Method of fabricating T-shaped polysilicon gate by using dual damascene process

摘要

A method of fabricating a T-shaped polysilicon gate by using dual damascene process. An oxide layer, a hard mask layer, and a patterned first photoresist layer in sequence are formed on a semiconductor substrate. Using the patterned first photoresist layer as a mask, an etching process is performed on the hard mask layer to form a first trench. The patterned first photoresist layer is removed. An organic layer is then deposited in the first trench. A patterned second photresist layer is formed on the semiconductor substrate. Using the patterned second photresist layer as a mask, an etching process is performed on the hard mask layer to define a second trench dimension. The patterned second photoresist layer and the organic layer are removed. An oxide layer and a polysilicon layer are deposited in the first trench and the second trench. The residual hark mask layer is removed to obtain a T-shaped profile polysilicon gate.