KR102133211B1 - Method for fabricating wire grid polarizer - Google Patents

Abstract

The method of manufacturing a wire grid polarizer of the present invention includes forming a photoresist on a portion corresponding to the wire pattern of a wire pattern layer including a plurality of side-by-side wire patterns, and two etching rates in spaces between the photoresists are different. Filling a block copolymer of branched monomers, aligning the block copolymers, selectively removing one monomer block of the aligned copolymers, and patterning the wire pattern layer according to the residual portion after the removal. Steps.

Description

Manufacturing method of wire grid polarizer {METHOD FOR FABRICATING WIRE GRID POLARIZER}

The present invention relates to a method of manufacturing a wire grid polarizer.

An array of parallel conductive wires that arrange parallel conductor lines in order to polarize only a specific polarization in electromagnetic waves is generally referred to as a wire grid.

The wire grid structure having a period smaller than the wavelength of the light has a polarization characteristic that reflects polarization in the wire direction and transmits polarization perpendicular to the wire direction with respect to non-polarized incident light. This has the advantage of being able to reuse the reflected polarization compared to the absorption polarizer.

In order to form such a pattern, various methods are possible, but a nano-imprint method for forming a pattern with a patterned mold is used.

However, in the case of a large-area wire grid polarizer used in a large display device, a method of imprinting by changing the position of a small mold is used rather than manufacturing the mold itself for imprint in a large format. Stitch lines that are not exerted are generated.

The problem to be solved by the present invention is to provide a method for manufacturing a wire grid polarizer without a stitch line.

The problems of the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the following description.

A method of manufacturing a wire grid polarizer according to an embodiment of the present invention for solving the above problems includes forming a photoresist on a portion corresponding to the wire pattern of the wire pattern layer including a plurality of parallel wire patterns. , Filling a block copolymer of two monomers having different etch rates in the space between the photoresists, aligning the block copolymers, selectively removing one monomer block of the aligned copolymers, and removing After that, it may include the step of patterning the wire pattern layer according to the residual portion.

The plurality of parallel wire patterns may be formed by a nanoimprint method.

The block copolymer may be a PS-PMMA block copolymer.

The alignment may be performed in the range of 200 °C to 250 °C.

The step of selectively removing the one monomer block may be performed by plasma etching.

The plasma etching gas may be at least one selected from the group consisting of O ₂ , carbon fluoride gas, and HF.

The fluorinated carbon gas may be one or more selected from the group consisting of C ₄ F ₈ , CHF ₃ , CH ₂ F ₂ , CF ₄ and C ₂ F ₆ .

The distance between the photoresists may range from 1 μm to 2 μm.

A method of manufacturing a wire grid polarizer according to another embodiment of the present invention for solving the above problems includes forming a plurality of parallel wire-shaped first photoresists on a wire pattern layer formed on a substrate, the first Filling and aligning the block copolymers of two monomers having different etch rates in the space between the photoresists, selectively removing one monomer block of the aligned copolymers, and removing the wire pattern layer according to the residual portion after the removal. 1 patterning, forming a second wire-shaped photoresist on the first patterned wire pattern layer, filling and aligning block copolymers of two monomers having different etch rates in the space between the second photoresists The method may include selectively removing one monomer block of the aligned copolymer, and secondly patterning the wire pattern layer according to the residual portion after the removal.

The block copolymer may be a PS-PMMA block copolymer.

The alignment may be performed in the range of 200 °C to 250 °C.

The step of selectively removing the one monomer block may be performed by plasma etching.

The plasma etching gas may be at least one selected from the group consisting of O ₂ , carbon fluoride gas, and HF.

The fluorinated carbon gas may be one or more selected from the group consisting of C ₄ F ₈ , CHF ₃ , CH ₂ F ₂ , CF ₄ and C ₂ F ₆ .

The spacing between the first photoresist and the spacing between the second photoresists may range from 0.1 μm to 5 μm, respectively.

The widths of the first photoresist and the second photoresist may range from 1 μm to 2 μm, respectively.

