JP2000294555A - Semiconductor device and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress delay in wiring, while keeping the reliability on copper wiring embedded in an insulating film. SOLUTION: For this device, a copper film 16 is embedded, via an aluminum film 14, 10 nm in thickness and a tantalum film 15, 10 nm in thickness in the order, within a wiring groove 13, 200 nm in width and 300 nm in depth made in the interlayer insulating film 12 consisting of a BCB film on a semiconductor substrate 11. Hereby, a copper wiring 17 consisting of the aluminum film 14, the tantalum nitride film 15, and the copper film 15 is made.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a semiconductor device having a copper wiring buried in a wiring groove formed in an insulating film on a semiconductor substrate and a method of manufacturing the same.

[0002]

2. Description of the Related Art In LSIs of the 0.18 μm generation or later, the delay due to the CR component of the wiring cannot be ignored with the increase in the speed of the transistor. For example, it is preferable to use copper.

FIG. 9A is a cross-sectional view of a conventional semiconductor device, and FIG. 9B is an enlarged view of a region B in FIG. 9A.

As shown in FIG. 9A, tantalum nitride (TaN) is formed in a wiring groove 3 having a width of 200 nm and a depth of 300 nm formed in an interlayer insulating film 2 made of a silicon oxide film on a semiconductor substrate 1. A copper film 5 is buried with the film 4 interposed therebetween, and a wiring 6 composed of the tantalum nitride film 4 and the copper film 5 is formed.

Since the tantalum nitride film 4 is formed as a barrier metal layer between the interlayer insulating film 2 and the copper film 5, diffusion of copper atoms constituting the copper film 5 can be prevented.
At this time, the thickness of the tantalum nitride film 4 required to prevent the diffusion of copper atoms is 30 nm.

Incidentally, the resistivity of tantalum nitride is about 25.
Since it is 0 μΩ · cm, which is 100 times or more larger than the resistivity of copper (about 2 μΩ · cm), the tantalum nitride film 4 hardly contributes to electric conduction. Specifically, when the thickness of the tantalum nitride film 4 is 30 nm, the substantial resistivity of the wiring 6 is about 1.7 times the resistivity of copper.

Therefore, in order to suppress the delay of the wiring 6, that is, to reduce the resistance of the wiring 6, it is desirable to make the thickness of the tantalum nitride film 4 as thin as possible.

[0008]

However, when the tantalum nitride film 4 is made thinner, the copper atoms (Cu) constituting the copper film 5 diffuse in the tantalum nitride film 4 as shown in FIG. As a result, the liquid leaks to the interface between the tantalum nitride film 4 and the interlayer insulating film 2. Then, the copper atoms that have permeated at the interface between the tantalum nitride film 4 and the interlayer insulating film 2 are oxidized by oxygen atoms contained in the interlayer insulating film 2 and are monovalent or divalent copper ions (Cu ⁺ or Cu ^{2 +} ). As a result, since copper ions drift in the interlayer insulating film 2 along the electric field, a short circuit occurs between wirings, and a new problem occurs in that the reliability of the semiconductor device cannot be guaranteed. Therefore,
It is not realistic to suppress the delay of the wiring 6 by reducing the thickness of the tantalum nitride film 4.

When an interlayer insulating film is further formed on the wiring 6, the wiring 6 is formed in order to prevent the oxygen atoms contained in the interlayer insulating film from coming into contact with the copper atoms constituting the wiring 6.
On the other hand, the silicon nitride film has a high relative dielectric constant of about 7, so that the parasitic capacitance of the wiring 6, for example, the coupling capacitance between adjacent wirings, increases. 6 has a problem that a delay occurs.

[0010] In view of the above, it is an object of the present invention to suppress the wiring delay while maintaining the reliability of the copper wiring embedded in the insulating film.

[0011]

In order to achieve the above object, a first semiconductor device according to the present invention comprises a copper film buried in a recess formed in an insulating film on a semiconductor substrate; And an aluminum film formed between the insulating film and the insulating film.

According to the first semiconductor device, since the aluminum film capable of preventing the diffusion of oxygen atoms and copper atoms is formed between the copper film and the insulating film, the copper film constituting the copper film is insulated from the copper film. Since contact with oxygen atoms contained in the film is prevented, and oxidation or ionization of copper atoms is less likely to occur,
It is possible to prevent a situation in which copper ions drift in the insulating film to cause a short circuit between wirings. Further, since the resistivity of the aluminum film (about 3 μΩ · cm) is lower than the resistivity of the barrier metal layer conventionally formed between the copper film and the insulating film, the copper wiring embedded in the insulating film can be used. Low resistance can be achieved.

A second semiconductor device according to the present invention is a semiconductor device comprising: a copper wiring embedded in a wiring groove formed in an insulating film on a semiconductor substrate; an interlayer insulating film deposited on the copper wiring; And an aluminum film formed between the interlayer insulating film.

