Patent ID: 7776756

Claim:
A method of manufacturing a semiconductor device comprising: forming a dielectric film over a semiconductor substrate; immersing the semiconductor substrate in an etching solution and selectively etching the dielectric film, the etching solution including sulfuric acid, hydrogen fluoride, and water, a concentration of the water being between 2 wt % to 4 wt %; circulating the etching solution; controlling a concentration of the etching solution to contain a concentration of hydrogen fluoride between 0.5 wt % to 2 wt % and the concentration of water between 2 wt % to 4 wt % so that an etching selectivity of borosilicate glass film against thermal oxide film is 100 or higher; and feeding a refilling chemical liquid including the sulfuric acid having a concentration higher than the sulfuric acid in the etching solution.