Method for forming a thin film using an organometallic compound, and thin film produced therefrom

Abstract

The present invention relates to a method for producing a thin film having excellent properties by vapor deposition of an organometallic compound (particularly an organometallic compound containing a rare earth metal), and to the produced thin film.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a thin film using an organometallic compound, and specifically, to a method for forming a thin film with excellent characteristics using atomic layer deposition (ALD) and a thin film with excellent characteristics.

Background Art

[0002] Silicon oxide (SiO 2 ) has recently been replaced by a metal gate / high-k transistor due to the dense packing of semiconductor elements and the miniaturized channel length.

[0003] In particular, the demand for the development of high dielectric constant materials and the processes for applying them has been increasing due to the miniaturization of the line width between elements.

[0004] On the other hand, a high-k dielectric should have a high bandgap and band offset, a high k value, excellent stability on silicon, a minimum SiO 2 interface layer, and a high-quality interface on the substrate. Also, an amorphous or highly crystalline film is desirable.

[0005] Typical high-k dielectric materials that have been actively studied and applied to replace silicon oxide include hafnium oxide (HfO 2 ), etc. In particular, in processes of 10 nm or less, next-generation high-k dielectric materials have been continuously demanded, and promising candidates for next-generation high-k dielectric materials include rare-earth-doped hafnium oxide, etc.

[0006] In particular, rare-earth element-containing materials are promising high-k dielectric materials for advanced silicon CMOS, germanium CMOS, and III-V transistor devices, and it has been reported that new-generation oxides based on these materials provide significant advantages in capacitance compared to ordinary dielectric materials.

[0007] In addition, rare earth element-containing materials are expected to be applied to the production of perovskite materials having properties such as ferroelectricity, pyroelectricity, piezoelectricity, and resistive switching. That is, through a vapor deposition process using an organometallic compound precursor, a perovskite of the ABO 3 form is produced, the types or compositions of A and B cations (rare earth or transition metals) are adjusted, and various properties such as the dielectric properties, electronic conductivity, and oxygen ion conductivity of the material are imparted, and research is being carried out for use in various industrial fields such as fuel cells, sensors, and secondary batteries.

[0008] In addition to this, rare earth element-containing materials are actively being studied for use as sealing materials that utilize the excellent water penetration resistance of the multilayer oxide thin film structure and for realizing next-generation non-volatile memories.

[0009] However, since it is still difficult to deposit the rare earth-containing layer, rare earth precursors having various ligands advantageous for deposition and deposition methods for efficient rare earth precursors have been studied.

[0010] Typical examples of ligands constituting rare earth precursors include compound groups such as amide, amidinate, β-diketonate, and cyclopentadienyl (Cp). However, these precursors have drawbacks such as high melting points, low deposition temperatures, high impurities in the thin film, and relatively low reactivity, making them difficult to apply to actual processes, and the development of deposition methods suitable for this has not proceeded smoothly.

[0011] As a result, the development of a deposition process applying a rare earth precursor improved for the deposition of rare earth-containing films is required.

Prior Art Documents

Patent Documents

[0012]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0013] Therefore, an object of the present invention is to provide an efficient method for manufacturing a thin film using a rare earth organometallic precursor compound, and a thin film having excellent properties manufactured thereby.

[0014] However, the problems to be solved by the present application are not limited to the above-described problems, and other problems not described above will be clearly understood by those skilled in the art from the following description.

Means for Solving the Problems

[0015] One aspect of the present application repeats a cycle including a first injection step of injecting an organometallic precursor compound into a chamber, a first purge step of purging the organometallic precursor compound from the chamber, a second injection step of injecting a reaction gas into the chamber, and a second purge step of purging by-products that do not react with or react with the organometallic precursor compound from the chamber, to deposit a thin film on a substrate, and provides a method for manufacturing a thin film, wherein the organometallic precursor compound includes a precursor represented by the following Chemical Formula 1.

Chem.

[0016] Another aspect of the present application provides a thin film having a carbon atom content of 1.5 atomic% or less, produced by the above production method.

Advantages of the Invention

[0017] The method for producing a thin film according to the present invention has the effect of efficiently producing a thin film with excellent characteristics.

[0018] In particular, the thin film has a high degree of thickness uniformity, a low impurity content, and exhibits excellent electrical characteristics (dielectric constant, leakage current, etc.).

[0019] In addition, the thin film with excellent characteristics produced by the method for producing a thin film of the present invention can be used in dielectrics of various electronic devices (especially High K / metal gate, DRAM capacitor), perovskite materials, displays, next-generation memories, etc.

