KR20230048755A - Group 5 metal compounds, precursor compositions including the same, and process for the formation of thin films using the same - Google Patents

Abstract

The present invention relates to a compound that can be deposited into a thin film through vapor deposition, and specifically, to a group 5 metal compound which is applicable to atomic layer deposition (ALD) or chemical vapor deposition (CVD) and has excellent thermal stability, a precursor containing the same, and a method of forming a thin film using the same. The compound is represented by chemical formula 1, and in the chemical formula 1, M is Ta or Nb and R1 to R3 are each independently hydrogen; and a linear or branched alkyl group having 1 to 6 carbon atoms.

Description

Group 5 metal compound, precursor composition for deposition containing the same, and method for forming a thin film using the same

The present invention relates to a vapor deposition compound capable of depositing a thin film through vapor deposition, and specifically, it is applicable to atomic layer deposition (ALD) or chemical vapor deposition (CVD) and has excellent thermal stability. It relates to a group 5 metal precursor, a precursor for deposition including the same, and a method of forming a thin film using the same.

A metal film of a group 5 metal, particularly tantalum (Ta) and niobium (Nb), and an oxide film or nitride film of tantalum and niobium may be used in manufacturing various semiconductor devices.

For example, niobium oxide thin films (Nb ₂ O ₅ ) have been applied as resistive films to high-k materials in dielectric layers. Nb ₂ O _{5 thin} films are used as dielectric layers in dynamic random access memory (DRAM) devices to reduce current leakage and provide higher k values.

Meanwhile, sputtering is mainly used to form a group 5 metal-containing film in a semiconductor device manufacturing process.

However, in order to form an extremely thin, several-nm-thick Group 5 metal-containing film on an uneven surface, chemical vapor deposition with excellent step coverage, especially atomic layer deposition, is required, and therefore a Group 5 metal precursor compound suitable for this is required. do.

Meanwhile, tBuN=Nb(EMA) ₃ (TBTEMNb), a representative niobium deposition precursor compound currently reported, is known to have a maximum ALD process temperature of about 325°C.

As the deposition temperature increases, the density of the Nb ₂ O ₅ thin film increases and the improvement in dielectric constant by crystallization is expected. rather increased.

This is because the niobium precursor is thermally decomposed at a high temperature, and thus it is necessary to develop a niobium precursor capable of high-temperature deposition in order to simultaneously obtain high step coverage and low leakage current.

Republic of Korea Patent Publication No. 10-2016-0124025

An object of the present invention is to provide a Group 5 metal precursor compound for deposition having excellent thermal stability in order to solve the problems of the existing Group 5 metal precursors mentioned above.

In addition, the present invention is to provide a thin film manufacturing method using the Group 5 metal precursor compound.

However, the problem to be solved by the present application is not limited to the above-mentioned problem, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

In order to solve the problem of the Group 5 metal precursor as mentioned above, the present inventors introduce a methyl group into the N-linked Cp (cyclopentadienyl) ligand to obtain a previously known Group 5 metal precursor compound. A Group 5 metal precursor having excellent thermal stability and capable of high-temperature deposition was synthesized.

One aspect of the present application provides a compound represented by Formula 1 below:

[Formula 1]

In Formula 1,

M is Ta or Nb;

R ₁ to R ₃ are each independently hydrogen; It is a linear or branched alkyl group having 1 to 6 carbon atoms.

Another aspect of the present disclosure provides a vapor deposition precursor comprising the compound.

Another aspect of the present disclosure provides a method for manufacturing a thin film, including introducing the vapor deposition precursor into a chamber.

The novel vapor-deposited Group 5 metal compound according to the present invention and the precursor including the vapor-deposited compound have excellent thermal stability and can be deposited at high temperatures.

In addition, the vapor deposition precursor of the present invention can deposit a uniform thin film, thereby securing excellent thin film properties, thickness, and step coverage.

The above physical properties provide precursors suitable for atomic layer deposition and chemical vapor deposition, and contribute to excellent thin film properties.

1 is a nuclear magnetic resonance (NMR) analysis result of the compound synthesized by Synthesis Example 1 of the present application.
Figure 2 is a nuclear magnetic resonance (NMR) analysis result of the compound synthesized by Synthesis Example 2 of the present application.
Figure 3 is a nuclear magnetic resonance (NMR) analysis result of the compound synthesized by Synthesis Example 3 of the present application.
4 is a result of thermogravimetric (TG) and differential thermal analysis of the compound synthesized by Synthesis Example 1 of the present application.
5 is a result of thermogravimetric (TG) and differential thermal analysis of the compound synthesized by Synthesis Example 2 of the present application.
6 is a result of thermogravimetric (TG) and differential thermal analysis of the compound synthesized by Synthesis Example 3 of the present application.

