Semiconductor device with insulator and manufacturing method therefor

摘要

It is possible to obtain a semiconductor device with an element isolation structure showing a good isolation characteristic by filing an interior of a minute trench with a good quality insulating film free of a defect such as a void, and a manufacturing method therefor. The semiconductor device includes a semiconductor substrate and an isolation insulator. A trench is formed on a main surface of the semiconductor substrate. The isolation insulator is formed in an interior of the trench using a thermal oxidation method to isolate element forming regions from each other on the main surface of the semiconductor substrate. The isolation insulator is a lamination body formed by a plurality of oxide film layers.