KR102662396B1 - Composition for forming thin film and manufacturing method of thin film - Google Patents

Abstract

The present invention relates to a composition for forming a thin film and a method for manufacturing a thin film, and relates to a composition for forming a thin film and a method for manufacturing a thin film that contains titanium tetrahalide and an alkoxyarene compound and has a reduced resistivity of the thin film and excellent step coverage. .

Description

Composition for forming thin films and method for manufacturing thin films {COMPOSITION FOR FORMING THIN FILM AND MANUFACTURING METHOD OF THIN FILM}

The present invention relates to a method for producing a thin film of a composition for forming a thin film.

The integration degree of memory and non-memory semiconductor devices is increasing day by day, and as their structures become more complex, the importance of step coverage in depositing various thin films on a substrate is increasing.

Such thin films for semiconductors include metal nitrides, metal oxides, metal silicides, and metals. Typical metal nitride thin films include titanium nitride (TiN), tantalum nitride (TaN), and zirconium nitride (ZrN). These thin films are doped with aluminum (Al) and copper, which are used as silicon layers of semiconductors and interlayer wiring materials. It is used as a diffusion barrier with (Cu) and as an adhesion layer when depositing a tungsten (W) thin film on a substrate.

In order to obtain excellent physical properties of a thin film deposited on a substrate, the selection of a thin film precursor is the most important requirement. For example, titanium chloride (TiCl ₄ ) is used to deposit titanium nitride (TiN), which is representative of the nitride metals. In this case, despite the excellent economic efficiency of this metal, it has several problems as follows.

First, chlorine atoms present in the thin film precursor may flow into the deposited titanium nitride thin film, causing corrosion of the aluminum wiring material. Second, since the deposition temperature is high at around 600°C, it is not applicable to aluminum wiring with a low melting point. Thirdly, non- _volatile by-products such as _titanium tetrachloride ammonia complex [TiCl ₄ : (NH ₃ ) cause.

In addition, methods for manufacturing titanium nitride (TiN) thin films using titanium amide [Ti(NR ₂ ) ₄ , R = CH ₃ or C ₂ H ₅ ] are being developed, but the development is hindered due to the instability and risk of the thin film precursor. There were problems that made it unsuitable for application to next-generation semiconductor devices because it was difficult and had limitations in applying the ALD process.

In order to solve the above problems, the purpose of the present invention is to provide a thin film forming composition and a thin film manufacturing method that can effectively remove process by-products generated during substrate formation and improve the uniformity of the thin film.

In order to solve the above problems, the present invention includes using titanium tetrahalide and an alkoxyarene-based compound to form a thin film.

Specifically, the present invention provides a composition for forming a thin film containing the titanium tetrahalide and an alkoxyarene compound.

In addition, the present invention provides a method for producing a thin film including the step of depositing a thin film on a substrate using the titanium tetrahalide and an alkoxyarene-based compound.

In the present invention, when forming a thin film on a substrate using titanium tetrahalide and an alkoxyarene compound, the content of Cl ions, which are a by-product of the process, can be effectively removed even if the deposition temperature for depositing the thin film on the substrate is increased. When manufacturing a thin film using this, the resistivity of the thin film can be reduced and step coverage can be improved.

Figure 1 is a TEM image of a TIN thin film of an example and a comparative example of the present invention, (a) is an example, and (b) is a comparative example.

Hereinafter, the present invention will be described in detail.

1. Composition for thin film formation

One aspect of the present invention provides a composition for forming a thin film.

The composition for forming a thin film of the present invention may include titanium tetrahalide and an alkoxyarene-based compound.

The titanium tetrahalide can be used as a thin film precursor for a composition for forming a thin film. The titanium tetrahalide may be at least one selected from the group consisting of TiF ₄ , TiCl ₄ , TiBr ₄ and TiI ₄ , for example, TiCl ₄ It is preferable, but is not limited to this.

The titanium tetrahalide has excellent thermal stability and does not decompose at room temperature and exists in a liquid state, so it can be usefully used as a thin film precursor for chemical vapor deposition or atomic layer deposition to deposit a thin film.

The composition for forming a thin film may use an alkoxyarene-based compound as a polar solvent for dissolving the thin film precursor.

The alkoxyarene compound preferably contains at least one of a benzene ring and a naphthalene ring in view of its low reactivity with titanium tetrahalide, and more preferably contains a benzene ring.

In addition, the alkoxyarene compound preferably contains an alkoxy group because the lone pair of oxygen atoms of the alkoxy group contains a halogen atom, and more preferably contains a C ₁ -C ₄ alkoxy group.

Furthermore, from the viewpoint of vapor pressure, the alkoxyarene compound preferably includes at least one selected from the group consisting of methoxybenzene, 1,3-dimethoxybenzene, and ethoxybenzene.

