| 摘要 |
PROBLEM TO BE SOLVED: To provide a semiconductor memory provided with a memory cell region and a peripheral circuit region, wherein a shallow trench is formed in the memory cell region so as to improve a manufacturing yield, and a deep trench is formed, especially in a high-voltage transistor region, in the peripheral circuit so as to improve a withstand voltage of element isolation. SOLUTION: A plurality of memory transistors where ONO films 15 serving as charge storage insulating films are arranged are formed in the memory cell region, and an element isolation groove 6 applied to the memory transistors is set shallow. Gate insulating films 16 and 17 different in structure from the ONO film 15 located in the memory cell region are arranged in the peripheral circuit region so as to form two kinds of transistors, a high-voltage transistor and a low-voltage transistor, and an element isolation groove 23 applied to, at least, the high-voltage transistor is set thick and deep. The memory cell region can be improved in manufacturing yield, and the peripheral circuit is capable of having a high withstand voltage. COPYRIGHT: (C)2005,JPO&NCIPI
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