 F8 /Ar is used to conduct etching, and the gas is replaced with a mixture gas of CHF3 /Co and then the etching is conducted, after the silicon nitride film 14 is exposed in a plasma. |