According to the second semiconductor device, since the aluminum film capable of preventing the diffusion of oxygen atoms and copper atoms is formed between the copper wiring and the interlayer insulating film, the copper atoms forming the copper wiring and Since contact with oxygen atoms contained in the interlayer insulating film is prevented and copper atoms are less likely to be oxidized, that is, ionized, it is possible to prevent copper ions from drifting in the interlayer insulating film and causing a short circuit between wirings. Further, since the relative permittivity of the aluminum film is lower than the relative permittivity of the silicon nitride film conventionally formed between the copper interconnect and the interlayer insulating film, the capacitance parasitic on the copper interconnect can be reduced.

A first method of manufacturing a semiconductor device according to the present invention includes a step of forming a concave portion in an insulating film on a semiconductor substrate, a step of forming an aluminum film on at least a wall surface of the concave portion, and a step of forming an aluminum film. And a copper film embedding step of embedding a copper film inside the aluminum film.

According to the first method for manufacturing a semiconductor device, an aluminum film is formed on at least the wall surface of the concave portion in the insulating film, and then the copper film is embedded inside the aluminum film in the concave portion. Can be interposed with an aluminum film.

In the first method for manufacturing a semiconductor device, the step of forming an aluminum film preferably includes a step of depositing an aluminum film by a CVD method.

According to a second method of manufacturing a semiconductor device according to the present invention, a concave portion forming step of forming a concave portion in an insulating film on a semiconductor substrate and a gas containing hydrogen atoms on at least a wall surface of the concave portion in the insulating film. The method includes a plasma processing step of performing a plasma processing using plasma, and a copper film embedding step of embedding a copper film in a recess subjected to the plasma processing.

According to the second method for manufacturing a semiconductor device, since the plasma processing of a gas containing hydrogen atoms is performed on the wall surface of the recess in the insulating film, the oxide layer near the wall surface of the recess in the insulating film is removed. As a result, oxidation or ionization of copper atoms constituting the copper film is less likely to occur, so that it is possible to prevent a situation in which copper ions drift in the insulating film to cause a short circuit between wirings. Further, since the barrier metal layer conventionally formed between the copper film and the insulating film can be thinned, the resistance of the copper wiring embedded in the insulating film can be reduced.

In the second method for manufacturing a semiconductor device, the copper film burying step preferably includes a step of burying the copper film in the concave portion without exposing the insulating film to the atmosphere after the plasma treatment.

In the second method of manufacturing a semiconductor device, the copper film burying step may include forming a barrier metal layer on at least a wall surface of the concave portion without exposing the insulating film to the atmosphere after the plasma treatment, and then forming a barrier metal layer on the concave portion. Preferably, the method includes a step of embedding a copper film inside the layer.

According to a third method of manufacturing a semiconductor device according to the present invention, there is provided a copper wiring forming step of burying a copper film in a wiring groove formed in an insulating film on a semiconductor substrate to form a copper wiring made of the copper film. And an aluminum film forming step of forming an aluminum film on the copper wiring, and an interlayer insulating film depositing step of depositing an interlayer insulating film on the aluminum film.

According to the third method of manufacturing a semiconductor device, an aluminum film is formed on a copper wiring, and then an interlayer insulating film is deposited on the aluminum film. A membrane can be interposed.

In the third method of manufacturing a semiconductor device, the step of forming an aluminum film preferably includes a step of depositing an aluminum film by a selective CVD method.

In the third method of manufacturing a semiconductor device, in the aluminum film forming step, after the copper wiring is subjected to a plasma treatment using a plasma comprising a gas containing hydrogen atoms, the copper wiring is exposed to the atmosphere without exposing the copper wiring to the atmosphere. It is preferable to include a step of forming an aluminum film on the wiring.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) A semiconductor device according to a first embodiment of the present invention will be described below with reference to the drawings.

FIG. 1A is a cross-sectional view of the semiconductor device according to the first embodiment, and FIG. 1B is an enlarged view of a region A in FIG. 1A.

As shown in FIG. 1A, the semiconductor substrate 11
The wiring groove 13 having a width of 200 nm and a depth of 300 nm formed on the interlayer insulating film 12 made of, for example, a BCB (benzocyclobutene) film.
A copper film 16 is buried in order through an aluminum film 14 having a thickness of 10 m and a tantalum nitride film 15 having a thickness of, for example, 10 nm, thereby forming a wiring 17 including the aluminum film 14, the tantalum nitride film 15 and the copper film 16. .

Since the aluminum film 14 and the tantalum nitride film 15 are formed between the interlayer insulating film 12 and the copper film 16, diffusion of copper atoms constituting the copper film 16 can be prevented.

