KR102117945B1 - Fabrication method of anti-reflection thin film by chemical vapor deposition method - Google Patents

Abstract

Disclosed is a method for manufacturing an antireflection film using a chemical vapor deposition method that does not require high vacuum. The method of manufacturing the anti-reflection film includes supplying chemical vapor deposition reaction materials into the reactor, diffusing the materials to the surface of the substrate arranged inside the reactor or a lower thin film surface on the substrate, and forming a MgF ₂ thin film on the substrate. It includes.

Description

Manufacturing method of anti-reflection film using chemical vapor deposition method {FABRICATION METHOD OF ANTI-REFLECTION THIN FILM BY CHEMICAL VAPOR DEPOSITION METHOD}

An embodiment of the present invention relates to a method for manufacturing an antireflection film, and more particularly, to a method for manufacturing an antireflection film using a chemical vapor deposition method.

In the solar cell, a pair of electrons and holes is generated in the semiconductor inside the solar cell by sunlight incident from the outside, and the generated electrons and holes move to an n-type semiconductor and a p-type semiconductor, respectively, to generate electric power.

However, since some of the incident sunlight is reflected from the surface of the solar cell, the amount of light entering the solar cell decreases, and thus, the energy conversion efficiency of the solar cell decreases.

In order to solve this problem, an antireflection layer is applied during solar cell manufacturing to minimize light reflected from the surface of the solar cell. As a method of manufacturing an anti-reflection film, wet coating methods such as spin coating or dip coating, and vacuum deposition methods such as physical vapor deposition (PVD) and chemical vapor deposition (CVD) There is this.

The wet coating method has an advantage in that the manufacturing cost is low, but the in-line process is difficult. Among the physical vapor deposition methods among vacuum deposition methods, there are evaporator and sputter methods using heat or electron beam. Among them, evaporation deposition method has an advantage of easy to implement an anti-reflection film, but it is difficult to implement large area, so productivity is low. There are disadvantages. The sputtering method is easy to implement an anti-reflection film and can be implemented in a large area, but requires a high vacuum of 10 ^-5 Torr (or 0.1 mPa) or less, resulting in a high manufacturing system cost and generating plasma during thin film production. Therefore, there is a disadvantage that the lower thin film is damaged.

The present invention is to solve the problems of the prior art described above, the object of the present invention is to prepare an antireflection film using a chemical vapor deposition method (chemical vapor deposition, CVD) that does not require a high vacuum of 10 ^-3 Torr (or 100mPa) or less To provide a method.

Another object of the present invention is to provide an antireflection film manufacturing method using a liquid magnesium (Mg) precursor to form a magnesium fluoride (MgF ₂ ) thin film on a substrate in a CVD process, not a liquid precursor.

The method for manufacturing an anti-reflection film according to an aspect of the present invention for solving the above technical problem includes supplying chemical vapor deposition reaction materials into the reactor using a source material including a liquid magnesium (Mg) precursor; Diffusing the materials to the surface of the substrate or the lower thin film surface on the substrate arranged inside the reactor; And forming a MgF ₂ thin film on the substrate.

In one embodiment, the thickness of the MgF ₂ thin film is 50 nm to 300 nm, and may be included in the antireflection film on the substrate. The substrate may be a transparent substrate or a glass substrate. The transparent substrate may have a transmittance of about 85 to 90% in the visible light region.

In one embodiment, in the step of supplying, as the precursor of the liquid magnesium (Mg), Bis (cyclopentadienyl)magnesium, Bis (ethylcyclopentadienyl)magnesium, Bis (pentamethylcyclopentadienyl)magnesium, Bis (n-propylcyclopentadienyl)magnesium, and Bis ( At least one selected from 2,2,6,6-tetramethyl-3,5-heptanedionato)magnesium can be used.

