JPH0482221A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To simultaneously eliminate resist residue remaining on a sacrificial film, by etching and eliminating the sacrificial film. CONSTITUTION:On a substratum semiconductor substrate 1, a silicon oxide film 2 is formed, on which an aluminum alloy film 3 is formed. Thereon a sacrificial thin film 10 is formed, on which a photo resist pattern 4 is formed. By using the photo resist pattern 4 as a mask, the sacrificial thin film 10 and the aluminum alloy film 3 are subjected to dry etching, thereby patterning the film 10 and the film 3. As the result, when the etching is ended, the pattern side walls of the photo resist 4 and the aluminum alloy film 3 are completely covered with a deposition film. When the photo resist is eliminated, resist residue is generated. Finally, the sacrificial thin film 10 is etched and eliminated, and rinsing is performed, thereby completely eliminating the resist residue.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a semiconductor device that removes resist residue generated on a layer to be etched. [Prior Art] In the manufacturing process of a semiconductor device, Currently, plasma etching using a reactive gas plasma or reactive ion etching (hereinafter abbreviated as RIE) is widely used as an etching process for forming aluminum alloy wiring patterns.

The side wall surface of the aluminum alloy film wiring pattern formed by the above method is contaminated by redeposition of reaction products generated in the plasma reaction, and removal of this contamination is currently an important technical issue. There are various problems caused by this contamination, and one particularly serious problem is the generation of resist residue. The mechanism of this resist residue generation and conventional methods for removing it will be described below.

FIGS. 2A to 2D are cross-sectional process diagrams showing a conventional method for manufacturing a semiconductor device in which an aluminum alloy wiring button is formed.

A silicon oxide film 2 is formed on a base semiconductor substrate 1, an aluminum alloy film 3 is formed thereon, and a photoresist pattern 4 is further formed thereon to obtain a structure as shown in FIG. 2A. Then, using the photoresist pattern 4 as a mask, the aluminum alloy film 3 is subjected to tri-etching using a chlorine-based gas plasma to form an aluminum alloy wiring pattern.

At this time, as shown in FIG. 2B, carbon accompanying the decomposition of the photoresist 1-hattern 4, aluminum chloride as a reaction product of the aluminum alloy film 3, chlorine-based gas plasma (for example, S
IC, Q4) deposition gas components, etc.
A complexly mixed deposition film 5 is formed on the sidewalls of the photoresist 4 and the aluminum alloy film 3.

As a result, at the end of etching, the pattern sidewalls of the photoresist 4 and aluminum alloy film 3 are completely covered with the debonding film 5, as shown in FIG. 2C.

In this state, when the photoresist 4 is removed (anoned) using a gas blaster whose main component is 02 residue (hereinafter referred to as 02 gas blaster), the photoresist pattern 4 whose main component is carbide is removed as CO2 gas by reaction with the 02 gas plasma. be done. Also, most of the carbon components in the deposition film 5 are removed. but,
0□ The aluminum component in the deposition film 5 cannot be removed by gas plasma. For this reason, the photoresist pattern 4
During removal, it is difficult to completely remove the deposition film 5, and a resist residue 6 containing aluminum reaction products as a main component is generated as shown in FIG. 2D. When a wiring layer is further stacked above the aluminum alloy film 3 which is the wiring pattern, the presence of this resist residue 6 causes unevenness in the upper wiring layer, significantly deteriorating the electrical reliability of the semiconductor device. Therefore, the resist residue 6 must be completely removed. For this reason, conventionally, a method of removing the resist residue 6 by cleaning with a liquid that slightly dissolves aluminum has been widely used.

[Problem to be solved by the invention]

However, when removing resist residue 6 by liquid cleaning, depending on etching conditions and etching conditions, if too much resist residue 6 is generated, removal may be incomplete, and it is difficult to remove resist residue 6 with a good margin. It was impossible.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a method for manufacturing a semiconductor device that can completely remove resist residue.

[Means for Solving the Problems] A method for manufacturing a semiconductor device according to the present invention includes a step of preparing a layer to be etched, a step of forming a sacrificial film on the second layer to be etched, and a step of forming a sacrificial film on the sacrificial film. a step of forming a resist pattern; a step of etching the layer to be etched and the sacrificial film using the resist pattern as a mask; a step of removing the resist pattern; and a step of etching the sacrificial film by etching it away. The method also includes a step of simultaneously removing any resist residue remaining on the surface.

[Effect]

In this invention, when the sacrificial film and the layer to be etched are etched using the resist pattern formed on the sacrificial film as a mask and the resist pattern is removed, the sacrificial film remains between the resist residue and the layer to be etched. . When the sacrificial film is removed by etching, the resist residue remaining on the sacrificial film is also removed at the same time.

