METHOD FOR MANUFACTURING SEMICONDUCTOR DEVICE

摘要

PURPOSE: A method for manufacturing a semiconductor device is provided to be capable of forming a small size floating gate on the first polysilicon layer without a mask process. CONSTITUTION: A tunnel oxide layer(12), the first polysilicon layer(14), and a pad nitride layer are sequentially formed on a semiconductor substrate(10). A trench is formed in the semiconductor substrate by selectively etching the resultant structure. An oxide layer is deposited on the entire surface of the resultant structure. A planarization is carried out on the oxide layer for exposing the pad nitride layer. The protrusion of an oxide layer is formed by etching the pad nitride layer. The second polysilicon layer(24) is deposited on the entire surface of the resultant structure. The second polysilicon layer is polished for exposing the protrusion. A floating gate(26) is formed by partially etching the protrusion. A dielectric layer(28) and a control gate are sequentially formed on the resultant structure.