In one embodiment, in the supplying step, nitrogen trifluoride (NF ₃ ), titanium tetrafluoride (TiF ₄ ) or tantalum pentafluoride (TaF ₅ ) is used as a precursor of fluorine (F) of the MgF ₂ thin film. Can be.

In one embodiment, in the supplying step, the liquid magnesium precursor and the fluorine precursor are selected from hydrogen (H), helium (He), nitrogen (N), and argon (Ar) gases, or a mixture thereof Diluted with can be used.

In one embodiment, the supplying step, the liquid Mg precursor and F precursor may be injected together or simultaneously to the vacuum chamber as the reactor.

In one embodiment, the supplying step may control the canister temperature of the liquid Mg precursor to 200°C or less at room temperature and the supply line temperature to 200°C or less at room temperature. Further, more preferably, in the supplying step, the canister temperature of the liquid Mg precursor may be adjusted to 30°C to 140°C, and the supply line temperature to 60°C to 180°C.

In one embodiment, the diffusion step, the temperature of the substrate may be controlled to 600 ℃ or less at room temperature. In addition, more preferably, in the diffusion step, the temperature of the substrate may be adjusted to 200°C to 400°C or less at room temperature.

In one embodiment, the supplying step or the diffusing step may control the internal pressure of the reactor vacuum chamber to 1 mTorr (0.133322Pa) to atmospheric pressure. Further, more preferably, the supplying step or the diffusing step may adjust the internal pressure of the vacuum chamber as the reactor to 5 mTorr (0.66661Pa) to 10 Torr (13.3322hPa).

In one embodiment, the method for manufacturing an anti-reflection film may further include heat-treating the MgF ₂ thin film after the forming step.

In one embodiment, the heat treatment step may control the heat treatment temperature to 80 ℃ ~ 600 ℃.

In one embodiment, in the heat treatment step, any one or a mixture thereof selected from the group consisting of argon (Ar), helium (He), and nitrogen (N) gases may be used in a vacuum atmosphere or as an atmospheric gas.

In one embodiment, before the supplying step, the substrate may include an AZO thin film as the lower thin film.

In one embodiment, the method of manufacturing an anti-reflection film may further include forming an AZO thin film as the lower thin film on the substrate before the supplying step. The thickness of the AZO thin film may be 0.5 μm to 2.0 μm.

Using the method for manufacturing an antireflection film according to the present invention, the use of a liquid magnesium (Mg) precursor for the MgF ₂ antireflection film prevents the continuous process of the existing wet method and the large area of the evaporation method and the difficulty of mass production. And can effectively lower the manufacturing cost, contributing to commercialization.

In other words, the use of liquid magnesium (Mg) precursor in the production of MgF ₂ thin film by chemical vapor deposition does not require high vacuum, so it is easy to implement a relatively low system price and large area, thereby mass-producing products at a low manufacturing cost. It has the advantage of being able to produce.

In addition, it is possible to provide an anti-reflection film having a high reflectivity in an electric and power manufacturing apparatus using sunlight. In addition, in the field of manufacturing display elements such as liquid crystal display (LCD) and organic electroluminescence display (OLED), it is possible to provide an antireflection film having excellent reflectance on a transparent substrate.

1 is a flowchart of a method of manufacturing an anti-reflection film according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view for explaining the antireflection film manufactured according to the method of manufacturing the antireflection film of FIG. 1.
FIG. 3 is a SEM cross-sectional image of a MgF ₂ thin film prepared by chemical vapor deposition using a specific magnesium precursor in the method of manufacturing the antireflection film of FIG. 1.
4 is a view showing an SEM surface image of the MgF ₂ thin film of FIG. 3.
5 is a graph showing reflectance by the MgF ₂ thin film of FIG. 3.
6 is a cross-sectional view for describing an anti-reflection film manufactured by a method for manufacturing an anti-reflection film according to another embodiment of the present invention.
7 is a view showing an SEM cross-sectional image of the MgF ₂ thin film prepared by chemical vapor deposition using a specific magnesium precursor in the method of manufacturing the anti-reflection film of FIG. 6.
8 is a view showing an SEM surface image of the MgF ₂ thin film of FIG. 6.
9 is a graph for explaining the reflectance of the MgF ₂ thin film of FIG. 6.

