Dynamic random access memory

摘要

A method includes forming a trench capacitor in a semiconductor body. A recess is formed in the upper portion of the capacitor with such recess having sidewalls in the semiconductor body. A first material is deposited over the sidewalls and over a bottom of the recess. A second material is deposited over the first material. A mask is provided over the second material. The mask has: a masking region to cover one portion of said recess bottom; and a window over a portion of said recess sidewall and another portion of said recess bottom to expose underlying portions of the second material. Portions of the exposed underlying portions of the second material are selectively removing while leaving substantially un-etched exposed underlying portions of the first material. The exposed portions of the first material and underlying portions of the semiconductor body are selectively removed. An isolation region is formed in the removed portions of the semiconductor body. The mask is provided over the second material with a masking region covering one portion of said recess sidewall and one portion of said recess bottom and with a window disposed over an opposite portion of said recess sidewall and an opposite portion of said recess bottom to expose underlying portions of the second material. Etching is provided into the exposed underlying portions of the semiconductor body to form a shallow trench in the semiconductor body. An insulating material is formed in the shallow trench to form a shallow trench isolation region. With such method, greater mask misalignment tolerances are permissible.