After the first patterning step and the second patterning step, the method may further include removing the remaining first photoresist and second photoresist.

Specific details of other embodiments are included in the detailed description and drawings.

According to embodiments of the present invention has at least the following effects.

It is possible to provide a large area wire grid polarizer having excellent optical properties.

The effects according to the present invention are not limited by the contents exemplified above, and more various effects are included in the present specification.

1 is a perspective view of a wire grid polarizer according to an embodiment of the present invention.
2 is a schematic cross-sectional view of a liquid crystal display device according to an exemplary embodiment of the present invention.
3 to 14 are cross-sectional views for each process of a method of manufacturing a wire grid polarizer according to an embodiment of the present invention.
15 to 25 are cross-sectional views of processes of a method of manufacturing a wire grid polarizer according to another embodiment of the present invention.

Advantages and features of the present invention, and methods for achieving them will be clarified with reference to embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various different forms, and only the present embodiments allow the disclosure of the present invention to be complete, and the general knowledge in the technical field to which the present invention pertains. It is provided to fully inform the holder of the scope of the invention, and the invention is only defined by the scope of the claims. The same reference numerals refer to the same components throughout the specification. In the drawings, the sizes and relative sizes of layers and regions may be exaggerated for clarity of explanation.

Elements or layers referred to as "on" or "on" of another element or layer are not only directly above the other element or layer, but also when intervening another layer or other element in the middle. All inclusive. On the other hand, when a device is referred to as “directly on” or “directly above”, it indicates that no other device or layer is interposed therebetween.

The spatially relative terms “below”, “beneath”, “lower”, “above”, “upper”, and the like are shown in the figure as one figure. It can be used to easily describe the correlation of a device or components with other devices or components. The spatially relative terms should be understood as terms including different directions of the device in use or operation in addition to the directions shown in the drawings.

Although the first, second, etc. are used to describe various components, it goes without saying that these components are not limited by these terms. These terms are only used to distinguish one component from another component. Therefore, it goes without saying that the first component mentioned below may be the second component within the technical spirit of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 is a perspective view of a wire grid polarizer according to an embodiment of the present invention, and FIGS. 2 to 13 are cross-sectional views of each method of a method of manufacturing a wire grid polarizer according to an embodiment of the present invention.

First, referring to FIG. 1, the wire grid polarizer 100 includes a substrate 110 and a plurality of parallel wire patterns 120 formed to protrude on the substrate 110.

If the substrate 110 can transmit visible light, the material can be appropriately selected according to the application or process. Examples include glass, quartz, acrylic, various polymers such as triacetylcellulose (TAC), cyclic olefin copolymer (COP), cyclic olefin polymer (COC), polycarbonate (PC), polyethylenenaphthalate (PET), and polyethersulfone (PES). It can, but is not limited to these. The substrate 110 may be formed of an optical film substrate having a certain degree of flexibility.

On the substrate 110, a wire pattern 120 including a conductive wire pattern (not shown) may be arranged side by side with a certain period. The period of the wire pattern 120 may have a higher polarization extinction ratio as the wavelength of the incident light is shorter. However, the shorter the cycle, the more difficult it is to manufacture. The visible light region is generally in the range of 380 nm to 780 nm, and in order for the wire grid polarizer to have a high extinction ratio for the three primary colors of red, green, and blue (R, G, B), at least 200 nm or less Polarization characteristics can be expected only when it has a period. However, in order to exhibit polarization performance equal to or greater than that of a conventional polarizer, it may have a period of 120 nm or less.

The conductive wire pattern can be used without limitation as long as it is a conductive material. In an exemplary embodiment, the conductive wire pattern may be a metal material, more specifically aluminum (Al), chromium (Cr), silver (Ag), copper (Cu), nickel (Ni), cobalt (Co) and It may be one metal or an alloy thereof selected from the group consisting of molybdenum (Mo), but is not limited to these.

