JPH05129297A - Semiconductor device and manufacturing method thereof - Google Patents

Abstract

PURPOSE:To suppress a generation of hillocks or voids in an upper part and a side wall part of an Al based material of a wire. CONSTITUTION:After an Al based material (Al-1%, Si-0.5%, Cu film) 13 and a first high melting point metallic film (TiN film) 14 are successively deposited on an interlayer insulating film 12, these films are patterned into a wiring pattern by photolithography and etching. Further, after a second high melting point metallic film (TiN film) 16 is deposited by a CVD method, the second high melting point metallic film 16 among the respective wires is performed etchback until the interlayer insulating film 12 is disclosed. Thus, a wiring is formed of which a central part is formed with the Al based material and of which an upper part and a side wall part are coated with the high melting point metallic film. As the wiring is suppressed in a migration in the upper and side wall parts of the Al based material, it can be prevented to generate hillocks and voids in the high and side wall parts.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device and a method of manufacturing the same, and particularly to a highly reliable wiring having good electromigration resistance and stress migration resistance (hereinafter, both migrations will be simply referred to as migration). And a manufacturing method thereof.

[0002]

2. Description of the Related Art Conventionally, as a wiring structure in a semiconductor device, there are structures shown in FIGS. 7 (a) and 7 (b). That is, FIG. 7A shows a structure in which wiring is formed only on the Al-based material such as the Al-1% Si film 3 on the surface of the interlayer insulating film 2 on the semiconductor substrate 1. Further, FIG. 7B shows that Al-1% Si is formed on the surface of the interlayer insulating film 2 on the semiconductor substrate 1 via the barrier metal 4 made of a refractory metal material such as a TiN film.
This is a laminated structure in which wiring is formed of an Al-based material such as -0.5% Cu film 5.

Further, FIG. 7 (c) shows an inverse laminated structure whose application is being considered because the wiring width at the 16M dynamic random access memory (DRAM) level is as thin as 0.5 μm to 0.6 μm. .. This reverse laminated structure has Al-1% Si-0.5% C on the surface of the interlayer insulating film 2 on the semiconductor substrate 1.
After forming the wiring with Al-based material such as u film 5, TiW
This is a structure in which refractory metal films 6 such as films are laminated.

[0004]

However, the wiring structure in the conventional semiconductor device has the following problems. That is, in the structure shown in FIG. 7 (a), when the wiring width is 1.2 μm or less, the life of the wiring until hillocks and voids are generated due to the migration of Al and the disconnection is significantly reduced, and the reliability of the wiring is reduced. There is a problem that sex deteriorates.

Further, in the laminated structure shown in FIG. 7B, alloy pits due to a reaction at the interface between the Al-based material and the semiconductor substrate 1 at the contact portion connecting the wiring made of the Al-based material and the semiconductor substrate 1 are formed. To prevent this, a barrier metal 4 such as a TiN film is formed under the Al-based material. Therefore, the grain size of the Al-based material is affected by the grain size of the underlying TiN and becomes small. Therefore, the above A
If the l-based material is formed of the Al-1% Si material as shown in FIG. 7 (a), the migration resistance is not improved so much.
Therefore, in the laminated structure in FIG. 7B, the Al-based material is Al-1% Si-0.5% Cu to improve the migration resistance. However, this method is also effective in the wiring width up to 0.8 μm, and there is a problem that the life until the disconnection is remarkably shortened with the wiring width less than 0.8 μm.

Further, in the reverse laminated structure shown in FIG. 7 (c), the refractory metal film 6 on the Al-based material suppresses migration, so that generation of voids leading to wiring breakage is suppressed to some extent. .. However, since migration at the upper portion of the wiring is suppressed, hillocks grow on the side wall of the wiring. Therefore, in the case of a wiring having a line width of 0.6 μm or less, the life until disconnection is significantly reduced due to the voids generated by the migration in the side wall portion of the wiring, and the wiring is owing to the hillock generated from the side wall. There is a problem that the space becomes narrow and a short circuit occurs between the wirings.

Therefore, an object of the present invention is to provide a semiconductor device having a highly reliable wiring in which hillocks and voids do not occur due to migration in the upper portion and side wall of the Al-based material forming the wiring, and a manufacturing method thereof. It is in.

