Method for manufacturing semiconductor device

A method for manufacturing a semiconductor device, the method comprising:

• forming an etching target film on an underlayer on a target substrate;
• forming a silicon-containing dielectric film, one selected from the group consisting of a silicon nitride film, a silicon oxynitride film, and a silicon oxide film, on the etching target film;
• doping a surface of the silicon-containing dielectric film with nitrogen to change an etching rate of the silicon-containing dielectric film relative to a predetermined solution such that the etching rate is lower at a surface layer thereof doped with nitrogen than at a base layer thereof below the surface layer, by use of a dose of nitrogen to obtain a nitrogen concentration of 10 to 60 atm% in the surface of the silicon-containing dielectric film;
• patterning the surface layer and the base layer of the silicon-containing dielectric film by a first etching process comprising anisotropic etching using a resist mask disposed on the silicon-containing dielectric film, thereby forming an etching mask;
• subsequent to the first etching process and removing of the resist mask, performing a second etching process comprising wet etching using the predetermined solution on a resultant structure on the target substrate, thereby removing etching residues derived from the base layer of the silicon-containing dielectric film;
• subsequent to the second etching process, patterning the etching target film by a third etching process using the etching mask;
• and
• subsequent to the third etching process, removing the etching mask.