Hereinafter, embodiments and synthetic examples of the present invention will be described in detail so that those skilled in the art can easily practice them. However, the present application may be implemented in many different forms and is not limited to the embodiments and synthesis examples described herein.

Hereinafter, embodiments and synthesis examples of the present application will be described in detail. However, the present application is not limited to these embodiments and synthesis examples and drawings.

One aspect of the present application provides a compound represented by Formula 1 below.

[Formula 1]

In Formula 1,

M is Ta or Nb;

R ₁ to R ₃ are each independently hydrogen; It is a linear or branched alkyl group having 1 to 6 carbon atoms.

The compound introduces a methyl (methyl) group into an N-linked Cp (cyclopentadienyl) ligand, and thus has excellent thermal stability and high-temperature deposition, compared to previously known group 5 metal precursor compounds.

In one embodiment of the present application, preferably, R ₁ to R ₃ are each independently methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl and tert -It may be any one selected from the group consisting of a butyl group, but is not limited thereto.

In one embodiment of the present application, preferably, the compound represented by Chemical Formula 1 may be any one selected from the group consisting of compounds represented by Chemical Formulas 1-1 to 1-3.

[Formula 1-1]

[Formula 1-2]

[Formula 1-3]

Another aspect of the present application provides a deposition precursor, preferably a vapor deposition precursor, containing the compound.

The vapor deposition precursor has excellent thermal stability because a methyl group is introduced into an N-linked cyclopentadienyl (Cp) ligand.

That is, the vapor deposition precursor has a high temperature [T _1/2 ] at which the weight is reduced by half compared to TBTEMNb, which is a known niobium vapor phase precursor compound that is widely used. That is, while the T _1/2 temperature of TBTEMNb was about 204°C, the T _1/2 temperature of the niobium vapor phase precursor compound of the present application was 250°C or higher.

Another aspect of the present disclosure provides a method for manufacturing a thin film comprising introducing the vapor deposition precursor into a chamber. Introducing the vapor deposition precursor into the chamber may include physisorption, chemisorption, or physisorption and chemisorption.

In one embodiment of the present application, the method of manufacturing the thin film may include atomic layer deposition (ALD) or chemical vapor deposition (CVD), and the chemical vapor deposition is a metal-organic chemical vapor deposition method. Metal Organic Chemical Vapor Deposition (MOCVD), Low Pressure Chemical Vapor Deposition (LPCVD), Pulsed Chemical Vapor Deposition (P-CVD), Plasma Enhanced Atomic Layer Deposition (PE-ALD), or a combination thereof It may include, but is not limited thereto.

In one embodiment of the present application, the method of manufacturing the thin film may further include injecting at least one of hydrogen (H ₂ ), a compound containing an oxygen (O) atom, and a compound containing a nitrogen (N) atom as a reaction gas. can

When the desired thin film contains oxygen, the reaction gas may be selected from oxygen (O ₂ ), ozone (O ₃ ), water (H ₂ O), hydrogen peroxide (H ₂ O ₂ ), and any combination thereof, but It is not limited.

When the desired thin film contains nitrogen, the reactant gas may be selected from, but not limited to, nitrogen (N ₂ ), ammonia (NH ₃ ), hydrazine (N ₂ H ₄ ), and any combination thereof.

Also, the thin film may contain metals other than Group 5 metals.

Hereinafter, the present application will be described in more detail using synthesis examples, synthesis examples, experimental examples, and preparation examples, but the present application is not limited thereto.

<Synthesis Example 1> Synthesis of ^t BuN=Nb(CMEN)(DMA)

After putting 5 g (17 mmol) of TBTDMNb and 150 mL of toluene in a Schlenk flask, 2.6 g (17 mmol) of CMEN ligand was slowly added thereto at 0° C., and the mixture was maintained at a low temperature for 30 minutes.

The mixture was heated at 60-70 °C for 4 hours and then stirred overnight at room temperature. When the reaction was completed, the solvent was removed and distilled under reduced pressure at 90 to 100 ° C @ 0.4 Torr to obtain a yellow liquid.

1 shows NMR measurement results of ^tBuN =Nb(CMEN)(DMA) prepared by Synthesis Example 1.