[0008]

In order to achieve the above object, the semiconductor device of the first invention is a semiconductor device having a wiring on a semiconductor layer, wherein the wiring is at least an Al-based material and this Al-based material. It is characterized by being formed of a refractory metal film covering the upper part and the side wall part.

The semiconductor device of the second invention is characterized in that, in the semiconductor device of the first invention, the surface of the refractory metal film forming the wiring is covered with a refractory metal oxide film. ..

A method of manufacturing a semiconductor device according to a third aspect of the present invention includes a step of sequentially depositing an Al-based material film and a first refractory metal film on a semiconductor layer, and the above-described Al-based material film by photolithography and etching. And a step of patterning the first refractory metal film into a wiring pattern, a step of depositing a second refractory metal film, and a step of etching back the second refractory metal film to form a space between the wirings. The method is characterized by including a step of removing the second refractory metal film.

According to a fourth aspect of the present invention, there is provided a method of manufacturing a semiconductor device, which comprises sequentially depositing a first refractory metal film, an Al-based material film and a second refractory metal film on a semiconductor layer, and photolithography. And a step of patterning the first refractory metal film, the Al-based material film and the second refractory metal film into a wiring pattern by etching, and a step of depositing a third refractory metal film, The method is characterized in that a step of etching back the third refractory metal film to remove the third refractory metal film between the wirings is provided.

According to a fifth aspect of the present invention, there is provided a semiconductor device manufacturing method according to the third or fourth aspect of the present invention, in which at least an upper portion and a sidewall portion of an Al-based material are formed on a semiconductor layer. The method is characterized by including a step of forming a wiring covered with a refractory metal film and a step of oxidizing the surface of the refractory metal film to form a refractory metal oxide film.

[0013]

According to the first aspect of the invention, at least the upper portion and the side wall of the Al-based material of the wiring formed on the semiconductor layer are covered with the refractory metal film. Therefore, generation of hillocks and voids due to migration at the upper portion and side wall of the Al-based material forming the wiring is suppressed.

Further, in the second invention, at least the upper portion and the side wall of the Al-based material of the wiring provided on the semiconductor layer are covered with the refractory metal film, and the refractory metal film is refractory metal oxide. It is covered with a film. Therefore,
The effect of suppressing migration in the upper portion and the side wall of the Al-based material forming the wiring is further enhanced, and the generation of hillocks and voids due to migration is further suppressed.

[0015]

The present invention will be described in detail below with reference to the embodiments shown in the drawings. <First Example> The first example relates to a semiconductor device having a wiring in which a central portion is formed of an Al-based material, and an upper portion and a side wall portion thereof are covered with a refractory metal material. Figure 1
2A and 2B are structural cross-sectional views of the semiconductor device in the present embodiment during the manufacturing process. The structure and manufacturing method of the semiconductor device according to this embodiment will be described below with reference to FIGS.

Although detailed description is omitted, a field region, an active region, a transistor element and the like are formed on the semiconductor substrate 11 by a known method, and the interlayer insulating film 12 is deposited thereon. Then, after forming a contact hole reaching the active region in the interlayer insulating film 12, a contact plug is formed in the contact hole to fill the contact hole.
1 and 2, the field region, active region, transistor element and the like are not shown.

Next, as shown in FIG. 1A, Al-1% Si-0.5 is formed on the surface of the interlayer insulating film 12 on the semiconductor substrate 11.
% Cu film 13 and the first refractory metal film 14 are sequentially deposited. In this embodiment, a TiN film is used as the first refractory metal film 14.

Next, as shown in FIG. 1B, the photoresist 15 is patterned into a wiring pattern by a photolithography process. Then, the first refractory metal film 14 and the Al-1% Si-0.5% Cu film 13 are etched by using the photoresist 15 as an etching mask.

Next, as shown in FIG. 1 (c), chemical vapor deposition (C
The second refractory metal film 16 is deposited by the VD) method.
In this embodiment, the second refractory metal film 16 is also formed of a TiN film. Then, the second refractory metal film 16 other than the wiring part
Is etched back until the underlying interlayer insulating film 12 is exposed, and as shown in FIG. 2D, an Al-1% Si-0.5% Cu film 13 is formed.
A wiring structure in which the central portion is formed and the upper portion and the side wall portions are covered with the refractory metal films 14 and 16 is obtained. After that,
A semiconductor device is formed through known steps.