The width of the wire pattern 120 may be in the range of 10 nm to 200 nm in a range capable of exhibiting polarization performance, but is not limited to this. Further, the thickness of the wire pattern 120 may be mentioned in the range of 10 nm to 500 nm, but is not limited to this.

The wire pattern 120 may further include a non-conductive wire pattern (not shown) in addition to the conductive wire pattern.

The non-conductive wire pattern can be formed on the conductive wire pattern. The width of the non-conductive wire pattern may be smaller than or equal to the width of the conductive wire pattern, and the thickness of the non-conductive wire pattern is in the range of 10 nm to 300 nm, but is not limited thereto.

The vertical cross-sectional shape of the non-conductive wire pattern may include a square, a triangle, a semi-circle, a semi-ellipse, etc., but is not limited thereto, and various shapes may be complexly formed for each thickness section.

The non-conductive wire pattern may be a non-conductive, transparent material. In exemplary embodiments, polymers, oxides, nitrides, etc. may be mentioned, and in more specific embodiments, silicon oxide or silicon nitride may be exemplified, but is not limited thereto.

2 is a schematic cross-sectional view of a liquid crystal display device according to an exemplary embodiment of the present invention.

Referring to FIG. 2 together with FIG. 1, the liquid crystal display 10 is stacked on the backlight unit 11, the backlight unit 11, which emits light, the lower substrate 13, the liquid crystal layer 14, and the upper portion It includes a liquid crystal panel (13, 14, 15) including a substrate 15, and the upper and lower polarizing plate 16 and the lower polarizing plate 12 disposed on the upper and lower portions of the liquid crystal panel (13, 14, 15).

When the two polarizing plates 12 and 16 are positioned above and below the liquid crystal panels 13, 14 and 15, the transmission axes of the upper polarizing plate 16 and the lower polarizing plate 12 may be orthogonal or parallel.

In FIG. 2, the upper and lower polarizing plates 16 and 12 are included in the upper and lower portions of the liquid crystal panels 13, 14 and 15, but in some cases, the upper polarizing plate 16 may be omitted.

Although not specifically illustrated, the backlight unit 11 may further include, for example, a light guide plate, a light source unit, a reflective member, an optical sheet, and the like.

The light guide plate (LGP) is a part that changes the path of light generated from the light source unit to the liquid crystal layer 14 side, and includes an incident surface provided to receive light generated from the light source unit and an exit surface facing the liquid crystal layer 14 can do. The light guide plate may be made of a material having a constant refractive index, such as poly methyl methacrylate (PMMA) material or polycarbonate (PC) material, which is one of the light transmissive materials, but is not limited thereto.

Since light incident on one or both sides of the light guide plate made of such a material has an angle within a critical angle of the light guide plate, it enters into the light guide plate, and when it enters the top or bottom surface of the light guide plate, the angle of light deviates from the critical angle, and outside the light guide plate It is not discharged, and is evenly transmitted inside the light guide plate.

A scattering pattern may be formed on one of the upper and lower surfaces of the light guide plate, for example, a lower surface facing the light exit surface so that guided light can be emitted upward. That is, a scattering pattern may be printed, for example, with ink, on one surface of the light guide plate so that light transmitted from the light guide plate can be emitted upward. The scattering pattern may be formed by printing ink, but is not limited thereto, and may form minute grooves or protrusions on the light guide plate, and various modifications are possible.

A reflective member may be further provided between the light guide plate and the bottom of the lower storage member. The reflecting member serves to supply light to the light guide plate by reflecting light emitted back to the bottom surface of the light guide plate, that is, on the opposite side to the light exit face. The reflective member may be formed in a film form, but is not limited thereto.

The light source unit may be disposed to face the light incident surface of the light guide plate. The number of light sources can be appropriately changed as necessary. For example, one light source may be provided on only one side of the light guide plate, and three or more of the four light guide plates may be provided to correspond to three or more side surfaces. It will also be said that a plurality of light source units disposed to correspond to any one of the side surfaces of the light guide plate may be possible. As described above, the side light method, which is a method in which the light source is located on the side of the light guide plate, has been described as an example, but there are other types such as a direct light method and a planar light source method depending on the backlight configuration.

