JPH1064909A - Method for manufacturing antireflective film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form aluminum nitride which is not converted into aluminum oxide and to impart the aluminum nitride with an antireflection effect against exposure light by, after forming an aluminum alloy wiring on a semiconductor substrate, forming an aluminum nitride film on the surface of it. SOLUTION: Afrer an aluminum alloy wiring 13 is formed on a semiconductor substrate 11, an aluminum nitride film 15 is formed on the surface of the aluminum alloy wiring 13. For example, after the aluminum film 13 is formed on a BBSG film 12 on the silicon substrate 11, while the substrate 11 is heated to 200 deg.C or above, the surface of the aluminum film 13 is plasma-processed with a mixed gas 14 of nitrogen and hydrogen. As a result, the aluminum nitride layer 15 is formed. Formation conditions of the aluminum nitride layer 15 are, for example, plasma irradiation period 0.5-1 hour, nitrogen:hydrogen=75:25, mixed gas flow rate = 24SCCM, pressure = 24 × 10<-4> Torr, heating period = 1 hour at 250 deg.C, and film thickness = 30nm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a semiconductor device, and more particularly to a method for manufacturing an antireflection film required for manufacturing a semiconductor device having an aluminum alloy wiring.

[0002]

2. Description of the Related Art As semiconductor devices have been miniaturized and the width of aluminum alloy wiring has been gradually reduced, it has become important to reduce the reflectance of aluminum alloy wiring. For this reason, conventionally, for example, a titanium nitride film is laminated as an antireflection film on an aluminum alloy wiring to prevent reflection of exposure light at the time of forming a resist pattern of the wiring.

However, even if a titanium nitride film is formed on the formed aluminum alloy wiring, electromigration occurs if aluminum oxide is present at the interface due to oxidation of the aluminum alloy wiring.
There is a problem that the reliability of the semiconductor device is reduced.

In order to solve this problem, for example, Japanese Patent Application Laid-Open No. Hei 7-263647 proposes a method of forming an aluminum nitride film between an aluminum film and a titanium nitride film. In this conventional method, as shown in FIG. 3, after an aluminum film 13 is formed on an insulating film (boron phosphorus silicate glass film) 12 on a silicon substrate 11, a plasma containing nitrogen as a main component is formed in the same device. An aluminum nitride film 15 is formed by irradiation or reactive sputtering or annealing in an atmosphere containing nitrogen as a main component. After the aluminum nitride film 15 is formed, a titanium nitride film 16 is formed. . that time,
As shown in FIG. 4, the formation of the titanium nitride film 16 is performed in the second
The sputtering apparatus, the formation of the aluminum nitride film 15 is the first
In this case, another sputtering apparatus was used.

[0005]

However, in the above prior art, if the conditions for forming the aluminum nitride film 15 are not appropriate, the aluminum nitride film reacts with moisture before the titanium nitride film 16 is formed due to the reaction with water. Occurs, which is transformed into aluminum oxide, and the reliability of the semiconductor is reduced by electromigration.

[0006] Titanium nitride used as an antireflection film has a high binding property to a basic substance. Therefore, when a chemically amplified resist is used as a patterning resist by a basic substance adhered on the surface of titanium nitride. At the interface between the chemically amplified resist and titanium nitride, there is a problem in that the resist has a pattern tail.

Accordingly, the present invention has been made in view of the above circumstances, and has as its object to form aluminum nitride which does not change into aluminum oxide, and to make aluminum nitride have an antireflection effect against exposure light. An object of the present invention is to provide a method for manufacturing an antireflection film as described above.

[0008]

In order to achieve the above object, a method of manufacturing an antireflection film according to the present invention comprises forming an aluminum alloy wiring on a semiconductor substrate and then forming an aluminum nitride film on the surface of the aluminum alloy wiring. Forming.

In the present invention, after the aluminum alloy wiring is formed on the semiconductor substrate, a plasma of a mixed gas of nitrogen and hydrogen is applied to the aluminum alloy wiring while heating the semiconductor substrate at a predetermined temperature. Irradiation.

In the present invention, after the aluminum alloy wiring is formed on the semiconductor substrate, plasma of a mixed gas of nitrogen and hydrogen is irradiated on the aluminum alloy wiring, and then the semiconductor substrate is exposed to a predetermined temperature. Heat treatment at a temperature.

In a preferred embodiment of the present invention, the predetermined temperature at which the semiconductor substrate is heat-treated is set to approximately 200 degrees Celsius or more.

According to the above-described method of manufacturing an antireflection film of the present invention, aluminum nitride can be prevented from being changed into aluminum oxide, and aluminum nitride can have an antireflection effect without using titanium nitride.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram for explaining a manufacturing method according to an embodiment of the present invention, and is a diagram schematically illustrating a cross section of a semiconductor device in a manufacturing process order.

As shown in FIG. 1A, a silicon substrate 1
After forming an aluminum film 13 on a boron-phosphorus silicate glass film 12 on the silicon substrate 1, as shown in FIG. 1B, while heating the silicon substrate 11 preferably at 200 degrees Celsius, a mixed gas 14 of nitrogen and hydrogen is used. The surface of the aluminum film 13 is subjected to plasma processing.