The present invention can be applied to various changes and can have various embodiments, and specific embodiments will be illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention. In describing each drawing, similar reference numerals are used for similar components.

Terms such as first, second, A, and B may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from other components. For example, the first component may be referred to as a second component without departing from the scope of the present invention, and similarly, the second component may be referred to as a first component. The term and/or includes a combination of a plurality of related described items or any one of a plurality of related described items.

The terminology used herein is only used to describe a specific embodiment, and is not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present specification, terms related to “comprises”, “haves”, and the like are intended to indicate that there are features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and one or more other features. It should be understood that the existence or addition possibilities of fields or numbers, steps, operations, components, parts or combinations thereof are not excluded in advance.

Unless otherwise defined herein, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person skilled in the art to which the present invention pertains. Terms, such as those defined in a commonly used dictionary, should be interpreted as meanings consistent with the contextual meaning of the related art, and are not to be interpreted as ideal or excessively formal meanings unless explicitly defined herein.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a flowchart of a method for manufacturing an anti-reflection film according to an embodiment of the present invention.

Referring to Figure 1, the method of manufacturing an anti-reflection film according to this embodiment, using a source material containing a liquid magnesium (Mg) precursor to supply the chemical vapor deposition reaction materials into the reactor (S11), arranged inside the reactor It may include the step of diffusing the material to the surface of the substrate or the lower thin film surface on the substrate (S12), and forming a MgF ₂ thin film on the substrate (S13).

The reactor may include a vacuum chamber. Materials for the chemical vapor deposition reaction are precursors of liquid magnesium (Mg) for MgF2 thin films, Bis(cyclopentadienyl)magnesium, Bis(ethylcyclopentadienyl)magnesium, Bis(pentamethylcyclopentadienyl) magnesium, Bis(n-propylcyclopentadienyl)magnesium, and Bis (2,2,6,6-tetramethyl-3,5-heptanedionato) may include at least one selected from magnesium. Further, the materials can take advantage of a nitrogen trifluoride (NF _3), titanium fluoride (TiF _4), or tantalum fluoride (TaF ₅₎ as a precursor of the fluorine (Fluorine, F) of MgF ₂ films.

In the above-described case, in the above supplying step, the liquid Mg precursor and F precursor for the MgF ₂ thin film may be supplied together or simultaneously to the vacuum chamber as a reactor.

In addition, in the supplying step, the canister temperature of the liquid Mg precursor for the MgF ₂ thin film can be controlled at room temperature to 200° C. or less, and the supply line temperature to 200° C. or less at room temperature, and preferably, The canister temperature of the liquid Mg precursor can be adjusted from 30°C to 140°C and the supply line temperature from 60°C to 180°C.

In addition, the step of supplying, for the supply of the fluorine precursor, nitrogen trifluoride, titanium tetrafluoride or tantalum pentafluoride is selected from hydrogen (H), helium (He), nitrogen (N) and argon (Ar) gases It can be used diluted with one or a mixture thereof.

In addition, in the case described above, the step of diffusing, the temperature of the substrate can be controlled to 600 ℃ or less at room temperature, preferably, the temperature of the substrate can be adjusted to 200 ℃ ~ 400 ℃ or less at room temperature.

In the above-described step of supply and/or diffusion, the internal pressure of the vacuum chamber, which is the reactor, can be controlled to 1 mTorr (0.133322 Pa) to atmospheric pressure, and preferably, the internal pressure of the vacuum chamber is 5 mTorr (0.66661 Pa) to It can be adjusted to 10 Torr (13.3322 hPa).