Brief Description of the Drawings

[0020]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0021] Hereinafter, the operations and effects of the invention will be described in more detail according to specific embodiments of the invention. However, these embodiments are merely presented as examples of the invention, and do not thereby define the scope of the invention.

[0022] Prior to this, terms or words used in this specification and the claims should not be construed as being limited to their ordinary and dictionary meanings. In accordance with the principle that the inventor can appropriately define the concept of a term in order to best explain his own invention, they should be construed in a meaning and concept consistent with the technical idea of the present invention.

[0023] Therefore, it should be understood that the configurations of the embodiments described in this specification are merely one of the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention, and there may be various equivalents and modifications that can replace them at the time of this application.

[0024] In this specification, singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as "including", "comprising", or "having" are intended to specify the presence of implemented features, numbers, steps, components, or combinations thereof, and should be understood not to preclude the presence or addition possibility of one or more other features, numbers, steps, components, or combinations thereof in advance.

[0025] A method for manufacturing a thin film according to one aspect of the present application includes a first injection step of injecting an organometallic precursor compound into a chamber, a first purge step of purging the organometallic precursor compound from the chamber, a second injection step of injecting a reaction gas into the chamber, and a second purge step of purging by-products that do not react with or react with the organometallic precursor compound from the chamber, and repeating a cycle including these steps to deposit a thin film on a substrate. The organometallic precursor compound can include a precursor represented by the following Chemical Formula 1.

[0026] [Chemical Formula] In the formula, M is any one of scandium (Sc), yttrium (Y), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), or lutetium (Lu); L is N(SiR 4 R 5 ) 2 ; R 1 ~R 5 are each independently hydrogen or a linear or branched hydrocarbon having 1 to 4 carbon atoms; x is an integer from 1 to 3.

[0027] The organometallic precursor compound of Chemical Formula 1 contains a rare earth atom and a silicon atom together, and can reduce the complexity of the conventional method for manufacturing a thin film in which a rare earth organometallic precursor compound and a silicon organometallic precursor have to be separately prepared and vapor-deposited to produce a thin film containing a rare earth atom and a silicon atom together.

[0028] Also, in the conventional manufacturing method, generally, the volatility and decomposition temperature between the two precursors are different, and it is difficult to maintain a uniform composition in a high aspect ratio structure. However, when the precursor of the present invention is used, such problems can be improved.

[0029] In one embodiment, L of Chemical Formula 1 can be bis(trimethylsilyl)amine (BTSA).

[0030] On the one hand, the method for manufacturing the thin film may be an atomic layer deposition (ALD) method, or may be a plasma-enhanced atomic layer deposition (PE-ALD) method among the atomic layer deposition methods, but is not limited thereto.

[0031] In addition, the step of injecting the organometallic precursor compound into the chamber may include a step of physically adsorbing, chemically adsorbing, or physically and chemically adsorbing.

[0032] In one embodiment, the method for manufacturing the thin film may further include a step of injecting at least one of an oxygen (O) atom-containing compound, a nitrogen (N) atom-containing compound, a carbon (C) atom-containing compound, and a silicon (Si) atom-containing compound as a reaction gas.

[0033] In one embodiment, 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 ), and may be at least one selected therefrom.

[0034] That is, when the desired rare earth-containing 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 is not limited thereto.

[0035] When the desired rare earth-containing film contains nitrogen, the reaction gas is nitrogen (N 2 ), ammonia (NH 3 ), hydrazine (N 2 H 4) and can be selected from these and any combination thereof, but is not limited thereto.

[0036] Also, when the desired rare earth-containing film contains other metals, the reaction gas may contain other metal atoms.

[0037] In one embodiment, the temperature of the canister of the organometallic precursor compound may be 150 °C or higher.

[0038] The canister is used to supply source gas into the chamber for the reaction in the thin film manufacturing method. Usually, after vaporizing the organometallic precursor compound to generate source gas, the canister supplies the source gas into the chamber.

[0039] If the temperature of the canister is less than 150 °C, the uniformity of the thickness of the thin film manufactured by the thin film manufacturing method may be significantly reduced.

[0040] This is because the supply amount of the organometallic precursor compound into the chamber at a canister temperature of less than 150 °C is insufficient.

[0041] In one embodiment, the process temperature for the vapor deposition may be 350 °C or lower.

[0042] As the process temperature increases, the deposition rate may increase. Also, the thin film manufactured at a process temperature of 250 °C to 350 °C has excellent uniformity and can be used for various applications.

