JP6136675B2 - Polarizer - Google Patents

Description

  The present invention relates to a polarizer having an excellent extinction ratio with respect to light having a short wavelength, and having excellent durability and cleanability.

A liquid crystal display device generally has a structure in which a counter substrate on which driving elements are formed and a color filter are arranged to face each other and the periphery is sealed, and a gap is filled with a liquid crystal material. The liquid crystal material has refractive index anisotropy, and the pixel is switched on and off from the difference between the state where the liquid crystal material is aligned along the direction of the voltage applied to the liquid crystal material and the state where no voltage is applied. Can be displayed. Here, the substrate sandwiching the liquid crystal material is provided with an alignment film for aligning the liquid crystal material.
For example, a film using a polymer material typified by polyimide is known as the alignment film, and the alignment film has an alignment regulating force by rubbing the polymer material with a cloth or the like. .
However, the alignment film to which the alignment regulating force is applied by such rubbing treatment has a problem that the cloth or the like remains as a foreign substance.

On the other hand, the alignment film that expresses the alignment regulating force by irradiating linearly polarized light, that is, the photo-alignment film, can apply the alignment regulating force without performing the rubbing treatment with the cloth as described above. In recent years, it has been attracting attention because it has no remaining defects.
As an irradiation method of linearly polarized light for imparting alignment regulating force to such a photo-alignment film, a method of exposing through a polarizer is generally used. As the polarizer, one having a plurality of fine wires arranged in parallel is used, and as a material constituting the fine wires, aluminum or titanium oxide is used (Patent Document 1, etc.).

Patent No. 4968165

  However, in the case of a polarizer having a thin wire made of the material as described above, the extinction ratio (P-wave transmittance / S-wave transmittance) in the case of short-wavelength light such as the ultraviolet region, that is, with respect to the thin wire The transmission of the thin line with respect to the transmittance of the parallel polarization component (S wave) (S wave component in the outgoing light / S wave component in the incident light, hereinafter sometimes referred to simply as S wave transmittance). The ratio of the transmittance of the polarization component (P wave) perpendicular to the thin line (P wave component in the outgoing light / P wave component in the incident light, hereinafter simply referred to as P wave transmittance) may be low. There was a problem. In addition, in order to obtain a desired extinction ratio, it is necessary to increase the thickness of the thin wire, and there is a problem that damage is likely to occur during cleaning and manufacturing, and cleaning with a chemical solution is difficult due to low resistance to the chemical solution. There was a problem that it might become.

  The present invention has been made in view of the above circumstances, and it is a main object of the present invention to provide a polarizer that is excellent in extinction ratio with respect to short-wavelength light and excellent in durability and detergency.

  As a result of repeated studies to solve the above problems, the present inventors have found that when a molybdenum silicide-based material is included as a material constituting a thin wire, the extinction ratio is improved even in the case of short-wavelength light. The present inventors have found that it can be excellent and that it has excellent resistance to acidic chemicals such as sulfuric acid, and have completed the present invention.

  That is, the present invention provides a polarizer characterized in that it has fine wires arranged in parallel in a straight line, and the fine wires have a molybdenum silicide-based material layer containing a molybdenum silicide-based material. .

  According to the present invention, since the thin wire includes a molybdenum silicide material layer, the extinction ratio of short-wavelength light is excellent, and the durability and cleaning properties are excellent.

In the present invention, it is preferable that the polarizer is for imparting an alignment regulating force to the photo-alignment film for a liquid crystal display device, and for generating linearly polarized light having a wavelength in the ultraviolet region.
This is because the effect of excellent extinction ratio of short wavelength light of the present invention can be more effectively exhibited.

  In the present invention, the film thickness of the fine wire is preferably less than 100 nm. Moreover, it is preferable that the pitch of the said fine wire exists in the range of 100 nm-150 nm. It is because it is easy to make it excellent in the extinction ratio of the light of a short wavelength because the shape of the said thin wire is the said range.

  In the present invention, it is preferable that the fine wire has a silicon oxide layer formed on the molybdenum silicide material layer and containing silicon oxide. This is because it is easy to form a thin line including the molybdenum silicide material layer.

