JPH07114203B2 - Method for manufacturing semiconductor device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device, and more particularly to a method for manufacturing a highly integrated semiconductor device including metal wiring having low resistance and high reliability. .

2. Description of the Related Art When a semiconductor device is manufactured by using a conventional semiconductor device manufacturing method, metal wiring is manufactured by processing a thin film of aluminum (hereinafter referred to as Al) or Al alloy that has low resistance and is easy to process. It was customary to run. Further, the deposition of Al or Al alloy thin film was usually performed by using a sputtering method.

However, such a metal wiring has a problem that reliability is deteriorated when it is miniaturized.
It has been proposed to use a structure in combination with a refractory metal such as tungsten (hereinafter referred to as W), molybdenum, or tantalum, or a refractory metal alloy such as tungsten silicide. (1) Metal wiring obtained by processing a metal thin film in which an Al thin film or an Al alloy thin film and a thin film of a high melting point metal or a high melting point metal alloy are laminated into a fine wire (for example, DSGardner et al.
Iii Transaction on Electron
Device (IEEE Tansaction on Electron Devicis) vo
l.32, 1985, p.174), (2) Metal wiring (for example, HP) in which a high melting point metal thin film or a high melting point metal alloy thin film is deposited on the upper surface and the side surface after processing the Al alloy thin film into a thin wire.
W. Hey et al., 1986 International Electron Device Meeting
e Meeting), Technical Digest, p.50) are examples.

It should be noted that these refractory metal thin films and refractory metal alloy thin films are deposited by a sputtering method and chemical vapor depositio
In some cases, it was deposited by the n (hereinafter abbreviated as CVD) method. An example of this is shown below.

Conventional Example 1 FIG. 14 shows a sectional view of a first example of a semiconductor device manufactured by a conventional method, and FIG. 15 shows a sectional view of an example of a process for manufacturing a semiconductor device by the conventional method.

First, the base insulating film 3 is deposited on the surface of the Si wafer 1, and the contact holes 4 are opened at required positions (FIG. 5 (a)). Next, an A1 alloy thin film 5 is deposited as a first metal thin film by a sputtering method. A surface oxide film 6 is formed on the surface of the A1 alloy thin film by taking it out from the sputtering apparatus and exposing it to the atmosphere (FIG. 15 (b)). The A1 alloy thin film 5 has an overhang shape on the side wall of the contact hole 4.

Next, the surface oxide film 6 of the A1 alloy thin film 5 is removed by sputter etching with argon (denoted as Ar in the figure) ions (FIG. 15 (c)). This process is 80 ° to the main surface of the substrate
Since it has no effect on the surface having an angle of about a certain degree or more, the surface oxide film 6 remains on the surface having an angle close to vertical in the contact hole 4 or the surface having an overhang shape.

Subsequently, without exposing the surface of the semiconductor substrate which has been subjected to the above treatment to the atmosphere, CVD is performed in an atmosphere containing WF ₆ and hydrogen to deposit a W thin film 9 on the surface of the Al alloy thin film 5 (FIG. 15 (d)). ). At this time, the Al alloy thin film 5 corresponding to the contact hole 4
Since the surface oxide film 6 remains on the surface, the delay time of W thin film deposition becomes long, and the film thickness of the W thin film 9 becomes thin as compared with other portions. In an extreme case, the W thin film 9 is not deposited on this portion at all.

After that, the metal thin film in which the Al alloy thin film 5 and the W thin film 9 are laminated is processed into a wiring shape to obtain a semiconductor device having the structure of FIG. However, the metal conductor wire of the semiconductor device shown in FIG.
And since the W thin film 9 is thin, it has low reliability.

Conventional Example 2 FIG. 16 shows a sectional view of a second example of a semiconductor device manufactured by a conventional method.

In this example, the W thin film 9 is deposited without any surface treatment of the A1 alloy thin film 5. Therefore, unlike the case of FIG. 15, the thickness of the surface oxide film 6 of the A1 alloy thin film 5 was almost the same in the whole sample, and therefore the delay time in depositing the W thin film 9 was also almost the same. The W thin film 9 was also deposited in the contact hole 4 to a substantially uniform thickness. However, in detail, the surface oxide film thickness has nonuniformity, and due to the influence, the film thickness uniformity of the W thin film 9 is not good. Also, A1 alloy thin film 5
Since the insulating surface oxide film 6 exists at the interface between the W thin film 9 and the W thin film 9, the contact resistance and other electrical characteristics are inferior to those of the semiconductor device manufactured by the method of the present invention.