As a result, an aluminum nitride layer 15 is formed on the aluminum film 13 as shown in FIG.

Further, as another embodiment of the present invention,
After forming the aluminum film 13 (step 201) as shown in the flow chart of the processing flow in FIG. 2, a plasma processing using a mixed gas 14 of nitrogen and hydrogen was performed (step 20).
2) Thereafter, the silicon substrate 11 is subjected to heat treatment in an ultra-high vacuum, preferably at 250 degrees Celsius for 1 hour or more (Step 203).
By this, the aluminum nitride layer 15 can be formed on the aluminum film 13 in the same manner.

An example illustrating a specific example of the embodiment of the present invention will be described.

In this embodiment, the conditions for producing aluminum nitride (AlN) are as follows:
5 to 1 hour, as a mixed gas, nitrogen: hydrogen = 75: 25,
Mixed gas flow rate: 24 SCCM, pressure: 24 × 10 ^-4 To
rr, heating time: 250 ° C., 1 hour, and the formed film thickness of aluminum nitride (AlN) was 30 nm.

In this embodiment, the aluminum film is used.
This film may be a pure metal of aluminum or an aluminum alloy containing silicon and copper (for example, Al-Si
0.5% -Cu 0.5%).

According to the above embodiment, when forming the aluminum nitride, the semiconductor substrate is irradiated with a mixed gas plasma of nitrogen and hydrogen or a mixed plasma of nitrogen and hydrogen while being heated at preferably 200 ° C. or more. ,
By performing a heat treatment on the semiconductor substrate at preferably 200 degrees Celsius or more, there is an effect of being able to form aluminum nitride that does not change into aluminum oxide. The reason is that impurities such as oxygen are removed by a reduction reaction of hydrogen existing on the aluminum nitride surface or the aluminum film surface with hydrogen by heat treatment, and aluminum nitride is generated. Is prevented from being transformed into aluminum oxide.

In the above embodiment, the wavelength 200
By forming stable aluminum nitride for exposure light of nm or less, it is not necessary to use titanium nitride as an antireflection film, and aluminum nitride can be used as an antireflection film as it is. The reason is that aluminum nitride is a direct transition type compound, and its band gap is 5.
9 eV. For this reason, the absorption of light having a wavelength of 200 nm or less is large, and the reflectance is 1% or less, and the film has a function as an antireflection film.

[0022]

As described above, according to the present invention,
When forming the aluminum nitride, the semiconductor substrate is irradiated with a mixed gas plasma of nitrogen and hydrogen while heating the semiconductor substrate preferably at 200 ° C. or higher, or after irradiating a mixed plasma of nitrogen and hydrogen, the semiconductor substrate is preferably heated to 200 ° C.
By performing the heat treatment at a temperature equal to or higher than that, it is possible to form aluminum nitride that does not change into aluminum oxide.

The reason is that in the present invention, heat treatment removes impurities such as oxygen by a reduction reaction of hydrogen present on the aluminum nitride surface or the aluminum film surface with hydrogen, and aluminum nitride is generated. Of aluminum nitride to aluminum oxide due to the reaction with water.

Further, according to the present invention, it is not necessary to use titanium nitride as an antireflection film by forming stable aluminum nitride for exposure light having a wavelength of 200 nm or less. It can be a membrane. The reason is that aluminum nitride is
It is a direct transition compound, and its band gap is 5.9 eV
It is. For this reason, the absorption of light having a wavelength of 200 nm or less is large, and the reflectance is 1% or less, and the film has a function as an antireflection film.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing a manufacturing method according to an embodiment of the present invention in the order of steps.

FIG. 2 is a flowchart showing a manufacturing process according to another embodiment of the present invention.

FIG. 3 is a cross-sectional view for explaining a conventional method for manufacturing an antireflection film.

FIG. 4 is a flowchart for explaining a conventional method for manufacturing an antireflection film.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Silicon substrate 12 Boron phosphorus calculation glass film 13 Aluminum film 14 Mixed gas of nitrogen and hydrogen 15 Aluminum nitride layer 16 Titanium nitride 17 Passivation film

Claims (4)

[Claims] 1. A method for manufacturing an anti-reflection film, comprising: forming an aluminum alloy wiring on a semiconductor substrate; and forming an aluminum nitride film on the surface of the aluminum alloy wiring. 2. After the aluminum alloy wiring is formed on the semiconductor substrate, a plasma of a mixed gas of nitrogen and hydrogen is irradiated onto the aluminum alloy wiring while heating the semiconductor substrate at a predetermined temperature. The method for producing an antireflection film according to claim 1, wherein: 3. After the aluminum alloy wiring is formed on the semiconductor substrate, a plasma of a mixed gas of nitrogen and hydrogen is irradiated on the aluminum alloy wiring, and then the semiconductor substrate is heated at a predetermined temperature. The method for producing an antireflection film according to claim 1, wherein: 4. The method according to claim 2, wherein a predetermined temperature at which the semiconductor substrate is heat-treated is set to approximately 200 degrees Celsius or higher.