JP3295108B2 - 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 method of manufacturing a semiconductor device, and more particularly to a method of manufacturing a semiconductor device capable of improving the coverage of a barrier metal layer such as TiN into a contact hole. In recent years, the wiring structure has
A three-layer wiring of a low-resistance wiring layer as described above, a layer called a barrier metal layer having a relatively higher resistance than Al, and a contact metal layer below the barrier metal layer are used below the Al wiring. Have been.

For this reason, the step coverage of the lower barrier metal has a great influence on the coverage of the upper wiring.

[0003]

2. Description of the Related Art FIG. 2 is a view for explaining a conventional method for manufacturing a semiconductor device. The illustrated example can be applied to a method of manufacturing a semiconductor device such as a MOS transistor and a bipolar transistor. In FIG. 2, reference numeral 31 denotes a Si substrate, on which a diffusion layer 32 is formed, and further on this Si substrate 31, SiO ₂ having a contact hole 33 is provided.
An insulating film 34 made of, for example, is formed. Then, a contact metal layer 35 of Ti or the like is formed so as to contact the diffusion layer 32 in the contact hole 33 formed in the insulating film 34.
A barrier metal layer 36 of TiN or the like and a wiring layer of Al or the like for preventing an Al-Si reaction due to interdiffusion of Al and Si.
37 are formed.

Next, a method of manufacturing the semiconductor device will be described. First, as shown in FIG.
A diffusion layer 32 is formed by ion implantation, annealing, or the like, SiO ₂ is deposited on the diffusion layer 32 by a CVD method or the like to form an insulating film 34, and then the insulating film 34 is etched by RIE or the like to form a diffusion layer. A contact hole 33 with the exposed 32 is formed. Note that the diffusion layer 32 may be formed after the formation of the contact hole 33.

[0005] Next, as shown in FIG. 2 (b), a contact metal layer 35 is formed by sputtering only Ti at room temperature using a Ti target so as to contact the diffusion layer 32 in the contact hole 33. , Additional N ₂ in the chamber
A gas is introduced to generate reactive spatter at room temperature, and T
A barrier metal layer 36 made of iN is formed. Then, by depositing Al so as to cover the barrier metal layer 36 by the sputtering method and forming the wiring layer 37, a wiring structure as shown in FIG. 2C can be obtained.

[0006]

However, in the above-described conventional method for manufacturing a semiconductor device, only a relatively high-resistance Ti is deposited on the Si substrate 1 by a sputtering method at room temperature using a Ti target. Since the contact metal layer 5 was formed, there was a possibility that the demand for a higher speed due to a stricter lower resistance could not be met.

Further, the formation of the TiN barrier metal layer 36
N at room temperature using Ti target _TwoGas chamber
By introducing reactive spatter
As shown in FIG.
Coverage of TiN barrier metal layer 36 on side wall of hole 33
And the Al wiring layer 37 is formed in this state.
Then, a step is formed on the surface of the Al wiring layer 37, and the surface is flattened.
There was a problem that it was difficult. This is apparent with miniaturization of devices.
There was a tendency to be written.

Therefore, the present invention relates to a method of manufacturing a semiconductor device, which can realize a high-speed element by lowering the resistance of a contact metal layer and achieve good coverage of a barrier metal layer in a contact hole. It is an object of the present invention to provide a method of manufacturing a semiconductor device capable of realizing surface flattening of a wiring layer on a barrier metal layer.

[0009]

In order to achieve the above object, a method of manufacturing a semiconductor device according to the present invention comprises the steps of forming an insulating film having an opening on a silicon substrate, and then heating the silicon substrate. A metal source gas is introduced into the chamber, and the inside of the opening is formed by chemical vapor deposition.
Selectively forming a contact metal layer made of metal silicide on the bottom silicon substrate;
Furthermore, a barrier metal source gas is introduced into the chamber,
The contact metal layer and the insulating film are formed by chemical vapor deposition.
Forming a barrier metal layer by depositing a barrier metal so as to cover the side wall of the semiconductor device, and then forming a wiring layer so as to cover the barrier metal layer.

In the present invention, the contact metal layer is formed to be a TiSi ₂ layer , and the barrier metal layer is formed to be a titanium hydride layer . Examples of the wiring layer according to the present invention include an aluminum layer and a tungsten layer.

[0011]

According to the present invention, as shown in FIG. 1, while heating a Si substrate 1, TiCl _{4 is used} as a metal source gas.
A gas is introduced into the chamber, and Ti is deposited on the Si substrate 1 in the contact hole 3 by the CVD method.
i, which reacts with Si on the Si substrate, has a lower T than Ti.
Since the contact metal layer 5 made of iSi ₂ is formed, the contact capacitance between the Si substrate 1 and the contact metal layer 6 can be reduced as compared with the case where a Ti contact metal layer is formed by a conventional normal temperature sputtering method.
Then, while further heating the Si substrate 1, TiCl
_{4 With the} gas introduced into the chamber, NH ₃ gas is further introduced as a barrier metal source gas into the chamber, and CVD is superior in terms of coverage compared to the sputtering method.
The barrier metal layer 6 is formed by depositing TiN so as to cover the contact metal layer 5 by the method. Therefore, the contact hole 3 in the contact hole 3 is particularly smaller than the conventional case where the TiN contact metal layer is formed by reactive sputtering even at normal temperature. The coverage of the barrier metal layer 6 on the side wall can be improved.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a diagram for explaining a method of manufacturing a semiconductor device according to one embodiment of the present invention. The illustrated example can be applied to a method of manufacturing a semiconductor device such as a MOS transistor and a bipolar transistor. In FIG. 1, 1 is a Si substrate,
A diffusion layer 2 is formed on the Si substrate 1, and an insulating film 4 made of SiO ₂ or the like having a contact hole 3 where the diffusion layer 2 is exposed is formed on the Si substrate 1. A contact metal layer 5 such as Ti, a barrier metal layer 6 such as TiN, and a wiring layer 7 such as Al are formed so as to be in contact with the diffusion layer 2 in the contact hole 3 formed in the insulating film 4. .

