JPH0794511A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To prevent the narrowing of a width of a wiring layer formed due to the widening of an opening window and turning into a tapered shape when forming a wiring film having a fine wiring width with respect to the improvement of the forming method for a metal laminated wiring of a semiconductor device. CONSTITUTION:In a production method for a semiconductor device having a process for forming laminated metal wiring containing patterns having a fine wiring width and a wiring interval by etching a laminated metal film comprising a plurality of metal materials, a process for forming an opening window to be used for etching an aluminum film at the highest layer of the laminated metal film is provided at a resist film 4 formed on the surface of the laminated metal film. And also included are the process for etching the aluminum film by using the opening window and the process for etching a TiN layer directly below the aluminum film by using an etching gas which does not react with the aluminum film by means of the opening window formed in the aluminum film in the etching process.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved method for forming metal laminated wiring in a method for manufacturing a semiconductor device.

Recent logic products and patterns of metal laminated wiring such as S-RAM are not uniform in wiring width like patterns of metal laminated wiring such as D-RAM, and patterns having fine wiring width are simultaneously formed. It is often included in the wiring layer to be formed. When a metal laminated wiring including a pattern having such a fine wiring width and a wiring interval is formed by etching, etching is performed in a portion where the width of the metal laminated wiring is very small. The shoulder of the surface layer of the resist film formed as a mask is etched during the etching process, and the shape of the opening window of the resist film formed as an etching mask becomes a tapered shape, and the opening window expands, the wiring width, the spacing. However, there is a case where the resist film disappears in the narrow portion and the metal is etched during the etching.

Under the above circumstances, the fine opening window provided in the resist film does not spread, or the size of the opening window of the resist film and the opening window that can maintain the shoulder portion of the surface layer of the resist itself are etched. There is a demand for a method of manufacturing a semiconductor device capable of performing the above.

[0004]

2. Description of the Related Art A method of manufacturing a semiconductor device in which a conventional metal laminated wiring film consisting of two layers of aluminum and titanium nitride used as a barrier metal is etched will be described with reference to FIGS.

5 to 6 are side sectional views showing a conventional method of manufacturing a semiconductor device in the order of steps. When etching a conventional metal laminated wiring film including a pattern having a fine wiring width, first, as shown in FIG. 5A, a titanium nitride film 22 () is formed on the surface of a base film 21 of a semiconductor substrate or an interlayer insulating film. Hereinafter, a TiN film 22 is abbreviated) and an aluminum film 23 are laminated.

Next, as shown in FIG. 5B, a resist film 24 is formed on the surface of the aluminum film 23, and the TiN film 22 and the aluminum film 23 are processed into a resist film by a lithography technique. Opening window used for patterning 24 and etching aluminum film 23 or TiN film 22
Forming 24a.

Next, as shown in FIG. 5 (c), the aluminum film 23 in the opening window 24a using chlorine gas (Cl ₂ ) is etched by dry etching to remove the aluminum wiring layer 23a (hereinafter referred to as Al wiring layer 23a). Abbreviated), the resist film 24 is also etched at the same time, so the opening window 24a before etching becomes the opening window 24b,
The space between the Al wiring layers 23a becomes wider, and the resist film disappears in the portion where both the wiring width and the space are narrow, and the shoulder portion of the surface layer of the aluminum film is etched.

As shown in FIG. 6 (a), sulfur hexafluoride (SF
₆ ) is used to dry the TiN film 22 in the opening window 24b to etch the TiN film 22 to thereby remove the TiN wiring layer 22.
After forming a, the resist film is finally removed as shown in FIG. 6 (b).

[0009]

In the step of forming a laminated wiring layer by dry etching in the above-described conventional method for manufacturing a semiconductor device, a portion in which a wiring layer having a fine wiring width is formed is shown in FIG. ), The resist film is also etched at the same time, and the opening window 24a expands,
These opening windows 24a become tapered opening windows 24b as shown in the drawing, and the width of the Al wiring layer 23a to be formed becomes narrower. Then, the TiN wiring is formed by etching as shown in FIG. 6 (a). There is a problem that the width of the layer 22a is also narrowed.

In view of the above situation, the present invention provides a method of etching a wiring film having a fine wiring width,
It is an object of the present invention to provide a method for manufacturing a semiconductor device that can prevent the width of a wiring layer to be formed from being narrowed by widening the opening window into a tapered shape.

[0011]

According to a method of manufacturing a semiconductor device of the present invention, a laminated metal film formed of a plurality of metal materials is etched to form a laminated metal wiring including a pattern having a fine wiring width and a wiring interval. A method of manufacturing a semiconductor device having a step of forming an opening window used for etching the uppermost first metal layer of the laminated metal film in the resist film formed on the surface of the laminated metal film, The step of etching the first metal layer using the opening window, and the first metal layer using an etching gas that does not react with the first metal layer due to the opening window formed in the first metal layer in the etching step. And a step of etching the second metal layer immediately below the substrate.

[0012]

That is, in the present invention, an opening window used for etching the uppermost first metal layer of the plurality of laminated metal films is formed in the resist film formed on the surface of this metal layer, and this opening window is used. After etching the first metal layer,
In this etching step, the second metal layer directly below the first metal layer is etched by the etching gas that does not react with the first metal layer due to the opening window formed in the first metal layer. Therefore, the opening window formed in the resist film is formed. It is possible to form a wiring layer having an interval equal to, and prevent the width of the wiring layer from becoming narrow.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. 1 and 2, and a second embodiment of the present invention will be described in detail with reference to FIGS.