  In the present invention, there is an effect that it is possible to provide a polarizer that is excellent in extinction ratio with respect to light having a short wavelength and that is excellent in durability and cleanability.

It is a schematic plan view which shows an example of the polarizer of this invention. It is the sectional view on the AA line of FIG. It is process drawing which shows an example of the manufacturing method of the polarizer of this invention. 4 is a graph showing the P-wave transmittance measurement result of the polarizer 1 obtained in Example 1. FIG. 3 is a graph showing the extinction ratio measurement result of the polarizer 1 obtained in Example 1. FIG.

  Hereinafter, the polarizer of the present invention will be described.

  The polarizer of the present invention is characterized in that it has a thin line in which a plurality of lines are arranged in parallel in a straight line, and the thin line has a molybdenum silicide-based material layer containing a molybdenum silicide-based material.

Such a polarizer of the present invention will be described with reference to the drawings. FIG. 1 is a schematic plan view showing an example of the polarizer of the present invention, and FIG. 2 is a cross-sectional view taken along line AA of FIG. As illustrated in FIGS. 1 and 2, the polarizer 10 of the present invention has a thin wire 2 in which a plurality of lines are arranged in parallel in a straight line, and the thin wire 2 contains a molybdenum silicide-based material. The material layer 3 is provided.
In this example, the thin wire 2 is formed on the molybdenum silicide material layer 3 and has a silicon oxide layer 4 containing silicon oxide, and is formed on the transparent substrate 1 made of synthetic quartz glass. Is.

According to the present invention, since the thin wire contains the molybdenum silicide material layer, the P-wave transmittance of light having a short wavelength can be improved. For this reason, it can be made excellent in the extinction ratio even for light of a short wavelength.
As a result, a sufficiently high extinction ratio can be obtained even when the film thickness is thin, so that the film thickness can be thin relative to the width of the thin wire, and at the time of cleaning or manufacturing the polarizer It can be made excellent in durability with little breakage of fine wires.
Furthermore, the molybdenum silicide-based material layer included in the fine wire has high resistance to chemicals such as acidic solvents, and furthermore, since it is less damaged during cleaning as described above, it should have excellent cleaning properties. Can do.

The polarizer of the present invention has fine wires.
Hereinafter, each structure of the polarizer of this invention is demonstrated in detail.

1. Thin wire The thin wire in the present invention is formed in a straight line and arranged in parallel, and has a molybdenum silicide material layer.

(1) Molybdenum silicide-based material layer The molybdenum silicide-based material layer is a layer containing a molybdenum silicide-based material.

  The molybdenum silicide-based material is not particularly limited as long as it includes molybdenum (Mo) and silicon (Si) and can achieve a desired extinction ratio. For example, molybdenum silicide (MoSi), molybdenum Silicide oxide (MoSiO), molybdenum silicide nitride (MoSiN), molybdenum silicide oxynitride (MoSiON), and the like can be given, among which molybdenum silicide (MoSi) is preferable. It is because it can be made excellent in extinction ratio by being the said material.

The molybdenum silicide material layer includes a molybdenum silicide material as a main raw material.
Here, the inclusion as the main raw material specifically means that the content of the molybdenum silicide-based material in the molybdenum silicide-based material layer is 70% by mass or more. Is preferably 90% by mass or more, particularly 100% by mass, that is, it is preferable that the molybdenum silicide-based material layer is made of a molybdenum silicide-based material. It is because it can be excellent in extinction ratio by being the said content.
The content measuring method is not particularly limited as long as the content can be measured with high accuracy. For example, a method of performing XPS surface analysis on the cross section of the thin wire can be mentioned. .

  The shape of the molybdenum silicide-based material layer in a cross-sectional view is not particularly limited as long as a desired extinction ratio can be obtained. For example, the shape can be a square shape such as a square or a rectangle.

(2) Fine wire The thin wire in the present invention has at least the molybdenum silicide-based material layer, and may have only the molybdenum silicide-based material layer. It may have a non-molybdenum silicide material layer containing another material as a main raw material.

