JPH04100221A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To form the surface of a high melting point metallic layer smooth and excellent in coverage so that the surface cannot become rough by making surface treatment to a high melting point metallic compound layer containing nitrogen in a plasma atmosphere containing either nitrogen or oxygen. CONSTITUTION:A high melting point metallic compound layer containing nitrogen is surface-treated in a plasma atmosphere containing either nitrogen or oxygen. In order to remove a natural oxide film, etc., produced on a barrier metal layer 5, the surface treatment is made on the barrier metal layer 5 with a solvent, such as hydrofluoric acid, etc. Then, after placing a sample on the susceptor 9 in a surface treatment chamber 8, a mixed gas of, for example, NF3 gas (10sccm) and N2 gas (100sccm) is introduced into the chamber 8 and an RF bias is applied across an RF electrode 10 below the susceptor 9 so as to make plasma treatment on the surface of the barrier metal layer 5 composed of TiN.

Description

[Detailed Description of the Invention] [Summary] Regarding a method for manufacturing a semiconductor device, when forming a high melting point metal layer on a barrier metal layer, the high melting point metal layer is smoothed and covered so as not to cause surface roughness. The purpose of the present invention is to provide a method for manufacturing a semiconductor device that can be formed well, and includes a step of surface treating a nitrogen-containing high melting point metal compound layer in a plasma atmosphere containing at least one of nitrogen or oxygen. Configure.

[Industrial application field]

The present invention relates to a method for manufacturing a semiconductor device that includes a step of forming a wiring layer made of a barrier metal layer such as TiN, a high melting point metal layer such as tungsten, and an aluminum layer.

In recent years, as semiconductor integrated circuits have become more highly integrated, the interconnect scale has become smaller. As a result, in conventional wiring mainly made of aluminum or the like, deterioration in reliability due to electro-migration silane and the like has become noticeable.

For this reason, there is a need for a wiring formation technology that uses a wiring material that is resistant to electro-migration silane, such as tungsten, instead of aluminum.

[Conventional technology]

FIG. 4 is a diagram illustrating a conventional method for manufacturing a semiconductor device. In FIG. 4, 31 is a substrate made of Si or the like;
33 is an insulating film made of 5iOz or the like; 34 is a contact hole formed in the insulating film 33; 35 is a barrier metal layer made of TiN or the like; 36
3 is a high melting point metal layer made of W or the like, and 37 is an insulating film made of 3i0z or the like.

Next, the manufacturing method will be explained.

First, as shown in FIG. 4(a), a diffusion layer 32 is formed on a substrate 31 by, for example, ion implantation, and an insulating film 33 is formed by depositing SiOz on the substrate 31 by, for example, CVD. The insulating film 33 is selectively etched by etching to form a contact hole 34 in the insulator 1133 and to expose the substrate 31 in which the diffusion layer 32 is formed in the contact hole 34.

Next, as shown in FIG. 4(b), a barrier metal layer 5 is formed by depositing TiN to make contact with the diffusion layer 32 in the contact hole 34 by, for example, the CVD method. In order to remove the natural oxide film etc. generated thereon, the surface of the barrier metal layer 35 is treated using a solvent such as hydrofluoric acid (sulfuric acid may also be used).

Then, the sample after the surface treatment of the barrier metal layer 35 is transferred from the wet processing device to the film forming device through the air atmosphere, and W is deposited on the barrier metal layer 35 by, for example, the CVD method.
is deposited to form a high melting point metal layer 36, as shown in FIG. 4(c).
A wiring layer consisting of a barrier metal layer 35 and a high melting point metal layer 36 in contact with the diffusion layer 32 can be obtained as shown in FIG. Note that the barrier metal layer 35 here is the substrate 3
In addition to having a function of preventing a reaction between St of No. 1 and W of the high melting point metal layer 36 due to thermal diffusion, the substrate 31 and the high melting point metal layer 3
It has a function as an adhesive layer for strongly adhering to 6.

[Problem to be solved by the invention]

In the conventional semiconductor device manufacturing method described above, when forming the high melting point metal layer 36 on the barrier metal layer 35, a solvent such as hydrofluoric acid is used to remove a natural oxide film etc. generated on the surface of the barrier metal layer 35. The surface treatment of the barrier metal layer 35 was carried out using the above method. For this reason, in the early stage of growth of tungsten that will become the high melting point metal layer 36, nucleation does not occur uniformly, and as a result, the crystal grain size increases and the surface shape of the high melting point metal layer 36 becomes rough rather than smooth. There was a problem with putting it away. As described above, if the surface shape of the high melting point metal layer 36 becomes rough, there is a problem that it becomes difficult to form the high melting point metal layer 36 with good coverage, especially as the structure becomes finer, and it becomes difficult to form the high melting point metal layer 36 with good coverage. This was a major hindrance.