The light source may be a white LED emitting white light, or a plurality of LEDs emitting red (R), green (G), and blue (B) colored light, respectively. When a plurality of light sources are embodied as LEDs that emit red (R), green (G), and blue (B) light, respectively, white light by color mixing may be realized by lighting them all at once.

The lower substrate 13 may be a TFT substrate. Although not specifically shown in FIG. 8, for example, a thin film transistor composed of a gate electrode, a gate insulating film, a semiconductor layer, a resistive contact layer, and a source/drain electrode on a substrate made of a transparent insulating material such as glass or plastic, and It may include a pixel electrode that is an electric field generating electrode formed of a transparent conductive oxide such as ITO or IZO.

The upper substrate 15 may be a color filter (CF) substrate. Although not specifically shown in FIG. 8, for example, a black matrix and a red, green, and blue color filter for preventing light leakage on the lower surface of a substrate made of a transparent insulating material such as glass or plastic, and transparent such as ITO or IZO It may include a common electrode that is an electric field generating electrode formed of a conductive oxide.

Plastic substrates that can be used for the lower substrate 13 and the upper substrate 15 can be used for displays, such as PET (polyethylene terephthalate), PC (polycarbonate), PI (polyimide), PEN (polyethylene naphthalate), PES (polyether sulfone) , Plastic substrates such as polyarylate (PAR) and cycloolefin copolymer (COC), but the present invention is not limited thereto. Further, the lower substrate 13 and the upper substrate 15 may be made of a flexible material.

The liquid crystal layer 14 serves to rotate the polarization axis of incident light, and is oriented in a constant direction and positioned between the upper substrate 15 and the lower substrate 13. The liquid crystal layer 14 may be a twisted nematic (TN) mode having a positive dielectric anisotropy, a vertical alignment (VA) mode, or a horizontal alignment (IPS, FFS) mode.

The lower polarizer 12 and the upper polarizer 16 may be wire grid polarizers 100 described above with reference to FIG. 1.

In the above, the liquid crystal display device is described as an example, but it can be applied to an organic light emitting display device that does not include a separate light source and a light guide plate or a plasma display device using plasma.

3 to 14 are cross-sectional views for each process of a method of manufacturing a wire grid polarizer according to an embodiment of the present invention.

Referring to these drawings, the wire pattern layer 120 and the photoresist layer 130 may be stacked on the substrate 110.

The step of forming the wire pattern layer 120 on the substrate 110 may use a general sputtering method, a chemical vapor deposition method, an evaporation method, etc., but this is only an example and is not limited thereto.

The step of forming the photoresist layer 130 may use spin coating, but is not limited thereto.

The photoresist layer 130 may be patterned by stamping the photoresist layer 130 several times with the imprint mold 140 having a pattern formed on the stacked photoresist layer 130.

In the photoresist layer 130 on which the pattern is formed, a portion where the pattern is not formed may exist at a position corresponding to the boundary of the mold. Thereafter, the remaining photoresist is removed to leave only the patterned photoresist layer 130, and through this, the wire pattern layer 120 is etched.

In this case, the wire pattern layer 120 is formed to include a patterned pattern portion and a non-patterned stretch portion, and then forms a photoresist 150 at a position corresponding to the pattern portion, and the photoresist 150 A block copolymer 160 of two monomers having different etch rates is formed on the wire pattern layer 120 therebetween, and the block copolymer 160 may be a PS-PMMA block copolymer.

Thereafter, the block copolymer 160 is treated at a temperature in the range of 200°C to 250°C to align each monomer block, and then one monomer block can be selectively removed.

The step of selectively removing the monomer block may be performed by plasma etching, and the gas used may be one or more selected from the group consisting of O ₂ , carbon fluoride gas, and HF, but is not limited thereto. The fluorinated carbon gas may be, for example, one or more selected from the group consisting of C ₄ F ₈ , CHF ₃ , CH ₂ F ₂ , CF ₄ and C ₂ F ₆ , but is not limited thereto.