The reaction of Synthesis Example 1 is represented by Reaction Formula 1 below.

[Reaction Chemical Formula 1]

<Synthesis Example 2> ^t BuN=Nb(CMEN)(EMA) synthesis

5 g (15 mmol) of TBTEMNb and 150 mL of toluene were added to a Schlenk flask, and 2.3 g (15 mmol) of CMEN ligand was slowly added thereto at 0° C., followed by maintaining the mixture at a low temperature for 30 minutes.

The mixture was heated at 60-70 °C for 4 hours and then stirred overnight at room temperature. When the reaction was completed, the solvent was removed, and the yellow liquid was obtained by distillation under reduced pressure at 100 to 120 ° C @ 0.4 Torr.

The NMR measurement results of ^tBuN =Nb(CMEN)(EMA) prepared by Synthesis Example 2 are shown in FIG. 2.

The reaction of Synthesis Example 2 is represented by Reaction Formula 2 below.

[Reaction Chemical Formula 2]

<Synthesis Example 3> Synthesis of ^t BuN=Nb(CMEN)(DEA)

After putting 5g (13 mmol) of TBTDENb and 150 mL of toluene in a Schlenk flask, slowly adding 2.0 g (13 mmol) of CMEN ligand at 0 ° C., the mixture was maintained at a low temperature for 30 minutes.

The mixture was heated at 60-70 °C for 4 hours and then stirred overnight at room temperature. When the reaction was completed, the solvent was removed and distilled under reduced pressure at 110 to 120 ° C @ 0.4 Torr to obtain a yellow liquid.

The NMR measurement results of ^tBuN =Nb(CMEN)(DEA) prepared by Synthesis Example 3 are shown in FIG. 3.

The reaction of Synthesis Example 3 is represented by Reaction Formula 3 below.

[Reaction Chemical Formula 3]

[Experimental Example 1] Thermogravimetric and Differential Thermal Analysis

Thermogravimetric and differential thermal analysis were performed to measure the thermal properties of the compounds synthesized in Synthesis Examples 1 to 3, and the results are shown in FIGS. 4 to 6, respectively.

The instrument used in the analysis was Mettler Toledo's TGA/DTA 1 STAR System, and an alumina crucible with a capacity of 20 μL was used. The compounds were heated up to 400 °C at a rate of 10 °C/min, and argon (Ar) gas was injected at a rate of 200 mL/min.

As a result of the analysis, the temperature at which the weight is reduced by half [T _1/2 ] was measured to be 259 °C for the compound of Synthesis Example 1, 260 °C for the compound of Synthesis Example 2, and 263 °C for the compound of Synthesis Example 3.

In addition, the amount of residue at 400°C was measured to be 12% for the compound of Synthesis Example 1, 9.6% for the compound of Synthesis Example 2, and 6.3% for the compound of Synthesis Example 3.

On the other hand, the temperature at which a weight loss of 5 wt % occurs was measured to be 192° C. for the compound of Synthesis Example 1, 193° C. for the compound of Synthesis Example 2, and 198° C. for the compound of Synthesis Example 3.

[Production Example 1]

A thin film was deposited on a substrate by alternately applying the novel niobium metal precursor and the reactant O ₃ synthesized in Synthesis Examples 1 to 3 of the present invention. The substrate used in this experiment is a p-type Si wafer, and its resistance is 0.02 Ω·m. Prior to deposition, the p-type Si wafer was cleaned by ultrasonic treatment (ultra sonic) in acetone-ethanol-DI water for 10 minutes each. The native oxide thin film formed on the Si wafer was immersed in a 10% HF (HF:H ₂ O=1:9) solution for 10 seconds and then removed.

The substrate was prepared by maintaining a temperature of 150-450° C., and the novel niobium precursor synthesized in Synthesis Example 1 was vaporized in a bubbler maintained at a constant temperature.

As a purge gas, argon (Ar) was supplied to purge the precursor and reaction gas remaining in the deposition chamber, and the flow rate of argon was set to 1000 sccm. Ozone (O ₃ ) at a concentration of 224 g/cm ³ was used as the reaction gas, and each reaction gas was injected by adjusting the on/off of a pneumatic valve and formed at a process temperature.

The ALD cycle included a 10/15 s precursor pulse followed by a 10 s argon purge, followed by a 2/5/8/10 s reactant pulse followed by a 10 s argon purge sequence. The pressure of the deposition chamber was adjusted to 1-1.5 torr, and the deposition temperature was adjusted to 150-450 °C.

