Method for manufacturing metal gate and method for manufacturing semiconductor device

Abstract

The invention provides a method for manufacturing a metal gate and a method for manufacturing a semiconductor device. Before a dummy gate is removed to form an opening for filling metal gate, a portion of an initial spacer on the sidewall of the dummy gate is firstly subjected to material modification in order that the initial spacer is transformed into a first spacer not subjected to material modification and a second spacer located on the first spacer and subjected to material modification. Thus, all or part of the second spacer can be removed simultaneously while the virtual gate is removed, so that the opening having an wide top and a narrow bottom and for filling the metal gate can be formed after the process of removing the virtual gate ends. The depth-to-width ratio of the opening is reduced so as to improve the subsequent gap filling capability of the metal gate, and reduce defects such as filling voids and gaps of the metal gate, thereby improving the performance of the finally manufactured semiconductor device.

Description

technical field [0001] The invention relates to the technical field of integrated circuit manufacturing, in particular to a method for manufacturing a metal gate and a method for manufacturing a semiconductor device. Background technique [0002] With the continuous improvement of the integration of semiconductor devices, when making MOS transistors, high-K metal gates with high-K (dielectric constant K greater than or equal to 10) materials as gate dielectric layers and metal materials as gate electrodes have become semiconductor devices. The mainstream technology for manufacturing 32nm and below processes, and currently it is mostly manufactured by the Gate-last process. The Gate-last process is a replacement metal gate process (Replacement Metal Gate), usually using the traditional polysilicon gate The dummy polysilicon gate (Dummy Poly Gate, also known as dummy gate or sacrificial gate) is manufactured by the electrode process, and after the high-temperature annealing tr...

AI Technical Summary

Problems solved by technology

However, at the new process technology node below 28nm, the size of the gate is gradually reduced, and the aspect ratio (Aspect Ratio) in the gate trench is gradually increased, which affects the gap filling of the high-K metal gate, and is prone to voids (Void) or Defects such as seams seriously affect the improvement of device performance

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