The pitch of the pattern may be adjusted according to the distance between the photoresist 150, the molecular weight of the block copolymer 160, and the block length.

The distance between the photoresists 150 is not particularly limited, but may be in the range of 0.1 μm to 5 μm, and may be in the range of 1 μm to 2 μm, for example, in more favorable conditions for alignment, but is limited to these. It is not.

For example, when using the PS-PMMA block copolymer, the PS block 161 and the PMMA block 162 are aligned in a wire form through alignment, and the etching rates of the PS block 161 and the PMMA block 162 are aligned. The difference may be used to selectively remove the PMMA block 162 through plasma etching. In general, since the PS block 161 and the PMMA block 162 have an etch rate of about 1: 3, the copolymerization composition may be adjusted in consideration of this ratio.

By etching the wire pattern layer 120 exposed between the PS blocks 161, it is possible to obtain the wire pattern layer 120 uniformly patterned without including a stitch as a whole, and to remove the remaining photoresist 150. have.

15 to 25 are cross-sectional views of processes of a method of manufacturing a wire grid polarizer according to another embodiment of the present invention.

Referring to these drawings, the wire pattern layer 220 may be stacked on the substrate 210 and may be formed by patterning the first photoresist 231 on the wire pattern layer 220.

A block copolymer 240 of two monomers having different etch rates is formed on the wire pattern layer 220 between the first photoresist 231, and the block copolymer 240 may be a PS-PMMA block copolymer. .

Thereafter, the block copolymer 240 is treated at a temperature in the range of 200°C to 250°C to align each monomer block, and then one monomer block can be selectively removed.

The pitch of the pattern may be adjusted according to the distance between the first photoresist 231 and the molecular weight and block length of the block copolymer 240.

The distance between the first photoresists 231 is not particularly limited, but may be in the range of 0.1 μm to 5 μm, and may be, for example, in the range of 1 μm to 2 μm as conditions more favorable for alignment, but only these It is not limited.

For example, when using the PS-PMMA block copolymer, the PS block 241 and the PMMA block 242 are aligned in a wire form through alignment, and the etch rates of the PS block 241 and the PMMA block 242 are aligned. The difference may be used to selectively remove the PMMA block 242 through plasma etching.

The wire pattern layer 220 exposed between the PS blocks 241 may be etched, and the remaining first photoresist 231 may be removed.

The wire pattern layer 220 includes a patterned pattern portion and a non-patterned portion that is not patterned, forms a second photoresist 232 at a position corresponding to the pattern portion, and wires between the second photoresist 232 A block copolymer 250 of two monomers having different etch rates may be formed on the non-pattern portion of the pattern layer 220.

Thereafter, the block copolymer 250 is treated at a temperature in the range of 200°C to 250°C to align each monomer block, and then one monomer block can be selectively removed.

The pitch of the pattern may be adjusted according to the distance between the second photoresist 232 and the molecular weight and block length of the block copolymer 250.

The space between the second photoresists 232 is not particularly limited, but may be in the range of 0.1 μm to 5 μm, and may be, for example, in the range of 1 μm to 2 μm as conditions more favorable for alignment, but only these It is not limited.

For example, when using the PS-PMMA block copolymer, the PS block 251 and the PMMA block 252 are aligned in a wire form through alignment, and the etch rates of the PS block 251 and the PMMA block 252 are aligned. The difference can be used to selectively remove the PMMA block 252 through plasma etching.

The non-pattern portion of the wire pattern layer 220 exposed between the PS blocks 251 is etched to obtain a uniformly patterned wire pattern layer 220 without including a stitch as a whole, and the remaining second photoresist 232 ) Can be removed.

Of the configurations of FIGS. 15 to 25, duplicate descriptions of the same or corresponding configurations of FIGS. 3 to 14 will be omitted.

The embodiments of the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments and may be manufactured in various different forms, and having ordinary knowledge in the technical field to which the present invention pertains. It will be understood that a person can be implemented in other specific forms without changing the technical spirit or essential features of the present invention. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive.