〔Example〕

FIGS. 1A to 1E are cross-sectional process diagrams showing an embodiment of the method for manufacturing a semiconductor device according to the present invention.

First, as in the prior art, a silicon oxide film 2 is formed on a base semiconductor substrate 1, and an aluminum alloy film 3 is formed thereon. A sacrificial thin film 10 that can be etched with chlorine gas plasma and fluorine gas plasma is formed on the aluminum alloy film 3, and a photoresist pattern 4 is formed thereon to obtain a structure as shown in FIG. 1A. Examples of materials for the sacrificial thin film 10 include polysilicon, titanium silicide, tungsten, and tungsten silicide.

Next, the sacrificial thin film 10 and the aluminum alloy film 3 are dry-etched using chlorine-based gas plasma and the photoresist pattern 4 as a mask, thereby patterning the sacrificial thin film 10 and the aluminum alloy film 3.

At this time, a deposition film 5 is formed on the sidewalls of the photoresist pattern 4 and the aluminum alloy film 3, as shown in FIG. 1B, using a mechanism similar to the conventional one. As a result, when etching is completed, the pattern sidewalls of the photoresist 4 and aluminum alloy film 3 are completely covered with the deposition film 5, as shown in FIG. 1C, as in the conventional case.

Next, when the photoresist is removed using 02 gas plasma, the photoresist 4 is removed as shown in FIG.
occurs.

Finally, the sacrificial thin film 10 is etched away using fluorine gas plasma. Then, the resist residue 6 formed on the sacrificial thin film 10 is also removed at the same time, and the aluminum alloy film 3 is removed.
Almost no resist residue 6 is generated thereon. Even if it occurs, the amount is small, and by cleaning, the resist residue 6 can be completely removed as shown in FIG. 1E. Therefore, even if a wiring layer is stacked above the aluminum alloy film 3, no unevenness will occur, and the electrical reliability of the semiconductor device will not deteriorate. Note that the aluminum alloy is not etched by the fluorine gas plasma, so the aluminum alloy film 3 is not etched when the sacrificial thin film 10 is removed.

In the above example, the sacrificial thin film 1 was formed on the aluminum alloy single layer film.
0 may be stacked or a laminated film of perilla metal/aluminum alloy may be used instead of a single layer film of aluminum alloy. Further, a more complicated laminated film structure of an aluminum alloy and another conductive film may be used.

Further, in the above embodiment, chlorine-based gas plasma or bromine-based gas plasma may be used to etch the sacrificial thin film 10 and aluminum alloy film 3. Alternatively, the sacrificial thin film 10 may be first etched using fluorine-based gas plasma, and then the aluminum alloy film 3 may be etched using chlorine-based gas plasma.

Furthermore, in the above embodiment, the case where the sacrificial thin film 10 is removed by etching using fluorine-based gas plasma has been described, but the present invention is not limited to this as long as only the sacrificial thin film 10 can be etched without etching the aluminum alloy film 3. .

Further, in the above embodiment, the aluminum alloy film 3 is used as the layer to be etched, but the present invention is not limited to this.

〔Effect of the invention〕

As described above, according to the present invention, there are a step of forming a sacrificial film on a layer to be etched, a step of forming a resist pattern on the sacrificial film, and etching the layer to be etched and the sacrificial film using the resist pattern as a mask. The resist pattern formed on the sacrificial film can be used as a mask because the resist pattern formed on the sacrificial film can be used as a mask. After etching the sacrificial film and the layer to be etched, when the resist pattern is removed, the sacrificial film remains between the resist residue and the layer to be etched. Therefore, when the sacrificial film is removed by etching, the resist residue remaining on the sacrificial film is also removed. removed at the same time. As a result, there is an effect that no resist residue remains on the layer to be etched.

[Brief explanation of drawings]

1A to 1E are cross-sectional process diagrams showing one embodiment of a method for manufacturing a semiconductor device according to the present invention, and FIGS. 2A to 2D are cross-sectional process diagrams showing a conventional method for manufacturing a semiconductor device. In the figure, 3 is an aluminum alloy film, 4 is a photoresist,
10 is a sacrificial thin film. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] (1) A step of preparing a layer to be etched, a step of forming a sacrificial film on the layer to be etched, a step of forming a resist pattern on the sacrificial film, and a step of preparing the layer to be etched and the layer to be etched using the resist pattern as a mask. Manufacturing a semiconductor device comprising: etching the sacrificial film; removing the resist pattern; and simultaneously removing resist residue remaining on the sacrificial film by etching the sacrificial film. Method.