KR100541511B1 - Method of forming an atomic layer and method of forming a thin film using the same - Google Patents

Abstract

Disclosed are an atomic layer deposition method including TaN and a thin film formation method using the same. A tantalum amine derivative represented by the formula Ta (NR ₁ ) (NR ₂ R ₃ ) ₃ (wherein R ₁ , R ₂ R ₃ is the same or different from each other as H or a C ₁ -C ₆ alkyl group) on a substrate Is introduced into the substrate to chemically adsorb a portion of the reactant onto the substrate. Reactants that do not chemically adsorb in the reactants are removed from the substrate. A reaction gas is introduced onto the substrate to remove elements having ligand bonds contained in the chemically adsorbed reaction material from the reaction material to form a TaN atomic layer. By repeating this process, a TaN thin film is formed. Even at low temperatures, the deposition rate is good and the step coverage characteristics are very good.

Description

Method of forming an atomic layer and method of forming a thin film using the same}

1A to 1D are cross-sectional views illustrating reactions performed on a substrate when performing an atomic layer deposition method.

2 is a graph illustrating a comparison of vapor pressures depending on temperatures of TBTDET and TAIMATA, which are sources for forming a TaN thin film.

3A and 3B are chemical formulas of TBTDET and TAIMATA, which are sources for TaN thin film formation, respectively.

4A and 4B are graphs showing the deposition rate according to the temperature of the stage heater when TAIMATA is deposited by CVD in an Ar atmosphere. FIG. 4A is a graph showing uniformity and FIG. 4B is a graph showing specific resistance.

Figures 5a and 5b is a graph showing the deposition rate according to the temperature of the stage heater when deposition by CVD method while simultaneously supplying NH ₃ reaction gas to the TAIMATA source, Figure 5a is a graph showing the uniformity and Figure 5b is a specific resistance It is a graph shown.

Figure 5c is a graph showing the deposition rate according to the NH ₃ flow rate with a specific resistance when the deposition by the CVD method while simultaneously supplying the NH ₃ reaction gas to the TAIMATA source.

Figure 6a is a graph showing the relative deposition rates according to whether NH ₃ shown during the deposition by ALD system while supplying a reaction gas at the same time, the NH ₃ TAIMATA source to several temperatures.

FIG. 6B is a graph illustrating the deposition rate along with the uniformity of TAIMATA shown in the ALD method while simultaneously supplying NH ₃ reactant gas to the TAIMATA source.

7A-7C are cross-sectional views illustrating a process of forming a TaN thin film by applying the method of the present invention on an insulating layer having an opening formed on a substrate.

FIG. 8 is a SEM photograph of a TaN thin film formed upon deposition in an ALD method while simultaneously supplying an NH ₃ reaction gas to a TAIMATA source on an insulating layer having an opening having a predetermined aspect ratio.

The present invention relates to an atomic layer deposition method and a thin film formation method using the same, and more particularly, to an atomic layer deposition method for performing a deposition process for depositing tantalum nitride by introducing a new tantalum precursor and a thin film formation method using the same. .

There is an increasing demand for metal layers used as metal wiring in semiconductor devices. Accordingly, in order to increase the density of elements formed on the substrate, the metal layer is formed in a multilayer structure. The metal layer is mainly formed using aluminum or tungsten. However, aluminum or tungsten is not suitable for multilayer structures because the resistivity is as high as 2.8x10E-8Ωm and 5.5x10E-8Ωm, respectively. Therefore, in recent years, copper, which has a relatively low specific resistance and good electromigration characteristics, has been frequently used as a metal layer having a multilayer structure.

Copper shows very high mobility in silicon and silicon oxide. However, copper has a disadvantage in that it easily oxidizes when reacted with silicon and silicon oxide. Therefore, it is necessary to prevent the oxidation of copper and the like by using the barrier metal layer.

Titanium nitride layer (TiN) is widely used as a barrier metal layer of copper. However, in order to inhibit the mobility of copper, the titanium nitride layer should have a thickness of at least 30 nm, but there is a problem in that the resistance is increased when the titanium nitride layer is formed at a thickness of about 30 nm. This is because the resistance of the titanium nitride layer is proportional to the thickness.

Accordingly, application of a tantalum nitride layer as a barrier metal layer of copper has been proposed. This is because the tantalum nitride layer can inhibit the mobility of copper even with a relatively thin thickness. In addition, since the tantalum nitride layer has excellent step coverage and gap fill capability, the tantalum nitride layer is suitable not only as a barrier metal layer but also for application to metal plugs, metal wirings, metal gates, capacitor electrodes, and the like.

Examples of how to form tantalum nitride layers are disclosed in US Pat. Nos. 6,204,204 (issued to Paranjpe et al.), 6,153,519 (issued to Jain et al.), 5,668,054 (issued to Sun et al.), And the like. It is. In particular, according to the contents disclosed in US Patent No. 5,668,054, terbutylimido-tris-diethylamido tantalum ((NEt ₂ ) ₃ Ta = NtBu; TBTDET) is used as a reaction material. Chemical vapor deposition is performed to deposit tantalum nitride layers. According to the disclosed method the deposition is carried out at a temperature of at least 600 ° C. If the deposition process is performed at a temperature of about 500 ° C., since the tantalum nitride layer has a resistivity value of about 10,000 μΩ · cm or more, the deposition temperature should be 600 ° C. or more.