1 to 2 are side sectional views showing a method of manufacturing a semiconductor device according to a first embodiment of the present invention in the order of steps, and FIGS.
FIG. 4 is a side sectional view showing a method of manufacturing a semiconductor device according to a second embodiment of the present invention in the order of steps.

When etching a laminated metal wiring film including a pattern having a fine wiring width according to the first embodiment, which is composed of an aluminum film and a TiN film according to the present invention, first of all,
As shown in 1 (a), the base film 1 of the semiconductor substrate or the interlayer insulating film
A TiN film 2 and an aluminum film 3 are formed by laminating on the surface of.

Next, as shown in FIG. 1 (b), a resist film 4 is formed on the surface of the aluminum film 3 and the resist film 4 is formed into a shape in which the TiN film 2 and the aluminum film 3 are processed by a lithography technique. The film 4 is patterned to form an opening window 4a used for etching.

Then, as shown in FIG. 1C, the aluminum film 3 in the opening window 4a is dry-etched by using chlorine gas (Cl ₂ ) to pattern the aluminum film 3 to form an Al wiring layer 3a. To do.

As shown in FIG. 2 (a), sulfur hexafluoride (SF ₆ )
This TiN film 2 is patterned by dry etching of the TiN film 2 in the opening window using, to form a TiN wiring layer 2a, and finally the resist film is removed as shown in FIG. 2 (b).

When etching a metal wiring layer including a pattern having a fine wiring width according to the second embodiment, which is composed of a tungsten film and an aluminum film according to the present invention, first, as shown in FIG. Alternatively, an aluminum film 12 and a tungsten film 13 are laminated and formed on the surface of a base film 11 of an interlayer insulating film.

Next, as shown in FIG. 3 (b), a resist film 14 is formed on the surface of the aluminum film 12, and the resist film 14 is patterned into a shape intended to be processed by the lithography technique. Then, the opening window 14a used for etching is formed.

Then, the tungsten film 13 in the opening window 14a is dry-etched by using sulfur hexafluoride (SF ₆ ) to pattern the tungsten film 13 to form a pattern shown in FIG. 3 (c).
As shown in FIG.
13a) is formed.

As shown in FIG. 4A, the aluminum film 12 in the opening window is dry-etched by using chlorine gas (Cl ₂ ) to pattern the aluminum film 12 to form an Al film.
The wiring layer 12a is formed, and finally the resist film is removed as shown in FIG. 4 (b).

After etching the first metal layer using the opening window thus formed in the resist film while the opening window is not widened to form the first metal wiring layer having an equal interval to the opening window, the first metal wiring layer is formed. Since the second metal wiring layer is etched by using the first metal layer as a mask with an etching gas which does not react with the metal wiring layer, the first metal layer and the second metal layer having the same interval as the opening window formed in the resist film are formed. It is possible to form a laminated wiring layer.

[0024]

As is apparent from the above description, according to the present invention, there is an advantage that it is possible to accurately etch a metal wiring layer having a fine wiring width by a very simple process change. It is possible to provide a method for manufacturing a semiconductor device, which can be expected to improve reliability.

[Brief description of drawings]

FIG. 1 is a side sectional view showing a method of manufacturing a semiconductor device according to a first embodiment of the present invention in the order of steps (1)

FIG. 2 is a sectional side view showing the method of manufacturing the semiconductor device of the first embodiment according to the present invention in the order of steps (2)

FIG. 3 is a sectional side view showing a method of manufacturing a semiconductor device according to a second embodiment of the present invention in the order of steps (1)

FIG. 4 is a sectional side view showing a method of manufacturing a semiconductor device according to a second embodiment of the present invention in the order of steps (2)

FIG. 5 is a sectional side view showing a conventional method of manufacturing a semiconductor device in the order of steps (1)

FIG. 6 is a side sectional view showing a conventional method of manufacturing a semiconductor device in the order of steps (2)

[Explanation of symbols]

 1,11 Underlayer film 2 TiN film 2a TiN wiring layer 3 Aluminum film 3a Al wiring layer 4 Resist film 4a Opening window 12 Aluminum film 12a Al wiring layer 13 Tungsten film 13a W wiring layer 14 Resist film 14a Opening window

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location H01L 21/88 D

Claims (3)

[Claims] 1. A method of manufacturing a semiconductor device, comprising: a step of etching a laminated metal film made of a plurality of metal materials to form a laminated metal wiring including a pattern having a fine wiring width and a wiring interval. Forming an opening window used for etching the uppermost first metal layer of the laminated metal film in the resist film formed on the surface of the laminated metal film; and etching the first metal layer using the opening window And a step of etching the second metal layer directly below the first metal layer using an etching gas that does not react with the first metal layer due to the opening window formed in the first metal layer in the etching step. A method of manufacturing a semiconductor device, comprising: 2. The method of manufacturing a semiconductor device according to claim 1, wherein the first metal layer is an aluminum film (3), the second metal layer is a titanium nitride film (2), and etching using chlorine gas is performed. A method of manufacturing a semiconductor device, characterized in that the titanium nitride film (2) is etched using sulfur hexafluoride gas through the opening window formed in the aluminum film (3). 3. The method for manufacturing a semiconductor device according to claim 1, wherein the first metal layer is a tungsten film (13), the second metal layer is an aluminum film (12), and sulfur hexafluoride gas is used. The tungsten film (1
A method for manufacturing a semiconductor device, characterized in that the aluminum film (12) is etched using chlorine gas through the opening window formed in 3) and the opening window remaining after etching the tungsten film (13).