KR102645319B1 - Composition for forming thin film, thin film and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a composition for forming a thin film, a thin film using the same, and a method for manufacturing the same. The composition for forming a thin film contains titanium tetrahalide and a silane-based compound, and the thin film produced therefrom has low resistivity and excellent step coverage. do.

Description

Composition for forming a thin film, a thin film using the same, and a method for manufacturing the same {COMPOSITION FOR FORMING THIN FILM, THIN FILM AND MANUFACTURING METHOD THEREOF}

The present invention relates to a composition for forming a thin film, a thin film using the same, and a method for manufacturing the same.

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), and 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 the precursor is the most important requirement. For example, when titanium chloride (TiCl ₄ ) is used to deposit titanium nitride (TiN), which is representative of the nitride metals, Despite the excellent economic efficiency of this metal, it has several problems as follows.

First, chlorine atoms present in the 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 difficult to apply in the case of aluminum wiring with a low melting point. , _Third , during the process, non-volatile by-products such as titanium chloride ammonia complex [ _{TiCl 4} : (NH ₃ ) do.

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 development is difficult due to the instability and risk of the precursor. There was a problem that it was not suitable for application to next-generation semiconductor devices because it had limitations in applying the ALD process.

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

Additionally, the present invention aims to provide a thin film formed using the thin film forming composition.

Additionally, the present invention aims to provide a method for manufacturing the thin film.

In order to solve the above problems, the present invention provides a composition for forming a thin film containing titanium tetrahalide and a silane-based compound.

Additionally, the present invention provides a thin film formed using the thin film forming composition.

Additionally, the present invention provides a method for producing a thin film including the step of depositing a thin film on a substrate using the thin film forming composition.

The composition for forming a thin film of the present invention does not react with TiCl ₄ even if the deposition temperature is increased to a high temperature (e.g., 100 to 700 ° C.) when forming a substrate, and reduces the amount of chlorine (Cl) ions generated as a process by-product. The step coverage of the manufactured thin film can be improved.

Hereinafter, the present invention will be described in detail.

1. Composition for thin film formation

The present invention provides a composition for forming thin films.

The composition for forming a thin film according to the present invention includes titanium tetrahalide and a silane-based compound.

The titanium tetrahalide is a precursor for a composition for forming a thin film. It has excellent thermal stability and does not decompose at room temperature and exists in a liquid state, so it is useful for depositing a thin film by using it as a precursor for a chemical vapor deposition method or an atomic layer deposition method. can be used

The titanium tetrahalide may include at least one selected from the group consisting of TiF ₄ , TiCl ₄ , TiBr ₄ and TiI ₄ . Specifically, in terms of protecting the lower film and being economical, the titanium tetrahalide may be TiCl ₄ .

The composition for forming a thin film includes a silane-based compound as a solvent.

The silane-based compound may include one or more compounds selected from the group consisting of alkyltrialkoxysilane, trialkylalkoxysilane, trialkylhalosilane, and trialkoxyhalosilane. At this time, the alkyl may be substituted or unsubstituted C ₁ -C ₁₀ alkyl, and the alkoxy may be substituted or unsubstituted C ₁ -C ₁₀ alkoxy.

Specifically, the silane-based compound is methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, trimethylmethoxysilane, trimethylethoxysilane, triethylmethoxysilane, triethyl selected from the group consisting of ethoxysilane, trimethylchlorosilane, trimethylbromosilane, triethylchlorosilane, triethylbromosilane, trimethoxychlorosilane, trimethoxybromosilane, triethoxychlorosilane and triethoxybromosilane. It may include one or more types.

Additionally, the silane-based compound may include a trialkyl halosilane that has low reactivity with titanium terahalide. Specifically, the silane-based compound may include trimethylchlorosilane or triethylchlorosilane.

The composition for forming a thin film may include titanium tetrahalide and a silane-based compound at a molar ratio of 1:0.5 to 3. Specifically, the composition for forming a thin film may include titanium tetrahalide and a silane-based compound at a molar ratio of 1:1 to 2. When the content of the silane compound exceeds the upper limit, impurities are generated and the resistance of the manufactured film increases. The level of impurities in the thin film may increase, and if the content of the silane-based compound is added below the lower limit, the effect of reducing halogen atoms in the thin film cannot be obtained.

2. Thin film

The present invention provides a thin film formed using the composition for forming a thin film as described above.

The thin film may include TiN or TiO ₂ .

3. Thin film manufacturing method

The method for producing a thin film according to the present invention includes depositing a thin film on a substrate using the composition for forming a thin film described above.

At this time, the deposition may be performed by an atomic layer deposition (ALD) process or a chemical vapor deposition process.

Specifically, a method for manufacturing the thin film will be described.

First, place the substrate in the reaction chamber.

The substrate may be a semiconductor substrate such as a silicon substrate, germanium substrate, silicon-germanium substrate, or a silicon-on-insulator (SOI) substrate. Additionally, the substrate may have a conductive layer or an insulating layer formed on one side.

Furthermore, the reaction 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 composition for forming a thin film described above is prepared. At this time, the composition for forming a thin film may be in a liquid form.