Recently, atomic layer deposition (ALD) method has been proposed as a technique to replace the above chemical vapor deposition. According to the atomic layer deposition method, the lamination can be performed at a lower temperature than a conventional thin film formation method, and there is an advantage that excellent step coverage can be realized. An example of a method for laminating tantalum nitride layers using an atomic layer deposition method is described in US Pat. No. 6,203,613 (issued to Gates) and other electrochemical and solid-state letters, 4 (4) C17-C19 (2001), Kang et. al.). According to a method such as steel, it is reported that a tantalum nitride layer having a specific resistance value of about 400 μΩ · cm can be formed by the atomic layer lamination method using the TBTDET. At this time, the lamination process is performed at a temperature of about 260 ℃. As described above, according to the method of steel or the like, a tantalum nitride layer having a low specific resistance can be easily formed at a relatively low temperature.

However, in the steel and the like, hydrogen radicals formed by plasma enhanced chemical vapor deposition are used as reducing agents. Thus, a power source is applied in the chamber when laminating. As such, the teaching method has process variables such as control of the power source. Therefore, the method of steel or the like has a disadvantage in that process variables such as control of a power source are added, although a thin film having a low specific resistance can be formed at a relatively low temperature. In addition, a method such as steel has a problem that damage to the substrate may occur because the power source is applied directly to the place where the substrate is placed.

Other documents related to TaN thin film deposition include ALD method using TaCl ₅ source (Controlled Growth of TaN, Ta ₃ N ₅ and TaOxNy Thin Films by Atomic Layer Deposition, Mikko Ritala et al., Chem. Mater. 1999, 11, pp1712 -1218) and CVD method using TBTDET source (Metalorganic chemical vapor deposition of Tantalum Nitride by Terbutylimidotris (Diethylamido) Tantalum for advanced metallization, Tsai MH et al., Applied Physics Letters, V. 67 N. 8, 19950821).

However, the existing TaN deposition process presents various problems due to problems with the source. Since TaCl ₅ uses a halogen source, the source itself is a solid having a high melting point, and when it is employed, particles are induced, and Cl impurities are left in the TaN thin film to be deposited, thereby causing additional problems. In addition, when using the TBTDET source has a disadvantage that the deposition rate is too slow due to the low vapor pressure.

On the other hand, Japanese Patent Laid-Open No. 2002-193981 discloses tertiary millimido-tris-dimethylamidotantalum (TAIMATA; Ta (NC (CH ₃ ) ₂ C ₂ H ₅ ) (N (CH ₃ ) ₂ ) ₃ Disclosed is a method of manufacturing a metal organic CVD (MOCVD) method using a precursor and a solution containing the same.

According to the above method, 1 mole of TaCl _5, 4 moles of LiNMe _2, and 1 mole of LiNHtAm are reacted in an organic solvent at room temperature, filtered, and the solvent is removed to prepare a novel compound TAIMATA. It is described that this raw material can be added to an organic solvent, such as a nucleic acid, to be dissolved and used to deposit on a substrate in a CVD chamber to form a TaN thin film.

However, according to the above method, the preparation of TAIMATA can be easily performed, but in the formation of TaN thin film using the same, it is described that only TAIMATA is used to form a film by its use alone. When performing a deposition process on a substrate by a CVD method alone, there is a problem that the vapor pressure is not high enough to be inefficient.

The present inventors have disclosed a method of forming an atomic layer and a thin film by using an organometallic precursor or a tantalum halide precursor as a reaction material. According to Korean Patent Laid-Open Publication No. 2003-0009093 (published Jan. 29, 2003, US Application No. 10 / 196,814, filed Jul. 17, 2002), a gaseous reactant is placed in a chamber in which a substrate is placed. A method of introducing and laminating it in atomic layer units has been reported.

According to the reported content, it is possible to easily form an atomic layer containing a metal element having a low specific resistance at a relatively low temperature. However, efforts to improve the process technology and research on raw materials that provide more improved effects compared to the disclosed technology should be made continuously.

The first object of the present invention can be used in the liquid state without containing halogen impurities such as chlorine in consideration of the above-mentioned advantages and disadvantages of the prior art as described above does not generate particles and has a high vapor pressure, so that the deposition rate is good. An atomic layer forming method is provided.

A second object of the present invention is to provide a thin film formation method which can form a thin film by a simple method by using the above-described atomic layer formation method.

A third object of the present invention is to provide a thin film forming method having excellent step coverage at a good deposition rate on an insulating layer having a high aspect ratio opening by applying the above-described thin film forming method.

It is a fourth object of the present invention to provide a new thin film formation method which can be used in a liquid state without containing halogen impurities such as chlorine, does not generate particles, and has a high vapor pressure, so that good deposition is possible.