Aluminum film 1 in interlayer insulating film 12
As shown in FIG. 1 (b), the portion in contact with 4 is oxidized by oxygen in the air before the aluminum film 14 is formed to form an oxidized BCB layer 12A having a thickness of about 10 nm and an aluminum film. Oxidized BCB layer 12 at 14
The portion in contact with A is oxidized by oxygen atoms diffused from the oxidized BCB layer 12A to form an aluminum oxide film 14A having a thickness of about 2 nm. This aluminum oxide film 14A prevents diffusion of oxygen atoms contained in oxide BCB layer 12A.

Since the thickness of the tantalum nitride film 15 covering both sides and the bottom surface of the copper film 16 is small, the copper film 1
6 diffuses in the tantalum nitride film 15 and seeps into the interface between the tantalum nitride film 15 and the aluminum film 14, while diffusion of oxygen atoms and copper atoms is prevented by the aluminum film 14. , Tantalum nitride film 15
Copper atoms oozing at the interface between the aluminum film 14 and
Contact with oxygen atoms contained in the oxidized BCB layer 12A, that is, the interlayer insulating film 12, is prevented.

According to the first embodiment, the aluminum film 14 that can prevent the diffusion of oxygen atoms and copper atoms is made of the copper film 1.
6 and the interlayer insulating film 12, contact between copper atoms constituting the copper film 16 and oxygen atoms contained in the interlayer insulating film 12 is prevented, and oxidation or ionization of copper atoms is prevented. Since it hardly occurs, it is possible to prevent a situation in which copper ions drift in the interlayer insulating film 12 to cause a short circuit between wirings. Further, the aluminum film 1 has a higher resistivity than the barrier metal layer (the tantalum nitride film 15 in the present embodiment) conventionally formed between the copper film 16 and the interlayer insulating film 12.
4 has a low resistivity (about 3 μΩ · cm), so that the resistance of the wiring 17 can be reduced. Therefore, the wiring delay can be suppressed while maintaining the reliability of the wiring 17.

In the first embodiment, a BCB film is used as an interlayer insulating film. However, the present invention is not limited to this.
(Please supplement the official name.) The same effect can be obtained even if a film is used.

In the first embodiment, an aluminum film is used to prevent diffusion of copper atoms and oxygen atoms. However, an equivalent effect can be obtained by using an iridium (Ir) film instead. Can be

Although the aluminum film and the tantalum nitride film are formed between the copper film and the interlayer insulating film in the first embodiment, an aluminum film is formed between the copper film and the interlayer insulating film instead. The same effect can be obtained by forming only the same.

Although the first embodiment is directed to the copper wiring buried in the wiring groove, the same effect can be obtained by targeting a contact made of a copper film buried in the connection hole instead. can get.

(Second Embodiment) Hereinafter, a method for manufacturing a semiconductor device according to a second embodiment of the present invention will be described with reference to the drawings.

2 (a) to 2 (c) and 3 (a),
(B) is sectional drawing which shows each process of the manufacturing method of the semiconductor device which concerns on 2nd Embodiment.

First, as shown in FIG. 2A, an interlayer insulating film 22 made of a BCB film is deposited on a semiconductor substrate 21 by, for example, a spin coating method, and then is deposited on the interlayer insulating film 22 by photolithography. A resist pattern (not shown) having an opening in a wiring formation region is formed, and then the interlayer insulating film 22 is formed using the resist pattern as a mask.
Is subjected to dry etching, for example, to a width of 200
A wiring groove 23 having a depth of 300 nm and a depth of 300 nm is formed.

Next, as shown in FIG.
3 over the entire surface of the interlayer insulating film 22 including, for example, P
After a titanium (Ti) film 24 having a thickness of 5 nm is deposited by the VD method, for example, C
An aluminum film 25 having a thickness of 10 nm is deposited by the VD method. By doing so, the step coverage of the CVD method is good, so that the film thickness 5
An aluminum film 25 having a thickness of nm or more is formed.

When the aluminum film 25 is deposited by the CVD method, since the aluminum film 25 is formed only on the conductive film, the titanium film 24 serving as a base is deposited before the aluminum film 25 is deposited. I have.

In this embodiment, when the thickness of the aluminum film 25 deposited by the CVD method is set to 5 nm or less,
When the film thickness of the aluminum film 25 formed on the wall surface of the wiring groove 23 becomes about 2 nm or less, diffusion of oxygen atoms contained in the interlayer insulating film 22 cannot be prevented.

In this embodiment, when the thickness of the aluminum film 25 deposited by the CVD method is set to 20 nm or more, the copper film 27 (see FIG.
(A)), the cross-sectional area decreases, and the actual wiring resistance increases.

Next, as shown in FIG. 2C, a 10 nm-thick tantalum nitride film 26 is deposited over the entire surface of the aluminum film 25 by, for example, a sputtering method. As shown, a copper film 27 is deposited over the entire surface of the tantalum nitride film 26 by, for example, an electroplating method so that the wiring groove 23 is completely filled.

