JP3328358B2 - Method for manufacturing semiconductor device - Google Patents

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 more particularly, to a semiconductor device having a metal wiring layer provided with a barrier metal having both a barrier property against a semiconductor substrate and high reliability of wiring, and a method of manufacturing the same. About.

[0002]

2. Description of the Related Art As semiconductor devices become finer and more highly integrated, problems such as spikes of aluminum, which is a wiring material, into a diffusion layer in a shallow diffusion layer and deposition of substrate silicon on aluminum wiring have arisen. Therefore, as an electrode wiring material, use of an aluminum alloy in which about 1% of silicon is mixed in advance in aluminum is used, and a diffusion barrier layer (barrier) is formed to prevent mutual diffusion of aluminum and silicon in a contact portion between the aluminum alloy and the silicon diffusion layer. Metal).

[0003] Titanium nitride is currently considered as the most promising material as a barrier metal. Titanium nitride (TiN) not only has excellent barrier properties but also has a relatively low resistance, and the same titanium compound, titanium silicide, can easily realize a low-resistance contact with a silicon substrate. This is because continuity is obtained, and when a tungsten plug is applied to the contact hole, the adhesiveness with tungsten is excellent. Conventionally, as a method of forming a titanium nitride film, a reactive sputtering method or a method in which titanium is formed by sputtering and then nitriding is performed.

[0004] Electromigration (EM) resistance of aluminum or aluminum alloy wiring is (11)
It is said that the film oriented in 1) is excellent, and as a method for this, Japanese Patent Application Laid-Open No. 3-262127 discloses a method in which a titanium nitride film is oriented to (111) and an aluminum wiring layer is formed thereon. Is disclosed.

[0005]

In the prior art, as described above, the (111) -oriented titanium nitride film is formed by forming titanium by a sputtering method and then nitriding the titanium nitride film. The film was formed by directly depositing by a sputtering method. However, when titanium nitride is formed by the CVD method, the orientation is (200) when the film quality (for example, low resistance, high film density, etc.) that can be used for wiring is obtained. It has been reported that a titanium nitride film oriented at least to (111) has a poor function as a diffusion barrier layer which is an essential purpose of a barrier metal.

That is, in the conventional CVD technique, (11)
1) There is no technique for forming a titanium nitride film which is oriented and has good film quality. Therefore, when titanium nitride having good film quality is formed by the CVD method, the titanium nitride has a (200) orientation, but the Al wiring thereon does not have a (111) orientation, so that there is a problem that the reliability of the semiconductor device is reduced. In the case of a titanium nitride film oriented in (111), the film quality is poor, and there are problems such as an increase in wiring resistance and a decrease in barrier properties.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a barrier metal having both a diffusion barrier property and high reliability of wiring as a base of a metal wiring layer made of aluminum or its alloy. An object of the present invention is to provide a semiconductor device in which the reliability of wiring is improved by forming a (111) oriented titanium nitride film, and a method of manufacturing the same.

[0008]

In order to achieve the above object, the present invention relates to a semiconductor device in which a metal wiring layer is a laminated wiring including aluminum or an alloy thereof, wherein (111) is formed under the metal wiring layer. It is an object of the present invention to provide a semiconductor device characterized in that an oriented titanium nitride film and a titanium film having a surface coverage of 50% or more and an average film thickness of 100 ° or less are laminated thereunder.

Further, the present invention provides a method for forming an underlayer of a metal wiring layer made of aluminum or an alloy thereof on a semiconductor substrate.
First, under the condition of (002) orientation, titanium or titanium nitride of (111) orientation having good film quality is coated to a surface coverage of 50% or more and an average film thickness of 100 ° or less,
Subsequently, titanium nitride is deposited under a condition that a good film quality can be obtained by a CVD method using a system containing a titanium compound to form a (111) -oriented titanium nitride film having good film quality. It is another object of the present invention to provide a method for manufacturing a semiconductor device, comprising depositing the metal wiring layer on a film.

Here, the titanium compound is preferably a titanium halide. The conditions under which good film quality can be obtained by the CVD method are preferably those for forming a (200) -oriented titanium nitride film.

According to the present invention, there is provided the method for manufacturing a semiconductor device according to any one of the above-mentioned metals, wherein the RTA step and the etch-back step are performed before depositing the metal wiring layer. It is an object of the present invention to provide a method of manufacturing a semiconductor device, which performs one or both of them.

[0012]

In the method of manufacturing a semiconductor device according to the present invention, titanium (Ti) is first used under the condition of (002) orientation.
A titanium nitride (TiN) film by sputtering, for example, or under the condition of orienting to (111), for example, nitriding after sputtering Ti, or a surface coverage of 50% or more by direct reactive sputtering, A step of forming an average film thickness of 100 ° or less is performed. Here, the Ti film and the TiN film do not need to be continuous films. Subsequently, when TiN is deposited under conditions that improve the film quality by a CVD method using a system containing a titanium compound, a (200) -oriented TiN film is obtained beforehand without Ti or TiN. If (111) oriented TiN is added, (111) oriented TiN is obtained. Moreover, the film quality of the (111) -oriented TiN film thus obtained is well maintained. After performing the above-described steps and, if necessary, one or both of the RTA step and the etch-back step, depositing Al or an Al alloy (hereinafter, referred to as an Al-based alloy) on TiN to form an Al-based alloy film I do. Thereafter, a semiconductor device in which a metal wiring layer is formed by patterning the Al-based alloy film is manufactured.

