| 摘要 |
PROBLEM TO BE SOLVED: To reduce the amount of sinking of an interlayer insulating film embedded in a trench when manufacturing a semiconductor device having a trench gate structure. SOLUTION: A field oxide film 11 is formed around an element and a trench 4 deeper than a p-well area 3 is formed in an element activation part. A gate oxide film 7 is formed thereon, polysilicon forming a gate electrode 8 is deposited thereon, and the inner area of the gate oxide film 7 in the trench 4 is filled with a polysilicon film. The polysilicon film is etched back until the polysilicon film comes below the main surface of an n-type substrate 100 in the element activation part. A silicon nitride film 13 is formed and an interlayer insulating film 10 is formed thereon. Chemical mechanical polishing is performed using, as a stopper, a part of the silicon nitride film 13 on the field oxide film 11 to flatten a surface of the interlayer insulating film 10. COPYRIGHT: (C)2006,JPO&NCIPI
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