| 摘要 |
PURPOSE:To prevent the precipitation of a crystal in a BPSG film even in a heat treatment process by forming an insulating protective film having damp- proofness onto the BPSG film before and after a flattening process for the BPSG film. CONSTITUTION:A channel stopping layer 4 and a field oxide film 6 are shaped to a P-type silicon substrate 2, and a gate oxide film 8 is formed. A polysilicon film is shaped, and a gate electrode 10 and a wiring 12 are formed. A source region 14 and a drain region 16 are shaped, and a BPSG film 18 containing 3mol% B and 6mol% P is formed as an insulating film. A PSG film 20 containing 8mol% P is shaped onto the BPSG film 18 through a normal pressure CVD method. The film 18 and the film 20 are flattened through a reflow at 900 deg.C. Contact holes are bored, and phosphorus is then diffused to form a metal wiring layer 22. Accordingly, the BPSG film 18 is not recrystallized even through heat treatment at a high temperature for diffusing phosphorus. |