According to the above-described configuration, a MgF ₂ thin film can be formed on the substrate. The thickness of the MgF ₂ thin film may be about 50 nm to about 300 nm. The MgF ₂ thin film may have a nanoparticle monolayer structure. The MgF ₂ thin film may be included in the antireflection film on the substrate. The MgF ₂ thin film may be directly formed on the surface of the substrate, and may be formed on the substrate by placing a lower thin film on the substrate depending on the implementation.

Meanwhile, the method for manufacturing an anti-reflection film according to the present embodiment may further include a step of heat-treating the MgF ₂ thin film after the step of forming. In the heat treatment step, the heat treatment temperature may be adjusted to 80°C to 600°C. Further, the step of heat treatment may be performed in a vacuum atmosphere, and/or as an atmosphere gas, any one or a mixture thereof selected from the group consisting of argon (Ar), helium (He), and nitrogen (N) gases may be used. You can.

According to the present embodiment, as in the case of using a liquid precursor in a semiconductor manufacturing process using atomic layer deposition (atomic layer deposition (ALD) or chemical vapor deposition (camical vapor deposition, CVD) method, see Table 1), By using a liquid magnesium (Mg) precursor, a good MgF ₂ antireflection film can be effectively formed on the substrate.

In particular, all of the magnesium (Mg) precursors used in the existing technology, such as the semiconductor field and the solar cell field, are solid, and there is no example of using the liquid magnesium precursor in the manufacture of the antireflection film anywhere in the existing technology. Therefore, in the existing technology, since the magnesium precursor in a solid state is used, there is a problem in that the thickness, quality, etc. of the thin film deposited by changing the vapor pressure during the process change. However, in this embodiment, the reproducibility of the deposited thin film can be easily secured by forming the MgF ₂ antireflection film on the substrate using a liquid magnesium precursor.

FIG. 2 is a cross-sectional view for explaining the antireflection film manufactured according to the method of manufacturing the antireflection film of FIG. 1.

Referring to FIG. 2, the anti-reflection film 30 manufactured by the method of manufacturing the anti-reflection film according to the present embodiment may be directly formed on the substrate 10. The substrate 10 may be a glass substrate or a transparent substrate. The substrate 10 may be a substrate used in a display device such as a liquid crystal display (LCD), an organic electroluminescence display (OLED), or a substrate used in an electric or power device using sunlight.

The anti-reflection film 30 may ring the reflection of the substrate 10 to increase the light transmittance of the substrate. That is, when sunlight enters the substrate or the lower thin film on the substrate, the sunlight is reflected from the surface. To minimize this, an antireflection film may be coated on the substrate or the lower thin film. In this embodiment, since the anti-reflection film 30 formed directly on the substrate is mainly described, the lower thin film will be omitted. However, when the lower thin film is on the substrate, the refractive index of the lower thin film may be considered instead of the refractive index of the substrate.

The anti-reflection film 30 is determined in consideration of the refractive index of the substrate (ns) and the refractive index of air (na = 1.0). In theory, the optimal antireflection film (narf) capable of removing solar reflection at a specific wavelength is It is the geometric mean value of the product of the substrate and air refractive indices. This is expressed by Equation (1).

If glass (n = 1.5) is used as the substrate, the refractive index of the antireflection film 30 should be about 1.22 according to Equation 1, but a material having such a low refractive index is difficult to exist. Therefore, a low refractive index material close to the required refractive index is needed. The oxide having the lowest refractive index is silicon dioxide (SiO2) (n = 1.4 to 1.5), and among some metal compounds, MgF ₂ (n = 1.38) has been used the most. However, since an optimal anti-reflection coating condition of 1.22 cannot be obtained with a single SiO ₂ or MgF ₂ thin film, a multi-layer thin film structure is also used to coat several layers of thin films to obtain a lower reflectance. However, the multilayer thin film structure has disadvantages in that the process time is long and the manufacturing cost is increased.