Next, as shown in FIG. 3B, portions of the titanium film 24, the aluminum film 25, the tantalum nitride film 26, and the copper film 27, which are exposed on the interlayer insulating film 22, are subjected to, for example, a CMP method. Then, a wiring 28 composed of a titanium film 24, an aluminum film 25, a tantalum nitride film 26, and a copper film 27 is formed inside the wiring groove 23.

According to the second embodiment, the aluminum film 25 which can prevent diffusion of oxygen atoms and copper atoms is formed on the copper film 2.
7 and the interlayer insulating film 22, contact between copper atoms forming the copper film 27 and oxygen atoms contained in the interlayer insulating film 22 is prevented, and oxidation of copper atoms, that is, ionization, hardly occurs. Therefore, it is possible to prevent a situation in which copper ions drift in the interlayer insulating film 22 to cause a short circuit between wirings. Further, since the resistivity of the aluminum film 25 is lower than the resistivity of the barrier metal layer (the tantalum nitride film 26 in this embodiment) conventionally formed between the copper film 27 and the interlayer insulating film 22, The resistance of the wiring 28 can be reduced. Therefore, the wiring delay can be suppressed while the reliability of the wiring 28 is maintained.

According to the second embodiment, since the aluminum film 25 is deposited by the CVD method, the wiring groove 23 is formed.
The aluminum film 25 having a good step coverage and a uniform film thickness is formed on the interlayer insulating film 22 including Is done. Therefore, the reliability of the wiring 28 can be further improved.

Although the BCB film is used as the interlayer insulating film in the second embodiment, the present invention is not limited to this.
The same effect can be obtained by using a film or the like.

In the second embodiment, an aluminum film is used to prevent diffusion of copper atoms and oxygen atoms, but the same effect can be obtained by using an iridium film instead.

In the second embodiment, the aluminum film and the tantalum nitride film are formed between the copper film and the interlayer insulating film. Instead, the aluminum film and the tantalum nitride film are formed between the copper film and the interlayer insulating film. The same effect can be obtained by forming only the same.

Although the second embodiment is directed to the copper wiring buried in the wiring groove, the same effect can be obtained by targeting a contact made of a copper film buried in the connection hole instead. can get.

(Third Embodiment) Hereinafter, a method for manufacturing a semiconductor device according to a third embodiment of the present invention will be described with reference to the drawings.

FIGS. 4A to 4C and FIGS.
(C) is sectional drawing which shows each process of the manufacturing method of the semiconductor device which concerns on 3rd Embodiment.

First, as shown in FIG. 4A, an interlayer insulating film 32 made of a BCB film is deposited on a semiconductor substrate 31 by, for example, a spin coating method, and then is deposited on the interlayer insulating film 32 by photolithography. A resist pattern (not shown) having an opening in a wiring formation region is formed, and thereafter, the interlayer insulating film 32 is formed using the resist pattern as a mask.
Is subjected to dry etching, for example, to a width of 200
A wiring groove 33 having a thickness of 300 nm and a depth of 300 nm is formed.

Incidentally, the interlayer insulating film 3 in which the wiring groove 33 is formed
2 is oxidized by oxygen in the air to form an oxidized BCB layer 32A having a thickness of about 10 nm.

Next, a reducing gas in which, for example, a hydrogen gas and a helium gas are mixed at a flow ratio of 1: 9 is introduced into a vacuum chamber (not shown) having a pressure of 50 mTorr and a counter electrode (not shown). During this time, an RF power of 200 W is applied to expose the interlayer insulating film 32 to the reducing gas plasma 34 for one minute as shown in FIG. 4B. Thereby, as shown in FIG. 4C, the oxidized BCB layer 32 is formed.
A is reduced and removed.

In this embodiment, the plasma 34
Helium gas is mixed with a reducing gas containing hydrogen gas to stabilize the gas.

Next, after the above-mentioned plasma processing is completed, the entire surface of the interlayer insulating film 32 including the wiring groove 33 is formed without exposing the interlayer insulating film 32 to the air, as shown in FIG. Then, a 10 nm-thick tantalum nitride film 35 is deposited as a barrier metal layer by, for example, a sputtering method. This can prevent the vicinity of the wall surface and the bottom surface of the wiring groove 33 in the interlayer insulating film 32 from being oxidized again.

Next, as shown in FIG. 5B, a copper film 36 is deposited over the entire surface of the tantalum nitride film 35 by, for example, an electroplating method so that the wiring groove 33 is completely filled. As shown in FIG. 5C, the tantalum nitride film 35
Then, a portion of the copper film 36 exposed on the interlayer insulating film 32 is removed by, for example, a CMP method to form a wiring groove 33.
A wiring 37 made of a tantalum nitride film 35 and a copper film 36 is formed inside.