As described above, in the semiconductor device of this embodiment, the center of the wiring is made of the Al-based material made of the Al-1% Si-0.5% Cu film 13, and the upper and side walls are made of the TiN film. It is covered with the first and second refractory metal films 14 and 16. Therefore, the migration of the Al-based material in the upper portion and the side wall portion is suppressed, and the generation of hillocks in the upper portion and the side wall portion is suppressed. Also, Al
The stress is retained in the system material, and plastic deformation (that is, generation of voids due to migration) accompanying the release of stress is suppressed.

In this way, it is possible to extend the life of the wiring having a wiring width of 0.8 μm or less until the wiring is broken, and to miniaturize the semiconductor device and improve its reliability.

<Second Embodiment> In the second embodiment, the central portion is formed of an Al-based material, and the upper portion and side wall portions thereof are doubly covered with the refractory metal material and the refractory metal oxide film. The present invention relates to a semiconductor device having wiring. Similar to the case of the first embodiment, the interlayer insulating film 1 on the semiconductor substrate 11 is formed.
Al-1% in which the first refractory metal film (TiN film) 14 is laminated on the upper surface as shown in FIG. 1 (b) by the film forming process, the photolithography process and the etching process on the surface of 2.
A Si-0.5% Cu film 13 is formed. Then, by the CVD method and the etch back, Al- as shown in FIG.
A second refractory metal film (TiN film) 16 is formed on the side wall of the 1% Si-0.5% Cu film 13, a central part is formed of an Al-based material, and the upper and side walls are formed of a refractory metal material. Get covered wiring structure.

After that, oxidation (3
(80 ° C., 5 minutes), and as shown in FIG. 3, a refractory metal oxide film (TiN oxide film) is formed on the surface of the refractory metal films 14 and 16.
Form 17. After that, a semiconductor device is formed through known steps.

As described above, in the semiconductor device according to the present embodiment, the center of the wiring is formed of the Al-based material composed of the Al-1% Si-0.5% Cu film 13, and the upper and side walls are composed of the TiN film. The first and second refractory metal films 14 and 16 and the refractory metal film oxide film 17 are doubly covered. Therefore, the occurrence of migration in the upper and side walls of the Al-based material is further suppressed as compared with the case of the first embodiment,
The formation of hillocks and the formation of voids from the upper portion and the side wall portion can be prevented more effectively.

<Third Embodiment> A third embodiment relates to a semiconductor device having a wiring in which a central portion is formed of an Al-based material, and an upper portion, a lower portion and a side wall portion thereof are covered with a refractory metal material. .. 4 and 5 are structural cross-sectional views of the semiconductor device in the present embodiment during the manufacturing process. The structure and manufacturing method of the semiconductor device according to the present embodiment will be described below with reference to FIGS.

As in the case of the first embodiment, the semiconductor substrate 2
A field region, an active region, a transistor element, etc. are formed on the first layer 1 and an interlayer insulating film 22 is deposited.
A contact plug is formed in the contact hole formed in.

Next, as shown in FIG. 4A, the first refractory metal film 23, Al-1% Si-0.5% Cu film 24 is formed on the surface of the interlayer insulating film 22 on the semiconductor substrate 21. Then, the second refractory metal film 25 is sequentially deposited. In this embodiment, TiN films are adopted as the first and second refractory metal films 23 and 25.

As shown in FIGS. 4 (b), 4 (c) and 5 (d), the wiring pattern is formed by photolithography and etching in the same manner as in FIG. 1 (b) onward of the first embodiment. Then, a third refractory metal film (TiN film) 27 is deposited by the CVD method, and the third refractory metal film 27 between the wirings is removed by etching back. Thus, as shown in FIG. 5 (d), Al-1% Si-0.5
A wiring structure is obtained in which the central portion is formed of the% Cu film 24, and the upper portion, the lower portion and the side wall portion are covered with the refractory metal films 23, 25 and 27. After that, a semiconductor device is formed through known steps.

