TW367546B - Manufacturing method of flash memory with self-aligned drain junction - Google Patents

Abstract

A kind of manufacturing method of flash memory with self-aligned drain junction which includes the following steps: provide a substrate; form sequentially the gate oxide, a floating polycrystalline silicon layer, a barrier and the first insulation on the surface of substrate; define the first insulation layer for etching and forming the first and the second openings on part of the surface of the exposed barrier; define the barrier to etch and form the third opening on part of the surface of the exposed floating polycrystalline silicon layer; through the third opening, form a thick bird-beak type insulation layer by applying thermal oxidation on the floating polycrystalline silicon; through the second opening, form a drain are by doping ions on one side of the substrate; remove the residual barrier and the first insulation layer; employ the thick bird-beak type insulation layer as the mask for anisotropic etching floating crystalline silicon layer to the surface of gate oxide; form sequentially a tunnel-penetrated oxide and a controlled polycrystalline silicon layer to elastically cover the substrate; define the controlled polycrystalline silicon layer and etched forming a specified pattern which constitutes a split gate with the tunnel-penetrated oxide, gate oxide, thick bird-beak insulation layer and floating polycrystalline silicon layer; and form a source area by doping ions on the other side of the substrate.