JPH08107145A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE: To provide a method of manufacturing a semiconductor device, wherein an upper Al wiring and a lower Al wiring can be electrically connected together, the lower wiring is restrained from becoming complicated in structure, and a Ti film is prevented from being separated off from an interlayer insulating film when a W film is formed through a selective CVD method. CONSTITUTION: A Ti film 2 is formed on a lower Al wiring, an interlayer insulating film 3 is formed thereon, and a contact hole 5 is provided to the interlayer insulating film 3 by etching, when the Ti film 2 is exposed at the bottom of the contact hole 5. Then, a TiN film is formed on all the surface through a sputtering method, and then a W film is formed inside the contact hole 5 through a selective CVD method. Next, a structure that the contact hole 5 is fully filled with W is formed by an etching-back operation. Thereafter, an upper Al wiring is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device, and is particularly suitable for being applied to the manufacture of a semiconductor device having a multilayer wiring structure.

[0002]

2. Description of the Related Art In a semiconductor device having a multilayer wiring structure, when an upper Al-based wiring is brought into contact with a lower aluminum (Al) -based wiring, the upper Al-based wiring is connected to a lower Al-based wiring through a barrier metal film. It is common to contact the wiring. On the other hand, the inside of the contact hole is filled with tungsten (W) formed by the selective chemical vapor deposition (CVD) method (selective CVD method), and the Al-based wiring of the upper layer is contacted with the Al-based wiring of the lower layer through this W. There is a way to do it.

However, according to the knowledge of the present inventor,
When this W embedding technique is applied to the manufacture of a semiconductor device in which the upper Al-based wiring is brought into contact with the lower Al-based wiring through the barrier metal film, when the W is formed by the selective CVD method, the barrier metal film is used as an underlying interlayer. There is a problem that it peels off from the insulating film.

According to the knowledge of the present inventor, the problem of peeling of the barrier metal film is that the barrier metal film is formed of titanium nitride (Ti).
N) The problem can be solved by using a single film layer. However, when the underlying Al-based wiring is exposed at the bottom of the contact hole, the surface of the Al-based wiring is nitrided by N ₂ plasma when the TiN film is formed by the sputtering method to form Al nitride. By doing
A new problem arises in that electrical connection cannot be established between the upper Al-based wiring and the lower Al-based wiring.

Therefore, the lower wiring has a laminated structure in which a Ti film having a thickness of about 30 nm and a TiN film having a thickness of about 100 nm are sequentially laminated on an Al-based wiring, and the TiN film is exposed at the bottom of the contact hole. It is possible to do so. However, in this case, there is a problem that the structure of the wiring in the lower layer becomes complicated.

Further, the lower wiring has a conventional structure in which an antireflection film is laminated on an Al-based wiring, and a TiN film is formed by a sputtering method when the Al-based wiring is exposed at the bottom of the contact hole. By forming a thin Ti film by sputtering in advance, electrical conduction can be established between the upper Al-based wiring and the lower Al-based wiring, and an interlayer can be formed when W is formed by the selective CVD method. It has been obtained that the peeling of the barrier metal film on the insulating film can be effectively prevented. This is T
By forming the Ti film thinly before forming the iN film, there is an effect that formation of Al nitride on the underlying Al-based wiring is suppressed when the TiN film is formed by the sputtering method, and the Ti film is formed. Since the thickness is thin, W by the selective CVD method
It is considered that peeling from the interlayer insulating film does not occur during formation of. However, in this process, it is not clear how much the margin of the film thickness of the Ti film with respect to the peeling or the electrical characteristics is, and the Ti film having a large thickness is peeled due to the variation in the film thickness of the Ti film. However, it is difficult to apply it to the actual manufacturing of a semiconductor device.

[0007]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to contact an upper aluminum-based wiring with a lower aluminum-based wiring through a titanium nitride film formed by a sputtering method, and When using the process of embedding with tungsten, it is possible to establish electrical continuity between the upper layer aluminum wiring and the lower layer aluminum wiring, without complicating the structure of the lower layer wiring, and selecting tungsten. It is an object of the present invention to provide a method for manufacturing a semiconductor device which does not have a problem of peeling of a titanium film from an interlayer insulating film when it is formed by a vapor phase growth method.

