Device isolation structure and device isolation method for a semiconductor power integrated circuit

摘要

The present invention relates to a device isolation structure and a device solation method in a semiconductor power IC. The device isolation structure according to the present invention includes: a semiconductor substrate including a high voltage region and a low voltage region; a trench overlapping the high voltage device region of the semiconductor substrate and an interfacing region formed between the high voltage device region and the low voltage device region; a fourth insulating film, a fifth insulating film, and a conductive film sequentially layered in the trench; a first insulating film pattern formed on the semiconductor substrate including the trench; and field insulating films respectively formed on the trench and on a portion of an upper surface of the semiconductor substrate which is exposed out of the first insulating film pattern. The present invention has several advantages concerning manufacturing costs and reliability, some of which being achieved by forming a thermal oxide film in an empty space of the conductive film by which oxygen is permeated thereinto and thus restraining breakdown from being generated between high voltage devices at a high voltage.