JPH04298041A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To prevent corrosion of etched wiring irrespective of variations in conditions such as humidity and temperature. CONSTITUTION:A film 1 to be patterned, an insulating film 2, and a resist mask 6 are formed in sequence on a semiconductor substrate 5. The insulating film 2 and the film 1 are masked with the resist 6 and dry-etched. After the resist is removed, the insulating film 2 is etched by ion sputtering so that sputtered particles are deposited to form the side wall 3 of the film 1.

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 a method for preventing corrosion of a film to be etched (wiring film, etc.) after etching.

With the miniaturization of semiconductor devices, etching, which is one of the manufacturing steps, has changed from wet to dry etching, and there is a need to prevent corrosion of aluminum (Al)-based interconnects after etching.

The present invention can be used as a manufacturing method that meets this requirement.

0004

2. Description of the Related Art Corrosion of wiring after dry etching is caused, for example, by reaction products produced by the reaction between chlorine remaining on the side walls of the wiring and moisture in the atmosphere.

Conventional methods for preventing such corrosion of wiring include the following. ■ Immediately after dry etching, perform wet processing using a developer, nitric acid, ammonia, alcohol, etc. ■ Perform in-line resist stripping (a type of wet processing). ■ Form a fluorine-based passivation film to cover the wiring.

Among these, methods (1) and (4) involve removing residual chlorine after dry etching by wet processing, but it was difficult to perform complete processing. The method (2) above uses a passivation film to block moisture from the atmosphere, but a sufficient effect was not obtained.

As described above, none of the corrosion prevention methods was perfect.

[0008]

[Problems to be Solved by the Invention] In the prior art, there has been a problem in that corrosion occurs even in response to slight fluctuations in unstable factors such as humidity and temperature.

An object of the present invention is to provide a manufacturing method that prevents corrosion of wiring even when unstable factors such as humidity and temperature change.

0010

[Means for solving the problem] The above problem can be solved by sequentially depositing a film to be etched (1) and an insulating film (2) on a semiconductor substrate (5), and applying a resist mask on the insulating film (2). (6) dry etching the insulating film (2) and the film to be etched (1) using the resist mask as an etching mask, and then removing the resist mask (6) and etching the insulating film. (2) perform ion sputter etching on the insulating film (2), and re-deposit the sputtered insulating film (2) on the side surface of the film to be etched (1) to form a sidewall deposited film (3). This is achieved by a manufacturing method.

[0011]

[Operation] FIGS. 1A to 1C are diagrams explaining the principle of the present invention. FIG. 1(A) is a cross-sectional view before etching.

In the figure, 1 is a film to be etched, 2 is an insulating film, 4 is an interlayer insulating film, 5 is a semiconductor substrate, and 6 is a resist mask. An interlayer insulating film 4, a film to be etched 1, and an insulating film 2 are sequentially laminated on a semiconductor substrate 5, a resist mask 6 is formed on the insulating film 2, and using this as an etching mask, the insulating film 2 and the film to be etched 1 are stacked. A pattern is formed by dry etching.

FIG. 1B is a cross-sectional view after etching. In the figure, the resist mask 6 is peeled off. Figure 1(C)
In this step, the surface of the substrate is subjected to ion sputter etching, and the sputtered insulating film 2 is reattached to the side surface of the film to be etched 1 to form a sidewall deposited film 3.

In the present invention, the sidewall deposited film 3 and the insulating film 2 remaining after etching cover the entire film to be etched including the sidewalls, block moisture in the atmosphere and residual chlorine, and prevent corrosion of the film to be etched. This is to prevent this from occurring.

[0015]

[Embodiment] An embodiment will be explained using FIG. Figure 1(A)
In this process, a silicon dioxide (SiO2) film 4 with a thickness of 4,000 Å was formed by vapor phase growth (CVD) as an interlayer insulating film on a silicon (Si) substrate 5 as a semiconductor substrate, and an aluminum film (with a thickness of 5,000 to 10,000 Å) as a film to be etched. Al) film (or Al alloy film) 1. CVD SiO2 films 2 with a thickness of 4000 Å are laminated in sequence as insulating films, and a resist mask 6 with a thickness of 2.0 μm is formed on the CVD SiO2 film 2, and this is used as an etching mask. C
A pattern is formed by dry etching the VD SiO2 film 2 and the Al film 1.

As the etcher, a reactive ion etching (RIE) device or an electron cyclotron resonance (ECR) etching device capable of anisotropic etching is used. For example, the conditions for dry etching are as follows.

Etching conditions for SiO2 Reactive gas:
CF4/CHF3 gas pressure: 0.3 Torr RF power: 600 W Al etching conditions Reactive gas: BCl3/SiCl4/Cl2 gas pressure: 0.1 Torr RF power: 300 W Figure 1(B) is the cross section after dry etching It is a diagram.

In the figure, the resist mask 6 is peeled off in-line. In Figure 1(C), CVD Si
Ion sputter etching is performed on the O2 film 2. At this time, the sputtered CVD SiO2 film 2 is attached to the Al film 1.
The sidewall deposited film 3 is formed by re-adhering to the side surface of the film.

An example of the conditions for ion sputter etching is as follows. Ion species: Ar, Xe Gas pressure: 0.1 Torr RF voltage: 800 W As a result of the above examples, as an additional effect, it is possible to prevent the formation of protrusions on the wiring due to heating during the formation of the insulating film after the wiring is formed. .

[0020]

Effects of the Invention: A manufacturing method has been obtained which completely prevents corrosion of wiring even if unstable factors such as humidity and temperature fluctuate.

As a result, it was possible to contribute to improving the reliability of the semiconductor device.

[Brief explanation of drawings]

[Figure 1] Diagram explaining the principle of the present invention

[Explanation of symbols]

1 Film to be etched: Al film 2 Insulating film: CVD SiO2 film 3 Sidewall deposited film 4 Interlayer insulation film: CVD SiO2 film 5 Semiconductor substrate: Si substrate 6 Resist mask

Claims (1)

[Claims] Claim 1: A film to be etched (1) and an insulating film (2) are sequentially deposited on a semiconductor substrate (5), a resist mask (6) is formed on the insulating film (2), and a resist mask (6) is formed on the insulating film (2). using the insulating film (2) as an etching mask.
and dry etching the film to be etched (1), then removing the resist mask (6), performing ion sputter etching on the insulating film (2), and removing the sputtered insulating film (2). A method for manufacturing a semiconductor device, comprising the step of forming a sidewall deposited film (3) by redepositing the film to be etched on the side surface of the film (1).