| 摘要 |
PURPOSE:To leave a semiconductor film in a diffusing region selectively in a groove functioning as an inter-element isolation region, and to form the inter- element isolation region by using a fact that an etching rate of the semiconductor film is faster than those in other regions in a self-alignment manner. CONSTITUTION:A PSG film 13 is formed onto a P type Si substrate 10. A photo- resist pattern 14 is formed onto regions except the isolation region. Si is etched, and the concave groove 15 is formed. An ion implantation region 16 is formed to the bottom of the groove 15. The pattern 14 is removed, and an SiO2 film 17 is formed to a groove 15 section. A poly Si film 18 is further formed. The whole is thermally treated. An Si film 18' is removed through etching by a mixed liquid of HNO3, HF and CH3COOH. The etching rate of the Si film 18' is faster than that of the Si film 18 in the groove 15 at that time. Accordingly, the Si film 18 of the groove 15 remains. The PSG film 13 is etched. The groove is buried with an SiO2 film 19. The surface is further etched. |
