KR20210056576A - Metal precursor for forming thin film, thin film composition comprising the same and method for forming thin film thereof - Google Patents

Abstract

The present invention relates to a metal precursor for forming a thin film, composition for forming thin film comprising same, and method for forming thin film. More specifically, the present invention relates to a metal precursor for forming a thin film which comprises a compound indicated by the below chemical formula 1 [Chemical formula 1] (In the chemical formula 1, M refers to a Group 4 transition metal, and R1 through R5 refer to respectively alkyl group with 1 to 3 of hydrogen or carbon number, and one of a and b is a single combination and the other is a dual combination.) According to the present invention, the metal precursor for forming the thin film has an excellent thermal stability, so the process stability of a high-temperature deposition process is improved. In addition, a specific solvent is included along with the metal precursor as a composition for forming the thin film, so the thermal stability, volatility, and viscosity are improved. Accordingly, an even thin film can be formed through a high-temperature process, and a step coverage is greatly improved.

Description

A metal precursor for thin film formation, a composition for thin film formation including the same, and a method of forming a thin film {METAL PRECURSOR FOR FORMING THIN FILM, THIN FILM COMPOSITION COMPRISING THE SAME AND METHOD FOR FORMING THIN FILM THEREOF}

The present invention relates to a metal precursor for forming a thin film, a composition for forming a thin film including the same, and a method for forming a thin film, and more particularly, a metal precursor for forming a high dielectric thin film suitable for application to a high-temperature process due to improved thermal stability, and the metal A composition for forming a thin film in which thermal stability, volatility and viscosity are improved by including a precursor and a specific solvent to greatly improve the uniformity and step coverage of a thin film through a high-temperature process, and a method for manufacturing a thin film using the same. will be.

The degree of integration of memory and non-memory semiconductor devices is increasing day by day, and as the structure becomes more complex, the importance of step coverage in depositing a thin film on a substrate is gradually increasing.

In order to obtain excellent thin film properties and uniform physical properties of the thin film deposited on the substrate, it is essential that the formed thin film has high step coverage. Therefore, an ALD (atomic layer deposition) process that utilizes a surface reaction is used rather than a CVD (chemical vapor deposition) process that mainly uses a vapor phase reaction, but there is still a problem in realizing 100% step coverage.

Since the ALD process proceeds at a high temperature, a high-k precursor compound that can be deposited at a high temperature is used as a thin film forming material. Although zirconium is mainly used as the high dielectric precursor compound, the thermal stability of the zirconium precursor is not sufficient to be applied to the ALD process, and thus thermal decomposition occurs during the thin film formation process.

In addition, when injecting raw materials into the ALD chamber, the liquid delivery system (LDS) method is mainly used, but in order to use the LDS method, the raw material for thin film formation must be a liquid, and even in the case of a liquid, if the viscosity is high, When the raw material is introduced into the chamber, it is not evenly dispersed, so it is difficult to form a thin film uniformly, and there is a problem in that the step coverage is inferior.

Accordingly, there is a need for development of a precursor or composition for forming a thin film with improved thermal stability, a complex structure, and improved viscosity and volatility, and a semiconductor substrate manufactured including the same.

Korean Patent Publication No. 2006-0034775

In order to solve the problems of the prior art as described above, the present invention includes a metal precursor for forming a thin film that can improve process stability by improving thermal stability, the metal precursor, and a specific organic solvent. An object of the present invention is to provide a composition for forming a thin film, which can form a thin film having improved volatility and excellent uniformity and step coverage when forming a thin film, and a method of manufacturing a thin film using the same.

All of the above and other objects of the present invention can be achieved by the present invention described below.

In order to achieve the above object, the present invention is the following Chemical Formula 1

[Formula 1]

(In Formula 1, M is a Group 4 transition metal, R ₁ to R ₅ are each independently hydrogen or an alkyl group having 1 to 3 carbon atoms, and one of a and b is a single bond and the others are double bonds.) It provides a metal precursor for thin film formation, characterized in that it comprises a compound.

In addition, the present invention provides a composition for forming a thin film comprising the metal precursor and an organic solvent for forming the thin film.

In addition, the present invention provides a method of forming a thin film comprising the step of forming a thin film by depositing the composition for forming a thin film on a substrate.