[0008]

In order to achieve the above object, a method of manufacturing a semiconductor device according to a first invention of the present invention is a method of manufacturing a semiconductor device comprising aluminum or an aluminum alloy.
Forming the titanium film (2) on the wiring (1), forming the interlayer insulating film (3) covering the titanium film (2) and the first wiring (1), and the interlayer insulating film (3). ) By selectively removing a predetermined portion of the contact hole (5)
And exposing the titanium film (2) at the bottom of the contact hole (5), and a titanium nitride film (at least on the titanium film (2) at the bottom of the contact hole (5). 6), a step of burying tungsten (7) in the contact hole (5), and an aluminum or aluminum alloy connected to the tungsten (7) buried in the contact hole (5). And a step of forming a second wiring (8) on the interlayer insulating film (3).

In a typical embodiment of the method for manufacturing a semiconductor device according to the first aspect of the present invention, a titanium nitride film (6) is formed by a sputtering method and tungsten (7) is formed by a selective chemical vapor deposition method. To form.

A method of manufacturing a semiconductor device according to a second aspect of the present invention comprises a step of forming an antireflection film (9) on a first wiring (1) made of aluminum or an aluminum alloy, and an antireflection film (9). ) And an interlayer insulating film (3) for covering the first wiring (1), and by selectively removing a predetermined portion of the interlayer insulating film (3) and the antireflection film (9), a contact hole (3) is formed. 5) and exposing the first wiring (1) at the bottom of the contact hole (5), and on the first wiring (1) at the bottom of the contact hole (5). Forming a titanium film (2) on the titanium film, and forming a titanium nitride film (6) on the titanium film (2) formed on the first wiring (1) at least at the bottom of the contact hole (5). And the contact hole ( ) Is filled with tungsten (7), and a second wiring (8) made of aluminum or an aluminum alloy connected to the tungsten (7) embedded in the contact hole (5) is formed on the interlayer insulating film ( 3) It has a process of forming above.

In one embodiment of the method for manufacturing a semiconductor device according to the second aspect of the present invention, titanium is ion-implanted into the first wiring (1) through the contact hole (5) after forming the contact hole (5). By doing so, a titanium film (2) is formed.

In another embodiment of the method for manufacturing a semiconductor device according to the second aspect of the present invention, the titanium film (2) is formed by a lift-off method.

In a typical embodiment of the method for manufacturing a semiconductor device according to the second aspect of the present invention, a titanium nitride film (6) is formed by a sputtering method and tungsten (7) is formed by a selective chemical vapor deposition method. Form.

[0014]

According to the method of manufacturing a semiconductor device according to the first aspect of the present invention having the above-described structure, the titanium film is exposed at the bottom of the contact hole when the titanium nitride film is formed. When the titanium nitride film is formed by the sputtering method, it is possible to effectively prevent the surface of the lower aluminum-based wiring from being nitrided to form aluminum nitride, which allows the upper aluminum-based wiring and the lower aluminum to be formed. Electrical connection with the system wiring can be established. Moreover, in comparison with the case of the conventional structure in which the titanium film and the titanium nitride film are sequentially laminated on the lower layer aluminum-based wiring, the case of the first invention of the structure in which the titanium film is laminated on the lower layer aluminum-based wiring Since the wiring contact portion has a lower resistance, better electrical conduction can be achieved. The lower wiring has a structure in which a titanium film is laminated on an aluminum wiring, which is simple. Further, since the titanium film is not formed on the interlayer insulating film, there is no problem that the titanium film is separated from the interlayer insulating film when tungsten is formed by the selective vapor deposition method.