It was confirmed that niobium oxide thin films were formed using the compounds of Synthesis Examples 1 to 3 as precursors.

[Production Example 2]

Using the novel niobium metal precursor synthesized in Synthesis Example 1 to Synthesis Example 3 of the present invention, a thin film containing elemental niobium was prepared by chemical vapor deposition. A starting precursor solution containing the precursors synthesized in Synthesis Examples 1 to 3 was prepared.

This precursor starting solution was delivered to a vaporizer maintained at a temperature of 90-150° C. at a flow rate of 0.1 cc/min. The vaporized precursor was delivered to the deposition chamber using 50 to 300 sccm helium carrier gas. Hydrogen (H ₂ ) and oxygen (O ₂ ) were used as reaction gases, and were supplied to the deposition chamber at a flow rate of 0.5 L/min (0.5 pm), respectively. The pressure of the deposition chamber was adjusted to 1 to 15 torr, and the deposition temperature was adjusted to 150 to 450 °C. The deposition process was performed for about 15 minutes under these conditions.

It was confirmed that the niobium thin film could be formed by using the compounds of Synthesis Example 1 to Synthesis Example 3 as a precursor through the preparation of the thin film through the above-described Preparation Example.

The Ta or Nb containing precursor and one or more reactant gases may be simultaneously introduced into the reaction chamber by chemical vapor deposition, atomic layer deposition, or some other combination.

In one example, the Ta or Nb containing precursor may be introduced in one pulse, and the two additional metal sources may be introduced together in separate pulses. Additionally, the reaction chamber may already contain the reactant species prior to introduction of the Ta or Nb containing precursor.

The reactant gases may be decomposed into radicals by passing through a plasma system remote from the reaction chamber. Alternatively, the Ta or Nb containing precursor may be continuously introduced into the reaction chamber while the other metal source is introduced by pulses.

For example, in an atomic layer deposition type process a vapor phase Ta or Nb containing precursor is introduced into a reaction chamber where, after contact with a suitable substrate, the Ta or Nb containing precursor may be removed from the reaction chamber by purging the reactor. .

An oxygen source is introduced into the reaction chamber, where it reacts with the absorbed Ta or Nb containing precursor in a self-limiting manner. Excess oxygen source may be removed from the reaction chamber by purging and/or degassing the reaction chamber. If the desired film is a Ta or Nb metal oxide film, the process may be repeated until the desired film thickness is obtained.

Through the above thin film production, the newly synthesized Ta or Nb-containing precursor not only compensates for the problems in thin film deposition of the existing Ta or Nb-containing precursor, but also can be applied to ALD as well as CVD, and has excellent thermal stability. Confirmed.

In addition, uniform thin film deposition is possible through the novel Ta or Nb-containing precursor, and thus excellent thin film properties, thickness, and step coverage can be secured.

The scope of the present invention is indicated by the claims to be described later rather than the detailed description above, and all changes or modifications derived from the meaning and scope of the claims and equivalent concepts thereof are interpreted as being included in the scope of the present invention. It should be.

Claims (8)

A compound represented by Formula 1 below:
[Formula 1]

In Formula 1,
M is Ta or Nb;
R ₁ to R ₃ are each independently hydrogen; It is a linear or branched alkyl group having 1 to 6 carbon atoms.
According to claim 1,
R ₁ to R ₃ are each independently selected from the group consisting of a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a sec-butyl group and a tert-butyl group, , compound.
According to claim 1,
The compound of Formula 1 is
Any one selected from the group consisting of compounds represented by Formulas 1-1 to 1-3,
compound.

[Formula 1-1]

[Formula 1-2]

[Formula 1-3]

A vapor deposition precursor comprising the compound according to any one of claims 1 to 3.
A method for producing a thin film comprising introducing the vapor deposition precursor of claim 4 into a chamber.
According to claim 5,
The method for producing the thin film includes an atomic layer deposition (ALD) or a chemical vapor deposition (CVD) method.
According to claim 6,
The method of manufacturing a thin film further comprising the step of injecting at least one of hydrogen (H ₂ ), a compound containing oxygen (O) atoms, and a compound containing nitrogen (N) atoms as a reaction gas.
According to claim 7,
The reaction gas is oxygen (O ₂ ), ozone (O ₃ ), water (H ₂ O), hydrogen peroxide (H ₂ O ₂ ), nitrogen (N ₂ ), ammonia (NH ₃ ) and hydrazine (N ₂ H ₄ ) Any one or more selected from among, a method for producing a thin film.

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