 A fifth object of the present invention is to provide a novel thin film forming method having excellent step coverage at a good deposition rate on an insulating layer having a high aspect ratio opening by applying the above-described thin film forming method.

In order to achieve the above object of the present invention in the present invention:

a) tantalum amine derivative represented by the formula Ta (NR ₁ ) (NR ₂ R ₃ ) ₃ , wherein R ₁ , R ₂ R ₃ is the same or different from each other as H or a C ₁ -C ₆ alkyl group; Introducing a onto a substrate;

b) chemically adsorbing a portion of the reactant onto the substrate;

c) removing from the substrate a reactant that is not chemically adsorbed in the reactant; And

d) introducing a reactant gas onto the substrate to remove elements having ligand bonds contained in the chemically adsorbed reactant from the reactant to form a solid material containing TaN ( ALD (Atomic Layer Deposition) method is provided.

The second object of the present invention described above is:

a) tantalum amine derivative represented by the formula Ta (NR ₁ ) (NR ₂ R ₃ ) ₃ , wherein R ₁ , R ₂ R ₃ is the same or different from each other as H or a C ₁ -C ₆ alkyl group; Introducing onto a substrate;

b) chemically adsorbing a portion of the reactant onto the substrate;

c) removing from the substrate a reactant that is not chemically adsorbed in the reactant;

d) introducing a reactant gas onto the substrate to remove elements having ligand bonds included in the chemically adsorbed reactant from the reactant to form a solid material containing TaN; And

(e) repeating steps a) -d) at least once to achieve a thin film formation method using atomic layer deposition (ALD) comprising forming the solid material into a TaN thin film.

In addition, a third object of the present invention is:

a) forming an insulating layer on the substrate;

b) etching a portion of the insulating layer to form an opening through which the surface of the substrate is exposed;

c) a tantalum amine derivative represented by the formula Ta (NR ₁ ) (NR ₂ R ₃ ) ₃ , wherein R ₁ , R ₂ R ₃ is the same or different from each other as H or a C ₁ -C ₆ alkyl group; Introducing into the insulating layer in which the opening is formed;

d) chemically adsorbing a portion of the reactant material on the insulating layer in which the opening is formed;

e) removing a reaction material that is not chemically adsorbed from the reaction material from the insulating layer in which the opening is formed;

f) introducing a reactant gas onto the substrate to remove elements having ligand bonds included in the chemically adsorbed reactant from the reactant to form a solid material containing TaN; And

(g) repeating the steps c) -f) at least once to form a TaN thin film on the insulating layer having the openings, which is achieved by a thin film forming method using atomic layer deposition (ALD). .

A fourth object of the present invention is to:

Tantalum amine derivatives and H ₂ represented by the formula Ta (NR ₁ ) (NR ₂ R ₃ ) ₃ , wherein R ₁ , R ₂ R ₃ are the same or different from each other as H or a C ₁ -C ₆ alkyl group And at least one reaction gas selected from the group consisting of NH ₃ , SiH ₄ and Si ₂ H ₆ .

In addition, the fifth object of the present invention described above is:

a) forming an insulating layer on the substrate;

b) etching a portion of the insulating layer to form an opening through which the surface of the substrate is exposed; And

c) a tantalum amine derivative represented by the formula Ta (NR ₁ ) (NR ₂ R ₃ ) ₃ , wherein R ₁ , R ₂ R ₃ is the same or different from each other as H or a C ₁ -C ₆ alkyl group; Mixing at least one reaction gas selected from the group consisting of H ₂ , NH ₃ , SiH ₄ and Si ₂ H ₆ is achieved by a thin film forming method comprising the step of depositing a TaN thin film on the insulating layer having the opening.

According to the present invention by using a tantalum amine derivative called TAIMATA as a precursor to deposit TaN by a deposition method such as ALD or CVD, the TAIMARA source can be applied in a liquid state and has a high vapor pressure, so that the process is performed at an improved deposition rate. It is possible to perform the TaN thin film formed by this method shows excellent step coverage characteristics.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

First, the atomic layer lamination method will be described in detail.

Tantalum amine derivatives represented by the formula Ta (NR ₁ ) (NR ₂ R ₃ ) ₃ , wherein R ₁ and R ₂ R ₃ are the same or different from each other as H or a C ₁ -C ₆ alkyl group, for example For example, tertiary amlimido-tris-dimethylamidotantalum (Ta (NC (CH ₃ ) ₂ C ₂ H ₅ ) (N (CH ₃ ) ₂ ) ₃ ) (hereinafter sometimes referred to as TAIMATA) is introduced on a substrate. Do it. The reactant material is introduced into the substrate, ie on the substrate, on which the substrate is placed.

Subsequently, a portion of the reaction material is allowed to chemically adsorb onto the substrate. At this time, the reaction material is preferably introduced in a liquid state. Some of the reactants are chemically adsorbed on the substrate and others are physically adsorbed. Accordingly, the reaction material which is not chemically adsorbed in the reaction material is removed from the substrate. Reactants that are not chemically adsorbed, ie, physically adsorbed reactants, are removed using an inert gas. Examples of such inert gas include Ar, He, N ₂ , and the like.