As the miniaturization of semiconductor devices progresses, it becomes necessary to form metal wiring on a substrate having a steep step such as a contact hole portion or a gate electrode side portion. . However, since the A1 thin film and the A1 alloy thin film deposited by the sputtering method have poor step coverage, the film thickness becomes extremely thin at the step portion, and the cross-sectional area when the wiring is formed becomes extremely small. For this reason, there is a high possibility that disconnection will occur at this portion, or the reliability against electromigration, stress migration, etc. will deteriorate. The use of refractory metals and refractory metal alloys has been proposed to improve this problem.However, if refractory metal thin films or refractory metal alloy thin films were deposited by the sputtering method, the step coverage could not be improved. It is scarce and cannot get a sufficient effect. Therefore, in a miniaturized semiconductor device, it is necessary to improve reliability by using a refractory metal thin film or a refractory metal alloy thin film deposited by a CVD method having excellent step coverage.

However, the CVD method has a problem that it is strongly influenced by the surface condition of the substrate. For example, on the surface of A1 thin film or A1 alloy thin film, the thickness of mainly alumina (represented by the chemical formula of Al ₂ O ₃ ) within a very short time by exposing to the atmosphere after deposition 2
A surface oxide film of about −3 nm grows. When a refractory metal film or refractory metal alloy thin film is deposited on this surface by the CVD method,
For example, there is a problem that deposition does not occur at all after a certain delay time even after the source gas is supplied (hereinafter, this time is referred to as a deposition delay time). Moreover, the surface oxide film thickness is highly non-uniform, and reproducibility between samples is poor. For this reason, there arises a problem that the film thickness uniformity and reproducibility of the deposited high melting point metal thin film or the high melting point metal alloy thin film deteriorates.
Furthermore, since an oxide film having poor electrical conductivity remains at the interface, the electrical characteristics are deteriorated. The surface oxide film also grows on metal thin films other than A1 or A1 alloy, so the same problems as above occur when depositing a high melting point metal thin film or a high melting point metal alloy thin film on it. To do.

Therefore, in order to uniformly and reproducibly deposit the refractory metal or the refractory metal alloy thin film by the CVD method, it is important to perform a treatment for removing the oxide film on the substrate surface.

For this reason, etching with a hydrofluoric acid solution is one of the methods generally used in the past. However, in this method, when the surface after etching is exposed to the atmosphere, a surface oxide film is formed again, so that a remarkable effect cannot be obtained (for example, Kamoshida et al., 1982, Biological Society, 18a-D-9). In addition, the A1 thin film or the A1 alloy thin film may be attacked, resulting in the occurrence of disconnection failure.

Also, the sputter etching method using argon ions,
For example, it has been studied in forming an interlayer contact for connecting two metal wiring layers (Nikkei Microdevice,
June 1988, p.58). However, in this method, the surface oxide film is removed by a physical sputtering action, so that it has almost no effect on a surface having an inclination of about 80 ° or more with respect to the principal surface of the substrate. Therefore, argon sputter etching is not suitable as a surface treatment method when depositing a refractory metal thin film or refractory metal alloy thin film for the purpose of improving reliability. When the surface of the A1 thin film or the A1 alloy thin film is deposited on a substrate having a step by a sputtering method, the surface of the A1 thin film or the A1 alloy thin film has a steeper step than the substrate surface due to the poor step coverage.
This is because an overhang shape is frequently taken, whereas argon sputter etching has no effect on such a portion.

On the other hand, it has been reported that the surface oxide film of A1 or other metals can be removed by active species containing halogen compounds or hydrogen produced by high-frequency discharge, or active species of hydrogen produced by irradiation with ultraviolet light. (For example, (1) Oda et al., 1979 IEICE General Conference, 2-28, (2) Yamamoto et al., 1982 IEICE General Conference, 2-233, (3) Hisashimu, Published Patent Gazette,
63-9953). Since these methods utilize the chemical action of active species, they can be expected to have an effect on the surface of a metal film deposited on a step. However, it has never been proposed to use these methods for the purpose of improving the reliability of metal wiring.