The composition for forming a thin film of the present invention may further include a polar solvent other than the alkoxyarene-based compound. These polar solvents include 1,2-Dichlorobutane, 1,2-Dichloroethane, Acetone, Acetonitrile, and Dimethyl Sulfoxide. sulfoxide), t-Butanol, i-Propanol, Ethanol, Methanol, 1-Butanol, 2-Butanol, Cyclo Cyclohexanol, Phenol, 2,2,2-Trifluoroethanol, Acetic acid, Pyridine, Piperidine, N ,N,N-Dimethylacetamide, Dimethylformamide, Cyclopentyl methyl ether, diethyl ether, Methyl t-butyl ether ), 1,4-Dioxane, Dimethoxymethane, Morpholine, ethylene glycol, N-methyl-2-pyrrolidinone (N-methyl- 2-pyrrolidinone, nitromethane, chlorobenzene, ethyl acetate, 1,3-propanediol, quinoline, glycerol, 3- 3-pentanol, formic acid, nitrobenzene, propionitrile, 2-aminoethanol, ethyl benzoate, methyl acetate , Methyl formate, Form amide, Ethyl formate, Benzonitrile, 2-Ethoxyethanol, 2-butanone, 1 ,2-Dichlorobenzene, 1,3-Dioxolane, Tetrahydropyran, Trifluoroacetic acid, N,N-dimethylaniline ( N,N-Dimethylaniline), Diethyl amine, Dimethylethyl amine, 1,1-Dichloroethane, 1,1-trichloroethane (1,1,1) -Trichlorethane), methyl iodide (Iodomethane), tetrahydrofuran (THF), and dichloromethane (Dichloromethane).

At this time, it is most preferable that the tetrahalogenated titanium:alkoxyarene compound is included in a molar ratio of 1:0.2 to 5.

If the content of the alkoxyarene compound is added in excess of the upper limit, impurities may be generated and the resistance and impurity level in the thin film may worsen, and if the content of the alkoxyarene compound is added below the lower limit, the addition of solvent may cause The effect of reducing halogen ions in the thin film is minimal.

2. Thin film and its manufacturing method

Another aspect of the present invention provides a thin film and a method for manufacturing the same.

The thin film of the present invention is formed by depositing the thin film on a substrate in a chamber using the above-described titanium tetrahalide and alkoxyarene-based compounds.

The first embodiment of the step of depositing a thin film on a substrate in the present invention may include preparing a composition containing titanium tetrahalide and an alkoxyarene compound in advance and introducing it into a chamber to deposit a thin film on the substrate. there is.

In addition, the second embodiment of the step of depositing a thin film on a substrate in the present invention includes depositing a thin film on the substrate while independently transporting titanium tetrahalide and an alkoxyarene compound into the chamber. It may be possible.

Hereinafter, the method for manufacturing a thin film using the first embodiment will be mainly described, but since the method for manufacturing a thin film using the second embodiment can be easily performed from this method, only a portion of the method will be described. do.

First, the substrate on which the thin film is to be formed is placed in the chamber.

The substrate may include a semiconductor substrate such as a silicon substrate, a germanium substrate, a silicon-germanium substrate, or a silicon-on-insulator (SOI) substrate. The substrate may further have a conductive layer or an insulating layer formed on its top. The chamber may be a chamber in which atomic layer deposition or chemical vapor deposition is performed.

In order to deposit a thin film on a substrate placed in the chamber, the above-described titanium tetrahalide and alkoxyarene compounds are prepared. At this time, the tetrahalogenated titanium and alkoxyarene compounds may be in a liquid state. The liquid titanium tetrahalide and alkoxyarene compounds are prepared in advance by preparing a composition containing the titanium tetrahalide and alkoxyarene compounds, or by preparing the titanium tetrahalide and alkoxyarene compounds independently, and transferring these compounds into the chamber. You can do it.

The method of transporting the tetrahalogenated titanium and alkoxyarene compounds into the chamber is a method of transporting volatilized gas using vapor pressure (Vapor Flow Control; VFC), direct liquid injection (DLI), or thin film precursor material. The Liquid Delivery System (LDS) can be used to transport the solution by dissolving it in an organic solvent.

As described above, in the present invention, a liquid transfer method is used in which a composition in which titanium tetrahalide, a thin film precursor material, is previously dissolved in an alkoxyarene compound, an organic solvent, is transferred into a chamber, or titanium tetrahalide, a thin film precursor material, and an alkoxyarene compound, an organic solvent. A method of injecting the compounds independently into the vaporizer and then transferring them in a volatilized vapor state can be used. At this time, one or more mixtures selected from argon (Ar), nitrogen (N ₂ ), and helium (He) may be used as a transport gas or dilution gas for moving the thin film forming composition onto the substrate.

Next, the titanium tetrahalide transferred into the chamber is adsorbed on the substrate, and the non-adsorbed titanium tetrahalide is purged. At this time, an inert gas may be used as the purge gas.

Next, reactants are supplied. The reactive material may include a reducing agent (eg, NH ₃ ) or a nitriding agent (eg, N ₂ ). A metal thin film may be deposited using the reducing agent, and a metal nitride (eg, TIN) thin film may be deposited using the nitriding agent. Meanwhile, the reactant may include an oxidizing agent such as H ₂ O, H ₂ O ₂ , O ₂ , O ₃ , N ₂ O, etc. The reactant and the adsorbed titanium tetrahalide may react to form a metal oxide (eg, TiO ₂ ) thin film. At this time, the temperature for depositing the thin film on the substrate may be 100 to 700 °C.

