| 摘要 |
PROBLEM TO BE SOLVED: To provide a cell of flash memory element, and its forming method, having a common source line lower than a multilayer gate pattern in which possibility of occurrence of short circuit can be eliminated between a bit line and a common source line. SOLUTION: The method for forming a flash memory device comprises a step for forming a substance layer on a semiconductor substrate 100 including a multilayer gate pattern forming region and a common source line forming region, a step for patterning the substance layer to make an opening for exposing the semiconductor substrate in the common source line forming region, a step for forming a floating gate conductive film, an inter-gate insulation film and a control gate conductive film on the entire surface of the semiconductor substrate provided with the opening, and a step for patterning the control gate conductive film, the inter-gate insulation film, the floating gate conductive film and the substance layer to form a common source line, being linked electrically with the common source line forming region through the multilayer gate pattern and the opening, in the multilayer gate pattern forming region.
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