Vapor phase etching using anhydrous hydrofluoric acid has also been proposed as an effective surface treatment method (for example, monthly Semiconducto
r World, March 1988, p.121). This uses only the chemical action, and can be expected to have an effect on the surface of the metal film deposited on the step. Moreover, the surface treated by this method is at least silicon (hereinafter referred to as Si)
On the surface, it has been reported that the regrowth of the surface oxide film is suppressed when exposed to the atmosphere after the treatment. But,
There has been no case where this method was examined as a method for treating a metal surface.

The present inventor has completed various inventions as a result of various devisings in view of the above-mentioned various drawbacks of the conventional semiconductor device manufacturing method.

A method of manufacturing a semiconductor device according to claim 1 or 2, wherein the surface of the first metal thin film made of an A1 thin film or an A1 alloy thin film deposited by sputtering on a substrate having steps is hydrogen, Treated in an atmosphere containing at least one active species of halogens or their compounds, and then depositing a refractory metal thin film or refractory metal alloy thin film by the CVD method without exposing the substrate surface to the atmosphere. Is.

The method for manufacturing a semiconductor device according to claim 3 or 4, wherein the surface of the first metal thin film made of an A1 thin film or an A1 alloy thin film deposited by sputtering on a substrate having a step is in an atmosphere containing anhydrous hydrofluoric acid gas. A high melting point metal thin film or a high melting point metal alloy thin film is deposited by the CVD method.

The method for manufacturing a semiconductor device according to claim 5, wherein after the first metal thin film made of the A1 thin film or the A1 alloy thin film is deposited on the substrate having the step by the sputtering method, the substrate surface is exposed to the atmosphere without being exposed to a high temperature. A melting point metal thin film or a high melting point metal alloy thin film is deposited by a CVD method, and then a metal thin film in which a first metal thin film and a high melting point metal thin film or a high melting point metal alloy thin film are laminated is processed into a wiring shape. is there.

In the method of manufacturing a semiconductor device according to claim 1 or 2,
Since the surface of the first metal thin film composed of the thin film or the A1 alloy thin film is processed in an atmosphere containing at least one active species of hydrogen, halogen or their compounds, a steep slope deposited on the step The surface oxide film is also removed in the portion on the surface of the substrate. Moreover, after that, the high-melting-point metal thin film or high-melting-point metal alloy thin film is deposited by the CVD method without exposing the surface of the substrate to the air, while keeping the surface oxide film absent. A refractory metal thin film or refractory metal alloy thin film having excellent properties can be obtained.

In the method of manufacturing a semiconductor device according to claim 3 or 4,
Since the surface of the first metal thin film composed of the thin film or the A1 alloy thin film is processed in the atmosphere containing the anhydrous hydrofluoric acid, the surface oxide film is formed even on the portion deposited on the step and having the steep slope on the substrate surface. It is also removed, and the re-growth of the surface oxide film when the surface of the substrate is subsequently exposed to the atmosphere is also suppressed.

Therefore, the refractory metal thin film or refractory metal alloy thin film is deposited by the CVD method on the surface where the surface oxide film does not exist, and the refractory metal thin film or refractory metal alloy excellent in uniformity and reproducibility even on steps. A thin film is obtained.

The method of manufacturing a semiconductor device according to claim 5, wherein after depositing the first metal thin film composed of the A1 thin film or the A1 alloy thin film, the high melting point obtained by the CVD method on the surface without the oxide film without exposing the substrate surface to the atmosphere. A metal thin film or a high melting point metal alloy thin film is deposited. Therefore, a high melting point metal thin film or a high melting point metal alloy thin film having excellent uniformity and reproducibility even on a step can be obtained.

EXAMPLES The present invention will be described in more detail with reference to the drawings.

Embodiment 1 FIG. 1 shows a cross-sectional view of a first example of a semiconductor device manufactured by the method according to the claim (1) of the present invention.

Here, an example is shown in which the A1 alloy thin film 5 is used as the first metal thin film and the W thin film is used as the second metal thin film. Like this
By combining the A1 alloy thin film and the W thin film, a metal wiring having high reliability and low resistance can be obtained.
Although various structures required for a semiconductor device are formed in the Si wafer 1, only the diffusion layer 2 is shown in FIG.

