JPH08191048A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE: To form easily a TiN film having a purposed film quality. CONSTITUTION: In a method of manufacturing a semiconductor device, which comprises a step of sputtering Ti on a silicon substrate 1 by a sputtering method to form a Ti film 2 on the substrate 1 and a step of nitriding the film 2 by heat-treating the film 2 in a nitrogen atmosphere after the formation of the film 2 to form a TiN film 3 on the substrate 1, nitrogen in the range of a pressure of 1% or higher to 10% or lower to the total pressure of argon gas at the time of the sputtering of the Ti is added to the argon gas.

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, which can be applied to a technique for forming a TiN film, and in particular, a semiconductor device which can easily form a TiN film having a desired film quality. Manufacturing method. In recent years, when forming a TiN film on a substrate, the TiN film is generally formed by reactive sputtering in which Ti is sputtered on a substrate in a nitrogen gas atmosphere by a sputtering device.

However, a TiN film formed by this reactive sputtering method has a sputtering apparatus (cathode, chamber shape, etc.), power, process gas (pressure,
Since it largely depends on the flow rate), a TiN film having different film quality may be formed even if sputtering is performed by the same sputtering apparatus. Therefore, when the TiN film is formed under the same sputtering condition, it is difficult to stably form the TiN film having a desired film quality.

Therefore, there is a demand for a method of manufacturing a semiconductor device which can stably form a TiN film having a desired film quality when the TiN film is formed under the same sputtering conditions.

[0004]

2. Description of the Related Art FIG. 8 is a diagram showing a conventional method for manufacturing a semiconductor device. Conventionally, as shown in FIGS. 8A and 8B, first, Ti is sputtered on the Si substrate 1001.
After forming the film 1002, as shown in FIG.
The Si substrate 1001 on which the film 1002 is formed is annealed in a nitrogen atmosphere to nitride the Ti film 1002 from the surface to form a TiN film 1003.

At this time, since the underlying substrate 1001 under the Ti film 1002 is made of Si, heat treatment causes Ti and Si to react with each other, and TiS is formed at the interface with the substrate 1001.
The i ₂ film 1004 is formed. In this way, the TiN film 1003 formed by nitriding the Ti film 1002 from the surface by annealing in a nitrogen atmosphere has less device dependency and the like and has a constant film quality as compared with the TiN film formed by reactive sputtering. Can be

[0006]

As described above, FIG.
In the conventional method of manufacturing a semiconductor device shown in FIG.
2 is formed by annealing the Si substrate 1001 in a nitrogen atmosphere to nitride the Ti film 1002 from the surface.
Since the iN film 1003 is formed, it has an advantage that it is less dependent on the device than the TiN film formed by reactive sputtering and can be formed with a constant film quality.

However, in this conventional method of manufacturing a semiconductor device, after the Ti film 1002 is formed by sputtering or the like, once exposed to the atmosphere, the surface of the Ti film 1002 is oxidized and the surface of the Ti film 1002 is covered with TiO ₂ or the like. An oxide film is generated. Therefore, even if annealing is performed in a nitrogen atmosphere with an oxide film formed on the surface of the Ti film 1002, the Ti film 10
02 There is a problem that the nitriding of the Ti film 1002 is suppressed by the oxide film formed on the surface and it is difficult to form the TiN film 1003 thick.

Further, the underlying substrate 100 under the Ti film 1002
Since 1 is composed of Si, the reaction rate with the underlying Si substrate 1001 is faster than the nitriding of the Ti film 1002, and T
There is a problem that it is difficult to form the iN film 1003 thick.
As a method of solving the above problem, a method of forming a thick TiN film by adding a small amount of nitrogen to Ti to suppress the reaction with the underlying Si substrate and the oxidation of the surface has been studied. However, the quality of the TiN film formed by the specific amount of nitrogen added is not mentioned and it has not been put into practical use.

Therefore, according to the present invention, the T having the desired film quality is obtained.
It is an object of the present invention to provide a method for manufacturing a semiconductor device that can easily form an iN film.