According to the present invention, it is possible to provide a metal precursor for forming a thin film with improved thermal stability and improved process stability of the deposition process, and the thin film is evenly formed on the substrate through the improvement of the viscosity and volatility of the thin film forming raw material to form a uniform thin film. It is possible to form a thin film evenly on a substrate having a complex shape, and thus there is an effect of providing a composition for forming a thin film having excellent step coverage and a method of manufacturing a thin film having excellent step coverage by using the same.

Hereinafter, the metal precursor for forming a thin film of the present disclosure, a composition for forming a thin film including the same, and a method for forming a thin film will be described in detail.

The inventors of the present invention were studying a precursor compound that can stably form a thin film even in a high-temperature deposition process through improved thermal stability, and the compound was stabilized by introducing a double bond to the ligand connected to the central metal. It was confirmed that the film quality of the thin film was improved by improving the crystallinity through high-temperature deposition, and based on this, the present invention was completed by further focusing on research.

The metal precursor for forming a thin film of the present invention, the following Formula 1

[Formula 1]

(In Formula 1, M is a Group 4 transition metal, R ₁ to R ₅ are each independently hydrogen or an alkyl group having 1 to 3 carbon atoms, and one of a and b is a single bond and the others are double bonds.) Characterized in that it comprises a compound to be.

In Formula 1, M is a Group 4 transition metal, for example, may be one selected from the group consisting of Zr, Hf, and Ti, and is preferably Zr. In this case, it is possible to form a high-k dielectric thin film, and the insulating property and dielectric constant of the thin film are high, so that high integration of the thin film substrate is easier.

Wherein a and b are three carbon elements connected between a cyclopentadienyl group (Cp) connected to the central metal (M) of the metal precursor for thin film formation and a nitrogen element (N) connected to the cyclopentadienyl group It represents a bond between, and one of a and b is a single bond and the other is a double bond. That is, it is a form including one double bond between the three carbon elements connecting Cp and N. In this case, the thermal stability of the metal precursor for thin film formation is greatly improved by the double bond included in the ligand, so that it can be used at high temperatures. Due to the thermal decomposition may be suppressed, crystallinity by high-temperature deposition such as ALD is improved, thereby forming a uniform thin film, and there is an excellent effect of improving the film quality of a thin film manufactured including the same.

R ₁ to R ₅ are each independently hydrogen or an alkyl group having 1 to 3 carbon atoms, preferably hydrogen or a methyl group, more preferably hydrogen, and in this case, the structure of the precursor is simplified to further improve the thermal stability and thus the deposition process Can improve the efficiency of.

The composition for forming a thin film of the present invention is characterized in that it contains the metal precursor and an organic solvent for forming the thin film. The composition for thin film formation of the present invention greatly improves thermal stability by including the metal precursor for thin film formation, so that when applied to a film formation process by a high temperature deposition process such as ALD, process stability is improved, and uniformity, film quality, and step coverage are improved. It can provide an excellent thin film.

The organic solvent is, for example, one or more selected from the group consisting of amines and ethers, and in this case, the viscosity and volatility of the composition for forming a thin film can be easily controlled.

The amines and ethers are for example 1:99 to 99:1, preferably 20:80 to 80:20, more preferably 30:70 to 70:30, more preferably 40:60 to 60:40 It can be included in a weight ratio, and in this case, the adsorption efficiency of the metal precursor for thin film formation to the substrate is improved to form a uniform thin film, stability is improved, the film formation process efficiency can be improved, and the step coverage improvement effect There is an effect that is further improved.

The amine may be, for example, a tertiary amine, and the boiling point (1 atm) is, for example, 70°C or less, preferably 30 to 65°C, more preferably 40 to 50°C, and the density (25°C) is as an example 0.6 to 0.8 g/cm ³ , preferably 0.65 to 0.75 g/cm ³ , and the vapor pressure (25° C., 1 atm) may be 400 to 700 mmHg, preferably 500 to 650 mmHg. In this case, the viscosity and volatility of the composition for thin film formation are appropriately controlled, so that vaporization using the liquid transfer method (LDS) is facilitated, and through this, the efficiency and stability of the substrate (WAFER) adsorption of the precursor for thin film formation are improved, thereby shortening the process time. And the composition for forming a thin film is uniformly applied to improve the uniformity and step coverage of the thin film. In addition, stability is further improved through an intermolecular interaction with a precursor for forming a thin film by an unshared electron pair contained in the molecule of the tertiary amine, thereby preventing unstable deposition during the film formation process and further improving the uniformity of the thin film.

