| 摘要 |
PROBLEM TO BE SOLVED: To provide a semiconductor device which can increase the operating speed of a system, by reducing resistance of wiring buried in a trench, and increasing signal transmitting speed between semiconductor elements. SOLUTION: In a semiconductor device, an element separating insulating film 25 formed on the side wall of a trench 21 is formed as a thermally oxide film in such a way that the film thickness of the oxide film is made thicker on a semiconductor substrate 20 side than that of the film in the trench 21. Therefore, the space surrounded by the insulating film in the trench 21 can be widened and the resistance of inner wiring 26 and 27 of memory cell buried in the trench 21 can be reduced, because the cross-sectional areas of the wiring 26 and 27 are increased. Moreover, the insulating film 25 is formed along an in-trench groove 24 formed into the side wall of the trench 21. |
