KR102671007B1 - Lens comprising anti-reflection coating layer and manufacturing method thereof - Google Patents

Abstract

One embodiment of the present invention includes preparing a substrate, depositing a MgF ₂ layer on the upper surface of the substrate, and irradiating the deposited MgF ₂ layer with a fluorocarbon-based plasma to form an anti-reflection coating layer. , a lens manufacturing method is provided in which fluorine is injected into the MgF ₂ layer by irradiation of the plasma, and through this, a lens including an anti-reflective coating layer with a reduced refractive index due to an increased ratio of F and a manufacturing method thereof can be provided. .

Description

Lens including anti-reflective coating layer and method of manufacturing same {LENS COMPRISING ANTI-REFLECTION COATING LAYER AND MANUFACTURING METHOD THEREOF}

The present invention relates to a lens including an anti-reflective coating layer and a method of manufacturing the same.

Optical coating is used to control the spectrum of reflection, transmission, absorption, etc. of optical components such as lenses and glass, and plays an important role as the final process in completing optical components. Such optical coating technology is considered an essential technology for improving optical functions.

Accordingly, anti-reflective coating is a technology that increases the light transmittance of various optical materials by reducing the light reflected from the surface of the optical lens or material. It is used not only for transparent materials such as spectacle lenses and camera lenses, but also for display panels and other materials that must have high light transmission characteristics. It is being applied to electronic device technologies such as high-efficiency solar cell materials.

In particular, as the current semiconductor line width decreases to the nanometer scale, the need for high-resolution lenses for semiconductor inspection equipment is increasing, and the importance of anti-reflection coating in the extreme ultraviolet region is gradually increasing.

The technical problem to be achieved by the present invention is to provide a lens including an MgF ₂ coating layer with excellent anti-reflection performance and a method of manufacturing the same.

The technical problem to be achieved by the present invention is not limited to the technical problem mentioned above, and other technical problems not mentioned can be clearly understood by those skilled in the art from the description below. There will be.

In order to achieve the above technical problem, an embodiment of the present invention includes the steps of preparing a substrate; Depositing a MgF ₂ layer on the upper surface of the substrate; and irradiating the deposited MgF ₂ layer with a fluorocarbon-based plasma to satisfy fluorine, and providing a method of manufacturing the low refractive index MgF ₂ layer anti-reflection layer and lens by irradiation of the plasma.

Additionally, in one embodiment of the present invention, the deposition of the MgF ₂ layer may be a lens manufacturing method using a physical vapor deposition method.

Additionally, in one embodiment of the present invention, the MgF ₂ layer may be formed to a thickness of 20 nm to 50 nm.

In addition, in one embodiment of the present invention, the deposition of the MgF ₂ layer may be a lens manufacturing method by sputtering.

Additionally, in one embodiment of the present invention, the fluorocarbon-based plasma may be a lens manufacturing method including fluorocarbon represented by the following formula (1):

[Formula 1]

C _x H _y F _z

The x is an integer of 0<x≤4, the y is an integer of 0≤y≤9, and the z is an integer of 0<z≤10.

Additionally, in one embodiment of the present invention, the fluorocarbon-based plasma may be a lens manufacturing method including CF ₄ .

Additionally, in one embodiment of the present invention, the sputtering may be a lens manufacturing method in which the sputtering is performed at a pressure of 16 mTorr to 20 mTorr.

Additionally, in one embodiment of the present invention, the anti-reflection coating layer may have a refractive index of less than 1.39 (based on a wavelength of 633 nm).

In order to solve the above technical problem, another embodiment of the present invention provides a lens formed by the method of any one of claims 1 to 8.

According to one embodiment of the present invention, a lens including an MgF ₂ coating layer with an increased ratio of F in the MgF ₂ coating layer and a method for manufacturing the same can be provided.

In addition, according to an embodiment of the present invention, a lens including an MgF ₂ coating layer with a lowered refractive index and a method for manufacturing the same can be provided.

The effects of the present invention are not limited to the effects described above, and should be understood to include all effects that can be inferred from the configuration of the invention described in the detailed description or claims of the present invention.

