KR102682682B1 - 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. Specifically, it is applicable to Atomic Layer Deposition (ALD) or Chemical Vapor Deposition (CVD) and has excellent thermal stability. It relates to a group metal compound, a precursor containing the same, and a method of forming a thin film using the same.

Description

Group 5 metal compound, precursor composition for deposition containing the same, and method of forming a thin film using the same {GROUP 5 METAL COMPOUNDS, PRECURSOR COMPOSITIONS INCLUDING THE SAME, AND PROCESS FOR THE FORMATION OF THIN FILMS USING THE SAME}

The present invention relates to a vapor deposition compound capable of depositing a thin film through vapor deposition. 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 deposition precursor containing the same, and a method of forming a thin film using the same.

Group 5 metals, especially metal films of tantalum (Ta) and niobium (Nb), and oxide or nitride films of tantalum and niobium can be used to manufacture various semiconductor devices.

For example, niobium oxide thin film (Nb ₂ O ₅ ) is applied as a resistive film to the high-k material of the dielectric layer. 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 film containing a Group 5 metal in the semiconductor device manufacturing process.

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

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

As the deposition temperature increases, the density of the Nb ₂ O ₅ thin film is expected to increase and the dielectric constant is expected to improve due to crystallization. However, in the case of thin films deposited at 350°C, the oxygen (O) content decreases, resulting in leakage current. Rather, it increased.

This is because the niobium precursor is thermally decomposed at high temperatures, so 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

The purpose of the present invention is to solve the problems of the existing Group 5 metal precursors mentioned above and to provide a Group 5 metal precursor compound for deposition with excellent thermal stability.

Additionally, the present invention seeks 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 problems mentioned above, 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 introduced a methyl group into the N-linked Cp (cyclopentadienyl) ligand to form a previously known Group 5 metal precursor compound. A Group 5 metal precursor with excellent thermal stability and capable of high temperature deposition was synthesized.

One aspect of the present application provides a compound represented by the following formula (1):

[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 application provides a vapor deposition precursor containing the above compound.

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

The novel vapor deposition Group 5 metal compound and the precursor containing the vapor deposition compound according to the present invention have excellent thermal stability and are capable of high temperature deposition.

In addition, the vapor deposition precursor of the present invention enables uniform thin film deposition, thereby ensuring excellent thin film physical properties, thickness, and step coverage.

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

Figure 1 shows the results of nuclear magnetic resonance (NMR) analysis of the compound synthesized in Synthesis Example 1 herein.
Figure 2 shows the results of nuclear magnetic resonance (NMR) analysis of the compound synthesized in Synthesis Example 2 of the present application.
Figure 3 shows the results of nuclear magnetic resonance (NMR) analysis of the compound synthesized in Synthesis Example 3 herein.
Figure 4 shows the results of thermogravimetric (TG) and differential thermal analysis of the compound synthesized in Synthesis Example 1 of the present application.
Figure 5 shows the results of thermogravimetric (TG) and differential thermal analysis of the compound synthesized in Synthesis Example 2 of the present application.
Figure 6 shows the results of thermogravimetric (TG) and differential thermal analysis of the compound synthesized in Synthesis Example 3 of the present application.

Hereinafter, implementation examples and synthesis examples of the present invention will be described in detail so that those skilled in the art can easily practice the present invention. However, the present application may be implemented in various different forms and is not limited to the implementation examples 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 the following formula (1).

[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 group into the N-linked Cp (cyclopentadienyl) ligand and has superior thermal stability compared to previously known Group 5 metal precursor compounds and enables high-temperature deposition.

In one embodiment of the present application, preferably, R ₁ to R ₃ are each independently methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, sec-butyl group 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 of Formula 1 may be any one selected from the group consisting of compounds represented by the following Formulas 1-1 to 1-3.

[Formula 1-1]

[Formula 1-2]

[Formula 1-3]

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

The vapor deposition precursor has excellent thermal stability due to the introduction of a methyl group into the N-linked Cp (cyclopentadienyl) ligand.

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

Another aspect of the present disclosure provides a method for manufacturing a thin film including introducing the vapor deposition precursor into a chamber. The step of introducing the vapor deposition precursor into the chamber may include physical adsorption, chemical adsorption, or physical and chemical adsorption.

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 an organic metal chemical vapor. Deposition (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 to this.

In one embodiment of the present application, the method of manufacturing the thin film may further include the step of 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. You 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. It is not limited.

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

Additionally, 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 production examples, but the present application is not limited thereto.

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

5 g (17 mmol) of TBTDMNb and 150 mL of toluene were added to the Schlenk flask, and 2.6 g (17 mmol) of CMEN ligand was slowly added at 0°C, followed by maintaining the temperature at low temperature for 30 minutes.