As described above, in the semiconductor device according to the present embodiment, the center of the wiring is formed of the Al-based material composed of the Al-1% Si-0.5% Cu film 24, and the upper portion, the lower portion and the side wall portion are made of Ti.
The first, second and third refractory metal films 23, 25 made of N film,
Covered with 27. Therefore, similarly to the case of the first embodiment, the occurrence of migration in the upper portion and the side wall portion of the Al-based material is suppressed, and the generation of hillocks and voids in the upper portion and the side wall portion is prevented.

Further, in the present embodiment, the Al-1% Si-0.5% Cu film 24 forming the center of the wiring is formed on the interlayer insulating film 22 via the first refractory metal film 23. Therefore, the Ai-1% Si0.5% -Cu film 24 and the semiconductor substrate 2 are
Alloy pits that occur at the contact portion connecting 1 and 1 are prevented. Therefore, according to this embodiment, the reliability of the semiconductor device can be improved.

Second refractory metal film 2 in the above embodiment
Although a TiN film is used as No. 5, the present invention is not limited to this. For example, when the wiring formed according to the above-described embodiment is used as a base wiring of a multilayer wiring and a tungsten (W) plug is formed as a through hole by a CVD method, the second refractory metal film 25 is made of titanium tungsten (TiW). Can be used.

<Fourth Embodiment> In the fourth embodiment, the central portion is formed of an Al-based material, the upper portion, the lower portion and the side wall portion are covered with a refractory metal material, and the upper portion and the side wall portion are formed. The present invention relates to a semiconductor device having a wiring covered with a refractory metal oxide film. Similar to the case of the third embodiment,
On the surface of the interlayer insulating film 22 on the semiconductor substrate 21, a first refractory metal film (TiN film) 23 is laminated on the lower part, and a second refractory metal film (TiN film) 25 is laminated on the upper part Al-1% A Si-0.5% Cu film 24 is formed and patterned into a wiring pattern. Further, a third refractory metal film (TiN film) 27 is formed on the side wall of the Al-1% Si-0.5% Cu film 24. Thus, FIG.
As shown in (d), the center is made of Al-based material and the upper part,
A wiring structure in which the lower portion and the side wall portion are covered with a refractory metal material is obtained.

After that, oxidation (3
(80 ° C., 5 minutes), and as shown in FIG. 6, a refractory metal oxide film (TiN oxide film) is formed on the surface of the refractory metal films 25 and 27.
28 is formed. After that, a semiconductor device is formed through known steps.

As described above, in the semiconductor device according to the present embodiment, the center of the wiring is formed of the Al-based material composed of the Al-1% Si-0.5% Cu film 24, and the upper portion, the lower portion and the side wall portion are made of Ti.
The first, second and third refractory metal films 23, 25 made of N film,
27, and further covered with a refractory metal film oxide film 28. Therefore, similarly to the third embodiment, alloy pits generated in the contact portion connecting the Al-1% Si-0.5% Cu film 24 forming the center of the wiring and the semiconductor substrate 21 are prevented. In addition, since the wiring is covered with the refractory metal oxide film 28, migration in the upper and side walls of the Al-based material is further suppressed as compared with the case of the third embodiment, and the upper and side walls are Therefore, the generation of hillocks and voids can be prevented more effectively.

The refractory metal films 14, 16, 23, 25, 27 in the semiconductor device of the present invention are not limited to the titanium nitride TiN in each of the above embodiments, but may be tungsten W, titanium Ti or titanium tungsten TiW.
Etc. can be used.

[0036]

As is apparent from the above, in the semiconductor device of the first invention, the wiring is formed of the Al-based material and the refractory metal film covering at least the upper portion and the side wall of the Al-based material. Generation of hillocks and voids due to migration in the upper portion and side wall portion of the system material is suppressed.

Further, in the semiconductor device of the second invention, since the surface of the refractory metal film forming the wiring in the first invention is further covered with the refractory metal oxide film, the upper part of the Al-based material and The effect of suppressing migration on the side wall portion is further enhanced, and the generation of hillocks and voids due to migration is further suppressed.

