| 摘要 |
PURPOSE:To reduce the possibility of a disconnection and to improve the reliability of an IC by wet etching, dry etching and heat treating to form a taper in a contact opening. CONSTITUTION:A pattern of a contact hole is formed on a resist on an insulating film 102 formed on a semiconductor substrate 101. Then, part of the film 102 is removed by wet etching, and the remainder of the insulating film is then removed by dry etching. When the resist is all removed, a conventional contact shape as in Fig. a is formed. Here, since the film 102 is of BPSG, a viscous fluidization is caused by heat treating at approx. 900 deg.C for approx. 30 min. Accordingly, a smooth contact shape as in Fig. (b) can be formed by the surface tension of the BPSG by a heat treating step.
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