| 摘要 |
PURPOSE:To prevent the displacement of a mask caused by patterning by forming the mask by self-alignment while using a material having selective properties to polysilicon and an oxide as the mask for anisotropic etching of a polysilicon film at the bottom of a groove arranged on a semiconductor substrate. CONSTITUTION:On a semiconductor substrate 1, a groove 2, a high-temperature oxidized film 3, a direct contact 4, a polysilicon film 5 including the opposite conductive type ions to the substrate 1, and a diffusion layer 6 composed of the opposite conductive type ions to the substrate 1 are formed. Next, such a substrate is etched back so as to leave a high-temperature oxide film 10 only inside the groove 2 and a high-melting-point metal 12 such as tungsten having selective deposition properties to polysilicon is arranged over the film 5. The film 10 is removed and anisotropic etching of the film 5 in the groove 2 is performed by using the metal 12 as a mask, after which the metal 12 is removed. Next, the film 5 is oxidized and a thin oxide film 13 and a polysilicon film 14 are formed in order. A charge storing capacity comprising the films 5 and 14 as electrodes is formed.
|
