A formation method for a semiconductor structure

Abstract

The invention provides a formation method for a semiconductor structure. The method includes the following steps: providing a substrate and forming a work function layer on the substrate. The step offorming the work function layer includes the step of forming a work function film once or multiple times. The step of forming a work function film includes the following steps: forming an initial workfunction film on the substrate, wherein the initial work function film has carbon atoms; performing de-carbon processing on the initial work function film and forming the work function film through ade-carbon precursor, wherein the de-carbon precursor is used for reacting with the carbon atoms of the initial work function film; forming grids on the work function layer. After the work function film is formed, de-carbon processing is performed on the initial work function film through the de-carbon precursor. The de-carbon precursor can be reacted with the carbon atoms of the initial work function film, so that the carbon atom content of the initial work function film is reduced, the work function of the work function layer is changed, the adjustment is performed on the threshold-voltage of a transistor, and the design requirements can be satisfied by the threshold-voltage of the transistor.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to a method for forming a semiconductor structure. Background technique [0002] With the continuous progress of semiconductor technology, the integration level of semiconductor devices has been continuously improved, which requires that more transistors can be formed on a chip. [0003] Threshold voltage is an important parameter of transistors, which has a great influence on the performance of transistors. Transistors with different functions often have different requirements on threshold voltages. During the process of forming different transistors, the threshold voltages of different transistors need to be adjusted. In order to adjust the threshold voltages of different transistors, a work function layer is often formed on the surface of the gate dielectric layer of the transistor. Transistors can have different threshold voltages by selecting the thickness and mater...

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Problems solved by technology

[0004] However, the threshold voltage of the transistor formed by the prior art is difficult to meet the design requirements

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