| 摘要 |
PROBLEM TO BE SOLVED: To reduce loss of capacitive coupling by removing an insulating film remaining on sidewalls, when back-etching the insulating film in an element isolation groove of a semiconductor substrate. SOLUTION: A gate insulating film 4, a polycrystalline silicon film 5 for a floating gate electrode, and a silicon nitride film 8 are laminated and formed on a silicon substrate 1. A plurality of trenches 1a are formed at prescribed intervals and each element isolation insulating film 2 is embedded and formed in each trench 1a. Each element isolation insulating film 2 in each trench 1a is back-etched to a prescribed depth. A photoresist is applied to the entire surface of the silicon substrate and is exposed under condition of preventing the bottom of each trench 1a from being exposed, so as to leave a resist 10a on the bottom surface of each trench 1a. A silicon oxide film is etched by wet etching, while using the resist 10a as a mask so as to remove the element isolation insulating film remaining on the sidewalls on each trench 1a. COPYRIGHT: (C)2011,JPO&INPIT
|
