Method for forming metal gate

Abstract

A method for forming a metal gate comprises the following steps: providing a semiconductor substrate which has a PMOS region and an NMOS region, wherein a first high-K gate dielectric layer, a first barrier layer and a first dummy gate are formed in the PMOS region from bottom to top, a second high-K gate dielectric layer, a second barrier layer and a second dummy gate are formed in the NMOS region from bottom to top, and the semiconductor substrate further has an interlayer dielectric layer; removing the first dummy gate to form a first trench; performing gas annealing on the first barrier layer and the first high-K gate dielectric layer; removing the second dummy gate to form a second trench; forming work function metal layers on the bottoms and side walls of the first trench and the second trench; and filling the first trench and the second trench with metal material. By adopting the method, the manufacturing process is simplified, and the process cost is reduced.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to a method for forming a metal gate. Background technique [0002] The main device in an integrated circuit, especially a VLSI, is a metal oxide semiconductor field effect transistor (MOS transistor for short). Since the MOS tube was invented, its geometric size has been continuously reduced. In this situation, various limitations and technical challenges begin to appear, and further reduction in device size is becoming more and more difficult. As the manufacturing process of Complementary Metal-Oxide-Semiconductor (CMOS, Complementary Metal-Oxide-Semiconductor) shrinks to a level below 32nm, technologies using new designs and materials are introduced. In the fabrication of MOS transistor devices and circuits, the most challenging thing is the high gate leakage current caused by the reduction in the thickness of the gate structure formed by polysilicon and silicon oxide...

AI Technical Summary

Problems solved by technology

[0009] As can be seen from the above description, the existing metal gate formation method needs to use different metal materials to form metal layers with different work functions, so the manufacturing process is complicated and the process cost is high.

[0010] For this reason, need a kind of new forming method of metal gate, in order to prevent from overcoming the problems of complex manufacturing process and high process cost of existing method

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