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US 2007/0176228 A1Published application
Non-volatile semiconductor memory device and method of manufacturing the same
AssigneeKabushiki Kaisha Toshiba
InventorEiji KAMIYA
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Abstract
A non-volatile semiconductor memory device includes a semiconductor substrate, a memory cell array formed on the semiconductor substrate, and including a first gate insulator having a first thickness. The device further includes a high-voltage transistor circuit formed on the semiconductor substrate, and including a second gate insulator having a second thickness greater than the first thickness, and a peripheral circuit formed on the semiconductor substrate, and including the second gate insulator.
Claims6
(canceled)
A method of manufacturing a non-volatile semiconductor memory device, comprising:
- successively depositing a first gate insulator having a first thickness, a first gate electrode film and a first mask insulator on a semiconductor substrate;
- leaving the first gate insulator, the first gate electrode film and the first mask insulator in only an array region and a first peripheral region;
- forming a second gate insulator having a second thickness greater than the first thickness in a second peripheral region excepting the array region and the first peripheral region;
- successively depositing a second gate electrode film thinner than the first gate electrode film and a second mask insulator on each of the first mask insulator and the second gate insulator;
- removing the second mask insulator and the second gate electrode film on the first mask insulator;
- forming an isolation trench on a surface of the semiconductor substrate to correspond to each position between the array region and first and second regions of the peripheral region;
- depositing a buried insulator on the entire surface;
- and
- polishing an upper surface of the buried insulator so that the upper surface can be planarized.
6 more elements
Dependencies are inferred from the claim text.