| 摘要 |
<P>PROBLEM TO BE SOLVED: To realize a level-2 gate insulating film process for DRAM, without increasing number of fabrication processes or number of photomasks. <P>SOLUTION: A gate electrode 7A of MISFET forming a memory cell is formed in a memory cell array region of a semiconductor substrate 1, then the substrate 1 is subjected to heat treatment (reoxidation processing). At that time, since the bird's beak of a thick gate insulating film 6' formed on the lower portion of the gate electrode 7A enters in the enter of the gate electrode 7A, there is formed a gate insulating film 6a having a larger thickness than that of a gate insulating film, before reoxidizing immediately under the center of the gate electrode 7A, while since the gate electrode in the peripheral circuit region has a longer gate length than that of the gate electrode 7A in the memory array region, thickness of the gate insulating film immediately under the center of the gate electrode has almost the same thickness as that before reoxidation processing. <P>COPYRIGHT: (C)2004,JPO |
