| abstract |
The present invention provides an etchant that etches a thermal oxide film and an SOD film at the same or similar etching rate and that hardly etches a poly-Si film, and more specifically, thermal oxidation. When the etching rate at 23 ° C. of the film and the SOD film is 50 liters / minute or less, the etching rate ratio of the SOD film / thermal oxide film is 1.25 or less, and the thermal oxide film is etched by 75 Å An object of the present invention is to provide an etching solution in which the etching amount of the Si film is 10 cm or less. [Solution] (1) 99% by weight or more of tripropylene glycol monomethyl ether with respect to the whole etching solution, (2) 0.4 wt% or less of water with respect to the whole etching solution, (3) An etching solution comprising one or two amines selected from hydrogen fluoride and (4) hydroxylamine and ammonia. [Selection] Figure 7 |