Next, unreacted materials are purged. Accordingly, excess reactants and generated by-products can be removed.

As above, the unit cycle consists of adsorbing titanium tetrahalide onto the substrate, purging the non-adsorbed titanium tetrahalide, supplying reactants, and purging unreacted substances, and forming a thin film of the desired thickness. For this reason, the unit cycle can be repeated.

The thin film manufactured in this way may be a TiN or TiO ₂ thin film.

Hereinafter, the present invention will be described in detail through examples. However, the following examples only illustrate the present invention, and the present invention is not limited by the following examples.

[ Example ]

A composition for forming a thin film was prepared by dissolving TiCl ₄ in methoxybenzene. Methoxybenzene 6g, TiCl ₄ A composition for forming a thin film was prepared by adding 4g. The composition for forming a thin film prepared in this way was placed in a bubbler and supplied to a vaporizer heated to 150°C at a rate of 0.05 g/min using an LMFC (Liquid Mass Flow Controller) while supplying argon gas at 100 sccm at room temperature. The composition grown in vapor phase in the vaporizer was introduced into the chamber for 5 seconds, and then argon gas was supplied at 100 sccm for 10 seconds to perform argon purging. At this time, the pressure within the reaction chamber was controlled at 1 Torr. Next, ammonia (NH ₃ ) as a reactive gas was introduced into the reaction chamber for 5 seconds, and then argon purging was performed for 10 seconds. At this time, the substrate on which the metal thin film was to be formed was heated to 440°C. This process was repeated 430 times to form a TIN thin film, which is a self-limiting atomic layer.

[ Comparative example ]

A TIN thin film was formed in the same manner as in the example, except that ₄ g of TiCl 4 was used.

[ Experiment example ]

Determination of Cl ion content

The content of Cl ions in the membranes of the examples and comparative examples was measured using a secondary ion mass spectrometer (magnetic sector type secondary ion mass spectrometer, CAMECA IMS 7f magnetic sector SIMS) and is shown in Table 1.

Example Comparative example Cl content 10177 16876

Resistivity characteristics

The sheet resistance of the TIN thin films prepared in the above examples and comparative examples was measured using a 4-point probe, and the results are shown in Table 2 below.

Example Comparative example resistivity 148 μΩ·cm 161 μΩ·cm

step Cloth properties

The step coverage of the TIN thin films prepared in the above examples and comparative examples was confirmed using TEM. The results are shown in Table 3 and Figure 1 below.

Example Comparative example Step coverage (%) 99.2% 96.7%

Referring to Tables 1 to 3 above, in the case of the example using titanium tetrahalide and an alkoxyarene compound, even if the thin film is manufactured by heating the substrate on which the metal thin film is to be formed to 440 ° C., the content of Cl ions, which are a process by-product, is It can be confirmed that this is relatively lower than the case of the comparative example containing only titanium tetrahalide, and as a result, it can be confirmed that the resistivity of the thin film is reduced and the step coverage is excellent compared to the comparative example.

Claims (14)

Contains TiCl ₄ and alkoxyarene-based compounds,
The alkoxyarene compound contains at least one of a benzene ring and a naphthalene ring,
A composition for forming a thin film comprising the TiCl ₄ and the alkoxyarene compound at a molar ratio of 1:0.2 to 5. delete delete delete In claim 1,
The alkoxyarene compound is a composition for forming a thin film containing an alkoxy group of C ₁ -C ₄ . In claim 1,
A composition for forming a thin film wherein the alkoxyarene compound includes at least one selected from the group consisting of methoxybenzene, 1,3-dimethoxybenzene, and ethoxybenzene. delete According to any one of claims 1, 5, and 6,
The thin film is a composition for forming a thin film containing at least one of TiN and TiO ₂ . Transferring TiCl ₄ as a thin film precursor material and an alkoxyarene-based compound as an organic solvent into a chamber, adsorbing the TiCl ₄ on a substrate, and then depositing a titanium-containing thin film on the substrate,
The alkoxyarene compound contains at least one of a benzene ring and a naphthalene ring,
A method of producing a thin film using the TiCl ₄ and the alkoxyarene compound at a molar ratio of 1:0.2 to 5. In claim 9,
Transferring the TiCl ₄ and the alkoxyarene compound into the chamber includes transferring a composition containing the TiCl ₄ and the alkoxyarene compound into the chamber. In claim 9,
Transferring the TiCl ₄ and the alkoxyarene compound into the chamber includes independently transferring the TiCl ₄ and the alkoxyarene compound into the chamber. The method according to any one of claims 9 to 11,
A method of producing a thin film wherein the deposition is performed by an atomic layer deposition (ALD) process or a chemical vapor deposition process. A thin film manufactured by the thin film manufacturing method of any one of claims 9 to 11. In claim 13,
The thin film is a thin film containing TiN or TiO ₂ .