| 摘要 |
PURPOSE: A manufacturing method of a flash memory is provided to reduce the resistance of source lines by widening the width of a field oxide film, freely control the width of sidewall spacers and protect an interlayer oxide film by surrounding the interlayer oxide film with a nitride film. CONSTITUTION: A field area is isolated from an active area, and then a gate oxide film(33) is formed on a field oxide film. Then, an interlayer insulating film(35) of oxide film shape or oxide/nitride/oxide shape is formed. Next, a control gate(36) and a gate electrode are formed and then the interlayer insulating film(35) is etched to complete a floating gate(34). Then, ions of low density are implanted. Then, a silicon nitride film, is deposited and then is etched to form remaining nitride films(40-1) on sidewalls of gate. Next, polysilicon is deposited and etched back to remain remaining polysilicon on sidewalls. Then, the sidewalls are removed by wet etching. The nitride films are etched and then ions of high density are implanted. Then, a source/drain(51) is formed by heat treatment.
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