| 摘要 |
PROBLEM TO BE SOLVED: To remove a fault due to a difference between the heights of element isolation. structures in a semiconductor device and to provide a highly reliable semiconductor device. SOLUTION: This device is a semiconductor device, which has a peripheral circuit formation region element-isolated by a field oxide film 8 and a memory cell formation region element-isolated by buried insulating films (trench type element isolation structures 15) of a height different from that of the film 8 on the same substrate 1. The thickness, which is located in the peripheral circuit formation region, of the substrate 1 is made different from that, which is located in the memory cell formation region, of the substrate 1 to set the upper surface of the film 8 and the upper surfaces of the structures 15 at the almost same level. |