The tertiary amine may preferably be a dialkylamine, more preferably dimethylethylamine, and in this case, the viscosity and volatility improvement effect of the composition for forming a thin film is more excellent, and due to excellent volatility, after the deposition process Since the residual rate of impurities is low, the film quality of the thin film can be improved, and the compatibility of the composition for forming the thin film is improved without reacting with the metal precursor for forming the thin film.

The ether may preferably be a cycloalkyl ether, a boiling point (1 atm) of 110°C or less, specifically 60 to 100°C, and a density (25°C) of 0.7 to 0.9 g/cm ³ , specifically 0.8 To 0.89 g/cm ³ may be more preferable. In this case, the viscosity and volatility of the composition for forming a thin film are appropriately adjusted to facilitate vaporization using a liquid transfer method (LDS), thereby improving the substrate adsorption efficiency and stability of the precursor for forming a thin film, thereby shortening the process time. , As the composition for forming a thin film is uniformly applied, there is an excellent effect of improving the uniformity and step coverage of the thin film.

The cycloalkyl ether may preferably be a cyclopentyl alkyl ether, and more preferably a cyclopentyl methyl ether. In this case, the composition has excellent solubility in organic compounds without reacting with the metal precursor for forming a thin film. There is an excellent effect of improving stability and maintaining a uniform composition to form a uniform thin film.

The composition for forming a thin film may include, for example, 1 to 99% by weight, preferably 2 to 90% by weight, of the metal precursor for forming the thin film, and the organic solvent is 1 to 99% by weight, preferably It may contain from 10 to 98% by weight. In this case, there is an excellent effect of improving the viscosity and volatility of the composition for forming a thin film, thereby improving the uniformity of the thin film and the step coverage.

For example, the composition for forming a thin film may have a viscosity (25°C) of 1 to 20 cP, specifically 3 to 15 cP, or 5 to 10 cP, and within this range, the viscosity of the composition for forming a thin film is As it is suitable for application to a deposition process, it has an excellent effect of improving substrate adsorption efficiency and process efficiency, and improving thin film uniformity and step coverage.

In the present description, the viscosity can be measured at 25°C using a viscometer (DV-II+ Viscometer™, Brookfield Co.).

The method of forming a thin film of the present invention is characterized in that it includes the step of forming a thin film by depositing the composition for forming a thin film on a substrate. In this case, the composition for forming a thin film has excellent thermal stability, and by using a specific solvent, the viscosity and volatility of the composition are improved to be suitable for the deposition process, thereby improving the deposition process efficiency at high temperatures and improving the film quality of the thin film. There is an excellent effect of greatly improving the uniformity and step coverage of.

The deposition may be, for example, CVD or ALD, and preferably ALD. The metal precursor for forming a thin film of the present invention has excellent thermal stability and excellent effect of improving the viscosity and volatility of the organic solvent, making it suitable for application to the ALD process, and the step coverage of the thin film can be further improved by the ALD process. have.

The deposition may be performed at, for example, a temperature of 300 to 600° C., and preferably may be performed at 450 to 550° C., and there is an effect of excellent film quality and step coverage of a thin film formed within this range.

In addition, the deposition may be carried out at a pressure in the range of 0.1 to 10 Torr, for example, preferably 0.5 to 5 Torr, more preferably 1 to 3 Torr, and uniform within this range. There is an effect of obtaining a thin film of thickness.

In the present disclosure, the deposition temperature and the deposition pressure may be measured as a temperature and pressure formed in the deposition chamber, or may be measured as a temperature and pressure applied to a substrate in the deposition chamber.

In a preferred embodiment, the method of forming a thin film includes: i) first purging the inside of the ALD chamber with a purge gas; Ii) vaporizing the composition for forming a thin film and adsorbing it to the surface of the substrate loaded in the ALD chamber; Iii) secondary purging the inside of the ALD chamber with a purge gas; Iv) supplying a reaction gas into the ALD chamber; And v) third purging the inside of the ALD chamber with a purge gas.

The thin film formation method is, for example, several tens or more times, specifically 10 to 1000 times, preferably 50 to 500 times, more preferably, until a thin film of a desired thickness is obtained by performing the steps i) to v) in one cycle. It may be repeated 100 to 300 times, the thickness of the thin film is appropriately controlled within the above range, and the properties of the desired thin film can be well expressed.

The method of delivering the composition for thin film formation to the deposition chamber is a method of transferring the volatilized gas using a mass flow controller (MFC) method (Vapor Flow Control; VFC) or a liquid mass flow controller. ; LMFC) method to transfer a liquid in which a metal precursor is dissolved in an organic solvent (Liquid Delivery System; LDS), etc., may be used, preferably the LDS method, and in this case, the viscosity of the composition for forming a thin film And since the volatility can be easily controlled, the process efficiency and the film quality of the thin film can be improved.