[0010]

According to the first aspect of the present invention,
A semiconductor device in which a Ti film is formed by sputtering Ti on a silicon substrate by a sputtering method, and then the Ti film is heat-treated in a nitrogen atmosphere to nitride the Ti film to form a TiN film on the silicon substrate. In the manufacturing method of
It is characterized by adding nitrogen in the range of 1% to 10% with respect to the total pressure in the argon gas at the time of i-sputtering.

According to a second aspect of the present invention, Ti is sputtered on a silicon substrate to form a Ti film by a sputtering method, and then the Ti film is heat treated in a nitrogen atmosphere to nitride the Ti film. In a method of manufacturing a semiconductor device in which a TiN film is formed on a silicon substrate, nitrogen is added to the argon gas during Ti sputtering in a range of 1% to 3% with respect to the total pressure.

In a third aspect of the present invention, Ti is sputtered on a silicon substrate by a sputtering method to form a Ti film, and the Ti film is heat treated in a nitrogen atmosphere to nitride the Ti film. In a method of manufacturing a semiconductor device in which a TiN film is formed on a silicon substrate, nitrogen is added to the argon gas during Ti sputtering in a range of 5% to 10% with respect to the total pressure.

The invention according to claim 4 is the above-mentioned claim 1,
In the invention described in any of 2 and 3, the heat treatment,
It is characterized in that it is first performed at 650 ° C. or lower and then at 800 ° C. or higher. The invention according to claim 5 is the same as the invention according to any one of claims 1, 2, 3 and 4,
After the Ti sputtering, the heat treatment is performed without being exposed to the atmosphere even once.

[0014]

1 to 3 show various types of ion-implanted Si.
A Ti film with a thickness of 80 nm is formed by adding each amount of nitrogen to argon gas at the time of sputtering on the substrate, and first heat treatment is performed at 650 ° C. for 1 minute in a nitrogen atmosphere in a halogen lamp annealing device without exposure to the air. And then 800
The results of sheet resistance measurement and X-ray diffraction measurement of the formed film after heat treatment at 30 ° C. for 30 seconds are shown. Moreover, FIGS.
Similarly, the results of sheet resistance measurement and X-ray diffraction measurement of the film when a Ti film is similarly formed, the substrate is temporarily left in the atmosphere and then heat-treated under the same conditions are shown.

From the sheet resistance measurement results shown in FIG. 1, when the Ti film having a nitrogen addition amount larger than 10% is heat-treated in a nitrogen atmosphere, the sheet resistance value of the TiN film becomes extremely large, which is preferable for practical use. Absent. Further, when the Ti film without nitrogen added is heat-treated in a nitrogen atmosphere, the sheet resistance value of the TiN film can be reduced, but the Ti film without added nitrogen can be obtained from the X-ray diffraction measurement results shown in FIGS. When X-ray diffraction measurement is performed when heat treatment is performed in a nitrogen atmosphere,
Peak value of TiN is low, by the peak value of the TiSi ₂ is high, TiSi ₂ film is thick, TiN film is seen that it is formed thin.

On the contrary, when the amount of nitrogen added exceeds 10%, the peak of the TiSi ₂ film disappears, but T
Since the peak of the iN film is gradually reduced and the sheet resistance of the TiN film is also rapidly increased, it can be seen that the normal TiN film is not formed. From this, considering that the TiN film is formed with a sufficiently small sheet resistance and a sufficiently large film thickness, the amount of nitrogen added during sputtering of the Ti film is 1%.
The range must be 10% or less.

From the X-ray diffraction measurement results shown in FIGS. 2 and 3, the TiN film with a nitrogen addition amount in the range of 1% or more and 3% or less has a strong (111) orientation and is 5% or more and 10% or less. It can be seen that the (200) orientation is stronger in the range. From this, it is possible to form a TiN film having a strong (111) orientation by setting the nitrogen addition amount within the range of 1% to 3%, and the nitrogen addition amount within the range of 5% to 10%. As a result, a TiN film having a strong (200) orientation can be formed. Therefore, it is possible to form a TiN film having different orientation depending on the amount of nitrogen added.

