| 摘要 |
PURPOSE:To form a channel stopper in a simple process, by a method wherein a oxide silicon film containing boron and a softening insulative film are continuously formed and subjected to a thermal treatment to form a channel stopper. CONSTITUTION:A thermally oxidized film 31, a polycrystal silicon film 32 and a photoresist film 33 are formed on a substrate 30. The films 31 and 32 are eliminated by applying the film 33 to a mask. The substrate 30 is subjected to an etching to form a trench 34, and an SiO2 film 35 containing boron is formed. A softening insulative film 36 is arranged, and a channel stopper 37 is formed by a heat treatment. Further a heating oxide film 38 is formed by a heat treatment, and then the film 36 is fluidized to fill the trench 34. After that, a photoresist film 39 is spread, the films 36 and 39 are subjected to a dry etching, the trench 34 is filled with the films 35 and 36, the films 32 and 31 are eliminated, and a MOS transistor is formed on an exposed substrate 30. Thus a channel stopper is formed by a simple process.
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