JPH05102151A - Method for manufacturing semiconductor device - Google Patents

Abstract

(57) [Summary] [Object] To improve a method for manufacturing a semiconductor device, and more particularly, to improve a method for forming a wiring made of aluminum or an aluminum alloy, to prevent mutual diffusion between an aluminum layer or an aluminum alloy layer and an antireflection film. It is an object of the present invention to provide a method of preventing the occurrence of the above-mentioned phenomenon, preventing an increase in contact resistance between laminated wirings, and improving the reliability of aluminum or aluminum alloy wirings. An aluminum layer or aluminum alloy layer 2 and an antireflection film 4 are sequentially laminated on a substrate 1, and a laminated film of the aluminum layer or aluminum alloy layer 2 and antireflection film 4 is patterned to form wiring. In the method for manufacturing a semiconductor device having steps, the oxide film 3 of aluminum or aluminum alloy is formed between the aluminum layer or aluminum alloy layer 2 and the antireflection film 4 to have a thickness of 20 to 50 Å.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a method for manufacturing a semiconductor device, and more particularly to an improvement in a method for forming wiring made of aluminum or aluminum alloy.

[0002] In recent years, LS has become more highly integrated with higher integration of LSI.
Since the I structure is becoming more complicated and the wiring is becoming finer, it is required to improve the accuracy of the line width and shape of the aluminum wiring.

[0003]

2. Description of the Related Art In a conventional wiring forming method, first, an aluminum layer or an aluminum alloy layer is formed on a substrate by a sputtering method or the like, and titanium nitride (Ti
An antireflection film made of N), tungsten titanium (TiW), tungsten (W), or the like is similarly formed by using a sputtering method or the like.

Next, a resist layer is formed and patterned by a lithographic method to remain on the wiring formation region. Using this resist pattern as a mask, the antireflection film and the aluminum layer or aluminum alloy layer are formed. The wiring is formed by patterning. The antireflection film is
It is formed in order to improve the resolution by reducing the reflection of exposure light from the surface of the aluminum layer or the aluminum alloy layer when the resist layer is patterned by using the lithography method.

[0005]

In the heat treatment process performed after the antireflection film is formed, mutual diffusion occurs between the aluminum layer or the aluminum alloy layer and the antireflection film such as TiN, TiW, and W, and aluminum or aluminum is formed. There is a problem that the resistance of the alloy wiring increases, or the contact resistance when connecting the lower layer wiring and the upper layer wiring to each other through a through hole increases, and the reliability of the wiring decreases.

An object of the present invention is to eliminate these drawbacks, and to prevent mutual diffusion between an aluminum layer or an aluminum alloy layer and an antireflection film to prevent contact resistance between laminated wirings. Another object of the present invention is to provide a method for preventing the increase in the number of wires and improving the reliability of aluminum or aluminum alloy wiring.

[0007]

The above object is to form an aluminum layer or an aluminum alloy layer (2) and an antireflection film (4) on a substrate (1) one by one, and to form the aluminum layer or aluminum alloy layer. A method of manufacturing a semiconductor device, comprising the step of patterning a laminated film of (2) and an antireflection film (4) to form wiring, wherein the aluminum layer or aluminum alloy layer (2) and the antireflection film ( This is achieved by a method for manufacturing a semiconductor device, which includes a step of forming an oxide film (3) of aluminum or an aluminum alloy in a thickness of 20 to 50 Å between the step 4) and the step 4). The formation of the oxide film (3) of aluminum or aluminum alloy described above is performed by applying concentrated nitric acid having a concentration of 70% or more and a temperature of 25 ° C. or less on the surface of the aluminum layer or aluminum alloy layer (2) for 5 to 10 minutes. It is preferable to contact for a period of time.

[0008]

[Operation] FIG. 1 is a diagram for explaining the principle. In the figure, 2 is aluminum or aluminum alloy wiring of the first layer formed on the substrate 1, 3 is an oxide film of aluminum or aluminum alloy containing Al ₂ O ₃ , and 4 is Ti.
An antireflection film such as N, TiW, and W, 5 is an interlayer insulating film, 7 is formed through a barrier metal layer 6 such as Ti, TiN, TiW, and W, and is a first layer of aluminum or aluminum alloy. A second layer of aluminum or aluminum alloy wiring connected to the wiring 2.

This is performed after the antireflection film is formed by forming an oxide film 3 of aluminum or aluminum alloy containing Al ₂ O ₃ between the first layer of aluminum or aluminum alloy wiring 2 and the antireflection film 4. Even in the heat treatment step, the mutual diffusion between the aluminum or aluminum alloy wiring 2 of the first layer and the antireflection film 4 is sufficiently suppressed and the reliability of the aluminum or aluminum alloy wiring 2 of the first layer is improved. An increase in contact resistance between the first layer wiring 2 and the second layer wiring 7 is also prevented.

The oxide film 3 of aluminum or aluminum alloy containing Al ₂ O ₃ is formed by bringing concentrated nitric acid having a concentration of 70% or more and a temperature of 25 ° C. or less into contact with the surface of the aluminum layer or aluminum alloy layer 2 for 5 to 10 minutes. It is formed. In addition, when nitric acid with low concentration and high temperature is contacted,
The etching rate becomes faster than the oxidation rate, and it becomes difficult to form an aluminum or aluminum alloy oxide film having good film quality and control the oxide film thickness, which is not preferable.

