Abstract: According to the method of manufacturing a semiconductor device having a multilayer interconnection structure, lower wires are formed on a semiconductor substrate. Then, a first reflow SiO.sub.2 film having a reflow form is formed on the semiconductor substrate and the lower wires by reacting SiH.sub.4 gas with H.sub.2 O.sub.2 in a vacuum at 650 Pa or less within a range from -10 to 10.degree.C. After the first reflow SiO.sub.2 film is formed, heat treatment is performed at a predetermined high temperature on the semiconductor substrate on which the first reflow SiO.sub.2 film, and a second reflow SiO.sub.2 film having a reflow form is formed on the semiconductor substrate and the lower wires by reacting SiH.sub.4 gas with H.sub.2 O.sub.2 in a vacuum at 650 Pa or less within a range from -10 to 10.degree.C. The heat treatment step performed after the first reflow SiO.sub.2 film forming step and the second reflow SiO.sub.2 film forming step subsequent thereto are respectively performed at least once.

Abstract: In a patterning method according to this invention, a surface region of a resist layer is solution-retarded by a developer, and, then, the resist layer is patterned. Therefore, a desired shape of a side wall of the resist layer may be obtained by varying a solubility of the resist layer, with the result that a resist pattern with the side wall orthogonal to a surface of the substrate or the overhung side may be formed.

Abstract: A manufacturing method of a semiconductor device of the present invention comprises a first step of exposing a periphery of a first region of a photoresist layer coating an insulating layer formed on a semiconductor substrate and a periphery of a second region for positioning, and a second step of heating said photoresist layer in ammonia atmosphere and forming an alkali insoluble portion in the periphery of the first region and that of the second region, a third step of exposing a third region, which is smaller than the first region, and the second region and developing these regions, a fourth step of etching the third region and the second region to a predetermined depth, and a fifth step of repeating the third and fourth steps once or more in a region, which is smaller than the third region, and the second region.