Accordingly, in this embodiment, a single thin film of MgF ₂ is deposited by a chemical vapor deposition method that does not use high vacuum to provide a method for manufacturing a low-refractive-index thin film in which sunlight reflection is minimized in a wide wavelength range of sunlight and an antireflection film using the same.

FIG. 3 is a SEM cross-sectional image of a MgF ₂ thin film prepared by chemical vapor deposition using a liquid magnesium (Mg) precursor in the method of manufacturing the antireflection film of FIG. 1. 4 is a view showing an SEM surface image of the MgF ₂ thin film of FIG. 3.

The MgF ₂ thin film, which is an anti-reflection film according to the present embodiment, is directly formed on a glass substrate. The MgF ₂ thin film is prepared using liquid Bis(ethylcyclopentadienyl)magnesium [Mg(EtCp) ₂ ]. The MgF ₂ thin film is deposited to a thickness of about 100 nm by chemical vapor deposition (CVD) on a 1.1 mm thick glass substrate.

MgF ₂ thin film as shown in Fig. SEM cross-section image that includes a thin film of MgF _2. 3 it can be seen that are directly formed on a glass substrate is included in the MgF ₂ / Glass structure, its thickness is 106㎚.

In addition, as can be seen in the SEM surface image of Figure 4, the MgF ₂ thin film has a uniform surface.

5 is a graph showing reflectance by the MgF ₂ thin film of FIG. 3.

In Figure 5, an embodiment of forming the MgF ₂ film on the substrate of this example, a substrate on the substrate are not formed in the MgF ₂ films (Glass only, comparative example), in this embodiment the reflectance of about 21.8 compared to Comparative Example It can be seen that there is a reduction effect of %.

That is, in the case of the comparative example, the average reflectance of 3.35% was observed in the wavelength range of 400 to 800 nm, which is the visible light region, and in the case of the present example, the average reflectance was 2.62%.

As described above, when the MgF ₂ thin film is deposited on the surface of the glass substrate by the method of manufacturing the anti-reflection film according to the present exemplary embodiment, a reflectance reduction effect of 20% or more can be obtained.

6 is a cross-sectional view for describing an anti-reflection film manufactured by a method for manufacturing an anti-reflection film according to another embodiment of the present invention.

Referring to FIG. 6, a plate provided with an anti-reflection film manufactured by the method for manufacturing an anti-reflection film according to the present embodiment may include a substrate 10, a lower thin film 20 and an anti-reflection film 30.

The substrate 10 may be a glass substrate as a transparent substrate. The thickness of the substrate 10 may be about 1 mm.

The lower thin film 20 may be a transparent oxide conductive film, or may be AZO (Al:ZnO). The thickness of the lower thin film 20 may be about 0.5 μm to about 2.0 μm. The lower thin film 20 may be first formed in the same vacuum chamber or other vacuum chambers before supplying chemical vapor deposition reaction materials for manufacturing the anti-reflection film 30.

The anti-reflection film 30 may have a single layer structure of nanoparticles, and the thickness on the lower thin film 20 may be about 50 nm to about 300 nm.

7 is a view showing an SEM cross-sectional image of the MgF ₂ thin film prepared by chemical vapor deposition using a specific magnesium precursor in the method of manufacturing the anti-reflection film of FIG. 6. 8 is a view showing an SEM surface image of the MgF ₂ thin film of FIG. 6.

The MgF ₂ thin film, which is an anti-reflection film according to the present embodiment, is formed on a lower thin film deposited on a glass substrate. The thickness of the glass substrate is 1.1 mm. The lower thin film uses AZO (Al:ZnO), which is a type of transparent oxide conductive film, but is not limited thereto. The thickness of AZO is 493 nm.

The MgF ₂ thin film is prepared by using liquid Bis(ethylcyclopentadienyl)magnesium [Mg(EtCp)2]. The MgF ₂ thin film is deposited to a thickness of about 100 nm by chemical vapor deposition (CVD) on the surface of the lower thin film on the glass substrate.

