Planarization of insulation film using low wettingness surface

Abstract

A planarization method comprises forming on an uneven surface an silicon oxide film having a low wettingness at least on its surface. The low wettingness of the silicon oxide film is obtained by increasing the silicon/oxygen atom ratio by means of argon sputtering or plasma CVD method. A silica solution is subsequently spin-coated onto the silicon oxide film. Since the surface of the silicon oxide film has a low wettingness, more of the coated silica solution stands on recessed portions than on raised portions, resulting in a flat surface of the coated solution. After the coated silica solution has been hardened, etching-back can be carried out until the coated silica solution is completely removed, thereby achieving the planarized surface of the silicon oxide film.

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