摘要 |
A heat treatment is performed to an insulating film composition, formed on a semiconductor substrate, at a temperature of 350° C. in an inert gas ambient to form a non-porous insulating film. Next, dry etching is performed using a resist pattern as a mask to form a trench in the non-porous insulating film, ashing is performed to remove the resist pattern, and the surface of the semiconductor substrate is cleaned. Thereafter, a second heat treatment is performed for the non-porous insulating film to form a porous insulating film. Since the second heat treatment is performed in an oxidizing-gas atmosphere, the pore-generating material can be removed at a temperature lower than the temperature of conventional methods to form an insulating film having a low dielectric constant.
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