Thereafter, a reaction gas is introduced onto the substrate to remove elements having ligand bonds included in the chemically adsorbed reaction material from the reaction material to form a solid material containing TaN. The ligand binding elements are removed using a reaction gas such as H ₂ , NH ₃ , SiH ₄ , Si ₂ H ₆ , mixtures thereof, and the like. Preferably, the reaction gas is activated by using a remote plasma or the like. In this way, a TaN layer can be formed on the substrate.

The above-described atomic layer deposition (ALD) method may be a thermal ALD method or a radical assisted ALD method using a remote plasma.

Such atomic layer deposition may be performed under constant pressure of about 0.01 to 30 torr. Preferably 0.01 to 10 torr, more preferably 0.01 to 5 torr. In addition, each step described above is preferably performed at a temperature range of 100 to 550 ° C, more preferably 100 to 450 ° C, most preferably 100 to 350 ° C.

An atomic layer lamination method is demonstrated in detail with reference to drawings. 1A to 1D are cross-sectional views illustrating reactions performed on a substrate when performing an atomic layer deposition method.

First, referring to FIG. 1A, a substrate 10 made of a silicon material is positioned in a chamber. Then, the inside of the chamber is set to have the above-described desirable pressure and temperature conditions. The reactant 12 is introduced onto the substrate 10 lying in the chamber. As a result, a portion of the reactant material 12 is chemically adsorbed onto the substrate 10.

Referring to FIG. 1B, an inert gas is introduced and purged onto the substrate. Accordingly, the reactants that are not chemically adsorbed among the reactants 12 are removed from the substrate 10.

Referring to FIG. 1C, any one of H ₂ , NH ₃ , SiH ₄ , Si ₂ H _6, and a mixture thereof may be introduced onto the substrate 10. More preferably, these reaction gases are introduced after being activated by the remote plasma.

Referring to FIG. 1D, ligand-bound elements 12a are removed among the binding elements of the chemically adsorbed chemicals on the substrate 10 by introduction of the reaction gas. Such removal may be by ligand exchange of ligand binding elements. Since the reaction force that the reaction gas reacts with the ligand binding element is greater than the binding force to which the ligand binding element is bound, the element having the ligand binding can be removed. At this time, since Ta = N bond is a double bond, it is not influenced by the said reaction gas. Therefore, by removing the ligand binding element, an atomic layer thin film containing Ta = N is laminated on the substrate. According to this principle, the atomic layer 14 containing TaN is laminated and formed on the substrate 10.

In the deposition of atomic layer thin films, the reaction mechanism using a reducing agent is disclosed in the literature of the steels disclosed in the prior art. However, according to the steel, it is considered that the reaction gas is not used to remove the ligand binding element as in the present invention, but is substituted with the ligand binding element using the hydrogen radical as the reducing agent.

According to the method for forming a thin film using the atomic layer stacking, a thin film having a low specific resistance can be easily formed at a relatively low temperature. In particular, since this method uses a reactive gas activated by a remote plasma method, it is possible to exclude process variables due to plasma formation. Thus, the process can be carried out at low temperatures.

By repeatedly performing the above-described atomic layer deposition method, a TaN thin film can be formed. When such a TaN thin film forming method is formed on a pattern in which openings having a predetermined aspect ratio are formed, a thin film having very excellent step coverage can be formed with a uniform thickness.

In addition, according to the present invention, a tantalum amine derivative is used as a precursor of a metal for forming a thin film, and a thin film having excellent step coverage can be formed at a further improved deposition rate by depositing with a reaction gas.

That is, a tantalum amine derivative represented by the formula Ta (NR ₁ ) (NR ₂ R ₃ ) ₃ , wherein R ₁ and R ₂ R ₃ are the same or different from each other as H or a C ₁ -C ₆ alkyl group, and A thin film may be formed by mixing and depositing a reaction gas of any one of H ₂ , NH ₃ , SiH ₄ , Si ₂ H _6, and a mixture thereof.

In particular, tertamimilimido-tris-dimethylamidotantalum (Ta (NC (CH ₃ ) ₂ C ₂ H ₅ ) (N (CH ₃ ) ₂ ) ₃ ) is easily applied as the tantalum amine derivative. In addition, chemical vapor deposition (CVD) is preferably applied as the deposition method, and thermal CVD, plasma enhanced chemical vapor deposition (PECVD), and the like are easily applied. Can be.

It is also preferable to mix and deposit an inert gas such as Ar, He, N _2, etc. together with the reaction material.

In addition, the reaction gas including the H ₂ , NH ₃ , SiH ₄ and Si ₂ H ₆ is preferably activated by using a remote plasma or the like. The deposition step is preferably performed at a temperature range of 100 to 550 ° C, more preferably 150 to 300 ° C. The pressure during deposition may be performed in the range of 0.05 to 30 torr, preferably in the range of 0.3 to 10 torr, more preferably in the range of 0.3 to 5 torr.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings. In the present invention, TAIMATA is applied as a particularly preferred tantalum amine derivative. In particular, in order to confirm the excellent properties of this compound, an experiment comparing with known TBTDET having excellent properties is performed, and the difference in the results according to the addition or absence of the reaction gas will be compared.

