Patent attributes
A method of manufacturing a flash memory device includes preparing a semiconductor substrate comprising a cell area and a peripheral area, forming a first well and an oxide-nitride-oxide (ONO) layer in the cell area, forming a second well in the peripheral area of the semiconductor substrate comprising the first well and forming a first oxide layer in the peripheral area, forming a first polysilicon layer over the ONO layer and the first oxide layer and performing a first etch process to form a memory gate comprising an ONO layer pattern and a first polysilicon pattern in the cell area, forming a second oxide layer pattern and a second polysilicon pattern over either sidewall of the memory gate and forming a gate in the peripheral area, performing a third etch process so that the second oxide layer pattern and the second polysilicon pattern remain over only the one sidewall of the memory gate to form a select gate, and forming a first impurity area in the semiconductor substrate between the memory gates adjacent to each other.
