Semiconductor device and manufacturing method of semiconductor device

Abstract

A method of manufacturing a semiconductor device includes forming a stacked structure with first material layers and second material layers that are alternately stacked with each other, forming a first opening that passes through the stacked structure, forming second openings between the first material layers, forming first sacrificial layers in the second openings, forming first isolation layers that protrude into the first opening by oxidizing the first sacrificial layers, forming mold patterns on the first material layers between the protruding portions of the first isolation layers, forming third openings by etching portions of the first isolation layers that are exposed between the mold patterns, forming second sacrificial layers in the third openings, and forming second isolation layers that protrude farther toward the center of the first opening than the mold patterns by oxidizing the second sacrificial layers.