Surface treatment method of copper metal layer subjected to chemically mechanical polishing

Abstract

The invention relates to a surface treatment method of a copper metal layer subjected to chemically mechanical polishing, which comprises the steps of: providing a semiconductor substrate, wherein a dielectric layer is arranged on the surface of the semiconductor substrate, an opening is formed in the dielectric layer, metal copper is filed in the opening; carrying out chemically mechanical polishing on the semiconductor substrate until the metal copper in the opening is level to the surface of the dielectric layer; cleaning the dielectric layer and the surface of the metal copper with an alkali preparation; preprocessing surface plasma on the dielectric layer and the surface of the metal copper; and forming an etching stopping layer on the dielectric layer and the surface of the metal copper. Through simple regulation of the process, the invention avoids oxidization of the surface of the copper and the diffusion of copper ions in the dielectric layer, repairs the crystal lattice and the surface state of the dielectric layer to be a certain extent, improves the electric performance parameters of breakdown voltage, TDDB (Time Dependent Dielectric Breakdown), and the like, and enhances the element performances.

Description

technical field [0001] The invention relates to the field of semiconductor technology, in particular to a surface treatment method for a copper metal layer after chemical mechanical polishing. Background technique [0002] With the continuous development of semiconductor technology, the geometric size of semiconductor devices continues to shrink, and has reached the order of 32nm at present. With the continuous shrinking of semiconductor device sizes, new parasitic effects continue to appear. Among them, the RC delay is one of the important factors affecting the response speed of the device. To solve this problem, it is necessary to improve the metal interconnect structure to reduce the RC delay. The corresponding technical solutions include increasing the electrical conductivity of the interconnection metal and reducing the dielectric constant (k) value of the dielectric layer. In the process below 90nm, copper has fully replaced aluminum as the interconnection metal. Co...

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Problems solved by technology

The U.S. Patent Application Publication No. 20080047592 proposes a method for cleaning the surface of a silicon wafer after CMP. This method is applicable to the case where the dielectric layer is a traditional oxide layer or a low dielectric constant material. However, the impact of the cleaning method on the device morphology was mainly discussed, and the improvement of the electrical parameters was not mentioned.

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