On the other hand, as shown in FIGS. 4 to 6, when the Ti film is formed and then exposed to the air, the surface of the Ti film is oxidized, so that the Ti film is not exposed to the air as shown in FIGS. ,
For example, when the amount of nitrogen added is 5%, the TiN film becomes thin and
The i ₂ film is thick and the sheet resistance is low. Further, when the amount of nitrogen added is 10%, almost no TiN film or TiSi ₂ film is formed, and the sheet resistance is high.

After the Ti film is formed, by performing heat treatment in a nitrogen atmosphere without exposing it to the air, oxidation on the surface of the Ti film can be suppressed more than in the case of exposing it to the air. In addition, a stable TiN film having a small sheet resistance can be easily formed.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 7 is a diagram showing a method of manufacturing a semiconductor device according to an embodiment of the present invention. In this embodiment, first, referring to FIG.
As shown in (a) and (b), after removing the natural oxide film formed on the surface of the Si substrate 1 into which As ⁺ ions have been implanted with an HF solution, the Si substrate 1 is magnetized by a magnetron sputtering device.
A Ti film 2 having a film thickness of 80 nm is formed thereon. At this time, 5% of nitrogen is added to the argon gas at the time of sputtering.

Next, after forming the Ti film 2 to which nitrogen is added in this way, the nitrogen-containing Ti film 2 is heat-treated in a nitrogen atmosphere by a halogen lamp annealing apparatus without being exposed to the air, and the film thickness is about 100 nm. Then, the TiN film 3 is formed. At this time, at the interface between the TiN film 3 and the Si substrate 1, Ti
Ti of the film 2 reacts with Si of the Si substrate 1 to be silicidized to form a TiSi ₂ film 4 (FIG. 7C). In this heat treatment, the surface of the nitrogen-containing Ti film 2 is first nitrided by heat treatment at 650 ° C. for 1 minute, and then the interface between the Si substrate 1 and the nitrogen-containing Ti film 2 is heated at 800 ° C. for 30 seconds. The formed TiSi ₂ film 4 is stabilized.

The TiN film 3 formed in this way has (2
00), and TiSi is formed at the interface with the substrate 1.
_{2 The} film 4 is hardly formed. Therefore, the stable TiN film 3 having a large film thickness can be easily formed. When the TiN film 3 having the (111) orientation is required or when the relatively thick TiSi ₂ film 4 is required at the interface with the Si substrate 1, the nitrogen addition amount during Ti sputtering is 1% or more as described above. The range is 3% or less.

Generally, when the TiN film 3 is used as an underlay of the wiring, the TiN film 3 having a strong (111) orientation is used.
Has a good barrier property, and conversely, the TiN film 3 having a strong (200) orientation as in this embodiment, when the wiring is an Al alloy or the like,
It is said that reliability such as electromigration is good. Therefore, when the TiN film 3 formed of the nitrogen-added Ti film 2 is used as the underlay of the wiring Al alloy, the amount of nitrogen added is set to be in the range of 1% or more and 3% or less at the initial stage of sputtering, so that The barrier property can be improved. Further, in the latter stage of sputtering, the reliability of the wiring can be improved by adding nitrogen in the range of 5% or more and 10% or less.

Further, in this embodiment, when the underlying layer is in contact with the Si substrate 1, the TiSi ₂ film 4 can be appropriately formed at the interface, so that the contact resistance can be reduced. When the TiN film 3 is used as a barrier metal, generally, the TiN film 3 is sputtered and then subjected to barrier annealing or the like to slightly oxidize the TiN film 3 to improve the barrier property. When the TiN film 3 is formed by the above, the same effect can be obtained by adding arbitrary oxygen during Ti sputtering.

[0025]

According to the present invention, T having the desired film quality is obtained.
The iN film can be easily formed, and the process can be stabilized and the cost can be reduced.