Figure 2 is a graph showing the vapor pressure according to the temperature of the TBTDET and TAIMATA as a source for forming a thin film of TaN. In Fig. 2, the horizontal axis represents temperature and the vertical axis represents vapor pressure. From Figure 2, it can be seen that under the same temperature conditions TAIMATA has a higher vapor pressure than TBTDET.

3A and 3B show the chemical formulas of TBTDET and TAIMATA as sources for TaN thin film formation. 3A and 3B, both compounds do not include halogen elements such as chlorine, fluorine, and bromine. However, in the case of TBTDET, the vapor pressure (Vp) at 60 ° C. is about 0.01 torr, and it is liquid at room temperature. In the case of TAIMATA, the vapor pressure (Vp) at about 60 ° C. is about 0.1 torr, which is about 10 times higher than TBTDET. Have In addition, TAIMATA is in a solid state at room temperature, but the melting point is about 34 ° C., which is low at 40 ° C. or lower. Therefore, the problem of particle generation can be easily solved by slightly heating when applied to the actual deposition process.

As a method of depositing TaN using TAIMATA, all methods such as CVD, PECVD, ALD, and RAALD are possible. As a reaction gas for forming TaN, NH ₃ , H ₂ , SiH ₄ , Si ₂ H _6, and the like may be used.

In order to examine the deposition characteristics of TAIMATA, TaN deposition experiments were performed by CVD under Ar gas atmosphere. 4A and 4B are graphs showing deposition rates according to temperatures of stage heaters when TAIMATA is deposited by CVD in an Ar atmosphere. Figure 4a is a graph showing the deposition rate according to the temperature of the stage heater with uniformity and Figure 4b is a graph showing the deposition rate according to the temperature of the stage heater with a specific resistance.

Referring to FIG. 4A, graph a shows deposition rate and graph b shows uniformity. As the TaN was deposited by CVD deposition in an Ar atmosphere while increasing the temperature of the stage heater from 100 to 550 ° C., deposition was started at a substrate temperature of 300 ° C. or higher and the deposition rate gradually increased as the temperature increased. The decomposition temperature of TAIMATA confirmed experimentally is about 300 ° C. As a result of the experiment in the section of 300 ℃ or more and 550 ℃, the deposition rate increased as the deposition temperature increased, but the result was not saturation, and thus the deposition rate was controlled by the surface reaction in the entire temperature range. there was. In addition, it was confirmed that the uniformity of the formed film also improved as the deposition temperature increased.

4B shows the result of measuring the specific resistance of the TaN film obtained by the above-described experiment. Graph a shows the deposition rate and graph c the specific resistance.

The resistivity obtained when TaN was formed by the CVD method without adding a reaction gas from the graph shown in FIG. 4B was found to be 400,000 μΩ · cm at 500 ° C and 100,000 μΩ · cm at 550 ° C. Could.

Next, a deposition experiment was performed by adding a reaction gas to the TAIMATA source. An experiment was performed in which a TaN film was formed by CVD while supplying NH ₃ simultaneously as a reaction gas. The results obtained are shown in FIGS. 5A-5C.

Figures 5a and 5b is a graph showing the deposition rate according to the temperature of the stage heater when deposition by CVD method while simultaneously supplying NH ₃ reaction gas to the TAIMATA source, Figure 5a is a graph showing the uniformity and Figure 5b is a specific resistance It is a graph shown.

Figure 5c is a graph showing the deposition rate according to the NH ₃ flow rate with a specific resistance when the deposition by the CVD method while simultaneously supplying the NH ₃ reaction gas to the TAIMATA source.

First, referring to Figure 5a, the deposition rate according to the temperature is shown as a graph. In the figures, graph a represents the deposition rate and graph b the uniformity.

As a result of depositing TaN while increasing the stage temperature from 100 ° C. to 550 ° C., the temperature at which deposition began was about 150 ° C. It can be seen that deposition is started at a temperature lower than 300 ° C. when only TAIMATA is deposited without adding a reaction gas.

Deposition rate was increased in the temperature range of more than 150 ℃ and less than 300 ℃ and the mass transport regime was confirmed that the deposition rate has a constant from 300 ℃ to 550 ℃. Based on these experimental results, the window section of ALD temperature by TAIMATA and NH ₃ reaction becomes 150-300 degreeC section.

On the other hand, referring to Figure 4a and Figure 5a, a deposition rate in the case of using only TAIMATA at 300 ℃ the evaporation rate of the addition of NH ₃ at about 8.0Å / min On the other hand, the same temperature as about 270Å / min of NH ₃ It can be seen that the deposition rate is increased by about 30 times or more by the addition.

5B shows the result of measuring the specific resistance of the TaN film obtained by the above-described experiment. Graph a shows the deposition rate and graph c the specific resistance.