[0043] Also, as the process temperature increases, the content of carbon atoms corresponding to impurities in the manufactured thin film may slightly increase, and as the dielectric constant slightly decreases, the leakage current may slightly increase, but the characteristics of the thin film manufactured at a process temperature of 250 °C to 350 °C fall within the range of excellent quality and can be used for various applications.

[0044] In one embodiment, the injection time of the organometallic precursor compound may be 1 second or more and 30 seconds or less, and the injection amount of the carrier gas of the organometallic precursor compound may be 10 sccm or more and 5000 sccm or less.

[0045] Also, the injection time of the reaction gas is 1 second or more and 30 seconds or less, the injection amount of the reaction gas is 10 sccm or more and 5000 sccm or less, and the concentration of the reaction gas is 50 g / m 3 or more and 500 g / m 3 or less.

[0046] In one embodiment, the purge gas injection times of the first purge step and the second purge step are each independently 1 second or more and 3 minutes or less, and the purge gas injection amounts of the first purge step and the second purge step are each independently 10 sccm or more and 5000 sccm or less.

[0047] When the process conditions for the above-described organometallic precursor compound, reaction gas, and purge gas are not satisfied, a thin film with excellent characteristics cannot be obtained.

[0048] On the other hand, the number of cycles of the method for manufacturing the thin film may be 1 or more and 100,000 or less.

[0049] A thin film according to another aspect of the present application is manufactured by the above manufacturing method, and the content of carbon (C) atoms, which are impurities, may be 1.5 atomic% or less.

[0050] Also, nitrogen (N) atoms, which are other impurities of the thin film, may not be detected by X-ray photoelectron spectroscopy (XPS).

[0051] In one embodiment, the thin film has a dielectric constant of 10 or more and a leakage current of 4.0×10 -7 A / cm 2 or less.

Example

[0052] Hereinafter, the present application will be described more specifically with reference to examples, but the present application is not limited thereto.

[0053] [Synthesis Example] [NH t BuCH 2 CH 2 NMe 2 [Production of Ligand] 1 eq of 2-chloro-N,N-dimethylethylamine hydrochloride was gradually dissolved in 100 mL of water, and 1 eq of an aqueous NaOH solution was slowly added at 0 °C. Then, 4 eq of t-butylamine was slowly charged using a dropping funnel at the same temperature, and the mixture was stirred overnight at room temperature. After completion of the reaction, 1 eq of NaOH was added and stirring was continued, followed by extraction using a hexane solvent. The organic layer was dehydrated with MgSO 4 , and then the solvent was removed and purified at normal pressure. The synthesized NH t BuCH 2 CH 2 NMe 2 was a colorless liquid, and the synthesis yield was 30%.

[0054] The chemical structural formula and NMR measurement results of the obtained NH t BuCH 2 CH 2 NMe 2 are as follows.

[0055] [NH t BuCH 2 CH 2 NMe 2 [Chemical Structural Formula of

[0056]

Chemical Formula

[0057] 1 1H-NMR (400 MHz, Benzene-D6): δ 1.06 (s, 9H), 2.06 (s, 6H), 2.33 (t, 2H), 2.56 (t, 2H)

[0058] [La(btsa) 2 (NH t BuCH 2 CH 2 NMe 2 )(La(N(SiMe 3 ) 2 ) 2 (NH t BuCH 2 CH 2 NMe 2 )'s production] La(btsa) 3 Put toluene as a solvent into a flask containing 1 eq, and add 1 eq of NH t BuCH 2 CH 2 NMe 2 heated at 70 °C overnight. After completion of the reaction, concentrate under reduced pressure and purify by sublimation at 110 °C and 56 mTorr to obtain La(btsa) 2 (NH t BuCH 2 CH 2 NMe 2 ).

[0059] The synthesized La(btsa) 2 (NH t BuCH 2 CH 2 NMe 2 ) is an ivory-colored solid, and the synthesis yield is 76%.

[0060] The chemical structural formula and NMR measurement results of the synthesized La(btsa) 2 (NH t BuCH 2 CH 2 NMe 2 ) are as follows.

[0061] [La(btsa) 2 (NH t BuCH 2 CH 2 NMe2 ) Chemical structural formula

[0062]

Chem.

[0063] The aforementioned La(btsa) 2 (NH t BuCH 2 CH 2 NMe 2 ) In the chemical structural formula, BTSA is a bis(trimethylsilyl)amine group and tBu is a tert-butyl group.

[0064] 1 H-NMR (400 MHz, THF-d8): δ 0.15 (s, 36H), 1.23 (s, 9H), 2.48 (s, 6H), 3.03 (t, 2H), 3.09 (t, 2H)

[0065] [Production Example] Using atomic layer deposition (ALD) equipment, the organometallic precursor compound produced by the aforementioned synthesis example was deposited as a thin film.