[Brief description of drawings]

FIG. 1 shows a Ti film in which each amount of nitrogen is added to argon gas at the time of sputtering is formed on a Si substrate into which As ions and BF ₂ ions are implanted, and then heat treatment is performed in a nitrogen atmosphere without exposure to the air. It is a figure which shows the measurement result of the sheet resistance of the TiN film formed in this way.

FIG. 2 is a TiN film formed by forming a Ti film in which each amount of nitrogen is added to argon gas at the time of sputtering on a Si substrate into which As ions have been ion-implanted, and then performing a heat treatment in a nitrogen atmosphere without exposing to the atmosphere; is a graph showing measurement results of X-ray diffraction of the TiSi ₂ film.

FIG. 3 is a TiN film formed by forming a Ti film in which each amount of nitrogen is added to argon gas at the time of sputtering on a Si substrate into which BF ₂ ions have been ion-implanted, and then performing heat treatment in a nitrogen atmosphere without exposing to the air. FIG. 5 is a diagram showing the measurement results of X-ray diffraction of a TiSi ₂ film.

FIG. 4 shows a Ti film in which each amount of nitrogen is added to argon gas at the time of sputtering is formed on a Si substrate into which As ions and BF ₂ ions have been implanted, and then exposed to the atmosphere, and then heat-treated in a nitrogen atmosphere. It is a figure which shows the measurement result of the sheet resistance of the TiN film formed in this way.

FIG. 5 is a TiN film formed by forming a Ti film in which each amount of nitrogen has been added to argon gas at the time of sputtering on a Si substrate into which As ions have been ion-implanted, and then exposing to the atmosphere, and then performing heat treatment in a nitrogen atmosphere. is a graph showing measurement results of X-ray diffraction of the TiSi ₂ film.

FIG. 6 is a TiN film formed by forming a Ti film in which each amount of nitrogen is added in argon gas at the time of sputtering on a Si substrate into which BF ₂ ions are ion-implanted, exposing it to the air, and then performing a heat treatment in a nitrogen atmosphere. FIG. 5 is a diagram showing the measurement results of X-ray diffraction of a TiSi ₂ film.

FIG. 7 is a diagram showing a method for manufacturing a semiconductor device according to an embodiment of the present invention.

FIG. 8 is a diagram showing a conventional method for manufacturing a semiconductor device.

[Explanation of symbols]

1 Si substrate 2 Ti film 3 TiN film 4 TiSi ₂ film

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location H01L 21/324 Z

Claims (5)

[Claims] 1. A Ti film (2) is formed by sputtering Ti on a silicon substrate (1) by a sputtering method.
When the film (2) is heat-treated in a nitrogen atmosphere, the Ti
In a method of manufacturing a semiconductor device, which comprises nitriding a film (2) to form a TiN film (3) on the silicon substrate (1),
1% or more of the total pressure in argon gas during sputtering 1
A method of manufacturing a semiconductor device, comprising adding nitrogen in an amount of 0% or less. 2. A Ti film (2) is formed by sputtering Ti on a silicon substrate (1) by a sputtering method.
When the film (2) is heat-treated in a nitrogen atmosphere, the Ti
In a method of manufacturing a semiconductor device, which comprises nitriding a film (2) to form a TiN film (3) on the silicon substrate (1),
1% to 3% of the total pressure in argon gas during sputtering
A method of manufacturing a semiconductor device, comprising adding nitrogen in the following range. 3. A Ti film (2) is formed by sputtering Ti on a silicon substrate (1) by a sputtering method.
When the film (2) is heat-treated in a nitrogen atmosphere, the Ti
In a method of manufacturing a semiconductor device, which comprises nitriding a film (2) to form a TiN film (3) on the silicon substrate (1),
5% or more of total pressure in argon gas during sputtering 10
% Of nitrogen or less is added, The manufacturing method of the semiconductor device characterized by the above-mentioned. 4. The heat treatment is performed at 650 ° C. or lower and then at 800 ° C. or higher.
2. A method of manufacturing a semiconductor device according to any one of 2 and 3. 5. The heat treatment is performed without exposing to the atmosphere even once after the Ti sputtering.
2. The method for manufacturing a semiconductor device according to 2, 3, or 4.