FIG. 2 shows a sectional view of an example of a process of manufacturing a semiconductor device by the method of claim 1 of the present invention.

First, the base insulating film 3 is deposited on the surface of the Si wafer 1, and the contact holes 4 are opened at required positions (FIG. 2 (a)). Next, an A1 alloy thin film 5 is deposited as a first metal thin film by a sputtering method. A surface oxide film 6 is formed on the surface of this A1 alloy thin film by taking it out from the sputtering apparatus and exposing it to the atmosphere (FIG. 2 (b)). Further, since the metal thin film deposited by the sputtering method has poor step coverage and the side wall of the contact hole 4 is vertically processed in FIG. 2, when the contact hole is miniaturized and the diameter is about 2 μm or less, As shown in FIG. 6B, the A1 alloy thin film 5 has an overhang shape on the side wall of the contact hole 4.

Next, a treatment is performed in an atmosphere containing active hydrogen gas, and the surface oxide film 6 of the A1 alloy thin film is removed by the reaction of Al ₂ O ₃ + 6H → 2Al + 3H ₂ O ↑ (FIG. 2 (c)). Since this reaction proceeds isotropically,
It is also removed on the surface of the side wall of the contact hole 4 having the overhang shape.

Subsequently, without exposing the surface of the semiconductor substrate that has been subjected to the above treatment to the atmosphere, CVD is performed in an atmosphere containing, for example, tungsten hexafluoride (hereinafter referred to as WF ₆ ) and hydrogen to form a W thin film 9 on the surface of the A1 alloy thin film 5. Deposit (FIG. 2 (d)). At this time, since the surface oxide film 6 does not exist on the surface of the A1 alloy thin film 5, the W thin film 9
Are uniformly and reproducibly deposited and have good electrical characteristics. Finally, the laminated metal thin film of the A1 alloy thin film 5 and the W thin film 9 is processed into the shape of the wiring to obtain the semiconductor device having the structure of FIG.

1 and 2 show the first metal thin film
Although only an example using the A1 alloy thin film is shown, it is also possible to use the A1 thin film, or to use the A1 thin film or the A1 alloy thin film and the metal thin film in which the high melting point metal thin film or the high melting point metal alloy thin film is laminated. It is possible. Further, FIGS. 1 and 2 show only an example in which a W thin film is used as the second metal thin film, but it is also possible to use a thin film of another refractory metal such as molybdenum, tantalum, etc. It is also possible to use a high melting point metal alloy thin film such as silicide or titanium nitride. Further, FIG. 2 shows only an example in which the W thin film is deposited in an atmosphere containing WF ₆ and hydrogen, but the deposition rate and the productivity are improved by performing the deposition in a gas containing WF ₆ and silane. It is possible.

In the process shown in FIG. 2, the treatment of the surface of the A1 alloy thin film 5 and the deposition of the W thin film 9 are carried out by using, for example, an apparatus having a structure as shown in FIG. The semiconductor substrate 32 having the shape shown in FIG. 2B is first mounted on the sample table 31 of the surface treatment tank 22 through the introduction tank 21. In this state, gas such as hydrogen (denoted as H _{2 in the} figure), ammonia (denoted as NH _{3 in the} figure), etc. is supplied from the gas system 29 to the surface treatment tank 22, and ultraviolet rays are emitted using the mercury lamp 26. The surface of the semiconductor substrate 32 is processed in a gas atmosphere containing active hydrogen created by irradiation with light.
Next, the semiconductor substrate 32 is transferred to the W deposition tank 23 through the valve 25 and mounted on the sample table 31. Halogen lamp 27
Is turned on, the semiconductor substrate 32 is heated to about 300 ° C. by infrared light, and exposed to a gas atmosphere containing WF ₆ , hydrogen, silane (indicated as SiH _{4 in the} figure), etc. to deposit a W thin film. Finally, the semiconductor substrate processed into the shape shown in FIG.