100: wire grid polarizer
110, 210: substrate
120, 220: wire pattern layer
130, 150: photoresist
160, 240, 250: block copolymer
161, 241, 251: PS block 162, 242, 252: PMMA block
231: first photo resist
232: second photo resist
10: liquid crystal display device
11: backlight unit 12: lower polarizer
13: lower substrate 14: liquid crystal layer
15: upper substrate 16: upper polarizer

Claims (17)

Preparing a wire pattern layer including a first region including a patterned pattern portion and a second region including a non-patterned portion as a wire pattern layer including a plurality of parallel wire patterns;
Forming a photoresist covering the first region and at least partially exposing the second region on the wire pattern layer;
Filling a block copolymer of two monomers having different etch rates in the space exposed by the photoresist;
Aligning the block copolymer;
Selectively removing one monomer block among the aligned copolymers; And
And patterning the second region of the wire pattern layer according to the residual portion after the removal. According to claim 1,
The plurality of parallel wire pattern is a method of manufacturing a wire grid polarizer formed by a nano-imprint method. According to claim 1,
The block copolymer is a PS-PMMA block copolymer method of manufacturing a wire grid polarizer. According to claim 1,
The alignment step is a method of manufacturing a wire grid polarizer made in the range of 200 ℃ to 250 ℃. According to claim 1,
The method of selectively removing the one monomer block is a method of manufacturing a wire grid polarizer made of plasma etching. The method of claim 5,
The plasma etching gas is O ₂ , a method of manufacturing a wire grid polarizer selected from the group consisting of carbon fluoride gas and HF. The method of claim 6,
The fluorinated carbon gas is C ₄ F ₈ , CHF ₃ , CH ₂ F ₂ , CF ₄ and C ₂ F ₆ is selected from the group consisting of one or more wire grid polarizer manufacturing method. According to claim 1,
The method of manufacturing a wire grid polarizer having a gap between the photoresists in the range of 0.1 μm to 5 μm. Forming a first photoresist covering the first region of the wire pattern layer and covering the first region of the wire pattern layer on the wire pattern layer including the first region and the second region alternately disposed on the substrate. step;
Filling and aligning a block copolymer of two monomers having different etch rates in the space exposed by the first photoresist;
Selectively removing one monomer block among the aligned copolymers;
Patterning the second region of the wire pattern layer according to a residual portion after the removal;
Forming a second photo resist on the first patterned wire pattern layer to cover the second region of the wire pattern layer and to at least partially expose the first region;
Filling and aligning a block copolymer of two monomers having different etch rates in the space exposed by the second photoresist;
Selectively removing one monomer block among the aligned copolymers; And
And after the removal, second patterning the first region of the wire pattern layer according to the residual portion. The method of claim 9,
The block copolymer is a PS-PMMA block copolymer method of manufacturing a wire grid polarizer. The method of claim 9,
The alignment step is a method of manufacturing a wire grid polarizer made in the range of 200 ℃ to 250 ℃. The method of claim 9,
The method of selectively removing the one monomer block is a method of manufacturing a wire grid polarizer made of plasma etching. The method of claim 12,
The plasma etching gas is O ₂ , a method of manufacturing a wire grid polarizer selected from the group consisting of carbon fluoride gas and HF. The method of claim 13,
The fluorinated carbon gas is C ₄ F ₈ , CHF ₃ , CH ₂ F ₂ , CF ₄ and C ₂ F ₆ is selected from the group consisting of one or more wire grid polarizer manufacturing method. The method of claim 9,
A method of manufacturing a wire grid polarizer in which a distance between the first photoresist and a distance between the second photoresist ranges from 0.1 μm to 5 μm, respectively. The method of claim 9,
The first photoresist and the second photoresist have a width of 0.1 μm to 5 μm, respectively. The method of claim 9,
And after the first patterning step and the second patterning step, removing the remaining first photoresist and second photoresist.

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