In the method for manufacturing a semiconductor device of the third invention, the Al-based material film and the first refractory metal film are sequentially deposited on the semiconductor layer, and then patterned into a wiring pattern by photolithography and etching. Since the second refractory metal film between the wirings is removed by etching back after depositing the second refractory metal film, the upper portion and the side wall of the Al-based material are covered with the refractory metal film. Wiring can be formed. Therefore, according to the present invention,
It is possible to easily manufacture a semiconductor device capable of suppressing the generation of hillocks and voids due to migration in the upper portion and side wall portions of the Al-based material forming the wiring.

Further, in the method for manufacturing a semiconductor device of the fourth invention, the first refractory metal film, the Al-based material film and the second refractory metal film are sequentially deposited on the semiconductor layer, and then photolithography and etching are performed. The third refractory metal film between the wirings is removed by etching back after patterning each wiring pattern with the third refractory metal film. Further, it is possible to form a wiring whose side wall is covered with the refractory metal film. Therefore, according to the present invention, in addition to the effect of the third invention, it is possible to prevent alloy pits generated in the contact portion connecting the Al-based material and the semiconductor substrate, and to manufacture a semiconductor device with higher reliability. be able to.

According to the method of manufacturing a semiconductor device of the fifth invention, at least the upper portion and the side wall portion of the Al-based material are raised on the semiconductor layer by the method of manufacturing the semiconductor device of the third or fourth invention. After forming the wiring covered with the melting point metal film, the surface of the high melting point metal film is oxidized to form the high melting point metal oxide film. Generation can be suppressed more effectively, and a semiconductor device in which hillocks and voids do not occur can be manufactured.

[Brief description of drawings]

FIG. 1 is a structural cross-sectional view during a manufacturing process according to a method for manufacturing a semiconductor device of a third invention.

FIG. 2 is a structural sectional view in the manufacturing process following FIG. 1, and is a structural sectional view of the semiconductor device of the first invention.

FIG. 3 is a structural cross-sectional view of a semiconductor device according to second and fifth inventions.

FIG. 4 is a cross-sectional view in the manufacturing process according to the method of manufacturing the semiconductor device of the fourth invention.

5 is a structural cross-sectional view in the manufacturing process following FIG. 4, and is a structural cross-sectional view of the semiconductor device of the first invention different from FIG.

FIG. 6 is a view of a semiconductor device according to second and fifth inventions.
It is a structure sectional view different from.

FIG. 7 is a structural cross-sectional view of a conventional semiconductor device.

[Explanation of symbols]

11, 21 ... Semiconductor substrate, 12, 22 ... Interlayer insulating film, 13, 24 ... Al-1% Si-0.5% Cu film, 1
4, 23 ... First refractory metal film, 15, 26 ... Photoresist, 16, 25 ... Second refractory metal film, 1
7, 28 ... Refractory metal oxide film, 27 ... Third refractory metal film.

Claims (5)

[Claims] 1. A semiconductor device having wiring on a semiconductor layer, wherein the wiring is formed of an Al-based material and a refractory metal film covering at least an upper portion and a side wall of the Al-based material. apparatus. 2. The semiconductor device according to claim 1, wherein a surface of the refractory metal film forming the wiring is covered with a refractory metal oxide film. 3. A step of sequentially depositing an Al-based material film and a first refractory metal film on a semiconductor layer, and the Al-based material film and the first refractory metal film as a wiring pattern by photolithography and etching. A patterning step, a step of depositing a second refractory metal film, and a step of etching back the second refractory metal film to remove the second refractory metal film between the wirings. A method for manufacturing a semiconductor device, comprising: 4. A step of sequentially depositing a first refractory metal film, an Al-based material film, and a second refractory metal film on a semiconductor layer, and the first refractory metal film by photolithography and etching. A step of patterning the Al-based material film and the second refractory metal film into a wiring pattern; a step of depositing a third refractory metal film; and a step of etching back the third refractory metal film. A method of manufacturing a semiconductor device, comprising a step of removing a third refractory metal film between wirings. 5. The method for manufacturing a semiconductor device according to claim 3 or 4, wherein A is formed on the semiconductor layer.
a step of forming a wiring in which at least an upper part and a side wall of the l-based material are covered with a refractory metal film; and a step of oxidizing the surface of the refractory metal film to form a refractory metal oxide film. A method of manufacturing a semiconductor device, which is characterized.