In the semiconductor device of the present invention or manufactured by the method of the present invention, a Ti film having a surface coverage of 50% or more and an average film thickness of 100 ° or less (or (111) oriented TiN (111) laminated on the film)
It has a structure in which an oriented TiN film is formed. The TiN film underlying the metal wiring layer has good film quality despite having a (111) orientation, and is optimal as a barrier metal having both diffusion barrier properties and high reliability of wiring. Therefore, since the semiconductor device of the present invention and the semiconductor device manufactured by the method of the present invention have a (111) -oriented TiN film with good film quality as a base of the metal wiring layer, the Al-based alloy wiring layer is electromigrated. A (111) oriented Al-based alloy film having high (EM) resistance can be easily formed, and the reliability of wiring is high.

In the present invention, the first step (00
2) The reason for limiting the coating amount of the oriented Ti film and the (111) oriented TiN film to 50% or more in surface coverage and 100% or less in average film thickness is to grow a TiN film preferentially oriented in (111). Because it is necessary.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A semiconductor device according to the present invention and a method of manufacturing the same will be described in detail with reference to preferred embodiments shown in the accompanying drawings.

FIGS. 1A to 1D are process diagrams showing steps of an embodiment of a method of manufacturing a semiconductor device according to the present invention.

First, as shown in FIG.
An insulating film (for example, BPSG) 2 is deposited thereon. Ti3 is deposited thereon by sputtering at a designed value of 50 [deg.]. At this time, Ti3 is not actually a continuous film of 50 °, but a state where nuclei of Ti3 are formed in some places so that the surface coverage is 50% or more, that is, a discontinuous film. It is possible (see FIG. 1B). That is, 5
0 ° means that it is sufficient to sputter Ti for a time obtained by calculation from the data of the film forming rate. However, when a continuous film of Ti was produced (00
Deposition is performed under the condition of orientation in 2).

Subsequently, a desired thickness of TiN4 is deposited by the CVD method as shown in FIG. However, FIG.
In (c), the thickness of the sputtered Ti does not need to be considered.
The raw material system of CVD is a system of titanium tetrachloride (TiCl ₄ ) / ammonia (NH ₃ ) / hydrogen (H ₂ ), and the film forming conditions are: substrate temperature: 650 ° C. TiCl ₄ : 2 sccm NH ₃ : 40 sccm H ₂ : 10 sccm Pressure: 0.1 Torr. At this time, it has been confirmed that when a film is directly formed on silicon under these conditions, (200) -oriented TiN is obtained, and that the electric resistivity is the smallest among the TiN films obtained by the present gas system. . Continuously, Al-0.5%
Cu5 is deposited to a desired thickness (see FIG. 1D).

The thus obtained TiN film 4 is shown in FIG.
(111) as shown in FIG. This is because Ti
This shows that the orientation of N4 is determined at the stage of nucleation at the initial stage of film formation. That is, the following mechanism can be considered. By slightly applying Ti3 to the surface in advance by Ti sputtering, CVD-TiN4 has this Ti3 as a nucleus, or the sputtered Ti3 is first nitrided by ammonia, which is one of the raw material systems of CVD, to become TiN, which becomes the nucleus. To start growing. That is, in the former case, TiN deposited on Ti (002) is strong (1
11) Since it shows orientation, in the latter case, Ti (00)
Since TiN obtained by nitriding 2) shows a strong (111) orientation, in the present invention, the sputtering Ti3 is changed to (00).
By attaching under the condition of orientation in 2), first in the future (1)
11) TiN4 nuclei to be oriented are formed. Even when the TiN film is deposited on silicon or its oxide film under the condition of (200) orientation, in the present invention, TiN nuclei having (111) orientation in the future are formed at the start of growth, so that the final The TiN film obtained in (11)
1) Indicates orientation. Naturally, Al on TiN (111) is also (111) oriented.

The Al-based alloy wiring 5 thus produced
Was not significantly different from the conventional wiring using TiN produced by sputtering. According to the method of the present invention, it is possible that, in the future, when metal wiring is formed, in addition to W plugs,
It is thought that it will be possible to adopt the VD method,
It shows that it can also be used for the main wiring section.

In the above embodiment, the film formation temperature is 650 ° C.
And is applicable only to the base of the first Al wiring (Al
Melting point of about 660 ° C.), but it is possible to lower the temperature of the film by changing the raw material system or by using the plasma CVD method, and by applying the lowering temperature technique, CVD-TiN can be applied to all parts of the wiring. . Therefore, it goes without saying that the technique of the present invention can also be applied to a portion other than the base of the first Al wiring.