The content of the molybdenum silicide-based material layer in the thin wire in the present invention is not particularly limited as long as a desired extinction ratio can be obtained.
Specifically, the content of the molybdenum silicide-based material layer in the fine wire is preferably 70% by mass or more, more preferably 80% by mass or more, and particularly 90% by mass or more. Is preferred. It is because it can be excellent in extinction ratio by being the said content. Further, the upper limit is not particularly limited because it is preferably as the content is large, but it is preferably 95% by mass or less in order to facilitate the formation of the molybdenum silicide material layer.
Further, the content refers to the mass ratio of the molybdenum silicide-based material layer in the cross-section in the width direction of the fine wire, and this measurement method is particularly limited as long as the content can be accurately measured. For example, a method similar to the method for measuring the content of the molybdenum silicide material can be used.

  The other material contained in the non-molybdenum silicide-based material layer is not particularly limited as long as a desired extinction ratio can be obtained, and examples thereof include silicon oxide. It preferably contains silicon oxide. When a silicon oxide layer containing silicon oxide is formed as a non-molybdenum silicide-based material layer on the molybdenum silicide-based material layer, a thin wire having the above structure is obtained by a dry etching method for the molybdenum silicide-based material film. This is because it is easy to form a thin line including the molybdenum silicide-based material layer.

When the non-molybdenum silicide-based material layer is a silicon oxide layer containing silicon oxide, the silicon oxide layer can be formed on the molybdenum silicide-based material layer as the formation site of the silicon oxide layer. When the layer is formed on the transparent substrate, it is preferably formed so as to cover the entire surface of the molybdenum silicide material layer other than the transparent substrate side surface.
In the present invention, the silicon oxide layer may be formed on the molybdenum silicide material layer via another non-molybdenum silicide material layer. It is preferably formed directly on the surface. This is because it is easy to form a thin line including the molybdenum silicide material layer.

  The silicon oxide layer is not particularly limited as long as it mainly contains silicon oxide, but the content of silicon oxide in the silicon oxide layer is preferably 80% by mass, and in particular, 90%. It is preferable that it is mass%, and it is especially preferable that it is 100 mass%, ie, a silicon oxide layer consists of silicon oxide. This is because the silicon oxide layer can be easily formed.

The film thickness of the silicon oxide layer is not particularly limited as long as a desired extinction ratio can be obtained, but it is preferably as thin as possible from the viewpoint of a high extinction ratio, for example, 10 nm or less. In particular, the thickness is preferably 6 nm or less, and particularly preferably 4 nm or less. This is because the film thickness can be excellent in the extinction ratio. Further, the lower limit of the film thickness is not particularly limited because it is preferably as thin as possible, but is preferably 2 nm or more because of easy production.
The film thickness of the silicon oxide layer refers to the maximum thickness from the surface of the molybdenum silicide material layer, and specifically refers to the thickness indicated by d in FIG.
As a method for measuring the film thickness, a general measurement method in the field of polarizers can be used. For example, by measuring the shape of the film surface layer with AFM and measuring the polarization characteristics with a transmission ellipsometer, The composition constituting the film and the respective film thickness can be obtained. In addition, the size such as the film thickness of the thin wire can be obtained by the above measuring method.

The film thickness of the thin wire is not particularly limited as long as it can have a desired extinction ratio. For example, it is preferably less than 100 nm, and in particular, in the range of 40 nm to 80 nm. It is preferable that it is in the range, and it is especially preferable to be in the range of 50 nm to 70 nm. This is because the film thickness can be excellent in the extinction ratio. Moreover, it is because formation of the said fine wire is easy.
The film thickness of the fine wire means the maximum thickness among the thicknesses in the direction perpendicular to the longitudinal direction and the width direction of the fine wire, and when the fine wire also has a non-molybdenum silicide material layer, non-molybdenum The film thickness includes the silicide-based material layer. Specifically, it refers to the thickness indicated by a in FIG.
The thin wires may have different thicknesses in one polarizer, but are usually formed with the same thickness.