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

The NMR measurement results of ^tBuN =Nb(CMEN)(DMA) prepared in Synthesis Example 1 are shown in Figure 1.

The reaction of Synthesis Example 1 is shown in the following reaction formula 1.

[Reaction 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 the Schlenk flask, and 2.3 g (15 mmol) of CMEN ligand was slowly added at 0°C, followed by maintaining the temperature at low temperature for 30 minutes.

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

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

The reaction of Synthesis Example 2 is shown in the following reaction formula 2.

[Reaction Formula 2]

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

5 g (13 mmol) of TBTDENb and 150 mL of toluene were added to the Schlenk flask, 2.0 g (13 mmol) of CMEN ligand was slowly added at 0°C, and the temperature was maintained at low temperature for 30 minutes.

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

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

The reaction of Synthesis Example 3 is shown in the following reaction formula 3.

[Reaction 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 Figures 4 to 6, respectively.

The instrument used for analysis was Mettler Toledo's TGA/DTA 1 STAR System, which used an alumina crucible with a capacity of 20 μL. The above compounds were heated 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 in Synthesis Example 1, 260°C for the compound in Synthesis Example 2, and 263°C for the compound in Synthesis Example 3.

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

Meanwhile, the temperature at which a weight loss of 5 wt% occurred 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 new niobium metal precursor and reactant O ₃ synthesized according to Synthesis Examples 1 to 3 of the present invention. The substrate used in this experiment was a p-type Si wafer, and the resistance was 0.02 Ω·m. Prior to deposition, the p-type Si wafer was cleaned by ultrasonic treatment in acetone-ethanol-deionized water (DI water) for 10 minutes each. The native oxide thin film formed on the Si wafer was removed after being immersed in a 10% HF solution (HF:H ₂ O=1:9) for 10 seconds.

The substrate was prepared by maintaining a temperature of 150-450°C, and the new 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 remaining precursor and reaction gas 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 controlling the on/off of the pneumatic valve and formed into a film at the process temperature.

The ALD cycle included a 10/15 second precursor pulse followed by a 10 second purge with argon, followed by a 2/5/8/10 second reactant pulse followed by a 10 second purge with argon. 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 a niobium oxide thin film was formed using the compounds of Synthesis Examples 1 to 3 as precursors.

[Production Example 2]

A thin film containing niobium element was manufactured by chemical vapor deposition using the new niobium metal precursor synthesized according to Synthesis Examples 1 to 3 of the present invention. A starting precursor solution containing the precursor synthesized according to 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 each was supplied to the deposition chamber at a flow rate of 0.5 L/min (0.5 pm). The pressure of the deposition chamber was adjusted to 1 to 15 torr, and the deposition temperature was adjusted to 150-450°C. The deposition process was performed for about 15 minutes under these conditions.

Through the preparation of the thin film through the above-described preparation examples, it was confirmed that a niobium thin film could be formed using the compounds of Synthesis Examples 1 to 3 as precursors.

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

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

The reactant gases may be decomposed into radicals by passing through a plasma system located away from the reaction chamber. Additionally, Ta or Nb containing precursors can be introduced into the reaction chamber continuously while other metal sources are introduced by pulses.

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

An oxygen source is introduced into the reaction chamber, where it reacts with the adsorbed Ta or Nb containing precursor in a self-limiting manner. Excess oxygen source can 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 above process can be repeated until the desired film thickness is achieved.

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

In addition, the novel Ta- or Nb-containing precursor enables uniform thin film deposition, thereby ensuring excellent thin film physical properties, thickness, and step coverage.

The scope of the present invention is indicated by the claims described below rather than the detailed description above, and all changes or modified forms derived from the meaning and scope of the claims and their equivalent concepts are interpreted to be included in the scope of the present invention. It has to be.

Claims (8)

It is represented by the following formula 1,
The temperature at which the weight is reduced by half (T _1/2 ) is 250 ℃ or more,
compound:

[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 paragraph 1,
R ₁ to R ₃ are each independently selected from the group consisting of methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, sec-butyl group and tert-butyl group. , compound.
According to paragraph 1,
The compound of Formula 1 is
Any one selected from the group consisting of compounds represented by the following 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 of producing a thin film, comprising introducing the vapor deposition precursor of claim 4 into a chamber.
According to clause 5,
The method of manufacturing the thin film includes Atomic Layer Deposition (ALD) or Chemical Vapor Deposition (CVD).
According to clause 6,
A method for producing a thin film, further comprising the step of 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.
In clause 7,
The reaction gases include 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 ). A method of producing a thin film, which is at least one selected from among.