Referring to FIG. 5B, the specific resistance of the TaN thin film obtained by the CVD method by the reaction of TAIMATA with NH ₃ is 300,000 μΩ · cm at 400 ° C., and the specific resistance decreases rapidly at 450 ° C. or higher, and 8,000 μΩ · cm at 550 ° C. As the deposition temperature increases, the specific resistance was found to decrease significantly.

Figure 5c shows the results of measuring the deposition rate and the specific resistance according to the flow rate of NH ₃ when the deposition temperature is increased by the deposition of TAIMATA in NH ₃ and CVD method at 500 ℃. In the figure, graph e represents the deposition rate and graph f represents the resistivity.

Referring to FIG. 5C, it can be seen that the specific resistance decreases from 400,000 μΩ · cm to 20,000 μΩ · cm as the flow rate increases.

As a result of performing CVD-TaN deposition basic test using TAIMATA, the decomposition temperature of TAIMATA was found to be 300 ° C. or higher and the ALD window section was in the range of 150 to 300 ° C. Now, the ALD-TaN deposition characteristics using TAIMATA and reactant gas in the ALD window section were evaluated to investigate the behavior of TaN deposition rate according to NH ₃ and TAIMATA, and are shown in FIGS. 6A and 6B.

Figure 6a is a graph showing against the deposition rate in accordance with whether NH ₃ shown during the deposition by ALD method while supplying the NH ₃ reaction gas at the same time the TAIMATA source in several temperature, Figure 6b while supplying NH ₃ reaction gas to TAIMATA sources at the same time It is a graph showing the deposition rate according to TAIMATA illustrated in the ALD method with uniformity.

The dose can be expressed as the product of the partial pressure of the source and the pulsing time, and the unit is Langmuir (1 Langmuir = 1E-6 torr.sec). The TaN-ALD process used here is as follows.

First, a gaseous TAIMATA precursor is introduced onto the substrate as a reactant. This allows some of the reactants to be chemically adsorbed onto the substrate. An inert gas is then introduced onto the substrate to remove reactants that do not chemically adsorb in the reactants from the substrate. Thereafter, any one of H ₂ , NH ₃ , SiH ₄ , Si ₂ H _6, and a compound thereof, preferably has elements having ligand bonds included in the chemically adsorbed reactants by introducing NH ₃ onto the substrate To form a solid material containing TaN. Each step described above is repeated at least once to form a solid material into a TaN thin film.

Referring to Figure 6a, the deposition rate according to the dose of NH ₃ is shown as a graph. In the figure, graph a corresponds to the case where the temperature of the stage heater is 200 ° C, graph b corresponds to the case where the temperature of the stage heater is 250 ° C, and graph c corresponds to the case where the stage temperature is 300 ° C. When the dose of NH ₃ was increased to 8E6L by increasing the pulsing time of NH ₃ at 200 ° C., the deposition rate increased below 4E6L, but the increase was sharply decreased at doses higher than 4E6L. Increasing the temperature of the stage heater to deposit at 250 ℃ increased the deposition rate compared to 200 ℃ at the same NH ₃ dose. Further experiments by further increasing the temperature to 300 ℃ also showed the same result as the deposition rate increases.

Referring to FIG. 6B, the deposition rate according to the dose of TAIMATA is shown in a graph. In the figures, graph a represents the deposition rate and graph b the uniformity. It can be seen from the figure that the deposition rate increases as the amount of TAIMATA increases. It can also be seen that the dose of NH ₃ is saturated at 4E6L or more, but in the case of TAIMATA, the dose is saturated at 2E4L or more.

The above-described thin film forming method by ALD-TaN method and CVD-TaN method is formed on a substrate and includes a pattern including an opening having a predetermined aspect ratio, for example TaN having excellent step coverage on an insulating layer. It can be applied as a means for forming a thin film. A method of forming a TaN thin film by applying the ALD-TaN method will be described first.

To this end, first, to form an insulating layer on the substrate. A predetermined portion of the insulating layer is etched to expose the substrate surface and to form an opening having a predetermined aspect ratio. Tantalum amine derivatives represented by the formula Ta (NR ₁ ) (NR ₂ R ₃ ) ₃ , wherein R ₁ , R ₂ R ₃ are the same or different from each other as H or C ₁ -C ₆ alkyl groups, preferably The TAIMATA is introduced onto the insulating layer in which the opening is formed.

A portion of the reaction material is chemically adsorbed on the insulating layer in which the opening is formed, and then, a reaction material that does not chemically adsorb in the reaction material is removed from the insulating layer in which the opening is formed. Thereafter, a reaction gas is introduced onto the substrate to remove elements having ligand bonds included in the chemically adsorbed reaction material from the reaction material to form a solid material containing TaN. The above-described steps are repeated at least once to form the TaN thin film on the insulating layer having the opening. By repeatedly performing the atomic layer deposition method, the atomic layer is formed into a TaN thin film having a predetermined thickness. The thickness of the thin film depends on the number of repetitions of the step. As a result, the thickness of the thin film can be accurately controlled by adjusting the number of repetitions of the above steps. In addition, since the thin film formation uses the atomic layer deposition method, a thin film having good step coverage can be formed.

