Forming bottle-shaped trench for capacitor of dynamic random access memory involves forming pad layer and hard mask layer on semiconductor substrate, forming trench, and etching trench unmasked by spacer

摘要

A bottle-shaped trench is formed by providing a semiconductor substrate (401) on the surface of which a pad layer (402) and a hard mask layer are sequentially formed, forming a trench; and etching the trench, unmasked by a spacer (409a), to a bottle shape. Formation of a bottle-shaped trench comprises: providing a semiconductor substrate on the surface of which a pad layer and a hard mask layer are sequentially formed; forming a trench; forming a dielectric layer (403) on the hard mask layer filling the trench; etching the dielectric layer in the trench to a predetermined depth; forming a spacer on the sidewall of the trench; removing the dielectric layer; and etching the trench, unmasked by the spacer, to a bottle shape.