Manufacturing method of semiconductor device
View Patent ↗A first film and a second film are formed on a semiconductor substrate in this order. A resist pattern is formed on the second film. An opening is formed by removing the second film exposed between the resist pattern at a state where the second film remains on the bottom. A first removal preventing film is formed on the side wall of the opening and the residual film is removed at a state where the projecting part of the second film protruding from the sidewall to the opening remains. The first film exposed in the opening is removed. A second removal preventing film is formed on the first removal preventing film and the surface of the semiconductor substrate exposed in the opening is removed at a state where the projecting part of the semiconductor substrate protruding from the side wall to the opening remains and a round part is formed at the projecting part of the semiconductor substrate. The semiconductor substrate exposed in the opening is further removed.
1. A manufacturing method of a semiconductor device comprising:
forming a first film and a second film on a semiconductor substrate in this order;
forming a resist pattern on the second film;
forming an opening in the second film utilizing the resist pattern, a bottom portion of the second film remaining after forming the opening in the second film;
removing the bottom portion of the second film and forming a first removal preventing film on a side wall of the second film, a projecting part of the second film protruding from the side wall of the second film;
removing the first film exposed in the opening;
removing the surface of the semiconductor substrate exposed in the opening and forming a second removal preventing film on the first removal preventing film, a projecting round shaped part of the semiconductor substrate protruding into the opening; and
removing the semiconductor substrate exposed in the opening.
2. The manufacturing method of the semiconductor device according to claim 1 , wherein the first film is an oxide film, and the second film is a nitride film.
3. The manufacturing method of the semiconductor device according to claim 1 , wherein the resist pattern is formed to have a shape that corresponds to a trench formed in the semiconductor substrate.
4. The manufacturing method of the semiconductor device according to claim 1 , wherein the first film, the second film, the residual film and the semiconductor substrate are removed by etching treatment.
5. The manufacturing method of the semiconductor device according to claim 1 , wherein the projecting part of the second film is tapered to have taper angle of 5° to 45° in the step of removing the residual film.
6. The manufacturing method of the semiconductor device according to claim 1 , wherein the thickness of the residual film is formed to be 3 nm to 20 nm in the step of removing the second film at a state where the residual film remains at the bottom.
7. The manufacturing method of the semiconductor device according to claim 1 , wherein a taper cutting of the upper end of the opening is carried out after the step of further removing the semiconductor substrate.