| 摘要 |
PURPOSE:To eliminate the need for the margin of the size of a cell contact and the positional accuracy of the cell contact by forming the cell contact onto the whole circumference of a trench in a self-alignment manner in the side wall of the upper section of the trench or on the adjacent transistor side in the side wall of the upper section of the trench in a semi-self-alignment manner. CONSTITUTION:An element isolation region is shaped, three layer films of oxide films 22, 23/first nitride film 25/oxide film 26 are formed, a shallow trench is shaped through isotropic etching, using the three layer films as masks, a second nitride film 28 is applied, and a nitride-film side wall 29 having a section buried into the shallow trench is formed through anisotropic etching. The shallow trench is dug down to a deep trench 30 through anisotropic etching, the inside of the trench is oxidized selectively and the nitride-film side wall 29 is removed, and a first conductive film 34 is applied. The first conductive film 34 is brought into contact with a semiconductor substrate section, which is exposed by getting rid of the nitride-film side wall 29 and functions as a cell contact 32, and a contact section is shaped together with a diffusion layer 33 in an adjacent transistor. Accordingly, the margin of the size of the cell contact and the positional accuracy of the cell contact can be unnecessitated. |