Figure 1 is a diagram showing the direction of travel of light (L ₁ ) according to reflection and refraction when it passes through a lens that does not include an anti-reflection coating layer.
Figure 2 is a diagram showing the direction of travel of light L2 according to reflection and refraction when it passes through a lens including an anti-reflection coating layer.
Figure 3 is a diagram showing a flow chart of a lens manufacturing method provided by an embodiment of the present invention.
Figure 4 is a diagram showing the deposition step of the lens manufacturing method provided by an embodiment of the present invention.
Figure 5 is a diagram showing the plasma irradiation step of the lens manufacturing method provided by an embodiment of the present invention.
Figures 6 and 7 are diagrams showing the experimental results of Experimental Example 1.
Figure 8 is a diagram showing the experimental results of Experimental Example 2.
Figure 9 is a diagram showing the experimental results of Experimental Example 3.

Hereinafter, the present invention will be described with reference to the attached drawings. However, the present invention may be implemented in various different forms and, therefore, is not limited to the embodiments described herein. In order to clearly explain the present invention in the drawings, parts unrelated to the description are omitted, and similar parts are given similar reference numerals throughout the specification.

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 above terms are used only for the purpose of distinguishing one component from another. For example, a first component may be named a second component without departing from the scope of the present invention, and similarly, the second component may also be named a first component. The term and/or includes any of a plurality of related stated items or a combination of a plurality of related stated items.

Throughout the specification, when a part is said to be "connected (connected, contacted, combined)" with another part, this means not only "directly connected" but also "indirectly connected" with another member in between. "Includes cases where it is. Additionally, when a part is said to “include” a certain component, this does not mean that other components are excluded, but that other components can be added, unless specifically stated to the contrary.

The terms used in this specification are merely used to describe specific embodiments and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise.

In this specification, terms such as “comprise” or “have” are intended to designate the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but are not intended to indicate the presence of one or more other features. It should be understood that this does not exclude in advance the possibility of the existence or addition of elements, numbers, steps, operations, components, parts, or combinations thereof.

When an element or layer is referred to as “on” or “on” another element or layer, it refers not only to being directly on top of another element or layer, but also to intervening with another element or layer. Includes all. On the other hand, when an element is referred to as “directly on” or “directly on”, it indicates that there is no intervening element or layer.

Figure 1 is a diagram showing the direction of travel of light (L ₁ ) according to reflection and refraction when it passes through a lens that does not include an anti-reflection coating layer.

Figure 2 is a diagram showing the direction of travel of light (L ₁ ) according to reflection and refraction when it passes through a lens including an anti-reflection coating layer.

As can be seen with reference to Figure 1, the lens 5 that does not include an anti-reflective coating layer simply includes the substrate 100, and when light (L ₁ ) passes through it, the light passes through the boundary surface of the substrate 100. In this case, it is divided into transmitted light (L _1-1 ) and reflected light (L ₂ ), and the presence of the reflected light (L ₂ ) causes a problem in that the performance of the lens 5 is deteriorated. .

However, when light (L ₁ ) passes through the lens 10 including the anti-reflection coating layer 200, the light (L1) is light that passes through both the anti-reflection coating layer 200 and the target substrate 100. It is divided into (L _1-1 ) and reflected light (L ₂ ). This reflected light (L ₂ ) is the light reflected from the target substrate 100 (L _2-1 ) and the light reflected from the anti-reflection coating layer. It is divided into (L _2-2 ). At this time, if the thickness (d ₁ ) of the anti-reflection coating layer is set to 1/4 of the wavelength (d ₂ ) of the light (L ₁ ), the reflected light (L ₂ ) will disappear using destructive interference. was able to improve the performance of the lens 10.

For example, the incident light L1 may be light having DUV and VUV wavelengths, and the anti-reflection coating layer 200 may include MgF ₂ . On the other hand, when MgF ₂ is deposited by a sputtering method, it is possible to form a high-density film, but the content ratio of Mg and F in the MgF ₂ coating layer may become partially uneven, and especially when the F content is low, the anti-reflection coating layer ( As the refractive index of the anti-reflection coating layer 200 increases, the anti-reflection efficiency of the anti-reflection coating layer 200 may decrease.

Accordingly, in order to solve the above technical problem, an embodiment of the present invention includes depositing a MgF ₂ layer and then irradiating the deposited MgF ₂ layer with a fluorocarbon-based plasma to form an anti-reflection coating layer, A lens manufacturing method is provided in which fluorine is injected into the MgF ₂ layer by irradiation of plasma, thereby making it possible to provide a lens including an anti-reflective coating layer with a lower refractive index and an increased F ratio.

Hereinafter, a method for manufacturing a lens according to an embodiment of the present invention will be described.

