Abstract: A semiconductor device and its manufacturing method are presented. The manufacturing method entails: forming a dielectric layer on a semiconductor substrate; forming a functional layer on the dielectric layer; forming a hard mask layer on the functional layer; patterning the semiconductor substrate to form an opening on the semiconductor substrate, wherein the opening goes through the hard mask layer, the functional layer and extends into the dielectric layer; performing an oxidization process on side surfaces of the functional layer inside the opening to form oxide layers; performing a first process on the semiconductor substrate to remove a portion of the dielectric layer underneath the opening to expose the semiconductor substrate; and removing the oxide layers on the side surfaces of the functional layer to form a contact hole. The contact hole has a wider opening in the upper part than in the lower part.

Abstract: A semiconductor device and its manufacturing method are presented. The manufacturing method entails: forming a dielectric layer on a semiconductor substrate; forming a functional layer on the dielectric layer; forming a hard mask layer on the functional layer; patterning the semiconductor substrate to form an opening on the semiconductor substrate, wherein the opening goes through the hard mask layer, the functional layer and extends into the dielectric layer; performing an oxidization process on side surfaces of the functional layer inside the opening to form oxide layers; performing a first process on the semiconductor substrate to remove a portion of the dielectric layer underneath the opening to expose the semiconductor substrate; and removing the oxide layers on the side surfaces of the functional layer to form a contact hole. The contact hole has a wider opening in the upper part than in the lower part.