Next, the liquid thin film forming composition can be injected into the vaporizer and then delivered into the chamber in vapor form. The method of delivering the thin film forming composition into the chamber is a method of transferring volatilized gas using vapor pressure, a direct liquid injection method, or a liquid transfer method (Liquid Injection) in which the precursor material is dissolved in an organic solvent and transported. Delivery System (LDS) can be used. Specifically, the method of delivering the thin film forming composition into the chamber is to apply a liquid transfer method in which titanium tetrahalide is dissolved in a silane compound, which is an organic solvent, and then transferred, changing the mixing ratio of the composition. It is desirable in terms of maintenance.

At this time, the tetrahalogenated titanium and the silane-based compound may be mixed at a molar ratio of 1:0.5 to 3.

Additionally, 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 on the substrate.

Next, the transferred thin film forming composition may be adsorbed on the substrate, and the non-adsorbed thin film forming composition may be purged. At this time, an inert gas may be used as the purge gas.

Next, the reactant is 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 thin film may be deposited using the nitriding agent.

Meanwhile, the reactive material may further include an oxidizing agent such as H ₂ O, H ₂ O ₂ , O ₂ , O ₃ , N ₂ O, etc. Furthermore, a metal oxide thin film may be formed by reacting the reactive material with the adsorbed composition for forming a thin film.

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

As described above, the manufacturing method includes the steps of adsorbing the composition for forming a thin film on a substrate, purging the non-adsorbed composition for forming a thin film, supplying a reactant, and purging the unreacted material. It is a unit cycle, and one unit cycle can be repeated to form a thin film of desired thickness.

At this time, the deposition temperature may be 100 to 700 °C.

Hereinafter, the present invention will be described in detail through examples. However, the following examples are merely illustrative of the present invention, and the present invention is not limited by the following examples.

[Example]

Example 1.

A composition for forming a thin film was prepared by dissolving titanium tetrachloride (TiCl ₄ ) in trimethylchlorosilane. At this time, trimethylchlorosilane and TiCl ₄ were mixed at a molar ratio of 1:1.

Thereafter, the substrate was placed in the reaction chamber, the prepared thin film forming composition was placed in a bubbler, and argon gas was supplied at 100 sccm at room temperature and 150° C. at a rate of 0.05 g/min using an LMFC (Liquid Mass Flow Controller). It was supplied to a vaporizer that was heated. 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.

The above-described process was repeated 430 times to form a TiN thin film, which is a self-limiting atomic layer.

Comparative Example 1.

A TiN thin film was formed in the same manner as Example 1, except that TiCl ₄ was used instead of the thin film forming composition.

Comparative Example 2.

An attempt was made to form a TiN thin film in the same manner as in Example 1, except that hexamethyldisiloxane, a polar silane solvent, was used instead of trimethylchlorosilane, but deposition was impossible due to the reaction between TiCl ₄ and hexamethyldisiloxane.

Experiment example.

1-1: Measurement of chlorine (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 1 Comparative Example 1 Comparative Example 2 Cl content (number) 7,168.3 5,384.6 not measurable

1-2: Resistivity characteristics

The sheet resistance of the TiN thin film prepared in Examples and Comparative Examples was measured using a 4-point probe, and the results are shown in Table 2.

Example 1 Comparative Example 1 Comparative Example 2 resistivity 172 μΩ·cm 194 μΩ·cm not measurable

As shown in Table 2, the sheet resistance of the thin film of Example 1 was lower than that of the thin film of Comparative Example 1.

1-3: Step covering characteristics

The step coverage of the TiN thin films prepared in Examples and Comparative Examples was confirmed using a transmission electron microscope (TEM), and the results are shown in Table 3.

Example 1 Comparative Example 1 Comparative Example 2 Step coverage (%) 98% 96.7% not measurable

As shown in Table 3, it can be seen that the step coverage of the thin film of Example 1 is superior to that of the thin film of Comparative Example 1.

Claims (11)

A composition for forming a titanium-containing thin film comprising titanium tetrahalide as a titanium precursor and a silane-based compound as a solvent,
A composition for forming a titanium-containing thin film, wherein the silane-based compound is a trialkylhalosilane. In claim 1,
The titanium tetrahalide is a composition for forming a titanium-containing thin film, including at least one selected from the group consisting of TiF ₄ , TiCl ₄ , TiBr ₄ and TiI ₄ . In claim 2,
The titanium tetrahalide is TiCl ₄ , a composition for forming a titanium-containing thin film. delete In claim 1,
The composition for forming a titanium-containing thin film, wherein the silane-based compound includes at least one selected from the group consisting of trimethylchlorosilane, trimethylbromosilane, triethylchlorosilane, and triethylbromosilane. In claim 5,
The composition for forming a titanium-containing thin film, wherein the silane-based compound includes trimethylchlorosilane or triethylchlorosilane. In claim 1,
A composition for forming a titanium-containing thin film, wherein the composition includes titanium tetrahalide and a silane-based compound in a molar ratio of 1:0.5 to 3. A titanium-containing thin film formed using the composition for forming a thin film according to claim 1. In claim 8,
The titanium-containing thin film includes TiN or TiO ₂ . A method of producing a titanium-containing thin film comprising the step of depositing the composition for forming a titanium-containing thin film according to claim 1 on a substrate. In claim 10,
A method of producing a titanium-containing thin film, wherein the deposition is performed by an atomic layer deposition (ALD) process or a chemical vapor deposition process.