| 摘要 |
PURPOSE: A method of forming a gate electrode having a polycide structure is provided to form a cobalt silicide having a lower resistivity without an etching process by forming the cobalt silicide using an insulating layer of a lower permittivity and a damascene process. CONSTITUTION: A gate oxide layer(22), a layer of a lower permittivity, and an oxide layer for hard masking are sequentially formed on a semiconductor substrate(21). After patterning the oxide layer for hard masking, the patterned oxide layer for hard masking is used to etch the layer of a lower permittivity and to form a trench for a gate electrode. Polysilicon(27) is formed over the entire structure including the trench and is recessed by an etch back to fill up the trench. A cobalt layer is deposited over the resultant structure and subjected to an annealing process to form a cobalt silicide layer(28) only on the recessed polysilicon. A nitride layer(29) for a cap gate is formed over the resultant structure to completely fill up the trench. Then, the nitride layer for a cap gate is subjected to a CMP process until the surface of the layer of a lower permittivity is exposed. The layer of a lower permittivity is removed with a plasma to form a gate electrode comprised of a stacked structure of the polysilicon, the cobalt silicide layer, and the nitride layer.
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