JPH0521431A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To provide a method wherein a reaction product which is formed on the sidewall of an interconnection metal during a reactive ion etching operation can be removed easily. CONSTITUTION:In the manufacturing method, of a semiconductor device, wherein an interconnection metal film 1 is formed to be a prescribed shape by a reactive ion etching operation, the following are executed continuously without changing a vacuum state by changing over etching material gases inside the same chamber: the first process wherein the interconnection metal film 1 is etched to be the prescribed shape by the reactive ion etching operation; and the second process wherein a reaction product 2 formed on the sidewall of the interconnection metal film 1 is removed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device, and more particularly to removal of reaction products generated during reactive ion etching in a semiconductor device manufacturing process.

[0002]

2. Description of the Related Art In the process of processing a wiring metal film in the process of manufacturing a semiconductor integrated circuit, fine processing can be performed by anisotropic etching, so that silicon tetrachloride (SiCl) is generally used.
₄ ) has been adopted.

[0003]

However, according to such a method, the reaction product 2 at the time of etching is formed on the side wall of the wiring metal 1 as shown in FIG. 2, resulting in the following problems. Has occurred. In the figure, 3 is a resist, 4 is a cation, and 5 is an etchant.

The reaction product 2 is formed of a complex of Si, Cl, C, Al and the like, and Cl in this becomes HCl to cause corrosion of the wiring metal.

The reaction product 2 formed on the side wall is removed in a later step using O ₂ or CF ₄ / O ₂ , but it may not be completely removed, which is an unstable step. ..

That is, the reaction product 2 is generally removed by ashing (ashing) in O ₂ plasma. In this case, the wafer is taken out from the reactive ion etching apparatus and transferred to the plasma ashing apparatus. During that time, the reaction product on the side wall is combined with oxygen in the air to form an oxide, which is difficult to completely remove.

The reaction product 2 formed on the side wall partially peels off and adheres in a later process, which causes a pattern defect.

The present invention has been made in view of these problems, and an object thereof is to provide a method capable of easily removing a reaction product formed on a sidewall of a wiring metal during reactive ion etching. It is in.

[0009]

SUMMARY OF THE INVENTION The present invention which solves the above problems is a method for manufacturing a semiconductor device in which a wiring metal film is formed into a predetermined shape by reactive ion etching. By switching the etching material gas in the same chamber between the first step of etching into a predetermined shape by and the second step of removing the reaction product formed on the side wall of the wiring metal in the first step. It is characterized by performing continuously without changing the vacuum state.

[0010]

The first step of forming the wiring metal film into a predetermined shape by the reactive ion etching and the second step of removing the reaction product formed on the side wall of the wiring metal film in the first step. Since the reaction is continuously performed without being exposed to the atmosphere, the reaction product is removed without remaining on the side wall.

As a result, the inconvenience caused by the reaction product remaining on the side wall is eliminated.

[0012]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a process chart showing an embodiment of the present invention. (A) shows a state before the wiring metal film 1 is etched by reactive ion etching. S on the Si substrate 6
An iO ₂ layer 7 is formed, and Al (containing Si) is formed as the wiring metal film 1 on the SiO ₂ layer 7 to form a three-layer structure. A resist 3 is formed on the wiring metal film 1. This step is intended to remove Al other than Al directly under the resist 3 by etching.

(B) shows a state immediately after the etching of the wiring metal film 1 by the reactive ion etching is completed. Reaction products 2 are formed on the side walls of the wiring metal film 1 and the resist 3 so that anisotropic etching is possible. When SiCl ₄ is used as the etching material gas for the reactive ion etching, the reaction products 2 are Si, Cl, C (contained in the resist 3), Al.
Becomes a complex of.

(C) shows a state in which the reaction product 2 is removed from the sidewalls of the wiring metal film 1 and the resist 3. The reaction product 2 is removed by etching immediately after the etching in step (B) by continuously switching the etching material gas to a mixed gas of CF ₄ and O ₂ without changing the vacuum state in the same chamber. As a result, the reaction product 2 does not come into contact with the atmosphere, and the reaction product 2 can be easily removed by etching.

(D) shows a state where the resist 3 is removed. The reaction product 2 is completely removed from the side wall of the wiring metal film 1.

[0017]

As described above in detail, according to the present invention, since the reaction product does not remain on the side wall as in the conventional case, the following effects can be obtained.

Corrosion of the wiring metal due to the reaction product can be prevented. The adverse effect caused by the reaction product formed on the side wall to the post-process such as the interlayer film process is eliminated.

It is possible to prevent the occurrence of pattern defects due to the reaction products formed on the sidewalls being partially peeled off and adhered in a later process.

[Brief description of drawings]

FIG. 1 is a process explanatory diagram of an example of the present invention.

FIG. 2 is an explanatory diagram of formation of a reaction product by reactive ion etching.

[Explanation of symbols]

1 Wiring Metal Film (Al) 2 Reaction Product 3 Resist 6 Si Substrate 7 SiO ₂ Layer

Claims (1)

Claim: What is claimed is: 1. A method of manufacturing a semiconductor device, wherein a wiring metal film is formed into a predetermined shape by reactive ion etching. The wiring metal film is etched into a predetermined shape by reactive ion etching. And the second step of removing the reaction product formed on the side wall of the wiring metal in the first step are continuously performed without changing the vacuum state by switching the etching material gas in the same chamber. And a semiconductor device manufacturing method.