According to the method of manufacturing a semiconductor device of the second aspect of the present invention configured as described above, since the titanium film is exposed at the bottom of the contact hole when the titanium nitride film is formed, When the titanium nitride film is formed by the sputtering method, it is possible to effectively prevent the surface of the lower aluminum-based wiring from being nitrided to form aluminum nitride, which allows the upper aluminum-based wiring and the lower aluminum to be formed. Electrical connection with the system wiring can be established. Moreover, in the case of the second invention of the structure in which the antireflection film is laminated on the lower aluminum-based wiring, as compared with the conventional structure in which the titanium film and the titanium nitride film are sequentially laminated on the lower-layer aluminum-based wiring. In this case, the resistance of the wiring contact portion is lower, so that better electrical conduction can be achieved. Also, the lower wiring has a structure in which an antireflection film is laminated on an aluminum wiring,
It's simple. Further, since the titanium film is not formed on the interlayer insulating film, there is no problem that the titanium film is separated from the interlayer insulating film when tungsten is formed by the selective vapor deposition method.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. In all the drawings of the embodiments, the same or corresponding parts are designated by the same reference numerals.

1 to 5 show a method of manufacturing a semiconductor device according to the first embodiment of the present invention. In the method of manufacturing a semiconductor device according to the first embodiment, as shown in FIG. 1, first, on a lower layer Al-Si wiring 1 formed on a semiconductor substrate such as a silicon (Si) substrate (not shown). Then, the Ti film 2 is formed by, for example, the sputtering method. The thickness of the Ti film 2 is preferably relatively large, for example, 1
It is set to about 00 nm. This Ti film 2 has a T
When the iN film 6 is formed by the sputtering method, Al-
In addition to being used to prevent the surface of the Si wiring 1 from being nitrided, it is also used as an antireflection film.

Next, as shown in FIG. 2, an interlayer insulating film 3 such as a phosphosilicate glass (PSG) film or a silicon dioxide (SiO ₂ ) film is formed on the entire surface by, for example, the CVD method.
To form.

Next, as shown in FIG. 3, after a resist pattern 4 having a predetermined shape is formed on the interlayer insulating film 3 by a lithography method, the resist pattern 4 is used as a mask by, for example, a reactive ion etching (RIE) method. Etching is performed in the direction perpendicular to the substrate surface. This etching is stopped in the middle of the thickness direction of the Ti film 2. As a result, the contact hole 5 is formed in the interlayer insulating film 3 and the Ti film 2 is exposed at the bottom of the contact hole 5.

Next, after removing the resist pattern 4,
As shown in FIG. 4, Ti is deposited on the entire surface by the sputtering method.
The N film 6 is formed. TiN by this sputtering method
When the film 6 is formed, Ti is formed on the bottom of the contact hole 5.
Since the film 2 is exposed and the Al—Si wiring 1 is not exposed, it is possible to prevent the surface of the Al—Si wiring 1 from being nitrided by N ₂ plasma.

Next, W is selectively formed inside the contact hole 5 by the selective CVD method, and then etched back in the direction perpendicular to the substrate surface by, for example, the RIE method. Thereby, as shown in FIG. 5, a structure in which the inside of the contact hole 5 is filled with the W film 7 is formed.

After that, an upper Al-Si wiring 8 is formed on the interlayer insulating film 3 so as to be connected to the W film 7, and a passivation film (not shown) is formed. Complete the semiconductor device.

As described above, according to this first embodiment,
Since the Ti film 2 is exposed at the bottom of the contact hole 5 when the TiN film 6 is formed by the sputtering method, the surface of the lower Al—Si wiring 1 is nitrided when the TiN film 6 is formed. It is possible to effectively prevent the formation of Al nitride, and thereby to prevent Al-S in the upper layer.
Electrical connection can be established between the i-wiring 8 and the underlying Al-Si wiring 1. Moreover, T is formed on the lower Al-based wiring.
Compared with the case of the conventional structure in which the i film and the TiN film are sequentially stacked, the resistance of the wiring contact portion is higher in the case of the structure in which the Ti film 2 is stacked on the lower Al—Si wiring 1 Is low, electrical conduction can be better achieved. In addition, the lower wiring is T-shaped on the Al-Si wiring 1.
It has a simple structure in which i films 2 are laminated. Furthermore, Ti film 2
Is not formed on the interlayer insulating film 3, there is no problem that the Ti film 2 is separated from the interlayer insulating film 3 when the W film 7 is formed by the selective CVD method.