In the present embodiment, after the above-described plasma processing is completed, a tantalum nitride film 35 is deposited on the interlayer insulating film 32 including the wiring groove 33 without exposing the interlayer insulating film 32 to the atmosphere. After that, the copper film 36 was deposited on the tantalum nitride film 35. Instead, the tantalum nitride film 35 was not deposited, and the interlayer insulating film 32 was exposed to the air after the completion of the plasma treatment. Instead, only the copper film 36 may be deposited on the interlayer insulating film 32 including the wiring groove 33.

According to the third embodiment, the interlayer insulating film 32 in which the wiring groove 33 is formed is subjected to the plasma processing using the plasma made of the reducing gas containing the hydrogen gas. Since the oxide layer is removed and oxidation or ionization of copper atoms constituting the copper film 36 is less likely to occur, it is possible to prevent a situation in which copper ions drift in the interlayer insulating film 32 to cause a short circuit between wirings. Further, since the barrier metal layer (the tantalum nitride film 35 in the present embodiment) conventionally formed between the copper film 36 and the interlayer insulating film 32 can be made thinner, the resistance of the wiring 37 can be reduced. Therefore, the wiring delay can be suppressed while the reliability of the wiring 37 is maintained.

In the third embodiment, a BCB film is used as an interlayer insulating film. However, the present invention is not limited to this.
The same effect can be obtained by using a film or the like.

In the third embodiment, the plasma processing is performed by the plasma of the reducing gas in which the hydrogen gas and the helium gas are mixed. Instead, another plasma containing a hydrogen atom such as an ammonia gas is used. The same effect can be obtained by performing plasma processing using a plasma of a reducing gas, that is, a plasma of another reducing gas that generates hydrogen ions.

Although the third embodiment is directed to the copper wiring buried in the wiring groove, the same effect can be obtained by targeting a contact made of a copper film buried in the connection hole instead. can get.

(Fourth Embodiment) Hereinafter, a semiconductor device according to a fourth embodiment of the present invention will be described with reference to the drawings.

FIG. 6 shows a sectional configuration of a semiconductor device according to the fourth embodiment.

As shown in FIG. 6, on the semiconductor substrate 41,
For example, a wiring groove 4 having a width of 200 nm and a depth of 300 nm formed in a first interlayer insulating film 42 made of, for example, a BCB film.
3, a copper film 45 is buried via a first aluminum film 44 having a thickness of, for example, 10 nm, and a wiring 46 including the first aluminum film 44 and the copper film 45 is formed. Further, a second aluminum film 47 having a thickness of, for example, 10 nm is formed on the wiring 46, and, for example, over the entire surface of the first interlayer insulating film 42 including the second aluminum film 47, for example, A second interlayer insulating film 48 made of a BCB film is formed.

According to the fourth embodiment, the first aluminum film 44 which can prevent diffusion of oxygen atoms and copper atoms is
Since it is formed between the copper film 45 and the first interlayer insulating film 42, contact between copper atoms constituting the copper film 45 and oxygen atoms contained in the first interlayer insulating film 42 is prevented. Since oxidation or ionization of copper atoms is less likely to occur, it is possible to prevent copper ions from drifting in the first interlayer insulating film 42 and causing a short circuit between wirings. In addition, the first aluminum film 44 has a higher resistance than a barrier metal layer formed conventionally between the copper film 45 and the first interlayer insulating film 42.
, The wiring 46 can have a low resistance. Therefore, the wiring delay can be suppressed while the reliability of the wiring 46 is maintained.

FIG. 7 shows, as a first comparative example, an upper interlayer insulating film formed on a buried copper wiring via a conventionally used silicon nitride film (relative permittivity of about 7). 1 shows a cross-sectional configuration of a semiconductor device.

In the first comparative example, the same members as those of the semiconductor device according to the fourth embodiment shown in FIG.

The first comparative example is different from the semiconductor device according to the fourth embodiment in that a 30 nm-thick silicon nitride film 49 is formed over the entire surface of the first interlayer insulating film 42 including the wiring 46. Is formed.

According to the first comparative example, the silicon nitride film 49 which can prevent the diffusion of copper atoms and oxygen atoms is formed by the wiring 46
And between the second interlayer insulating film 48 and
The contact between the copper atoms constituting the wiring 46 and the oxygen atoms contained in the second interlayer insulating film 48 is prevented, so that oxidation of the copper atoms, that is, ionization is less likely to occur, while the silicon nitride film 4
Since the relative dielectric constant of 9 is as high as about 7, the parasitic capacitance of the wiring 46, for example, the coupling capacitance between adjacent wirings increases, and the wiring 46 is delayed.

