Manufacturing method of metal grid

Abstract

The invention discloses a manufacturing method of a metal gate. The manufacturing method comprises the following steps of 1, providing a semiconductor substrate forming a pseudo grid electrode structure, a silicon nitride side wall and a contact etching stop layer; 2, forming an interlayer film; 3, flattening the interlayer film by using a primary chemical mechanical grinding process, and forminga disc-shaped recessed structure on the surface of the interlayer film; 4, etching silicon nitride by a secondary etching process, and enabling the surface of the silicon nitride at the two sides of apolysilicon gate to be lower than the disc-shaped recessed structure; 5, eliminating the polysilicon gate; 6, filling a metal material layer corresponding to the metal grate; and 7, flattening the metal material layer by a secondary chemical mechanical grinding process, completely eliminating the metal material layer on the surface of the interlayer film by the secondary chemical mechanical grinding process; and enabling the metal material layer to be only filled in the polysilicon gate removal region for thus forming the metal grate. The metal residue of the chemical mechanical grinding process of the metal gate on the interlayer film can be eliminated.

Description

technical field [0001] The invention relates to a method for manufacturing a semiconductor integrated circuit, in particular to a method for manufacturing a metal gate. Background technique [0002] In the current advanced logic chip process, in order to increase the electrical performance of components, the original polysilicon gate is removed and replaced with metal. The process method used is metal chemical mechanical polishing. [0003] However, since the silicon oxide chemical mechanical polishing in the previous process will form dish-shaped (Dish) depressions on the top surface of the silicon oxide dielectric layer between the polysilicon gates, that is, the interlayer film, which may cause subsequent metal chemical mechanical polishing. Produces metal residues. This metal residue will cause a circuit short circuit when the metal plug is deposited after the contact hole is etched, directly impacting the product yield. Now explain as follows according to the accompan...

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Problems solved by technology

This metal residue will cause a circuit short circuit when the metal plug is deposited after the contact hole is etched, directly impacting the product yield

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