Figure 3 is a diagram showing a flow chart of a lens manufacturing method provided by an embodiment of the present invention.

Referring to Figure 3, an embodiment of the present invention includes preparing a substrate 100 (S100); Depositing an MgF ₂ layer 200 on the upper surface of the substrate (S200); and forming an anti-reflective coating layer (200b) by irradiating the deposited MgF ₂ layer with a fluorocarbon-based plasma (S300); wherein fluorine is injected into the MgF ₂ layer by irradiation of the plasma, manufacturing a lens. Provides a method.

Hereinafter, the step (S100) of preparing the substrate 100 will be described.

In this step, the target substrate 100 of the lens 10 is prepared.

The substrate 100 is an object coated with an anti-reflective coating layer formed through a step of depositing an MgF ₂ layer 200 to be described later (S200) and a step of forming an anti-reflective coating layer 300 by irradiating plasma (S300). It is a substance.

In one embodiment, the substrate 100 may be any material to be coated that can be adopted by those skilled in the art, including, for example, materials used as lenses, materials used as displays, etc. there is. In one embodiment of the present invention, CaF ₂ is used, but it is not limited to the above example.

Hereinafter, MgF ₂ The step of depositing a layer (S200) will be described.

Figure 4 is a diagram showing the deposition step (S200) of the lens manufacturing method provided by an embodiment of the present invention.

In this step, the MgF ₂ layer 200 is deposited on the upper surface of the prepared substrate 100.

In one embodiment, the step of depositing the MgF ₂ layer 200 on the upper surface of the prepared substrate 100 may be performed by a physical vapor deposition method. By using the physical vapor deposition method, a low-temperature process is possible and a high-quality MgF ₂ layer 200 can be formed stably.

In one embodiment, the deposited MgF ₂ layer 200 may be formed to have a thickness of 50 nm or less in one example, 40 nm or less in another example, 20 nm to 50 nm in another example, In another example, it may be formed with a thickness of 20 nm to 40 nm, and in another example, it may be formed with a thickness of 25 nm to 40 nm.

Through the plasma irradiation step (S300), which will be described later, the lost fluorine (F) is injected into the MgF ₂ layer 200. If the thickness of the MgF _{2 layer 200 is more than 50 nm, the corresponding fluorine (F) is injected into the MgF 2} layer 200. ) may not sufficiently reach the inside of the deposited MgF ₂ layer 200, which may cause problems in that the uniformity of MgF ₂ in the coating layer and the overall content satisfied are lowered.

Additionally, when the thickness of the MgF ₂ layer 200 is less than 20 nm, there is a problem in that the durability of the coating layer is lowered.

In addition, the MgF ₂ layer 200 can be manufactured in various ways depending on the purpose for which the lens manufactured by the lens manufacturing method provided by the embodiment is used, and is not limited to the above numerical range.

The physical vapor deposition method includes, for example, vacuum evaporation, ion plating, and sputtering methods.

In one embodiment, the physical vapor deposition method may be a sputtering method.

In the sputtering method, each particle has thermal energy and large kinetic energy, and the energy is 1,000 to 100,000 times higher than that of vacuum deposition, so the thin film is dense and has high adhesion, making it an appropriate method for manufacturing the anti-reflective coating layer of a lens.

The sputtering method can vary the deposition rate by adjusting the pressure used to vary various characteristics of the elements during deposition, such as the ionization rate and mean-free path of the particles used.

In addition, the sputtering method adjusts the pressure used, so that the energy of the particles reaching the substrate varies depending on the pressure when the thin film is formed, so the characteristics and roughness of the thin film can vary, resulting in a difference in refractive index. You can make it happen.

In one embodiment, in the reaction chamber 20 of the physical vapor deposition process, the MgF ₂ substrate 205 is placed on the opposite side of the substrate 100, and then plasma is irradiated on the MgF ₂ substrate 205 to produce MgF. ₂ particles 210 may be released, and the released MgF ₂ particles 210 may be dispersed on the substrate 100 to form the MgF ₂ layer 200.

In one embodiment, the physical vapor deposition method is a sputtering method, and the sputtering is performed at a pressure of 20 mTorr or less according to one example, at a pressure of 18 mTorr or less according to another example, and according to another example, According to another example, it may be performed at a pressure of 16 mTorr or more and 18 mTorr or less.

When sputtering is performed at a pressure exceeding 20 mTorr, the mean free path is reduced, making it difficult for particles to reach the substrate. Therefore, it is preferable to perform sputtering at a pressure of 20 mTorr or less.