On the other hand, according to the fourth embodiment, the second aluminum film 4 capable of preventing diffusion of oxygen atoms and copper atoms is provided.
Since 7 is formed between wiring 46 and second interlayer insulating film 48, contact between copper atoms forming wiring 46 and oxygen atoms contained in second interlayer insulating film 48 is prevented. Therefore, oxidation or ionization of copper atoms is less likely to occur,
It is possible to prevent a situation where copper ions drift in the second interlayer insulating film 48 to cause a short circuit between wirings. Also, since the relative permittivity of the second aluminum film 47 is lower than the relative permittivity of the silicon nitride film 49 conventionally formed between the interconnect 46 and the second interlayer insulating film 48, Parasitic capacitance can be reduced. Therefore, the wiring delay can be suppressed while the reliability of the wiring 46 is maintained.

In the fourth embodiment, the BCB film is used as the interlayer insulating film. However, the present invention is not limited to this.
The same effect can be obtained by using a film or the like.

In the fourth embodiment, an aluminum film is used to prevent diffusion of copper atoms and oxygen atoms, but the same effect can be obtained by using an iridium film instead.

(Fifth Embodiment) Hereinafter, a method for manufacturing a semiconductor device according to a fifth embodiment of the present invention will be described with reference to the drawings.

FIGS. 8A to 8C are cross-sectional views showing steps of a method for manufacturing a semiconductor device according to the fifth embodiment.

First, a first interlayer insulating film 5 made of a BCB film is formed on a semiconductor substrate 51 by, for example, spin coating.
2, a resist pattern (not shown) having an opening in a wiring formation region is formed on the first interlayer insulating film 52 by photolithography, and then the first interlayer is formed using the resist pattern as a mask. Dry etching is performed on the insulating film 52 to form a wiring groove 53 having a width of 200 nm and a depth of 300 nm, for example. Next, the wiring groove 5
After a first aluminum film 54 having a film thickness of 10 nm is deposited on the entire surface of the first interlayer insulating film 52 including the nitride film 3 by, for example, the CVD method, the entire surface is formed on the first aluminum film 54. For example, the copper film 55 is formed by an electrolytic plating method.
The wiring groove 53 is deposited so as to be completely filled.
The portions of the aluminum film 54 and the copper film 55 exposed above the first interlayer insulating film 52 are removed by, for example, a CMP method, and as shown in FIG.
A wiring 56 composed of a first aluminum film 54 and a copper film 55 is formed inside the substrate.

The conductive film serving as a base when the first aluminum film 54 is deposited by the CVD method is not shown.

The surface of the copper film 55 constituting the wiring 56 is oxidized by oxygen in the air to form a copper oxide layer (not shown).

Next, a reducing gas in which, for example, a hydrogen gas and a helium gas are mixed at a flow ratio of 1: 9 is introduced into a vacuum chamber (not shown) having a pressure of 50 mTorr, and a counter electrode (not shown) is introduced. During this time, an RF power of 200 W is applied to expose the wiring 56 to the plasma of the reducing gas for one minute. Thus, the copper oxide layer on the surface of the copper film 55 is reduced and removed.

Next, after the above-mentioned plasma processing is completed, without exposing the wiring 56 to the atmosphere, as shown in FIG.
On the wiring 56, for example, a film thickness of 10 n is formed by a selective CVD method.
After the second aluminum film 57 of FIG.
As shown in (c), the second interlayer insulating film 5 made of a BCB film is formed on the entire surface of the first interlayer insulating film 52 including the second aluminum film 57 by, for example, a spin coating method.
8 is deposited.

Since the second aluminum film 57 is deposited by the selective CVD method, the second aluminum film 57 is deposited only on the wiring 56.
Since the aluminum film 57 is deposited, the process can be simplified.

After the above-described plasma processing, the second aluminum film 57 is deposited on the wiring 56 without exposing the wiring 56 to the atmosphere, so that the surface of the copper film 55 is oxidized again. Can be prevented.

According to the fifth embodiment, the first aluminum film 54 that can prevent diffusion of oxygen atoms and copper atoms is
A second aluminum film 57 formed between the copper film 55 and the first interlayer insulating film 52 and capable of preventing diffusion of oxygen atoms and copper atoms is formed between the wiring 56 and the second interlayer insulating film 58. Therefore, contact between copper atoms forming the copper film 55 and oxygen atoms contained in the first interlayer insulating film 52 or the second interlayer insulating film 58 is prevented, and oxidation or ionization of the copper atoms is prevented. Since this hardly occurs, it is possible to prevent a situation in which copper ions drift in the first interlayer insulating film 52 or the second interlayer insulating film 58 to cause a short circuit between wirings. Also,
Since the resistivity of the first aluminum film 54 is lower than the resistivity of a barrier metal layer conventionally formed between the copper film 55 and the first interlayer insulating film 52, the resistance of the wiring 56 can be reduced. At the same time, since the relative permittivity of the second aluminum film 57 is lower than the relative permittivity of the silicon nitride film conventionally formed between the wiring 56 and the second interlayer insulating film 58,
The parasitic capacitance of the wiring 56 can be reduced. Therefore, the wiring 5
6, the wiring delay can be suppressed.

