Metal gate and manufacturing method thereof

Abstract

The invention discloses a metal gate. A gate groove is divided into a bottom groove and a top groove. The bottom groove is composed of a removed region of the dummy gate structure, and the width of the bottom groove is set to be the critical dimension of the gate; the height of the bottom groove is adjusted by a planarization process of the zeroth interlayer film and the dummy gate structure, and the height-to-width ratio of the bottom groove is reduced by reducing the height of the bottom groove and is adjusted to enable the metal gate to fill the bottom groove without holes. The top groove is located over the bottom groove, the width of the top groove is larger than that of the bottom groove, the height-width ratio of the top groove is smaller than that of the bottom groove, and the height of the top groove is used for compensating height reduction of the bottom groove. The invention further discloses a manufacturing method of the metal gate. According to the invention, the filling difficulty of the metal gate can be reduced under the condition that the critical size of the gate is kept unchanged or reduced, and the process health degree is improved due to the process window of metal gate filling.

Description

technical field [0001] The present invention relates to the field of semiconductor integrated circuits, and in particular, to a metal gate (metal gate, MG). The invention also relates to a manufacturing method of a metal gate. Background technique [0002] In the existing semiconductor industry, polysilicon is widely used in semiconductor devices such as MOS transistors, and is generally used as a standard gate filling material. However, as the size of MOS transistors decreases, conventional polysilicon gates have problems such as reduced device performance due to the boron penetration effect and unavoidable depletion effects, resulting in an increase in the thickness of the equivalent gate dielectric layer. , the gate capacitance value decreases, which in turn leads to the deterioration of the device performance. Therefore, the semiconductor industry has tried to replace the traditional polysilicon gate with a new gate filling material, such as a work function (WF) metal ...

AI Technical Summary

Problems solved by technology

However, the gate width is the key dimension of the gate, corresponding to the channel length, so the increase of the gate width will affect the performance of the device; and the decrease of the gate height will affect the resistance of the metal gate, so the window for process adjustment is often very small

Images