METHOD FOR MANUFACTURING SEMICONDUCTOR DEVICE USING TWO-STEP GATE ETCHING

摘要

PURPOSE: A method for manufacturing a semiconductor device is provided to achieve CD(Critical Dimension) uniformity and profile stability of a gate by using two-step gate etching. CONSTITUTION: A gate oxide layer(23) and a polysilicon layer are sequentially formed on a substrate(21) with an isolation layer(22). A poly gate is formed by etching the polysilicon layer and the gate oxide layer. An LDD region is formed in the substrate. The first nitride layer(26) as a spacer is formed and a source/drain region is formed through the first nitride layer. An oxide layer(27) is formed on the first nitride layer. The poly gate is exposed by CMP of the first nitride layer and the oxide layer. A tungsten silicide layer and the second nitride layer are sequentially formed on the exposed poly gate, the first nitride layer and the oxide layer. By etching the second nitride layer, the tungsten silicide layer, a gate(31) including the polysilicon layer, the tungsten silicide layer and the second nitride layer as a hard mask is then formed. The third nitride layer(32) as a spacer is formed.