METHOD FOR MANUFACTURING FLASH MEMORY DEVICE

摘要

PURPOSE: A method for manufacturing a flash memory device is to reduce a manufacturing step by etching a predetermined region for forming a source at once and to improve an operation velocity of the device by enlarging an overlapped region between a source region and a gate region. CONSTITUTION: A substrate(31) having a field region(21) and a source region(23) is etched using an isolation oxide mask and a cell source mask. After carrying out a well forming process and an ion implanting process, a tunnel oxide film(32) is formed on the entire surface of the substrate. The first conductive layer(33) for a floating gate is formed on the entire surface of the substrate, and the first conductive layer positioned on the first conductive layer etching region is removed. A dielectric layer(34), the second conductive layer(35) for a control gate, and a reflection preventive layer are subsequently formed on the entire surface of the substrate. The second conductive layer is patterned so that a portion of the control gate is overlapped on the etched portion of a trench of the source region.