Manufacture of semiconductor device

Abstract

Abstract PURPOSE:To flatten a surface by using only one type of insulating film and to accomplish isolation by providing trenches which are uniformly filled up flat by a method wherein an impurity-containing insulating film is deposited, a resist film is formed on recesses, the insulating film is subjected to etching, another insulating film is deposited, heat treatment is accomplished, and then another etching process is accomplished. CONSTITUTION:A trench 5 is provided in a substrate 1, and a PSG film is removed. By CVD, an oxide film (HTO) 4 and a silica glass (BPSG) 6 containing boron and phosphorus are deposited, equivalent in thickness to a step involved. Next, a resist film 7, narrower than a recess produced in a previous stage, is formed by photolithography. Anisotropic etching is accomplished against the BPSG film 6, which continues until the HTO film 4 is exposed. The resist film 7 is removed, another BPSG film 6' is deposited, to be as thick as to adequately cover the step. Heat treatment is accomplished under appropriate conditions, realizing a uniform-quality, flattened BPSG film 6''. The whole surface of the BPSG film 6'' is etched, which continues until a polycrystalline silicon film 3 is exposed. Finally, the entire surface is subjected to etching, which continues until an SiO2 film 2 is completely removed.

Inventors

• 👤 Hisashi Ogawa

Bibliographic Details