According to the fifth embodiment, the wiring 56
Since the second aluminum film 57 is formed on the wiring 56 without subjecting the wiring 56 to the atmosphere after performing a plasma process using a plasma comprising a reducing gas containing hydrogen gas on the copper film, Since the oxidized layer on the surface of the copper film 55 is removed and the surface of the copper film 55 is prevented from being oxidized again, the reliability of the wiring 56 can be further improved.

In the fifth embodiment, the BCB film is used as the interlayer insulating film. However, the present invention is not limited to this.
The same effect can be obtained by using a film or the like.

In the fifth embodiment, an aluminum film is used to prevent diffusion of copper atoms and oxygen atoms. However, an equivalent effect can be obtained by using an iridium film instead.

Further, in the fifth embodiment, the plasma processing is performed by the plasma of the reducing gas in which the hydrogen gas and the helium gas are mixed. However, instead of this, another plasma containing hydrogen atoms such as ammonia gas is used. Even if plasma processing is performed using a plasma of a reducing gas, that is, a plasma of another reducing gas that generates hydrogen ions, or a vacuum treatment (specifically, a state of a pressure of 10 ⁻⁷ Torr or less) is performed.
The same effect can be obtained by performing the heat treatment at 00 ° C.

[0090]

According to the first semiconductor device, the resistance of the copper wiring buried in the insulating film can be reduced while preventing the occurrence of a short circuit between the wirings due to copper ions, so that the reliability of the copper wiring can be maintained. Wiring delay can be suppressed.

According to the second semiconductor device, the parasitic capacitance of the copper wiring buried in the insulating film can be reduced while preventing the short circuit between the wirings due to the copper ions, so that the reliability of the copper wiring can be maintained. Wiring delay can be suppressed.

According to the first method of manufacturing a semiconductor device, since an aluminum film can be interposed between a copper film and an insulating film, the aluminum film can be embedded in the insulating film while preventing a short circuit between wirings caused by copper ions. The first semiconductor device capable of reducing the resistance of the copper wiring can be reliably manufactured.

In the first method for manufacturing a semiconductor device, when the step of forming an aluminum film includes the step of depositing an aluminum film by a CVD method,
Since an aluminum film having a good step coverage and a uniform film thickness is formed, an aluminum film having a predetermined film thickness is also formed on the wall surface of the concave portion. Properties can be further improved.

According to the second method of manufacturing a semiconductor device, the resistance of the copper wiring buried in the insulating film can be reduced while preventing the short circuit between the wirings due to the copper ions, so that the reliability of the copper wiring is maintained. In addition, wiring delay can be suppressed.

In the second method for manufacturing a semiconductor device, if the copper film embedding step includes a step of embedding the copper film in the concave portion without exposing the insulating film to the atmosphere after the plasma treatment, Since the vicinity can be prevented from being oxidized again, the reliability of the copper wiring embedded in the insulating film can be further improved.

In the second method for fabricating a semiconductor device, the copper film burying step includes forming a barrier metal layer on at least a wall surface of the concave portion without exposing the insulating film to the air after the plasma treatment, and then forming the barrier metal layer on the concave portion. When the step of embedding the copper film inside the layer is included, the situation where the wall surface of the concave portion in the insulating film is oxidized again can be prevented, so that the reliability of the copper wiring embedded in the insulating film can be further improved.

According to the third method of manufacturing a semiconductor device, an aluminum film can be interposed between a copper wiring and an interlayer insulating film. The second semiconductor device capable of reducing the parasitic capacitance can be reliably manufactured.

In the third method of manufacturing a semiconductor device, if the step of forming an aluminum film includes a step of depositing an aluminum film by a selective CVD method, the aluminum film is deposited only on the copper wiring, so that the process is simplified. Can be

In the third method of manufacturing a semiconductor device, in the aluminum film forming step, after the copper wiring is subjected to a plasma treatment using a plasma comprising a gas containing hydrogen atoms, the copper wiring is exposed without being exposed to the atmosphere. The step of forming an aluminum film on the wiring includes removing the oxide layer on the surface of the copper wiring and preventing the surface of the copper wiring from being oxidized again. Can be further improved.

[Brief description of the drawings]

FIG. 1A is a cross-sectional view of a semiconductor device according to a first embodiment, and FIG. 1B is an enlarged view of a region A in FIG.

FIGS. 2A to 2C are cross-sectional views illustrating respective steps of a method for manufacturing a semiconductor device according to a second embodiment.

FIGS. 3A and 3B are cross-sectional views illustrating respective steps of a method for manufacturing a semiconductor device according to a second embodiment.

