SEMICONDUCTOR DEVICE AND METHOD FOR MANUFACTURING THE SAME

PROBLEM TO BE SOLVED: To solve such a problem that modification of a dielectric film does not progress, a wet etching rate accelerates and thereby a yield decreases.SOLUTION: This semiconductor device comprises: a semiconductor substrate that has a plurality of grooves, at least one pillar part formed between the grooves, and a side wall recess formed at a lower part of a side wall of the pillar part; a polysilicon film that covers a side wall surface in the side wall recess; and a dielectric film that is embedded in the groove and also is densified.