The purging is preferably 1,000 to 10,000 sccm, more preferably 2,000 to 7,000 sccm, more preferably 2,500 to 6,000 sccm, and within this range, the thin film growth rate per cycle is appropriately controlled, and process by-products are reduced.

As a specific example, when describing the method of forming the thin film,

First, a substrate on which a thin film is to be formed is placed in a deposition chamber capable of atomic layer deposition, and a firing temperature is maintained.

The substrate may be used without particular limitation as long as it is used for semiconductor manufacturing, and specifically, a silicon substrate, a silica substrate (SiO ₂ ), a silicon nitride substrate (SiN), a silicon oxynitride substrate (SiON), a titanium nitride substrate ( TiN), a tantalum nitride substrate (TaN), a tungsten substrate (W) or a noble metal substrate, for example, a platinum substrate (Pt), a palladium substrate (Pd), a rhodium substrate (Rh) or a gold substrate (Au), etc. may be used. have. The substrate may preferably be a silicon substrate or a silicon oxide substrate.

The substrate may further have a conductive layer or an insulating layer formed thereon.

Next, an inert gas is injected into the deposition chamber to purify the inside of the deposition chamber.

Next, the above-described composition for forming a thin film is prepared in order to deposit a thin film on the substrate placed in the deposition chamber.

Thereafter, the prepared composition for forming a thin film is injected into a vaporizer, converted into a vapor phase, transferred to a deposition chamber, and adsorbed onto the substrate, and the unadsorbed composition for forming a thin film is purged.

In the present description, the method of transferring the composition for forming a thin film to the deposition chamber is, for example, a method of transferring the volatilized gas using a mass flow controller (MFC) method (Vapor Flow Control; VFC) or liquid phase flow control. Using the (Liquid Mass Flow Controller; LMFC) method, a liquid delivery system (LDS) can be used, and preferably an LDS method is used.

At this time, one or two or more mixed gases selected from _{argon (Ar), nitrogen (N 2} ), and helium (He) may be used as a transport gas or a dilution gas for moving the composition for forming a thin film on the substrate, but the limitation is no.

In the present description, an inert gas may be used as an example as the purge gas, and preferably the transport gas or the diluting gas may be used.

Next, a reaction gas is supplied. The reaction gas is not particularly limited if it is a reaction gas commonly used in the technical field to which the present invention belongs, and may preferably include a reducing agent, a nitrifying agent, or an oxidizing agent, and preferably an oxidizing agent. Here, the reducing agent and the thin film precursor compound adsorbed on the substrate react with the reaction gas to form a metal thin film, a metal nitride thin film is formed by the nitriding agent, and a metal oxide thin film is formed by the oxidizing agent. do.

The reducing agent may be preferably ammonia gas (NH ₃ ) or hydrogen gas (H ₂ ), and the nitriding agent may be preferably nitrogen gas (N ₂ ), and the oxidizing agent is H ₂ O, H ₂ O _It may be one or more selected from the group consisting of 2, O ₂ , O ₃ and N _{2 O.}

Finally, the residual unreacted reaction gas is purged using an inert gas. Accordingly, it is possible to remove not only an excessive amount of reaction gas but also generated by-products.

The thin film formed through the method of forming the thin film preferably has a thickness of 20 nm or less, a specific resistance value of 0.1 to 400 μΩ·cm, a step coverage ratio of 90% or more, and has excellent performance as a diffusion barrier within this range, Although there is an effect of reducing the corrosion of the metal wiring material, it is not limited thereto.

The thin film may have a thickness of, for example, 20 nm or less, preferably 10 nm or less, more preferably 5 nm or less, and has excellent thin film properties within this range.

The thin film has a resistivity value of, for example, 0.1 to 400 μΩ·cm, preferably 50 to 400 μΩ·cm, more preferably 200 to 400 μΩ·cm, more preferably 300 to 400 μΩ·cm, even more preferably Specifically, it may be 330 to 380 μΩ·cm, most preferably 340 to 370 μΩ·cm, and the thin film properties are excellent within this range.

The substrate on which the thin film is formed by the thin film formation method is a semiconductor substrate, and may be applied to, for example, a DRAM memory (dynamic random access memory, DRAM) device.