When sputtering is performed at a pressure of less than 16 mTorr, a problem arises in that the ionization rate of the plasma is low to form an excellent thin film, so it is preferable to perform sputtering at a pressure of 16 mTorr or more.

Hereinafter, MgF ₂ The step of plasma processing on the layer (S300) will be described.

When the MgF ₂ layer 200 is formed by sputtering, the MgF ₂ layer 200 may be formed with a dense film structure, but the content ratio of fluorine (F) and magnesium (Mg) may be partially uneven. . More specifically, as the content of fluorine (F) may decrease, the refractive index may increase and the performance of the anti-reflective coating layer may deteriorate.

Accordingly, according to the present invention, the anti-reflection coating layer 300 can be finally formed by irradiating the deposited MgF ₂ layer 200 with fluorocarbon-based plasma and supplying fluorine (F) to the MgF ₂ layer 200. .

Figure 5 is a diagram showing the plasma irradiation step (S300) of the lens manufacturing method provided by an embodiment of the present invention.

Referring to Figure 5, by irradiating plasma to the MgF ₂ layer 200 disposed on a substrate, fluorine (F) is injected into the MgF ₂ layer 200, thereby providing anti-reflection properties to the MgF ₂ layer 200. A coating layer 300 is formed.

In one embodiment, the fluorocarbon-based plasma may contain fluorocarbon represented by the following formula (1):

[Formula 1]

C _x H _y F _z

Where x is an integer of 0<x≤4, y is 0≤y≤9, and z is 0<z≤10, and in one embodiment, x=1, y=0, z=4. , the fluorocarbon-based plasma contains CF ₄ .

Fluorocarbon-based plasma is a plasma containing fluorine, and if it contains the compound represented by Formula 1, fluorine can be more effectively injected into the MgF ₂ layer 200, thereby satisfying the deficiency of F in the MgF ₂ layer 200. Thus, the refractive index can be lowered.

In one embodiment, in the step of forming an anti-reflection coating layer by irradiating plasma (S300), fluorocarbon-based plasma may be irradiated at an intensity of 200 W to 300 W.

In one embodiment, in the step of forming an anti-reflection coating layer by irradiating plasma (S300), irradiation of fluorocarbon-based plasma may cause F/Mg in the anti-reflection coating layer to be higher than before irradiation of plasma.

As an example, the F/Mg may be raised by 0.1 or more after irradiation of plasma, another example is allowed to rise by 0.1 to 0.3, another example is made to rise by 0.1 to 0.2, Another example may be to increase it by 0.15 to 0.2.

In one embodiment, in the step of forming an anti-reflective coating layer by irradiating plasma (S300), the anti-reflective coating layer 300 is formed by injecting fluorine into the MgF ₂ layer 200 by plasma irradiation so that F/Mg is, for example, For example, it may include a MgF ₂ layer with an F/Mg of 1.7 or more, another example includes an MgF ₂ layer with an F/Mg of 1.7 to 2.0, and another example includes an MgF ₂ layer with an F/Mg of 1.7 to 1.9. It may include.

In one embodiment, in the step of forming an anti-reflection coating layer by irradiating plasma (S300), the anti-reflection coating layer 300 is formed by injecting fluorine into the MgF ₂ layer 200 by plasma irradiation. The refractive index may be less than 1.45.

Hereinafter, a lens according to another embodiment of the present invention will be described.

Another embodiment of the present invention provides a lens manufactured by any one of the lens manufacturing methods provided by the above-described embodiment of the present invention.

This lens includes a substrate 100 and an anti-reflective coating layer 300 located on the upper surface of the substrate.

At this time, duplicate and detailed descriptions of the substrate 100 and the anti-reflective coating layer 300 are replaced with those based on the lens manufacturing methods described above.

Hereinafter, manufacturing examples and experimental examples of the present invention will be described. However, these manufacturing examples and experimental examples are intended to explain the configuration and effects of the present invention in more detail, and the scope of the present invention is not limited thereto.

Manufacturing Example 1 - Manufacturing a lens coated with an anti-reflective coating layer.

In this Production Example 1, a lens coated with a MgF ₂ layer was manufactured.

The specific manufacturing process is as follows.

A MgF ₂ layer was coated on a CaF ₂ material substrate using a sputtering method, and F was injected by irradiating plasma onto the coated MgF ₂ layer.