By setting the thickness of the oxide film of aluminum or aluminum alloy to 20 to 50 Å, it is possible to avoid adversely affecting the contact resistance between the laminated wirings.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method of forming a wiring of a semiconductor device according to an embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 2, a silicon dioxide film 8 is formed on the silicon substrate 1 and removed from the impurity diffusion region forming region, and the silicon substrate 1 in the region where the silicon dioxide film 8 is removed is, for example, n-type. Of the impurities are diffused to form an n-type impurity diffusion region 9. Next, a BPSG film 10 is formed, removed from above the n-type impurity diffusion region 9 to form an opening 11, and then a barrier metal layer 12 made of a laminated film of Ti and TiN and a first film are formed by a sputtering method. The aluminum layer or aluminum alloy layer 13 of the layers is sequentially laminated.

As shown in FIG. 3, an oxide film 14 of aluminum or aluminum alloy containing Al ₂ O ₃ is formed on the surface of the aluminum layer or aluminum alloy layer by the following method.

First, for example, concentrated nitric acid having a concentration of 70% and a temperature of 20 ° C. is brought into contact with the surface of the first aluminum layer or aluminum alloy layer 13 for 5 to 10 minutes, and then washed with ultrapure water (by immersion and running water. ) For 15 minutes and then spin-drying for 10 minutes, or blowing nitrogen gas at 50 ° C for 15 minutes to dry.

When the period of contact with concentrated nitric acid is 5 minutes, an aluminum oxide film having a good Al ₂ O ₃ structure is formed to a thickness of about 30Å, and when it is 10 minutes, the aluminum oxide film of similar film quality is formed. An oxide film is formed with a thickness of approximately 35Å. It should be noted that no significant change in film quality was observed even after contacting for 10 minutes or more, and only the film thickness increased.

As shown in FIG. 4, an antireflection film 15 of TiN, TiW, W or the like is formed by using the sputtering method. After the antireflection film 15, the aluminum or aluminum alloy oxide film 14 and the first aluminum layer or aluminum alloy layer 13 are patterned and removed from the region except the wiring formation region, as shown in FIG. Forming an inter-layer insulating film 16 of the like, and patterning this to form a contact hole 17 on the first layer of aluminum or aluminum alloy wiring 13;
A barrier metal layer 18 made of i, TiN, TiW, W, etc. and a second aluminum layer or aluminum alloy layer 19 are sequentially laminated to form the barrier metal layer 18 and the second aluminum layer or aluminum alloy layer 19. It is patterned and removed from the region except the wiring formation region.

[0018]

As described above, in the method of manufacturing a semiconductor device according to the present invention, the reflection film is formed by forming an aluminum or aluminum alloy oxide film between the aluminum layer or aluminum alloy layer and the antireflection film. Even in the heat treatment step after the formation of the anti-reflection film, mutual diffusion between the aluminum layer or the aluminum alloy layer and the antireflection film can be prevented, so that good contact between the laminated wirings can be achieved and the aluminum or aluminum alloy wiring The reliability is significantly improved.

[Brief description of drawings]

FIG. 1 is a diagram illustrating the principle of the present invention.

FIG. 2 is an explanatory diagram of a laminated wiring forming process.

FIG. 3 is an explanatory diagram of a laminated wiring forming process.

FIG. 4 is an explanatory diagram of a laminated wiring forming process.

FIG. 5 is an explanatory diagram of a laminated wiring forming process.

[Explanation of symbols]

1 substrate 2 first layer aluminum or aluminum alloy wiring 3 ・ 14 aluminum or aluminum alloy oxide film 4 ・ 15 antireflection film 5 ・ 16 interlayer insulating film 6 ・ 12 18 barrier metal layer 7 second layer aluminum or aluminum alloy wiring 8 dioxide Silicon film 9 Impurity diffusion region 10 BPSG layer 11 ・ 17 Contact hole 13 First aluminum layer or aluminum alloy layer 19 Second aluminum layer or aluminum alloy layer

Claims (2)

[Claims] 1. An aluminum layer or an aluminum alloy layer (2) and an antireflection film (4) are sequentially laminated on a substrate (1), and the aluminum layer or aluminum alloy layer (2) and the antireflection film (4) are formed. In the method for manufacturing a semiconductor device, which comprises a step of patterning a laminated film with the above) to form wiring, an aluminum or aluminum alloy layer is formed between the aluminum layer or aluminum alloy layer (2) and the antireflection film (4). A method of manufacturing a semiconductor device, comprising a step of forming an oxide film (3) to a thickness of 20 to 50 Å. 2. The aluminum or aluminum alloy oxide film (3) is formed on the surface of the aluminum layer or aluminum alloy layer (2) at a concentration of 70% or more at a temperature of
2. The method of manufacturing a semiconductor device according to claim 1, wherein concentrated nitric acid at 25 [deg.] C. or lower is contacted for 5 to 10 minutes.