6 to 11 show a method of manufacturing a semiconductor device according to the second embodiment of the present invention. In the method of manufacturing the semiconductor device according to the second embodiment, as shown in FIG.
First, a TiON film 9 as an antireflection film is formed on the lower Al-Si wiring 1 formed on a semiconductor substrate such as a Si substrate (not shown) by, for example, a sputtering method. The thickness of the TiON film 9 is preferably relatively small and is set to, for example, about 30 nm.

Next, as shown in FIG. 7, an interlayer insulating film 3 such as a PSG film or a SiO ₂ film is formed on the entire surface by, eg, CVD method.

Next, as shown in FIG. 8, a resist pattern 4 having a predetermined shape is formed on the interlayer insulating film 3 by a lithography method, and then the resist pattern 4 is used as a mask to be perpendicular to the substrate surface by, for example, RIE method. Etching in the direction. This etching is performed on the lower layer of Al--Si.
Repeat until reaching wiring 1. As a result, the interlayer insulating film 3
A contact hole 5 is formed in the contact hole 5, and the underlying Al-Si wiring 1 is exposed at the bottom of the contact hole 5.

Next, after removing the resist pattern 4,
As shown in FIG. 9, Ti is ion-implanted on the entire surface. In this case, the film thickness of the interlayer insulating film 3 is selected to be sufficiently large, and this interlayer insulating film 3 serves as a mask for Ti ion implantation. As a result, Ti is ion-implanted into the surface of the underlying Al-Si wiring 1 through the contact hole 5, but stops in the interlayer insulating film 3 at the other portions. In this way, as shown in FIG.
A Ti film 2 is formed by ion-implanted Ti on the surface of the lower Al-Si wiring 1 at the bottom of the. here,
The Ti ion-implanted into the interlayer insulating film 3 is distributed over a wider range in the depth direction than the Ti ion-implanted into the Al-Si wiring 1. Therefore, no Ti film is formed on the surface of the interlayer insulating film 3. . After that, the TiN film 6 is formed on the entire surface by the sputtering method. The Ti ion implantation may be performed before the resist pattern 4 is removed.

Next, similarly to the first embodiment, the selected CV
After W is selectively formed in the contact hole 5 by the D method, etchback is performed in the direction perpendicular to the substrate surface by, for example, the RIE method, and as shown in FIG. 7 to form a buried structure.

After that, an upper Al-Si wiring 8 is formed on the interlayer insulating film 3 so as to be connected to the W film 7, and a passivation film (not shown) is formed. Complete the semiconductor device.

As described above, according to the second embodiment,
Since the Ti film 2 is exposed at the bottom of the contact hole 5 when the TiN film 6 is formed by the sputtering method, the surface of the lower Al—Si wiring 1 is nitrided when the TiN film 6 is formed. It is possible to effectively prevent the formation of Al nitride, and thereby to prevent Al-S in the upper layer.
Electrical connection can be established between the i-wiring 8 and the underlying Al-Si wiring 1. Moreover, T is formed on the lower Al-based wiring.
Compared with the case of the conventional structure in which the i film and the TiN film are sequentially stacked, the structure of the second embodiment having the structure in which the TiON film 9 as the antireflection film is stacked on the Al-Si wiring 1 of the lower layer is more preferable. The resistance of the wiring contact portion is low, and electrical conduction can be better achieved. Also, the lower wiring is Al-
This is a simple structure in which a TiON film 9 is laminated on the Si wiring 1. Further, since the Ti film 2 is not formed on the interlayer insulating film 3, when the W film 7 is formed by the selective CVD method, Ti film 2 is formed.
There is no problem that the film 2 is separated from the interlayer insulating film 3.