Therefore, the present invention provides a method for manufacturing a semiconductor device that can form a high melting point metal layer on a barrier metal layer smoothly and with good coverage without causing roughness in the surface shape. is intended to provide.

[Means to solve the problem]

In order to achieve the above object, the method for manufacturing a semiconductor device according to the present invention includes a step of surface treating a nitrogen-containing high melting point metal compound layer in a plasma atmosphere containing a small amount of either nitrogen or oxygen.

The plasma containing at least one of nitrogen or oxygen according to the present invention may be a plasma containing any one of nitrogen, a nitrogen-containing compound, oxygen, and an oxygen-containing compound (for example, Nt, Nz01Ox, Nt+Hz
Examples include plasma consisting of O+og (ox is preferably 1% or less from the viewpoint of barrier properties) and the like. In addition, the nitrogen-containing high melting point metal compound layer includes TiN, WN, Ti0N, M
Examples include oN, ZrN, and the like.

In the present invention, the nitrogen-containing high-melting point metal compound layer may be subjected to the plasma surface treatment after being subjected to the Unisito treatment to remove a natural oxide film or the like formed on the surface thereof.

In the present invention, when performing the surface treatment in the plasma atmosphere, the nitrogen-containing high melting point metal compound layer may be irradiated with ions. In this case, the chemical surface treatment is performed using only radicals without ion irradiation. This is preferable because the surface condition of the nitrogen-containing high melting point metal compound layer can be made smoother than in the case where it is carried out. This is presumed to be because sputter etching of the surface of the nitrogen-containing high melting point metal compound layer by ions is performed in a non-selective manner.

In the present invention, after the surface treatment, the high melting point metal layer may be continuously formed on the nitrogen-containing high melting point metal compound layer without being exposed to the atmosphere, in which case,
The high melting point metal compound layer can be prevented from being oxidized to prevent an oxide film from forming on the high melting point metal compound layer, and the contact resistance between the nitrogen-containing high melting point metal compound layer and the high melting point metal layer can be increased. The high melting point metal layer can be stably formed on the nitrogen-containing high melting point metal compound layer without any problems.

[Function] For example, TiN, which becomes the nitrogen-containing high melting point metal compound layer, is deposited with NaC! immediately after deposition or after annealing. Although it is a polycrystalline material with a structure, it is thought that oxygen and the like are adsorbed to the Ti dangling bonds (or defects) that partially exist on the outermost surface.

Conventionally, it is thought that the surface shape of the high melting point metal layer deteriorates because nucleation concentrates on such defects in the early stage of growth of tungsten, which becomes the high melting point metal layer. On the other hand, when the plasma treatment of the present invention is performed, the TiN surface has a uniform surface condition, tungsten nuclei are uniformly formed, and the crystal orientation is uniform, so it is considered that the TiN surface has a flat shape.

〔Example〕

1 to 3 are diagrams for explaining one embodiment of the method for manufacturing a semiconductor device according to the present invention, FIG. 1 is a diagram for explaining the method for manufacturing one embodiment, and FIG. 2 is a diagram for explaining one embodiment. FIG. 3 is a diagram illustrating the effects of one embodiment.

In these figures, 1 is a substrate made of Si or the like, 2 is a diffusion layer such as a source/drain, 3 is an insulating film made of 5int, etc., and 4 is an insulation! A contact hole formed in I3,
5 is a barrier metal layer made of TiN or the like, 6 is a high melting point metal layer made of W or the like, 7 is an insulating film made of Sin, etc., 8 is a surface treatment chamber for plasma surface treatment of the barrier metal layer 5;
9 is a susceptor, 10 is an RF electrode for plasma generation, 11
The sample is transferred from the surface treatment chamber 8 to the growth chamber 1 via the transfer chamber 12.
3, or a gate valve for allowing the growth chamber 13 to enter and exit the surface treatment chamber 8.

Next, the manufacturing method will be explained.

First, as shown in FIG. 1(a), an impurity such as As is introduced into the substrate 1 by, for example, ion implantation, and an n-type diffusion layer 2 is introduced.
An insulating film 3 having a film thickness of, for example, 6000 is formed by depositing Sin on the substrate 1 by, for example, the CVD method.
For example, by selectively etching the insulating film 3 by RIE, a contact hole 4 having a width of, for example, 0.5 μm is formed in the insulating film 3.
At the same time, a diffusion layer 2 is formed in the contact hole 4.
The substrate 1 on which is formed is exposed.

Next, as shown in FIG. 1(b), TiN is deposited by, for example, the CVD method so as to make contact with the diffusion layer 2 in the contact hole 4 to form a barrier metal layer 5 having a film thickness of, for example, 500. After that, the surface of the barrier metal layer 5 is treated using a solvent such as hydrofluoric acid (sulfuric acid may also be used) in order to remove a natural oxide film etc. generated on the barrier metal layer 5. Next, the susceptor 9 in the surface treatment chamber 8 shown in FIG.
A sample is placed on top of the sample, and for example N F s gas (10 sec
The surface of the barrier metal layer 5 made of TiN is plasma-treated by introducing a mixed gas of N, m), N, and gas (100 scc+++) and applying an RF bias to the RF electrode 10 under the susceptor 9 (FIG. 1(C)) ).

