Filling method of contact hole

Abstract

A padding method for contact hole is provided, which comprises: providing an underlay with at least one open mouth on its surface; forming the adhesion layer on the said underlay; forming the barrier layer on the said adhesion layer; reduction processing to the said barrier layer at bottom of the open mouth of the contact hole; forming W-Plug inside the said open mouth of the contact hole. The padding method in the invention reduces the thickness of the barrier layer at bottom of the contact hole and improves the electrical properties of the contact hole.

Description

technical field [0001] The invention relates to the technical field of semiconductor manufacturing, in particular to a method for filling a contact hole. Background technique [0002] As the production of integrated circuits develops towards ultra-large-scale integrated circuits (ULSI), the internal circuit density is getting larger and larger, and the number of components contained is increasing, making the surface of the wafer unable to provide enough area to make the required interconnection ( Interconnect). Therefore, in order to meet the increased demand for interconnection lines after component shrinkage, the design of multilayer metal interconnection lines with more than two layers has become a necessary method for VLSI technology. At present, the conduction between different metal layers is achieved by digging an opening in the insulating layer between the two metal layers and filling it with a conductive material to form a contact hole structure that conducts the t...

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Problems solved by technology

[0007] The above filling method is currently the most commonly used contact hole filling method, but the contact hole filled by this method still has a problem of high resistance value, because the low resistance TiSi formed at the bottom of the contact hole x There is also a high-resistance TiN layer between the metal tungsten and the metal tungsten, which still leads to a large resistance value of the contact hole

[0008] The Chinese patent application number 200410067835.5 discloses a method for depositing a tungsten plug barrier layer when filling a contact hole. This method uses a Ti / TiN layer with a certain thickness as the barrier layer of the tungsten plug, which improves the contact hole and the underlying metal layer. The problem of high contact hole resistance and poor uniformity caused by line dislocations

However, this method does not do any treatment to the high-resistance TiN with a thickness of 200 to 300 Ȧ, and does not improve the problem of high resistance of the contact hole caused by the existence of TiN, and cannot further reduce the resistance of the contact hole. Improve electrical characteristics of contact holes

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