| 摘要 |
PURPOSE:To form an insulating film only on the bottom of a groove in a self- aligning manner by forming the groove on a semiconductor substrate, depositing a silicon nitride film thereon, ion implanting the nitride film, heat treating it, retaining the nitride film formed on the bottom of the groove and a part except the groove, removing by etching the nitride film, depositing a resist, and removing by etching the nitride film together with the resist. CONSTITUTION:A groove is formed by reactive ion etching on a silicon substrate 1. Then, silicon nitride films 2 are formed on the bottom of the groove, the sidewall and a part except the groove. Arsenic, antimony, nitrogen, gallium or xenon is ion implanted to the nitride film at an incident angle of 7 deg. or less. Further, it is heat treated in an inert gas, hydrogen, oxygen or steam atmosphere at least 750 deg.C or more. Then, it is so etched as to retain the nitride film only on the sidewall of the groove. Only the nitride film of the sidewall is removed, and the nitride films on the bottom and the part except the groove remain. Then, a resist 4 is deposited, the nitride film 2 of the part except the groove is etched together with the resist, the resist 4 in the groove is etched, and only the film 2 on the bottom remains. |