As the reaction gas, H ₂ , NH ₃ , SiH ₄ , Si ₂ H _6, etc. may be used, and a preferable temperature range is in the range of 100 to 350 ° C. In addition, it is preferable to apply a mixture of an inert gas such as Ar, He, N ₂ with the reaction material.

In addition, even when the opening has a very large aspect ratio, the present invention can be easily applied, and even when the aspect ratio is 10: 1 or more, a thin film having very excellent step coverage can be easily formed. In addition, the TaN thin film may be easily applied not only on an insulating layer pattern having an opening but also on a multilayer wiring structure formed on a substrate.

Hereinafter, a method of forming a TaN thin film by applying the CVD-TaN method will be described.

First, an insulating layer is formed on a substrate. Thereafter, a predetermined portion of the insulating layer is etched to form an opening through which the surface of the substrate is exposed. Tantalum amine derivatives and H ₂ represented by the formula Ta (NR ₁ ) (NR ₂ R ₃ ) ₃ , wherein R ₁ , R ₂ R ₃ are the same or different from each other as H or a C ₁ -C ₆ alkyl group and to deposit a TaN thin film on the insulating NH _3, SiH ₄ and Si ₂ H ₆ are mixed at least one reaction gas wherein the opening of the formed layer.

The deposition process is preferably carried out at a temperature range of 100 ~ 350 ℃, it is possible to mix an inert gas such as Ar, He, N ₂ with the reaction material. In addition, the method of the present invention can be easily applied even when the aspect ratio of the opening is 10: 1 or more.

7A to 7C are cross-sectional views illustrating a method of forming a TaN thin film on an insulating layer having an opening formed on a substrate.

Referring to FIG. 7A, an insulating layer 52 is formed of an oxide or the like on a substrate 50 such as a silicon substrate used in a semiconductor process.

Referring to FIG. 7B, an insulating layer pattern 52a including an opening having a predetermined aspect ratio is formed by etching a portion of the insulating layer 52 using a photolithography process.

Referring to FIG. 7C, the TaN thin film 54 is formed on the insulating layer pattern 52a including the opening by using the ALD-TaN method or the CVD-TaN method.

FIG. 8 shows a SEM photograph showing the step coverage of a TaN thin film formed by ALD deposition while simultaneously supplying NH ₃ as a reaction gas to a TAIMATA source on an insulating layer having an opening having a predetermined aspect ratio. A mixed gas of hydrogen 1000 sccm and Ar 500 sccm was used as the purge gas, and Ar gas was used at a flow rate of 100 sccm as a carrier gas of TAIMATA. NH ₃ as the reaction gas was injected at a flow rate of 600 sccm.

Both the top and bottom of the contact hole have a thickness of ˜250 Pa, the CD of the top of the contact hole is 250 nm, and the step is 25000 Pa. The aspect ratio is ˜10. The thin film formed from the figure can be seen that the step coverage characteristics close to 100% is obtained.

The photo shown in Figure 8 is a photograph of the thin film formed by the ALD method. In order to compare the characteristics of the thin films formed by the ALD-TaN method and the CVD-TaN method, a thin film having the same thickness was formed on the same target and then its components were analyzed. The results are shown in Table 1 below.

CVD-TaN ALD-TaN Ta (%) 31.9 36.2 N (%) 36.5 54.7 O (%) 24.8 5.6 C (%) 6.8 3.5 N / Ta 1.144 1.511

From Table 1 it can be seen that the content of impurities in the thin film formed by the ALD method is low. As described above, by performing the deposition process using the TAIMATA source, a TaN thin film having a high deposition rate and excellent step coverage without particles may be manufactured. In addition, although both CVD and ALD can be applied, it can be seen that the thin film characteristics by the ALD method are slightly better.

As described above, in the present invention, the formation of a thin film having improved step coverage and gap fill capability may be realized by introducing a new tantalum precursor in a new manner to perform a deposition process.

In addition, the tantalum precursor used in the present invention does not contain a halogen impurity such as chlorine and can be used in a liquid state so that particles are not generated during the performance of the process and have a high vapor pressure even at low temperature, so that the deposition rate is good. This is expected to increase productivity and improve yield.

Although described above with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below I can understand that you can.

Claims (37)

