| 摘要 |
PURPOSE:To improve the characteristics and reliability of a semiconductor storage device by forming a trench capacitor consisting of a capacitance insulating film thicker than the lower bottom of a trench to the upper section of the trench. CONSTITUTION:The section 15 of an Si3N4 film on a sidewall surface (approximately one third of the depth of a trench from a main surface) in the upper section of the trench has film thickness of 12nm when the section 15 is shaped while the section 15' of the Si3N4 film on the residual sidewall surface (a section up to the bottom from approximately one third of the depth of the trench) and the base of the trench has film thickness of 6nm. An insulating film forming the capacitance of a trench capacitor has the three-layer structure of a first capacitance oxide film 14 composed of SiO2, capacitance nitride films 15, 15 ' made up of Si3N4 and a second capacitance oxide film 16 consisting of SiO2, and the upper section of the trench is made thicker than the bottom of the trench. Accordingly, yield and reliability can be improved. |
