Tungsten chemical mechanical polishing method and manufacture method of tungsten plug

Abstract

The invention relates to a method for tungsten chemico-mechanical grinding. The method comprises the following steps: providing a semiconductor structure provided with a medium layer, wherein the medium layer is provided with an opening, and the opening and the medium layer are provided with a metal barrier layer and a tungsten metal layer sequentially; performing the first stage of chemico-mechanical grinding to remove the tungsten metal layer of partial thickness on the medium layer; performing the second stage of the chemico-mechanical grinding to remove the remaining tungsten metal layer and the metal barrier layer on the medium layer; and performing the third stage of the chemico-mechanical grinding to remove the medium layer of partial thickness. The invention also provides a method for manufacturing a tungsten plug. The sunken defects can be reduced in the process of manufacturing the tungsten plug.

Description

technical field [0001] The invention relates to the technical field of semiconductor manufacturing, in particular to a tungsten chemical mechanical grinding method and a tungsten plug manufacturing method. Background technique [0002] Metal tungsten has good electrical conductivity, and also has good step coverage through vapor deposition. Therefore, it is often used as a material for contact plugs or connection plugs in the manufacturing process of semiconductor integrated circuits. [0003] The process steps of forming a contact plug or a connection plug are generally as follows: First, a contact hole or a connection hole is formed in the dielectric layer through a photolithography and etching process, and the bottom of the contact hole and the connection hole exposes the electrode or the metal wire of the lower layer; Next, a metal barrier layer is deposited on the bottom and side walls of the contact hole and connection hole, and the surface of the dielectric layer; the...

AI Technical Summary

Problems solved by technology

[0012] In the manufacturing process of the tungsten plug, when chemical mechanical polishing is carried out, the first chemical mechanical polishing is mainly used for grinding and removing thicker tungsten. In order to increase the grinding rate, the first chemical mechanical polishing is applied to the grinding The pressure of the head is also higher than that of the second or third chemical mechanical polishing. When the polishing process of the Chinese patent application document is used to manufacture tungsten plugs, it is easy to produce depressions, especially in denser tungsten plugs. plugged area, will produce as Figure 8 The eroded recess (Erosion) 48a shown will cause the contact plug to be disconnected from the upper metal interconnection line, affecting the electrical properties of the device

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