METHOD FOR MANUFACTURING FLASH MEMORY DEVICE

摘要

A method for fabricating a flash memory device is provided to control lifting of an ONO(oxide nitride oxide) layer in a subsequent re-oxidation process by forming a thin spacer on both sidewalls of an ONO layer in fabricating a flash memory cell in which an ONO layer is interposed. A tunnel oxide layer(11) is formed on a substrate(10). A conductive layer for a floating gate(12a), a dielectric layer(13) and a conductive layer for a control gate(14a) are sequentially deposited on the tunnel oxide layer. The conductive layer for the control gate and the dielectric layer are partially etched to form a control gate. A first spacer is formed on both sidewalls of the control gate and the dielectric layer to prevent both the sidewalls of the dielectric layer from being oxidized in an oxide process. The conductive layer for the floating gate exposed to both sides of the first spacer and the tunnel oxide layer are etched to form a floating gate. The process for forming the first spacer includes the following steps. A nitride layer or an oxide layer(20) is deposited along the step on the floating gate including the control gate. A dry etch process is carried out.