Manufacturing Example 2 - Manufacturing a lens coated with an anti-reflective coating layer.

In this Preparation Example 2, a lens coated with an MgF ₂ layer was manufactured in the same manner as in Preparation Example 1 except that the thickness of the MgF ₂ layer was different.

Manufacturing Example 3 - Manufacturing a lens coated with an anti-reflective coating layer.

In this Preparation Example 3, a lens coated with an MgF ₂ layer was manufactured in the same manner as in Preparation Example 1 except that the conditions of the CF ₄ plasma irradiated were different.

During CF ₄ plasma, when the CF ₄ gas flow rate was less than 100 sccm and the plasma irradiation time was less than 30 minutes, the effect of F injection into the MgF ₂ thin film was found to be minimal, and the refractive index reduction effect could be confirmed under more conditions.

Manufacturing Example 4 - Manufacturing a lens coated with an anti-reflective coating layer.

In this Preparation Example 4, a lens coated with an MgF ₂ layer was manufactured in the same manner as in Preparation Example 1, except that the sputtering process conditions were different.

When the experiment was conducted at a process pressure of 18 mTorr or less during the sputtering process, it was confirmed that the refractive index value increased as the process pressure decreased. This was due to the failure of sufficient ionization of the plasma to form an excellent MgF ₂ thin film. You can.

Experimental Example 1 - Confirmation of binding energy

In this Experimental Example 1, an experiment was conducted to confirm the change in binding energy of the anti-reflective coating layer of the lens coated with the MgF ₂ layer prepared in Preparation Example 1.

Figures 6 and 7 are diagrams showing the experimental results of Experimental Example 1.

As can be seen from Figures 6 and 7, after irradiation with fluorocarbon-based plasma, F/Mg increased from 1.69 to 1.85, and the ratio of F increased.

Experimental Example 2 - Confirmation of refractive index

In this Experimental Example 2, an experiment was conducted to check the refractive index of the anti-reflective coating layer of the lens coated with the MgF ₂ layer prepared in Preparation Example 2 and Preparation Example 3.

Figure 8 is a diagram showing the experimental results of Experimental Example 2.

As can be seen from Figure 8, when the thickness exceeds 50 nm, the refractive index exceeds 1.53, so it can be seen that the effect of reducing the refractive index does not appear.

Experimental Example 3 - Confirmation of refractive index

In this Experimental Example 3, an experiment was conducted to check the refractive index of the anti-reflective coating layer of the lens coated with the MgF ₂ layer prepared in Preparation Example 4.

Figure 9 is a diagram showing the experimental results of Experimental Example 3.

As shown in Figure 9, when sputtering is deposited in the range of 16 to 20 mTorr, it can be seen that the refractive index of the deposited coating layer is lowered and the effect is excellent.

The description of the present invention described above is for illustrative purposes, and those skilled in the art will understand that the present invention can be easily modified into other specific forms without changing the technical idea or essential features of the present invention. will be. Therefore, the embodiments described above should be understood in all respects as illustrative and not restrictive. For example, each component described as single may be implemented in a distributed manner, and similarly, components described as distributed may also be implemented in a combined form.

The scope of the present invention is indicated by the patent claims described below, and all changes or modified forms derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present invention.

Claims (9)

Preparing a substrate;
Depositing a MgF ₂ layer on the upper surface of the substrate; and
Comprising: forming an anti-reflective coating layer by irradiating the deposited MgF ₂ layer with a fluorocarbon-based plasma,
Fluorine is injected into the MgF ₂ layer by irradiation of the plasma,
The step of depositing the MgF ₂ layer is deposited by sputtering,
The sputtering is performed at a pressure of 16 mTorr to 20 mTorr,
The MgF ₂ layer is formed from 20 nm to 50 nm,
A method of manufacturing a lens, wherein the anti-reflective coating layer is formed by irradiating plasma of 200 W to 300 W. delete delete delete According to paragraph 1,
A lens manufacturing method wherein the fluorocarbon-based plasma contains fluorocarbon represented by the following formula (1):
[Formula 1]
C _x H _y F _z
The x is an integer of 0<x≤4, the y is an integer of 0≤y≤9, and the z is an integer of 0<z≤10. According to clause 5,
The fluorocarbon-based plasma includes CF ₄ . delete According to paragraph 1,
A method of manufacturing a lens, wherein the anti-reflective coating layer has a refractive index of less than 1.45. A lens formed by the method of any one of claims 1, 5, 6, and 8.