Hereinafter, preferred embodiments and drawings are presented to aid the understanding of the present invention, but the following examples and drawings are merely illustrative of the present invention, and various changes and modifications are possible within the scope and spirit of the present invention to those skilled in the art. It is obvious, and it is natural that such modifications and modifications fall within the appended claims.

Example 1

A thin film-forming composition including a compound represented by the following Formula 2 as a metal precursor for thin film formation, and dimethylethylamine and cyclopentylmethyl ether as solvents was prepared, and a thin film was formed through an ALD process.

[Formula 2]

First, the prepared composition for forming a thin film was put in a canister and supplied to a vaporizer heated at 150° C. at a flow rate of 0.05 g/min using a Liquid Mass Flow Controller (LMFC) at room temperature. After the composition for forming a thin film vaporized in the vapor phase in the vaporizer was introduced into the deposition chamber loaded with the substrate for 5 seconds, argon gas was supplied at 300 sccm for 10 seconds to perform argon purging. At this time, the pressure in the reaction chamber was controlled to 1.3 Torr. Next, ozone gas as a reactive gas was added to the reaction chamber for 5 seconds, followed by purging with argon for 10 seconds. At this time, the substrate on which the metal thin film is to be formed was heated to 300°C. This process was repeated 200 times to form a zirconium oxide thin film.

Comparative Example 1

It was carried out in the same manner as in Example 1, except that a precursor that does not contain a double bond in the ligand was used as the metal precursor for thin film formation.

In order to check the uniformity and step coverage of the thin films prepared in Example 1 and Comparative Example 1, the thickness deviation and step coverage of the thin film were measured. Compared to that, it was lowered by 10% or more, and it was confirmed that the step coverage was higher by 15% or more. Accordingly, it can be seen that in the case of a thin film manufactured using the composition for forming a thin film including the metal precursor for forming a thin film of the present invention, the uniformity and step coverage of the thin film are greatly improved.

Claims (13)

Formula 1
[Formula 1]

(In Formula 1, M is a Group 4 transition metal, R ₁ to R ₅ are each independently hydrogen or an alkyl group having 1 to 3 carbon atoms, and one of a and b is a single bond and the others are double bonds.) Characterized in that it comprises a compound
Metal precursor for thin film formation.
The method of claim 1,
In Formula 1, M is zirconium, characterized in that
Metal precursor for thin film formation.
Including a metal precursor and an organic solvent for thin film formation,
The metal precursor for forming the thin film is the following Formula 1
[Formula 1]

(In Formula 1, M is a Group 4 transition metal, R ₁ to R ₅ are each independently hydrogen or an alkyl group having 1 to 3 carbon atoms, and one of a and b is a single bond and the others are double bonds.) Characterized in that it comprises a compound
Composition for forming a thin film.
The method of claim 3,
The organic solvent is characterized in that at least one selected from the group consisting of amines and ethers.
Composition for forming a thin film.
The method of claim 4,
The amine is a tertiary amine, characterized in that the boiling point (1 atm) is 70°C or less, the density (25°C) is 0.6 to 0.8 g/cm ³ , and the vapor pressure (25°C, 1 atm) is 400 to 700 mmHg. to
Composition for forming a thin film.
The method of claim 5,
The tertiary amine is characterized in that it is a dialkylamine
Composition for forming a thin film.
The method of claim 4,
The ether is a cycloalkyl ether, characterized in that it has a boiling point (1 atm) of 110°C or less, and a density (25°C) of 0.7 to 0.9 g/cm ³
Composition for forming a thin film.
The method of claim 7,
The cycloalkyl ether is characterized in that it is a cyclopentyl alkyl ether
Composition for forming a thin film.
The method of claim 3,
The composition for forming a thin film is characterized in that it contains 1 to 99% by weight of a metal precursor for forming a thin film and 1 to 99% by weight of an organic solvent
Composition for forming a thin film.
The method of claim 3,
The composition for forming a thin film is characterized in that the viscosity (25 ℃) is 1 to 20 cP
Composition for forming a thin film.
It characterized in that it comprises the step of forming a thin film by depositing the composition for forming a thin film according to any one of claims 3 to 10 on a substrate.
Method of forming a thin film.
The method of claim 11,
The deposition is a method of forming a thin film, characterized in that the deposition is carried out by chemical vapor deposition (CVD) or atomic layer deposition (ALD).
The method of claim 11,
The deposition method of forming a thin film, characterized in that carried out at a temperature of 300 to 600 ℃.