PURPOSE: To taper etch a hole by anisotropically after locally forming a taper in the hole thereby to be able to effectively connect wirings by forming the hole in an insulating film which can be fluidized by heat treating on a semiconductor substrate and heat treating it.

CONSTITUTION: An insulating film 3 which can be fluidized is formed on a semiconductor substrate 1, and a hole 5 is selectively formed in the film 3. Then, the film 3 is heat treated to form a taper 6 locally in the hole 5, and the film 3 is anisotropically etched to taper etch the hole 5. For example, an insulating film 2, such as a silicon oxide film is formed on the substrate 1, and an AsSG film 3 is formed as a reflow film thereon. Then, with a photoresist 4 as a mask the hole 5 which penetrates the films 2 and 3 is formed by anisotropically etching. Thereafter, the film 3 is allowed to reflow by heat treating to form a taper 6. Subsequently, the whole surface is etched back by anisotropically etching to move back the taper 6.