Although FIG. 3 shows only an example of an apparatus provided with an independent surface treatment bath and W deposition bath, it is possible to perform the surface treatment and W deposition in the same bath. Further, although FIG. 3 shows only a surface treatment tank for obtaining a gas atmosphere containing active species by irradiating a gas containing hydrogen with ultraviolet light, for example, a halogen gas such as a fluorine gas or a chlorine gas, or a CFC or the like is used. It is also possible to use a gas atmosphere containing an active halogen or an active halogen compound obtained by irradiating a halogen compound gas with ultraviolet light. Further, for example, when a device having a structure as shown in FIG. 4 attached to the surface treatment tank 22 of FIG. 3 is used, a gas atmosphere containing active hydrogen obtained by applying plasma to hydrogen gas is obtained. It is also possible to carry out the processing inside.

Figure 5 compares the deposition delay time observed when W thin film was deposited on A1 alloy thin film, without surface treatment and with surface treatment with hydrofluoric acid solution or active hydrogen. The graph is shown. However, W deposition
The substrate temperature is 28 with CVD using WF ₆ and hydrogen gas.
The temperature was 0 ° C.

It can be seen from FIG. 5 that there is an extremely long deposition delay time of about 10 minutes when the surface treatment is not performed. This is because an oxide film exists on the surface of the A1 alloy thin film.
This delay time has a large non-uniformity within the sample and changes depending on the history. Moreover, since the W thin film used for the purpose of improving the reliability of the metal wiring is as thin as about 100 nm or less, this phenomenon extremely deteriorates the uniformity and reproducibility of the W thin film. This problem is particularly noticeable when the deposition is performed at a high rate using a gas atmosphere containing WF ₆ and silane.

It is also seen from FIG. 5 that when the hydrofluoric acid solution treatment is performed, the deposition delay time may still be 5 minutes or more, although it is shortened as compared with the case where the surface treatment is not performed. . This is because the surface oxide film regrown when exposed to the air after removing the surface layer with a hydrofluoric acid solution exists on the surface of the A1 alloy thin film. Therefore, it is difficult to deposit the W thin film uniformly and reproducibly even if the surface treatment with the hydrofluoric acid solution is performed.

On the other hand, it can be seen from FIG. 5 that when the surface treatment with active hydrogen is performed, the deposition delay time becomes extremely short, which is 2 minutes or less. This result shows that A1 treated with active hydrogen
It shows that there is almost no oxide film on the surface of the alloy thin film. Therefore, the W thin film can be deposited uniformly and with good reproducibility by performing the treatment with active hydrogen.

Although omitted in FIG. 5, when the sputter etching with argon ions is performed as the surface treatment, the deposition delay time is almost the same as when the active hydrogen treatment is performed on the surface close to the main surface of the substrate. Was observed.
However, this method is naturally not effective for a surface having a high angle with respect to the main surface of the substrate. This is because the sputter yield is extremely reduced. In fact, no significant shortening of the deposition delay time was observed on the surface with an angle of about 80 ° or more.

From the above results, the surface treatment using active hydrogen is extremely effective as a method for removing the oxide film on the surface of the metal thin film, and the method according to claim 1 or 2 of the present application provides highly reliable metal wiring. It is obvious that it is extremely effective for manufacturing the semiconductor device provided with the device.

Embodiment 2 FIG. 6 is a sectional view showing a second example of a semiconductor device manufactured by the method of claim 1 of the present invention.

Here, by processing the metal thin film in which the A1 alloy thin film 5 and the W thin film 9-1 are laminated into a wiring shape by the process shown in FIG. 2 and then depositing the W thin film 9-2 again, only the upper surface is formed. An example of manufacturing a semiconductor device having metal wiring whose side surface is covered with a W thin film is shown.

By coating the upper surface and the side surfaces with the high melting point metal thin film or the high melting point metal alloy thin film as described above, the reliability is higher than that of the metal wiring having only the upper surface provided in the semiconductor device shown in FIG. It is possible to obtain highly reliable metal wiring.

Embodiment 3 FIG. 7 is a sectional view showing a third example of a semiconductor device manufactured by the method of claim 1 of the present invention.