Next, there is a diagram illustrating a method of manufacturing the semiconductor device. First, as shown in FIG. 1A, a diffusion layer 2 is formed on a Si substrate 1 by ion implantation, annealing, or the like, and SiO ₂ is deposited by a CVD method or the like to have a film thickness of 6000 Å.
After forming the insulating film 4 to a degree, the insulating film 4 is formed by RIE or the like.
Is etched to form a contact hole 3 where the diffusion layer 2 is exposed. Note that the diffusion layer 2 is formed in the contact hole 3
It may be formed after formation.

Next, as shown in FIG. 1B, the pressure in the chamber is set to about 1 to 100 mTorr,
Is heated to about 60 to 700 ° C., and TiCl ₄ gas is supplied as a metal source onto the Si substrate 1 in the contact hole 3.
About 200 sccm is introduced, Ti is deposited by the CVD method, and this Ti reacts with Si of the Si substrate 1 to selectively form a film having a thickness of 500 to 150 on the Si substrate 1 at the bottom of the contact hole 3.
A contact metal layer 5 of TiSi _{2 of} about 0 ° is formed. Although it does not correspond to the present embodiment, TiSi
₂ 2~200sccm about TiCl ₄ Si2H ₆ a (disilane)
Can be formed directly by mixing with However, in this case, as shown by a dotted line in FIG. 1B , the contact metal layer 5 is formed so as to cover not only the bottom of the contact hole 3 but also the insulating film 4. Next, the Si substrate 1 is
Further heating to about 800 ° C., while introducing NH ₃ gas, further introducing TiCl ₄ gas as a barrier metal source gas into the chamber at about 2 to 200 sccm, and the CVD method is applied to the contact metal layer 5 and the side wall of the insulating film 4. depositing a TiN to cover the door to form a barrier metal layer 6 having a thickness of about 200～2000A.

By depositing Al so as to cover the barrier metal layer 6 by a sputtering method or the like and forming a wiring layer 7 having a thickness of about 5000 °, a wiring structure as shown in FIG. Can be. As described above, in the present embodiment, the Si substrate 1 is heated, and at the same time, the TiCl ₄ gas is introduced into the chamber as the metal source gas, and the CVD is performed.
Ti is deposited on the Si substrate 1 in the contact hole 3 by a method, and the Ti and Si of the Si substrate 1 are reacted to form a contact metal layer 5 made of TiSi ₂ or silicide by a direct reaction with polysilane. Is formed, the contact capacitance between the Si substrate 1 and the barrier metal layer 6 can be reduced. For this reason, high-speed operation of the element can be realized. Then, the Si substrate 1 is further heated, and an NH ₃ gas is further introduced as a barrier metal source gas into the chamber in a state where the TiCl ₄ gas is introduced into the chamber. The barrier metal layer 6 is formed by depositing TiN so as to cover the contact metal layer 5 by the method described above. The coverage of the barrier metal layer 6 on the side wall can be improved. Therefore, when the Al wiring layer 7 is formed on the barrier metal layer 6,
A step can be made hardly to occur on the surface of the Al wiring layer 7, and A
The surface flatness of the l wiring layer 7 can be realized.

In this embodiment, the case where the TiN barrier metal layer 6 is formed as a barrier metal layer between the Si substrate 1 and the wiring layer 7 made of Al has been described. TiN barrier metal layer 6 between
May be formed. In this case, the TiN barrier metal layer 6
Can function not only as a barrier metal layer but also as an adhesion layer.

[0017]

According to the present invention, the resistance of the contact metal layer can be reduced to realize a high-speed device, and the coverage of the barrier metal layer in the contact hole can be improved. There is an effect that the surface of the wiring layer on the barrier metal layer can be flattened.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a method for manufacturing a semiconductor device according to one embodiment of the present invention.

FIG. 2 is a diagram illustrating a method for manufacturing a conventional semiconductor device.

FIG. 3 is a diagram illustrating a problem of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Si substrate 2 Diffusion layer 3 Contact hole 4 Insulating film 5 Contact metal layer 6 Barrier metal 7 Wiring layer

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-229814 (JP, A) JP-A-2-83978 (JP, A) JP-A-3-286527 (JP, A) (58) Survey Field (Int.Cl. ⁷ , DB name) H01L 21/28-21/288 H01L 21/3205-21/3213 H01L 21/768

Claims (3)

(57) [Claims] An insulating film having an opening is formed on a silicon substrate.
Forming and then heating the silicon substrate
In both cases, metal source gas is introduced into the chamber,
On the silicon substrate at the bottom in the opening by vapor deposition
Metal consisting of metal silicide selectively
Forming a layer and then further burr into the chamber
A metal source gas is introduced, and the
A cover is formed to cover the contact metal layer and the side wall of the insulating film.
Step of depositing rear metal and forming barrier metal layer
Then, a wiring layer is formed so as to cover the barrier metal layer.
Manufacturing a semiconductor device, comprising:
Method. 2. The method according to claim 1, wherein said contact metal layer is a TiSi ₂ layer , and said barrier metal layer is a titanium hydride layer. 3. The method according to claim 1, wherein said wiring layer is an aluminum layer or a tungsten layer.