METHOD FOR FABRICATING MEMORY DEVICE

摘要

PURPOSE: A method for fabricating a memory device is provided to preventing a polycrystalline silicon layer from being damaged and improve uniformity by planarization-etching the polycrystalline silicon layer of a floating gate through a chemical mechanical polishing(CMP) process using slurry for polishing the polycrystalline silicon layer. CONSTITUTION: A pad insulation layer is formed on a semiconductor substrate(31) in which an isolation region is defined. The pad insulation layer and the semiconductor substrate in the isolation region are etched to form a trench. An isolating oxide layer(35) for filling the trench is formed and the pad insulation layer is eliminated. A tunnelling oxide layer(36) is grown on the exposed semiconductor substrate and a conductive layer is formed on the resultant structure. The conductive layer is planarization-etched to form the floating gate(37) by using the isolating oxide layer as an etch barrier layer and performing a CMP process using the slurry for polishing the polycrystalline silicon layer.