a) introducing teriamilimido-tris-dimethylamidotantalum (Ta (NC (CH ₃ ) ₂ C ₂ H ₅ ) (N (CH ₃ ) ₂ ) ₃ ) as a reactant on the substrate; b) chemically adsorbing a portion of the reactant onto the substrate; c) removing from the substrate a reactant that is not chemically adsorbed in the reactant; And d) introducing an reactant gas onto the substrate to remove elements having ligand bonds included in the chemically adsorbed reactant from the reactant to form a solid material (ALD; atomic layer) deposition method. The method of claim 1, wherein the atomic layer stack is a radical assisted ALD stack using thermal ALD or remote plasma. The method of claim 1, wherein the reactant material is introduced in a liquid state. delete The method of claim 1, wherein the chemically non-adsorbed reactant is removed using an inert gas. The method of claim 5, wherein the inert gas is Ar, He, or N ₂ . The method of claim 1, wherein the reaction gas is at least one selected from the group consisting of H ₂ , NH ₃ , SiH _4, and Si ₂ H ₆ . The method of claim 1, wherein the reaction gas is at least one selected from the group consisting of activated H ₂ , NH ₃ , SiH _4, and Si ₂ H ₆ . The method of claim 8, wherein the activation is by a remote plasma method. The method of claim 1, wherein the solid material is TaN. The method of claim 1, wherein the steps a) -d) are performed at a temperature in the range of 100 to 350 ° C. a) introducing teriamilimido-tris-dimethylamidotantalum (Ta (NC (CH ₃ ) ₂ C ₂ H ₅ ) (N (CH ₃ ) ₂ ) ₃ ) as a reactant on the substrate; b) chemically adsorbing a portion of the reactant onto the substrate; c) removing from the substrate a reactant that is not chemically adsorbed in the reactant; d) introducing a reactant gas onto the substrate to remove elements having ligand bonds included in the chemically adsorbed reactant from the reactant to form a solid material containing TaN; And (e) repeating steps a) -d) at least once to form the solid material into a TaN thin film. delete The method of claim 12, wherein the reaction gas is at least one selected from the group consisting of H ₂ , NH ₃ , SiH _4, and Si ₂ H ₆ . The method of claim 12, wherein the method is performed at a temperature in the range of 100 to 350 ° C. 13. The method of claim 12, wherein the chemically non-adsorbed reactant is removed using at least one inert gas selected from the group consisting of Ar, He, and N ₂ . a) forming an insulating layer on the substrate; b) etching a portion of the insulating layer to form an opening through which the surface of the substrate is exposed; c) Teriamilimido-tris-dimethylamidotantalum (Ta (NC (CH ₃ ) ₂ C ₂ H ₅ ) (N (CH ₃ ) ₂ ) ₃ ) as a reaction material on the insulating layer formed with the opening Introducing; d) chemically adsorbing a portion of the reactant material on the insulating layer in which the opening is formed; e) removing a reaction material that is not chemically adsorbed from the reaction material from the insulating layer in which the opening is formed; f) introducing a reactant gas onto the substrate to remove elements having ligand bonds included in the chemically adsorbed reactant from the reactant to form a solid material containing TaN; And (g) repeating steps c) -f) at least once to form a TaN thin film on the insulating layer on which the opening is formed. A method of forming a thin film using atomic layer deposition (ALD). delete The method of claim 17, wherein the reaction gas is at least one selected from the group consisting of H ₂ , NH ₃ , SiH _4, and Si ₂ H ₆ . The method of claim 17, wherein the method is performed at a temperature in the range of 100 to 350 ° C. 18. The method of claim 17, wherein the chemically non-adsorbed reactant is removed using at least one inert gas selected from the group consisting of Ar, He, and N ₂ . 18. The method of claim 17, wherein the aspect ratio of the opening is at least 10: 1. Teriamilimido-tris-dimethylamidotantalum (Ta (NC (CH ₃ ) ₂ C ₂ H ₅ ) (N (CH ₃ ) ₂ ) ₃ ) and H ₂ , NH ₃ , SiH ₄ and Si as reactants Mixing at least one reaction gas selected from the group consisting of ₂ H ₆ ; And Depositing a thin film on the substrate by chemical vapor deposition by introducing the mixed gases onto the substrate. delete delete 24. The method of claim 23, wherein the deposition is thermal CVD or plasma enhanced chemical vapor deposition (PECVD). 24. The method of claim 23, wherein an inert gas is mixed with the reactant to be deposited. The method of claim 27, wherein the inert gas is at least one selected from the group consisting of Ar, He, and N ₂ . The method of claim 23, wherein the reaction gas is at least one selected from the group consisting of activated H ₂ , NH ₃ , SiH _4, and Si ₂ H ₆ . 30. The method of claim 29, wherein the activation is by a remote plasma method. 24. The method of claim 23, wherein said thin film is a TaN film. The method of claim 23, wherein the depositing step is performed at a temperature in a range of 100 to 550 ° C. 24. 24. The method of claim 23, wherein the depositing step is performed at a temperature in the range of 150 to 300 ° C. a) forming an insulating layer on the substrate; b) etching a portion of the insulating layer to form an opening through which the surface of the substrate is exposed; And c) teriamilimido-tris-dimethylamidotantalum (Ta (NC (CH ₃ ) ₂ C ₂ H ₅ ) (N (CH ₃ ) ₂ ) ₃ ) and H ₂ , NH ₃ , SiH _{4 as} reactants; And depositing a TaN thin film on the insulating layer on which the opening is formed by mixing at least one reaction gas selected from the group consisting of Si ₂ H ₆ . 35. The method of claim 34, wherein the method is performed at a temperature in the range of 100 to 350 ° C. 35. The method of claim 34, wherein at least one inert gas selected from the group consisting of Ar, He, and N ₂ is mixed with the reactant. 35. The method of claim 34 wherein the aspect ratio of the openings is at least 10: 1.

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