| abstract |
(57) [Problem] To provide an etching stock solution that can be commonly used in a plurality of etching steps. SOLUTION: H 2 SO 4 and NH 4 F or H 2 SO 4 And HF as main components and a method of manufacturing a semiconductor device having an etching step using an etching stock solution containing 5 wt% or less of H 2 O. Further, the present invention is a method for manufacturing a semiconductor device, comprising the step of selectively etching a SiN film using a mixed solution of H 2 SO 4 and H 2 O or an etching solution obtained by adding a small amount of hydrofluoric acid to this mixed solution. . |