Next, the sample after the surface treatment of the barrier metal layer 5 is transferred from the surface treatment chamber 8 to the growth chamber 13 via the vacuum transfer chamber 12,
For example, W is deposited on the barrier metal layer 5 by a CVD method to form a high melting point metal layer 6 having a film thickness of, for example, 300 nm. The W film forming conditions here are WF-gas 10105c, S
I Ha gas 5 scc■, Hz gas 200sec
, the pressure was 200 mTorr, and the growth temperature was 400°C.

Then, a wiring layer consisting of a barrier metal layer 5 and a high melting point metal layer 6 which are in contact with the diffusion layer 2 can be obtained as shown in FIG. 1(d). The barrier metal layer 5 here has a function of preventing the reaction between St of the substrate 1 and W of the high melting point metal layer 6 due to thermal diffusion, and also has the function of strongly adhering the substrate 1 and the high melting point metal layer 6. It has a function as an adhesive layer for this purpose.

That is, in the case where the high melting point metal layer 6 is formed after the conventional barrier metal layer 5 is treated only with chemicals, the reflectance of the high melting point metal layer 6 is 43% with respect to Ar (visible light λ = 400 nm) and the surface shape is In contrast, in the above example of the present invention, the reflectance of the high melting point metal layer 6 was 51% of that of A2, and the surface shape was found to be smoother than that of the conventional example. Therefore, it is possible to form the high melting point metal layer 36 with better coverage than in the past, and it is possible to further realize multilayer wiring and planarization.

In addition, as shown in FIG. 3, the reflectance of the high melting point metal layer 6 was found to be were all low and the surface shape was rough, but when N2 treatment was applied (invention 1), NFs treatment (invention 2), and NF3 +Nt (radical only) treatment (
It was found that in Invention 3) and in the case of NFs + Nz (ion irradiation) treatment (Invention 4), the reflectance was higher than that of the comparative example, and the surface shape was smooth.

In addition, it was found that the ion irradiation according to the present invention 4 is preferable because it is possible to increase the reflectance of the high melting point metal layer 6 and make the surface shape smoother than when the radical treatment according to the present invention 3 is applied. .

In addition, the surface treatment conditions of the present invention 3 and the present invention 4 are as follows.

(Invention 3) (Triode type): 10W, 13.56M7 substrate, no substrate bias, N F 310sccm.

r’h 101005c.

Pressure: 40 mTorr, processing time: 60 seconds.

(Invention 4) (Parallel plate type): 20W, 13.56MHz substrate bias is approximately 1.3kV.

NF 310105c, NzNz1005c.

Pressure: 40 mTorr, processing time: 60 seconds.

〔Effect of the invention〕

According to the present invention, when forming a high melting point metal layer on a barrier metal layer, there is an effect that the high melting point metal layer can be formed smoothly without causing roughness in the surface shape and with good coverage.

[Brief explanation of drawings]

1 to 3 are diagrams for explaining one embodiment of the method for manufacturing a semiconductor device according to the present invention, FIG. 1 is a diagram for explaining the method for manufacturing one embodiment, and FIG. 2 is a diagram for explaining one embodiment. FIG. 3 is a diagram illustrating the effects of one embodiment, and FIG. 4 is a diagram illustrating a conventional manufacturing method. 5...Barrier metal layer, 6...High melting point metal layer. 5: Diagram explaining the manufacturing method of the pariah metal layer 1 Figure N-containing plasma 6: Diagram explaining the manufacturing method of the high melting point metal layer 1 Example Pretreatment ml HF treatment r N NF. NF3+N NF1+Nl Diagram explaining the effect of one embodiment

Claims (4)

[Claims] (1) Nitrogen-containing high melting point metal compound layer (5) in a plasma atmosphere containing at least one of nitrogen or oxygen
1. A method for manufacturing a semiconductor device, comprising the step of surface treating. (2) The method for manufacturing a semiconductor device according to claim 1, wherein the nitrogen-containing high-melting point metal compound layer (5) is irradiated with ions during the surface treatment in the plasma atmosphere. (3) The method for manufacturing a semiconductor device according to claim 1, wherein the nitrogen-containing high melting point metal compound layer (5) is wet-treated and then subjected to the plasma surface treatment. (4) After the plasma surface treatment, the nitrogen-containing high melting point metal compound layer (5) is continuously applied without being exposed to the atmosphere.
2. The method of manufacturing a semiconductor device according to claim 1, further comprising forming a high melting point metal layer (6) thereon.