Here, an example is shown in which an upper portion of the contact hole 4 is inclined, and a buried W film 10 is further deposited below the contact hole 4 to reduce the step difference on the substrate surface when the A1 alloy thin film 5 is deposited. Therefore, the first
Unlike the case of FIGS. 2, 2 and 6, no overhang is formed on the surface of the A1 alloy thin film 5. However, in this case as well, there is a part that is almost perpendicular to the main surface of the substrate,
For example, by using argon sputter etching as the surface treatment, the W thin film 9 can be uniformly and reproducibly
It is difficult to deposit on the alloy thin film 5. On the other hand, when the surface treatment with active hydrogen or active halogen is performed, the surface oxide film in a portion substantially perpendicular to the main surface of the substrate is also removed, and the W thin film 9 can be deposited uniformly and with good reproducibility. .

Example 4 FIG. 8 is a sectional view showing a fourth example of a semiconductor device manufactured by the method of claim 1 of the present invention.

Here, an example is shown in which the method of the present invention is applied in the step of producing the second-layer metal wiring.

Needless to say, the method of the present invention can be applied to the manufacture of a semiconductor device having three or more metal wiring layers.

Fifth Embodiment FIG. 9 shows a sectional view of an example of a process of manufacturing a semiconductor device by the method of claim 2 of the present invention.

First, the base insulating film 3 is deposited on the surface of the Si wafer 1, and the contact holes 4 are opened at required positions (FIG. 9 (a)). Next, an A1 alloy thin film 5 is deposited as a first metal thin film by a sputtering method and processed into a wiring shape to obtain an A1 alloy thin wire 14. A surface oxide film 6 is formed on the surface of the A1 alloy thin wire 14 (FIG. 9 (b)).

Next, the surface oxide film 6 of the A1 alloy thin wire 14 is removed by performing a treatment in an atmosphere containing active hydrogen gas (FIG. 9 (c)). Since this reaction proceeds isotropically, the surface oxide film 6 is removed not only on the overhang-shaped surface of the side wall of the contact hole 4 but also on the side surface of the A1 alloy thin wire formed vertically.

Subsequently, without exposing the surface of the semiconductor substrate subjected to the above treatment to the atmosphere, CVD is performed in an atmosphere containing WF ₆ and hydrogen to deposit a W thin film 9 on the upper surface and the side surface of the A1 alloy thin wire 14 (FIG. 9). (D)). At this time, since there is no oxide film on the surface of the A1 alloy thin wire 14, the W thin film 9 is uniformly and reproducibly deposited on the upper surface and the side surface, and the electric characteristics are improved.

When depositing a refractory metal thin film or a refractory metal alloy thin film on a vertical side surface in this way, it is extremely difficult to remove the surface oxide film on the side surface by the conventional method. Is particularly effective.

Embodiment 6 FIG. 10 shows a sectional view of an example of a process of manufacturing a semiconductor device by the method of claim 3 of the present invention.

First, the base insulating film 3 is deposited on the surface of the Si wafer 1, and the contact holes 4 are opened at required positions (FIG. 10 (a)). Next, an A1 alloy thin film 5 is deposited as a first metal thin film by a sputtering method. A surface oxide film 6 is formed on the surface of this A1 alloy thin film by taking it out from the sputtering apparatus and exposing it to the atmosphere (FIG. 10 (b)). The A1 alloy thin film 5 has an overhang shape on the side wall of the contact hole 4.

Next, a treatment is performed in an atmosphere containing anhydrous hydrofluoric acid gas to remove the surface oxide film 6 of the A1 alloy thin film 5 by, for example, the reaction of Al ₂ O ₃ + 6HF → 2Al + 3H ₂ O ↑ + 3F ₂ ↑ (see FIG. 10 ( c)). Since this reaction proceeds isotropically,
The surface oxide film 6 is also removed from the overhanging surface of the sidewall of the contact hole 4.

Then, for example, CVD is performed in an atmosphere containing WF ₆ and hydrogen to deposit a W thin film 9 on the surface of the A1 alloy thin film 5 (FIG. 10 (d)).
At this time, since there is no oxide film on the surface of the A1 alloy thin film 5, the W thin film 9 is deposited uniformly and with good reproducibility, and the electrical characteristics are improved. Finally, the laminated metal thin film of the A1 alloy thin film 5 and the W thin film 9 is processed into a wiring shape to obtain a semiconductor device having a structure similar to that shown in FIG.