[0066] The substrate used in this experiment was a p-type Si(100) wafer with a resistivity of 0.02 Ω·m. Prior to deposition, the p-type Si wafer was ultrasonically cleaned in acetone - ethanol - deionized water (DI water) for 10 minutes each. The native oxide thin film on the Si wafer was removed after immersion in a 10% HF (HF:H 2 O = 1:9) solution for 10 seconds. The HF-cleaned Si wafer was immediately transferred to the atomic layer deposition (ALD) chamber. The organometallic precursor compound used in the experiment, La(btsa) 2 (NH t BuCH 2 CH 2 NMe 2It is a precursor containing both La and Si, which are rare earth metals, and the temperature of the canister was maintained at 130 °C to 160 °C.

[0067] La(btsa) 2 (NH t BuCH 2 CH 2 NMe 2 )(10 seconds) - Ar (30 seconds) - ozone (O 3 )(10 seconds) - Ar (30 seconds) were supplied in this order.

[0068] The ozone (O 3 ) used as the reaction gas was injected at a flow rate of 1,000 sccm by adjusting the on / off of the pneumatic valve. At this time, the concentration of ozone was 220 g / m 3 .

[0069] La(btsa) 2 (NH t BuCH 2 CH 2 NMe 2 ) and the flow rate of argon (Ar) for purging ozone was set to 1,500 sccm.

[0070] The reactor pressure was set to 1 torr in the process temperature range of 250 °C to 350 °C, and the number of cycles was set to 200 times.

[0071] The process conditions for thin film production are shown in Table 1 below.

[0072]

Table 1

[0073] The deposition rate, thickness uniformity, and components and their composition ratios of the thin film produced by the above production example were analyzed.

[0074] (1) Measurement of deposition rate The deposition rate was calculated by the following Equation 1. [Equation 1] Evaporation rate (Å / cycle) = Evaporation thickness / Number of ALD cycles The evaporation thickness in Formula 1 was measured with an ellipsometer and confirmed using FE-SEM.

[0075] (2) Measurement of thickness uniformity The thickness uniformity was calculated by the following Formula 2. [Formula 2] Thickness uniformity (%) = (Maximum thickness - Minimum thickness) / (2 × Average thickness) The maximum, minimum, and average thicknesses in Formula 2 were determined from the values measured at nine locations on the wafer where the thin film was formed. The measurement was performed with an ellipsometer (manufacturer: Ellipso Technology, model name: Elli-SE-UaM8). The nine locations on the wafer were the center (C), right (R), left (L), top (T), bottom (B), top right (RT), top left (LT), bottom right (RB), and bottom left (LB), respectively.

[0076] (3) Measurement of components and composition ratio The components and composition ratio of the manufactured thin film were analyzed using X-ray photoelectron spectroscopy (XPS).

[0077] [Example 1] The process temperature was fixed at 250°C under the process conditions described in Table 1 above, and the temperature of the canister was varied in the range of 130°C to 160°C. A thin film was manufactured according to the above manufacturing example, and the evaporation rate (GPC) and thickness uniformity of the thin film were measured. The results are shown in FIG. 1.

[0078] As shown in FIG. 1, as the temperature of the canister increased, the evaporation rate increased and the thickness uniformity decreased.

[0079] When the temperature of the canister was 130°C and 140°C, the thickness variations at the measurement positions of the thin film were 30.3% and 18.6% respectively, which were very high. Therefore, the non-uniformity of the thin film could be confirmed.

[0080] On the other hand, when the temperature of the canister was raised to 150 °C and 160 °C, the thickness variations due to the measurement positions of the thin films were very low, at 1.4% and 1.6% respectively, and thus thin films with a very uniform thickness were formed.

[0081] That is, it was found that the temperature of the canister significantly affects the deposition rate and thickness uniformity of the thin film.

[0082] [Example 2] The temperature of the canister was fixed at 150 °C under the process conditions described in Table 1 above, and the process temperature was varied in the range of 250 °C to 350 °C to manufacture a thin film according to the above Production Example. The deposition rate (GPC) and thickness uniformity of the thin film were measured, and the results are shown in Figure 2.

[0083] As shown in Figure 2, it was confirmed that the deposition rate increased as the process temperature increased.

[0084] Also, when the process temperatures were 250 °C, 300 °C, and 350 °C, the thickness variations due to the measurement positions of the thin films corresponded to 1.4%, 1.0%, and 4.2% respectively. Thus, it was confirmed that the thickness uniformity of the thin film was very excellent.