FIG MgF ₂ thin film, as shown in cross-section SEM image of a plate containing MgF ₂ thin film 7 is formed on the AZO on the glass substrate containing the MgF2 / AZO / Glass structure, the thickness can be seen that the 97.5㎚ .

In addition, as can be seen in the SEM surface image of Figure 8, the MgF ₂ thin film has a uniform surface. For reference, since the SEM surface image of FIG. 4 for the MgF ₂ thin film is a 30,000 magnification picture, and the SEM surface image of FIG. 8 is a 50,000 magnification picture, the particle size or particle size of FIG. 8 is larger than that of FIG. 4. Seems like.

9 is a graph for explaining the reflectance of the MgF ₂ thin film of FIG. 6.

Referring to FIG. 9, a structure in which AZO having a thickness of 0.7 µm is deposited on a glass substrate having a thickness of 1.1 mm (AZO/Glass) (comparative example) and a MgF ₂ thin film having a thickness of about 100 nm is formed on the structure of the comparative example. As a result of experimenting the reflectance for the light of various wavelengths for the embodiment, it can be seen that the reflectance of this embodiment has a reduction effect of about 65% compared to the comparative example.

That is, in the case of the comparative example, the average reflectivity was 6.70% in the wavelength range of 400 to 800 nm, which is the visible light region, and in the case of this example, the average reflectance was 2.33%. It can be seen that the reflectance in the structure of the comparative example is considerably higher than the average reflectance of the glass substrate only 3.35%. On the other hand, it can be seen that the reflectance in the structure according to the present embodiment is lower than the reflectance of only the glass substrate in most visible light regions.

As described above, when the lower thin film on the glass substrate is an AZO thin film by the method of manufacturing the anti-reflective film according to the present embodiment, when the MgF ₂ thin film is deposited thereon, a reflectance reduction effect of 60% or more can be obtained.

Although described above with reference to preferred embodiments of the present invention, those skilled in the art variously modify and change the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. You can understand that you can.

Claims (7)

Supplying chemical vapor deposition reaction materials into the reactor using a source material including a liquid magnesium (Mg) precursor;
Diffusing the materials to the surface of the substrate or the lower thin film surface on the substrate arranged inside the reactor; And
Forming a thin film of magnesium fluoride (MgF ₂ ) on the substrate,
The supplying step, as the liquid Mg precursor,
Bis(cyclopentadienyl)magnesium,
Bis(ethylcyclopentadienyl)magnesium,
Bis(pentamethylcyclopentadienyl)magnesium,
Bis(n-propylcyclopentadienyl)magnesium, and
Bis (2,2,6,6-tetramethyl-3,5-heptanedionato) using at least one material selected from magnesium,
In the supplying step, nitrogen trifluoride (NF ₃ ) or tantalum pentafluoride (TaF ₅ ) is used as a fluorine (F) precursor for the MgF ₂ thin film,
Before the supplying step, the substrate further includes forming an AZO thin film as a lower thin film, wherein the thickness of the AZO thin film is 0.5 μm to 2.0 μm,
The thickness of the MgF ₂ thin film is 50 nm to 300 nm and is included in the anti-reflection film on the substrate, the substrate is a transparent substrate or a glass substrate, and the transparent substrate has a transmittance of 85 to 90% in the visible light region, reflection Method of manufacturing a barrier. delete delete According to claim 1,
In the supplying step, the liquid Mg precursor and the fluorine precursor are diluted with any one selected from hydrogen (H), helium (He), nitrogen (N), and argon (Ar) gases or a mixture thereof. A method for manufacturing an antireflection film. According to claim 1,
In the supplying step, the liquid Mg precursor and the fluorine precursor are supplied to the vacuum chamber as the reactor, and the antireflection film manufacturing method is performed. According to claim 1,
In the supplying step, the canister temperature of the liquid Mg precursor is controlled to 200° C. or less at room temperature and the supply line temperature to 200° C. or less at room temperature. delete

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