Since a large amount of fluorine is present on the surface of the A1 alloy thin film treated with the anhydrous hydrofluoric acid gas, reoxidation hardly progresses even if the surface is exposed to the atmosphere after the treatment. Therefore, even if the W thin film 9 is deposited after exposing the surface of the semiconductor substrate to the atmosphere after the treatment, it is possible to deposit the W thin film 9 uniformly and with good reproducibility. Further, if the W thin film 9 is deposited without being exposed to the atmosphere after the treatment, it is possible to further improve the uniformity and reproducibility.

Of the steps shown in FIG. 10, the step of treating the surface of the A1 alloy thin film 5 is carried out by using, for example, an apparatus having a structure as shown in FIG.
The semiconductor substrate 32 having the shape shown in FIG. 10B is mounted on the sample table 31. In this state, gases of anhydrous hydrofluoric acid (denoted by HF in the figure) and water vapor (denoted by H ₂ O in the figure) are supplied from the gas system 29, and the surface treatment of the semiconductor substrate 31 is performed.

Embodiment 7 FIG. 12 shows a sectional view of an example of a process of manufacturing a semiconductor device by the method of claim 4 of the present invention.

First, the base insulating film 3 is deposited on the surface of the Si wafer 1, and the contact holes 4 are opened at required positions (FIG. 12 (a)). Next, an A1 alloy thin film 5 is deposited as a first metal thin film by a sputtering method and processed into a wiring shape to obtain an A1 alloy thin wire 14. A surface oxide film 6 is formed on the surface of the A1 alloy thin wire 14 (FIG. 12 (b)).

Then, the surface oxide film 6 of the A1 alloy thin wire 14 is removed by performing a treatment in an atmosphere containing anhydrous hydrofluoric acid gas (FIG. 12 (c)).
Since this reaction proceeds isotropically, the surface oxide film 6 is removed not only on the overhanging surface of the side wall of the contact hole 4 but also on the side surface of the A1 alloy thin wire 14 formed vertically.

Then, for example, CVD is performed in an atmosphere containing WF ₆ and hydrogen to deposit a W thin film 9 on the surface of the A1 alloy thin film 5 (FIG. 12 (d)).
At this time, since there is no oxide film on the surface of the A1 alloy thin film 5, the W thin film 9 is deposited uniformly and with good reproducibility, and further the electric characteristics are improved.

When the refractory metal thin film or refractory metal alloy thin film is deposited on the vertical side surface as described above, it is extremely difficult to remove the surface oxide film on the side surface by the conventional method. Is particularly effective.

Embodiment 8 FIG. 13 is a sectional view showing an example of steps of manufacturing a semiconductor device by the method of claim 5 of the present invention.

First, the base insulating film 3 is deposited on the surface of the Si wafer 1, and the contact holes 4 are opened at required positions (FIG. 13 (a)). Next, an A1 alloy thin film 5 is deposited as a first metal thin film by a sputtering method. Then, for example, CVD is performed in an atmosphere containing WF ₆ and hydrogen to deposit a W thin film 9 on the surface of the A1 alloy thin film 5 (FIG. 13 (c)). At this time, since there is no oxide film on the surface of the A1 alloy thin film 5, the W thin film 9 is deposited uniformly and with good reproducibility, and the electrical characteristics are improved. Finally, the laminated metal thin film of the A1 alloy thin film 5 and the W thin film 9 is processed into a wiring shape to obtain the semiconductor device of FIG. 13 (d).

The deposition of the A1 alloy thin film 5 and the deposition of the W thin film 9 in the process of FIG. 3 can be performed by using, for example, an apparatus in which a sputter deposition tank and a CVD deposition tank are connected through a transfer tank.

EFFECTS OF THE INVENTION The method for manufacturing a semiconductor device of the present invention is configured as described above, and the surface of the first metal thin film deposited by the sputtering method is used regardless of which method is used. A second metal thin film made of a refractory metal or a refractory metal alloy can be uniformly and reproducibly deposited thereon, and reliability of metal wiring becomes serious as semiconductor devices are miniaturized. It is extremely effective in solving the problem of deterioration. Moreover, the method is easy,
It does not significantly reduce productivity.

Therefore, the semiconductor device manufacturing method of the present invention is extremely valuable industrially.