[0085] Also, as shown in Figure 3, the elements of the thin films manufactured according to Example 2 with the process temperature varied were analyzed.

[0086] In all the thin films, the elements La, Si, and O were detected, and the impurity nitrogen (N) was not detected.

[0087] The impurity carbon (C) was detected in all the thin films, and its content varied depending on the process temperature.

[0088] That is, although the content of carbon, which is an impurity in the thin film, increased as the process temperature increased, the thin films manufactured at process temperatures of 250 °C to 350 °C showed excellent characteristics with a very low carbon content of 1.3 atomic% or less.

[0089] In addition, there is almost no difference in the ratios of La, Si, and O in the thin film due to changes in the process temperature during manufacturing. The atomic ratio of La:Si:O is 1:1:3, and LaSiO 3 It was confirmed that the thin film was formed.

[0090] On the other hand, as a result of measuring the electrical properties (dielectric constant and leakage current) of the manufactured thin film, it was confirmed that the higher the process temperature during thin film manufacturing, the lower the measured value of the dielectric constant and the higher the measured value of the leakage current.

[0091] The measured values of the dielectric constant and leakage current of the thin film manufactured at a process temperature of 250°C to 350°C both fell within a sufficiently excellent range for use in actual applications.

[0092] It was found that excellent thin films can be formed through ALD with various process conditions adjusted by the above thin film manufacturing method.

[0093] In particular, it was confirmed that the characteristics of the thin film can be improved by adjusting the canister temperature and the process temperature.

[0094] That is, by adjusting the process conditions, it is possible to manufacture a thin film with a uniform thickness and ensure excellent thin film physical properties (electrical properties such as impurity content and dielectric characteristics).

[0095] The scope of the present invention is defined by the claims set forth hereinafter rather than the above detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts are to be construed as being included within the scope of the present invention.

Industrial Applicability

[0096] The method for manufacturing a thin film according to the present invention has the effect of being able to efficiently manufacture a thin film with excellent characteristics.

[0097] In particular, the thin film has a high degree of thickness uniformity, a low impurity content, and exhibits excellent electrical properties (dielectric constant, leakage current, etc.).

[0098] In addition, the thin film with excellent properties manufactured by the method for manufacturing a thin film of the present invention can be used in dielectrics (particularly, High K / metal gate, DRAM capacitor) of various electronic devices, perovskite materials, displays, next-generation memories, and the like.

Claims

1. A first injection step of injecting an organometallic precursor compound into a chamber; A first purge step of purging the organometallic precursor compound from the chamber; A second injection step of injecting a reaction gas into the chamber; Repeating a cycle including a second purge step of purging by-products that do not react with or are produced by reacting with the organometallic precursor compound from the chamber to deposit a thin film on a substrate, The organometallic precursor compound is a method for manufacturing a thin film containing a precursor represented by the following Chemical Formula 1, The temperature of the canister of the organometallic precursor compound is 150 °C or higher, The thin film has a dielectric constant of 10 or more and a leakage current measured under an electric field applied at -1 MV / cm is 4.0×10 -7 A / cm 2 or less. A method for manufacturing the thin film is as follows. 【Chemical 1】 (In the formula, M is any one of scandium (Sc), yttrium (Y), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb) or lutetium (Lu), L is N(SiR 4 R 5 R 6 ), 2 and is R 1 ~R 6 are each independently hydrogen or a linear or branched hydrocarbon having 1 to 4 carbon atoms, x is an integer of 1 or 2.)

2. The method for manufacturing a thin film according to Claim 1, wherein L in Chemical Formula 1 is a bis(trimethylsilyl)amine group.

3. The reaction gas is at least one selected from the group consisting of ozone (O 3 ), and water (H 2 O), The method for producing a thin film according to claim 1.

4. The method for manufacturing a thin film according to Claim 1, wherein the process temperature is 350 °C or lower.

5. The injection time of the organometallic precursor compound is 1 second or more and 30 seconds or less, The injection amount of the carrier gas of the organometallic precursor compound is 10 sccm or more and 5000 sccm or less, The injection time of the reaction gas is 1 second or more and 30 seconds or less, The injection amount of the reaction gas is 10 sccm or more and 5000 sccm or less, The concentration of the reaction gas is 50 g / m 3 or more and 500 g / m 3 or less. The method for producing a thin film according to claim 1.

6. The purge gas injection time of the first purge step and the second purge step is independently 1 second or more and 3 minutes or less, The method for manufacturing a thin film according to Claim 1, wherein the purge gas injection amount of the first purge step and the second purge step is independently 10 sccm or more and 5000 sccm or less.

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