If the Ti ion implantation for forming the Ti film 2 is performed before removing the resist pattern 4,
Since Ti can be almost stopped in the resist pattern 4 without reaching the interlayer insulating film 3, the Ti is also removed when the resist pattern 4 is removed. Therefore, almost no Ti can remain in the interlayer insulating film 3, and the problem of peeling of the Ti film 2 when the W film 7 is formed by the selective CVD method can be almost completely eliminated.

12 to 14 show a method of manufacturing a semiconductor device according to the third embodiment of the present invention. In the method of manufacturing the semiconductor device according to the third embodiment, first, as in the method of manufacturing the semiconductor device according to the second embodiment, as shown in FIG.

Next, with the resist pattern 4 used for forming the contact hole 5 left, a Ti film 2 is formed on the entire surface by a sputtering method as shown in FIG.

Next, the resist pattern 4 is removed together with the Ti film 2 formed thereon by the lift-off method,
As shown in FIG. 13, the Ti film 2 is left only inside the contact hole 5. After that, Ti is sputtered.
The N film 6 is formed on the entire surface.

Next, similarly to the first embodiment, the selected CV
After selectively forming W in the contact hole 5 by the D method, etching back is performed in the direction perpendicular to the substrate surface by, for example, the RIE method, and the W film is formed inside the contact hole 5 as shown in FIG. 7 to form a buried structure.

After that, an upper Al-Si wiring 8 is formed on the interlayer insulating film 3 so as to be connected to the W film 7, and a passivation film (not shown) is further formed. A target semiconductor device is completed.

As described above, according to the third embodiment,
Since the Ti film 2 is exposed at the bottom of the contact hole 5 when the TiN film 6 is formed by the sputtering method, the surface of the lower Al—Si wiring 1 is nitrided when the TiN film 6 is formed. It is possible to effectively prevent the formation of Al nitride, and thereby to prevent Al-S in the upper layer.
Electrical connection can be established between the i-wiring 8 and the underlying Al-Si wiring 1. Moreover, T is formed on the lower Al-based wiring.
Compared to the case of the conventional structure in which the i film and the TiN film are sequentially stacked, the structure of the third embodiment having the structure in which the TiON film 9 which is the antireflection film is stacked on the lower Al—Si wiring 1 is more preferable. The resistance of the wiring contact portion is low, and electrical conduction can be better achieved. Also, the lower wiring is Al-
This is a simple structure in which a TiON film 9 is laminated on the Si wiring 1. Further, since the Ti film 2 is not formed on the interlayer insulating film 3 when the W film 7 is formed by the selective CVD method, the Ti film 2 is not formed on the interlayer insulating film 3 when the W film 7 is formed.
There is no problem of peeling from. Further, since the Ti film 2 can be formed thicker by the sputtering method, as compared with the case of the second embodiment in which the Ti film 2 is formed by the ion implantation of Ti, the upper Al—Si wiring 8 and the lower Al are formed. -Si
It is possible to achieve better electrical continuity with the wiring 1.

The embodiments of the present invention have been specifically described above, but the present invention is not limited to the above-mentioned embodiments, and various modifications can be made based on the technical idea of the present invention.

For example, in the above-described second and third embodiments, the TiON film 9 is used as the antireflection film, but another type of film such as a TiN film is used as the antireflection film. May be.

Further, in the above-mentioned first embodiment, second embodiment and third embodiment, the case where the present invention is applied to the manufacture of the semiconductor device using the Al--Si wirings 1 and 8 has been described. This invention is applicable to Al wiring and Al-Si-Cu.
It can be applied to the manufacture of semiconductor devices using various Al-based wiring such as wiring.

[0041]

As described above, according to the present invention, the upper aluminum-based wiring is brought into contact with the lower aluminum-based wiring through the titanium nitride film formed by the sputtering method, and the inside of the contact hole is closed. When using the process of embedding with tungsten, it is possible to establish electrical continuity between the upper layer aluminum wiring and the lower layer aluminum wiring, without complicating the structure of the lower layer wiring, and selecting tungsten. There is no problem of peeling of the titanium film from the interlayer insulating film when the film is formed by the vapor phase growth method.