FIGS. 4A to 4C are cross-sectional views illustrating respective steps of a method for manufacturing a semiconductor device according to a third embodiment.

FIGS. 5A to 5C are cross-sectional views illustrating respective steps of a method for manufacturing a semiconductor device according to a third embodiment.

FIG. 6 is a sectional view of a semiconductor device according to a fourth embodiment.

FIG. 7 is a cross-sectional view of a semiconductor device in which an upper interlayer insulating film is formed on a buried copper wiring via a silicon nitride film as a first comparative example.

FIGS. 8A to 8C are cross-sectional views illustrating respective steps of a method for manufacturing a semiconductor device according to a fifth embodiment.

FIG. 9A is a sectional view of a conventional semiconductor device,
(B) is an enlarged view of a region B in (a).

[Explanation of symbols]

 Reference Signs List 11 semiconductor substrate 12 interlayer insulating film 12A oxide BCB layer 13 wiring groove 14 aluminum film 14A aluminum oxide film 15 tantalum nitride film 16 copper film 17 wiring 21 semiconductor substrate 22 interlayer insulating film 23 wiring groove 24 titanium film 25 aluminum film 26 tantalum nitride film Reference Signs List 27 copper film 28 wiring 31 semiconductor substrate 32 interlayer insulating film 32A oxidized BCB layer 33 wiring groove 34 plasma 35 tantalum nitride film 36 copper film 37 wiring 41 semiconductor substrate 42 first interlayer insulating film 43 wiring groove 44 first aluminum film 45 Copper film 46 Wiring 47 Second aluminum film 48 Second interlayer insulating film 49 Silicon nitride film 51 Semiconductor substrate 52 First interlayer insulating film 53 Wiring groove 54 First aluminum film 55 Copper film 56 Wiring 57 Second aluminum Film 58 Second interlayer insulating film

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Mitsuru Sekiguchi 1-1, Yukicho, Takatsuki-shi, Osaka Matsushita Electronics Co., Ltd. (72) Inventor Haruhiko Sato 1-1-1, Yukicho, Takatsuki-shi, Osaka Matsushita Electronics F term (reference) 5F033 HH08 HH11 HH18 HH32 MM01 MM08 MM12 MM13 PP07 PP15 PP27 QQ09 QQ11 QQ48 QQ94 QQ98 RR21 SS21 TT08 XX10

Claims (10)

[Claims] 1. A semiconductor device comprising: a copper film embedded in a recess formed in an insulating film on a semiconductor substrate; and an aluminum film formed between the copper film and the insulating film. Semiconductor device. 2. A copper wiring buried in a wiring groove formed in an insulating film on a semiconductor substrate, an interlayer insulating film deposited on the copper wiring, and between the copper wiring and the interlayer insulating film. And an aluminum film formed on the semiconductor device. A recess forming step of forming a recess in the insulating film on the semiconductor substrate; an aluminum film forming step of forming an aluminum film on at least a wall surface of the recess; and a copper film inside the aluminum film in the recess. A method of manufacturing a semiconductor device, comprising a step of embedding a copper film. 4. The method according to claim 1, wherein the step of forming the aluminum film is performed by CVD.
4. The method according to claim 3, further comprising a step of depositing the aluminum film by a method. 5. A recess forming step of forming a recess in an insulating film on a semiconductor substrate; and a plasma processing step of performing a plasma process using a plasma containing a gas containing hydrogen atoms on at least a wall surface of the recess in the insulating film. And a copper film burying step of burying a copper film in the plasma-processed concave portion. 6. The method according to claim 5, wherein the copper film burying step includes a step of burying the copper film in the concave portion without exposing the insulating film to the atmosphere after the plasma processing. A method for manufacturing a semiconductor device. 7. The copper film embedding step includes, after the plasma processing, forming a barrier metal layer on at least a wall surface of the concave portion without exposing the insulating film to the air, and then forming the barrier metal layer in the concave portion. 6. The method according to claim 5, further comprising a step of burying the copper film inside. 8. A copper wiring forming step of burying a copper film in a wiring groove formed in an insulating film on a semiconductor substrate to form a copper wiring made of the copper film; and forming an aluminum film on the copper wiring. A method of manufacturing a semiconductor device, comprising: an aluminum film forming step of forming an aluminum film; and an interlayer insulating film depositing step of depositing an interlayer insulating film on the aluminum film. 9. The method according to claim 1, wherein the step of forming the aluminum film includes the step of selecting C.
9. The method according to claim 8, further comprising a step of depositing the aluminum film by a VD method. 10. The aluminum film forming step, after performing a plasma treatment on the copper wiring with a plasma comprising a gas containing hydrogen atoms, exposing the copper wiring to the air without exposing the copper wiring to the atmosphere. 9. The method according to claim 8, further comprising a step of forming the aluminum film.