Plasma processing method

Abstract

The present invention is a plasma processing method including: a step of introducing a substrate into a processing container, a metal or metallic compound film being formed on a surface of the substrate; a step of supplying a noble gas and an H2 gas into the processing container; and a step of generating plasma in the processing container while the noble gas and the H2 gas are supplied, so that a natural oxide film formed on a surface of the metal or metallic compound film is removed by means of the plasma. According to the invention, the noble gas and the H2 gas are supplied into the processing container, the plasma is generated in the processing container, and the plasma acts on the natural oxide film formed on a surface of the metal or metallic compound film. Thus, active hydrogen in the plasma reduces the natural oxide film, and active species of the noble gas etch the natural oxide film. As a result, the natural oxide film can be removed with a satisfactory selective ratio.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a plasma processing method that is used to remove a natural oxide film formed on a metal film or a metallic compound film, in particular on a CoSi2 film, of a surface of a substrate. DESCRIPTION OF THE RELATED ART [0002] In a semiconductor manufacturing process, a Ti film is deposited on a bottom of a contact hole formed in a silicon wafer as an object to be processed. A barrier layer such as TiN is formed on a TiSi layer, which is formed by interdiffusion of the Ti film and the silicon wafer. In addition, an Al layer, a W layer, a Cu layer or the like is formed on the barrier layer. Thereby, filling of the contact hole and forming of wirings are carried out. Conventionally, a metal-deposition system having a plurality of chambers is used for carrying out the above successive steps. In such a metal-deposition system, in order to obtain good electrical contacts, prior to the deposition process, a process for removing a na...

AI Technical Summary

Benefits of technology

[0008] This invention is developed by focusing the aforementioned problems in order to resolve them effectively. An object of the present invention is to provide a plasma processing method wherein a natural oxide film on a metal or metallic compound film, in particular a CoSi2 film, can be efficiently removed with a sufficient selective ratio.

[0010] According to the present invention, the noble gas and the H2 gas are supplied into the processing container, the plasma is generated in the processing container, and the plasma acts on the natural oxide film formed on a surface of the metal or metallic compound film. Thus, active hydrogen in the plasma reduces the natural oxide film, and active species of the noble gas etch the natural oxide film. As a result, the natural oxide film can be removed with a satisfactory selective ratio.

[0012] It is preferable that the plasma is one of inductive coupling plasma, helicon wave plasma and microwave plasma. Such plasma can be generated independently from a bias-voltage control of a lower electrode for drawing-in the plasma. Thus, the natural oxide film can be removed while less damage is given to the metal or metallic compound film by ions.

[0014] According to the present invention, the noble gas and the H2 gas are supplied into the processing container, the inductive coupling plasma is generated in the processing container, and the plasma acts on the natural oxide film formed on a surface of the CoSi2 film. Thus, active hydrogen in the plasma reduces the natural oxide film, and active species of the noble gas etch the natural oxide film. As a result, the natural oxide film formed on the surface of the CoSi2 film can be removed with a satisfactory selective ratio and without giving any damage by ions to the CoSi2 film. In the case, it is preferable that an etching selective ratio of the natural oxide film with respect to the CoSi2 film is 3 or more.

Problems solved by technology

However, when the natural oxide film on the CoSi2 film is removed by the conventional pre-clean process, the etching selective ratio may not be sufficient.

Thus, it is difficult to use this method for recent miniaturized devices.

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