[Brief description of drawings]

FIG. 1 is a sectional view for illustrating a method for manufacturing a semiconductor device according to a first embodiment of the present invention.

FIG. 2 is a cross sectional view for illustrating the method for manufacturing the semiconductor device according to the first embodiment of the present invention.

FIG. 3 is a sectional view for illustrating the method for manufacturing a semiconductor device according to the first embodiment of the present invention.

FIG. 4 is a sectional view for illustrating the method for manufacturing the semiconductor device according to the first embodiment of the present invention.

FIG. 5 is a sectional view for illustrating the method for manufacturing the semiconductor device according to the first embodiment of the present invention.

FIG. 6 is a cross sectional view for illustrating the method for manufacturing the semiconductor device according to the second embodiment of the present invention.

FIG. 7 is a cross sectional view for illustrating the method for manufacturing the semiconductor device according to the second embodiment of the present invention.

FIG. 8 is a cross sectional view for illustrating the method for manufacturing the semiconductor device according to the second embodiment of the present invention.

FIG. 9 is a cross sectional view for illustrating the method for manufacturing the semiconductor device according to the second embodiment of the present invention.

FIG. 10 is a cross sectional view for illustrating the method for manufacturing the semiconductor device according to the second embodiment of the present invention.

FIG. 11 is a cross sectional view for illustrating the method for manufacturing the semiconductor device according to the second embodiment of the present invention.

FIG. 12 is a cross sectional view for illustrating the method for manufacturing the semiconductor device according to the third embodiment of the present invention.

FIG. 13 is a cross sectional view for illustrating the method for manufacturing the semiconductor device according to the third embodiment of the present invention.

FIG. 14 is a cross sectional view for illustrating the method for manufacturing the semiconductor device according to the third embodiment of the present invention.

[Explanation of symbols]

 1, 8 Al-Si wiring 2 Ti film 3 Interlayer insulating film 4 Resist pattern 5 Contact hole 6 TiN film 7 W film 9 TiON film

Claims (8)

[Claims] 1. A step of forming a titanium film on a first wiring made of aluminum or an aluminum alloy; a step of forming an interlayer insulating film covering the titanium film and the first wiring; Forming a contact hole by selectively removing a predetermined portion and exposing the titanium film at the bottom of the contact hole at that time; and at least on the titanium film at the bottom of the contact hole. A step of forming a titanium nitride film, a step of burying tungsten inside the contact hole, a second wiring made of aluminum or an aluminum alloy connected to the tungsten buried inside the contact hole, and the interlayer insulation A method of manufacturing a semiconductor device, the method comprising: forming on a film. . 2. The method for manufacturing a semiconductor device according to claim 1, wherein the titanium nitride film is formed by a sputtering method. 3. The method of manufacturing a semiconductor device according to claim 1, wherein the tungsten is formed by a selective chemical vapor deposition method. 4. A step of forming an antireflection film on a first wiring made of aluminum or an aluminum alloy, a step of forming an interlayer insulating film covering the antireflection film and the first wiring, and the interlayer insulation. Forming a contact hole by selectively removing a predetermined portion of the film and the antireflection film, and exposing the first wiring to the bottom of the contact hole at that time; and the contact hole. Forming a titanium film on the first wiring at the bottom of the contact hole, forming a titanium nitride film on the titanium film formed on the first wiring at least at the bottom of the contact hole, A step of burying tungsten inside the contact hole, and a step of connecting the tungsten embedded inside the contact hole. And a second step of forming a second wiring made of aluminum or an aluminum alloy on the interlayer insulating film. 5. The semiconductor device according to claim 4, wherein the titanium film is formed by ion-implanting titanium into the first wiring through the contact hole after forming the contact hole. Manufacturing method. 6. The method of manufacturing a semiconductor device according to claim 4, wherein the titanium film is formed by a lift-off method. 7. The method of manufacturing a semiconductor device according to claim 4, wherein the titanium nitride film is formed by a sputtering method. 8. The method of manufacturing a semiconductor device according to claim 4, wherein the tungsten is formed by a selective chemical vapor deposition method.