FABRICATION METHOD OF FLASH MEMORY DEVICE

摘要

PURPOSE: A fabrication method of a flash memory device is provided to prevent a generation of polymer during an etch process of a dielectric layer. CONSTITUTION: In a fabrication of a flash memory device, first a cell region(B) and a periphery circuit region(A) are defined by an isolation process. A tunnel oxide layer and an undoped polysilicon layer are then formed on a substrate. Next, impurities are implanted into the undoped polysilicon layer and then diffused. Subsequently, a dielectric layer is formed and then etched. To restrain a generation of a carbonized cure layer on the cell region(B) during an etch process of the dielectric layer on the periphery circuit region(A), the etch process is performed by use of a mixed gas of carbon hydrogen fluorine and carbon fluorine. In addition, to prevent an easy creation of a polymer, mean free path of ions is shortened.