METHOD FOR MANUFACTURING FLASH MEMORY DEVICE

摘要

PURPOSE: A method for manufacturing a flash memory device is provided to improve a charge retention characteristic by reducing a damage of a tunnel oxide layer. CONSTITUTION: A tunnel oxide layer(31) and the first polysilicon layer(32) are formed sequentially on a semiconductor substrate(30). The first polysilicon layer(32) and the tunnel oxide layer(31) are patterned by performing an etching process. A dielectric layer(33), the second polysilicon layer(34), a tungsten silicide layer(35), and an anti-reflective layer(36) are formed sequentially on the whole structure. The anti-reflective layer(36), the tungsten silicide layer(35), and the second ploysilicon layer(34) are patterned by performing the etching process. A poly spacer is formed at a sidewall of the patterned polysilicon layer. An exposed portion of the dielectric layer(33) is removed. An exposed portion of the first polysilicon layer(32) is etched and the poly spacer is removed. The exposed dielectric layer(33) is removed. The first polysilicon layer(32) is removed. The first doping process is performed by using a cell source mask. An edge portion of the first polysilicon layer(32) is removed. A drain(41) and a source(40) of a DDD(Double Doped Drain) structure are formed by performing a source/drain ion implantation process.