In the above embodiment, the (111) orientation T
Although Ti3 was deposited on the underlayer of the iN film 4 by a sputtering method, the method of depositing Ti3 is not particularly limited.
Any method may be used as long as Ti3 can be deposited on the insulating film 2 with a surface coverage of 50% or more and an average film thickness of 100 ° or less. In the present invention, the (002) orientation T
Since i3 is used for nucleation at the early stage of film formation for determining the orientation of CVD-TiN4, that is, for nucleation of TiN having (111) orientation in the future, (1) is used instead of Ti.
11) A predetermined amount of TiN may be deposited under the conditions for orientation. For example, Ti deposited under the condition of (002) orientation
3 may be nitrided by heat treatment (such as lamp annealing) in N ₂ gas to prepare TiN in advance (the TiN obtained by nitriding Ti (002) as described above has a strong (111) (111), and sputter in a N ₂ atmosphere by reactive sputtering instead of Ti 3 (111)
Under the conditions for orientation, TiN is directly deposited on the insulating film 2 in an amount required for nucleation, that is, a surface coverage of 50% or more and an average film thickness of 1%.
The deposit may be less than 00 °.

In the above embodiment, the raw material system for CVD is Ti
Although it is a Cl ₄ / NH ₃ / H ₂ system, it is not particularly limited as long as it is a system containing a titanium compound.
Those using titanium halide such as r ₄ and TiI ₄ and organic compounds such as tetradiethylaminotitanium can also be used. N ₂ or N ₂ H ₄ (hydrazine) may be used instead of NH ₃ . The conditions for the CVD film formation are not limited to those in the above embodiment, and may be any conditions that can form a TiN film having good film quality when formed directly on a semiconductor substrate. For example, a TiCl ₄ / NH ₃ / H ₂ system can be used. At a substrate temperature of 650-750 ° C. and a partial pressure ratio of TiCl ₄ and NH ₃ of 1:
1-1: 25, the partial pressure ratio between NH ₃ and H ₂ is 1: 0 to 1:
1. The total pressure can be 10 mTorr to 10 Torr.

Further, the thickness of the CVD-TiN film 4 and A
The thickness of the l-based alloy film 5 is not particularly limited, and may be appropriately selected as needed.

In the above embodiment, if necessary, RTA (rapid heat treatment: Rapid Th
(Ermal Anneal) or etch back or both are performed because RTA is expected to improve the low resistivity ratio and crystallinity of TiN, and the etch back adjusts the film thickness of TiN (for example, in a hole). In the case of forming a TiN film in a hole, if the film thickness is required to be larger than the flat portion in the hole, it may be necessary to temporarily increase the thickness and then cut off the portion of the flat portion that is too thick.

[0026]

As described above in detail, according to the semiconductor device of the present invention, since the (111) oriented titanium nitride film having good film quality is provided under the aluminum or aluminum alloy wiring layer, the barrier property is improved. In addition, the electromigration resistance of the metal wiring layer is high, and high reliability and miniaturization of the wiring can be achieved.

Further, according to the method of manufacturing a semiconductor device of the present invention, titanium nitride having good film quality and oriented to (111) can be easily deposited as a barrier metal by the CVD method. A semiconductor device can be easily manufactured by a simple process.

[Brief description of the drawings]

FIGS. 1A to 1D are process diagrams showing one embodiment of a method for manufacturing a semiconductor device of the present invention.

FIG. 2 is a graph showing the X-ray diffraction intensity of each crystal phase of one embodiment of the semiconductor device of the present invention.

[Explanation of symbols]

 Reference Signs List 1 semiconductor substrate (silicon substrate) 2 insulating film 3 Ti 4 CVD-TiN 5 Al alloy (Al-0.5% Cu) film

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-262127 (JP, A) JP-A-5-13366 (JP, A) JP-A-5-190493 (JP, A) European Patent Application Publication 525637 (EP, A1) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 21/28-21/288 H01L 21/3205-21/3213 H01L 21/768

Claims (3)

(57) [Claims] 1. As a base of a metal wiring layer made of aluminum or an alloy thereof on a semiconductor substrate, (002)
Titanium or a good film quality (1
11) A first titanium nitride having an orientation of 5
0% or more, coated below the average film thickness 100 Å, followed by CVD method using systems comprising a titanium compound, in advance before
With titanium or the first titanium nitride
If not, titanium nitride film of (200) orientation
Depositing titanium nitride under the conditions for forming
A method for manufacturing a semiconductor device, comprising: forming a second titanium nitride film having good film quality and having a (111) orientation; and depositing the metal wiring layer on the second titanium nitride film. 2. A method of manufacturing a semiconductor device according to claim 1 wherein the titanium compound is a titanium halide. 3. The method of manufacturing a semiconductor device according to claim 1 , wherein said metal wiring layer is deposited before said metal interconnect layer is deposited.
A method of manufacturing a semiconductor device, comprising performing one or both of a process and an etch-back process.