[Brief description of drawings]

1 is a sectional view of a semiconductor device manufactured by the method for manufacturing a semiconductor device according to claim 1, FIG. 2 is a sectional configuration diagram of a semiconductor device manufacturing process by the method, and FIG. 3 is a sectional view of the semiconductor device in the same process. Schematic diagram of the equipment used for manufacturing, Fig. 4 is a schematic diagram of the equipment for carrying out the surface treatment process, and Fig. 5 is observed when the W thin film was deposited on the A1 alloy thin film. FIG. 6 is a characteristic view showing the relationship between the deposited delay time and the surface treatment method, FIG. 6 is a sectional view of a second example of a semiconductor device manufactured by the method of the present invention, and FIG. 7 is manufactured by the method of the present invention. A sectional view of a third example of a semiconductor device, FIG. 8 is a sectional view of a fourth example of a semiconductor device manufactured by the method of the present invention, and FIG. 9 is a manufacturing process by the method of manufacturing a semiconductor device according to claim 2. A sectional view and FIG. 10 show a method for manufacturing a semiconductor device according to claim 3. Manufacturing process sectional view, FIG. 11 is a conceptual diagram of the structure of an apparatus for performing a surface treatment with anhydrous hydrofluoric acid gas, FIG. 12 is a manufacturing process sectional view according to the method for manufacturing a semiconductor device of claim 4, and FIG. FIG. 14 is a sectional view of a semiconductor device manufactured by the conventional method, FIG. 14 is a sectional view of a semiconductor device manufactured by the conventional method, and FIG. 15 is a semiconductor device manufactured by the conventional method. Process cross section,
FIG. 16 shows the second semiconductor device manufactured by the conventional method.
It is sectional drawing of the example of. 1 ... Si wafer, 2 ... Diffusion layer, 3 ... Base insulating film, 4 ... Contact hole, 5 ... A1 alloy thin film, 9 ... W thin film.

 ─────────────────────────────────────────────────── --- Continuation of the front page (72) Inventor Tsutomu Fujita 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-62-264644 (JP, A) JP-A-55-6844 (JP, A)

Claims (5)

[Claims] 1. A step of depositing a first metal thin film on a substrate having a step, and the surface of the first metal thin film in an atmosphere containing at least one active species of hydrogen, halogen or a compound thereof. Including a step of treating and a step of depositing a second metal thin film on the first metal thin film, and
The metal thin film is an aluminum thin film or an aluminum alloy thin film deposited by a sputtering method, or a laminated thin film including them, and the second metal thin film is a chemical thin film.
It is a refractory metal thin film or a refractory metal alloy thin film deposited using the vapor deposition method, and does not include a step of exposing the substrate surface to the atmosphere between the processing step and the second metal thin film deposition step. A method for manufacturing a characteristic semiconductor device. 2. The method for manufacturing a semiconductor device according to claim 1, wherein a processing step is performed in an atmosphere containing active species after processing the first metal thin film into a wiring shape. 3. A step of depositing a first metal thin film on a substrate having a step, a step of treating the surface of the first metal thin film in an atmosphere containing anhydrous hydrofluoric acid gas, and the first metal thin film. Depositing a second metal thin film thereon, and the first
Is a thin aluminum film or aluminum alloy thin film deposited by a sputtering method, or is a laminated thin film including them, and the second thin metal film is a CVD (che
A method of manufacturing a semiconductor device, which is a refractory metal thin film or a refractory metal alloy thin film deposited by using a mical vapor deposition method. 4. The method for manufacturing a semiconductor device according to claim 3, wherein a processing step with anhydrous hydrofluoric acid gas is carried out after processing the first metal thin film into a wiring shape. 5. A step of depositing a first metal thin film on a substrate having steps, a step of depositing a second metal thin film on the first metal thin film, and the first and second metal thin films. And a step of processing the laminated metal thin film into a wiring shape,
And whether the first metal thin film is an aluminum thin film or an aluminum alloy thin film deposited by a sputtering method,
Alternatively, the second metal thin film is a laminated thin film containing them.
A refractory metal thin film or refractory metal alloy thin film deposited by using a CVD ((chemical vapor deposition) method,
Further, a method of manufacturing a semiconductor device is characterized in that the step of exposing the substrate surface to the atmosphere is not included between the first metal thin film deposition step and the second metal thin film deposition step.