The width of the thin line is not particularly limited as long as it can have a desired extinction ratio, and can be, for example, in the range of 40 nm to 80 nm, and in particular, 45 nm to It is preferably within the range of 60 nm, and particularly preferably within the range of 50 nm to 55 nm. It is because it can be excellent in extinction ratio by being the said width | variety.
The width of the fine line means a length perpendicular to the longitudinal direction of the fine line. When the fine line also includes a non-molybdenum silicide material layer, the width includes the non-molybdenum silicide material layer. That's what it says. Specifically, it refers to the length indicated by b in FIG.
The width of the thin line may include one having different widths in one polarizer, but is usually formed with the same width.

  The duty ratio of the fine line, that is, the ratio of the width of the fine line to the pitch (width / pitch) is not particularly limited as long as it can have a desired extinction ratio. It can be in the range of 0.4 to 0.7, and is preferably in the range of 0.5 to 0.65, and particularly preferably in the range of 0.55 to 0.6. . It is because it can be excellent in durability and washability by being the said aspect ratio.

The pitch of the thin line is not particularly limited as long as it can have a desired extinction ratio, and varies depending on the wavelength of light used for generating linearly polarized light, For example, it can be in the range of 100 nm to 150 nm, preferably in the range of 100 nm to 120 nm, particularly preferably in the range of 100 nm to 110 nm. This is because the pitch is excellent in the extinction ratio even for light having a wavelength of 300 nm or less.
The pitch of the fine line means the maximum width of the pitch between the fine lines adjacent in the width direction. When the fine line includes a non-molybdenum silicide-based material layer, it includes a non-molybdenum silicide-based material layer. . Specifically, the width indicated by c in FIG.
Moreover, although the pitch of the said thin wire | line may include the thing of a different pitch in one polarizer, it is normally formed with the same pitch.

  The number and length of the fine wires are not particularly limited as long as they can have a desired extinction ratio, and are appropriately set according to the use of the polarizer of the present invention. It is.

2. Transparent substrate Although the polarizer of this invention has the said fine wire, it has a transparent substrate with which the said fine wire is formed normally.

The transparent substrate is not particularly limited as long as it can stably support the fine wires, has excellent light transmittance, and can be less deteriorated by exposure light. For example, optically polished synthetic quartz glass, fluorite, calcium fluoride, and the like can be used. However, there are usually used synthetic quartz glass that is frequently used and stable in quality. In the present invention, synthetic quartz glass can be preferably used. This is because the quality is stable and there is little deterioration even when short wavelength light, that is, high energy exposure light is used.
The thickness of the transparent substrate can be appropriately selected according to the use and size of the polarizer of the present invention.

3. Polarizer The polarizer of the present invention has the fine wire.
The extinction ratio (P-wave transmittance / S-wave transmittance) of light having a wavelength of 250 nm of the polarizer is preferably 20 or more, more preferably 40 or more, particularly 60 or more. Is preferred. It is because the alignment control force to a photo-alignment layer can be stably provided because it is the said range.
Moreover, since it is preferable that the extinction ratio is larger, the upper limit is not particularly limited.
As the method for measuring the extinction ratio, a general measurement method in the field of polarizers can be used. For example, a transmission ellipsometer capable of measuring the polarization characteristics of ultraviolet light, such as VUV- It can be measured by using a transmission ellipsometer such as VASE.

The P wave transmittance of the polarizer (P wave component in outgoing light / P wave component in incident light) is not particularly limited as long as a desired extinction ratio can be obtained. The light with a wavelength of 250 nm is preferably 0.3 or more, more preferably 0.4 or more, and particularly preferably 0.6 or more. This is because the P-wave transmittance can efficiently impart an alignment regulating force to the photo-alignment layer.
In addition, as a measuring method of P wave transmittance, a general measuring method in the field of a polarizer can be used. For example, a transmission ellipsometer capable of measuring the polarization characteristics of ultraviolet light, for example, manufactured by Woollam Co., Ltd. It can be measured by using a transmission ellipsometer such as VUV-VASE.

  As a method for adjusting the extinction ratio of the polarizer, a method of changing the ratio of the P wave transmittance and the S wave transmittance can be used. For example, when the fine wire is covered with a silicon oxide layer, a method for increasing the P-wave transmittance includes a method of reducing the proportion of the molybdenum silicide-based material layer in the fine wire. Examples of a method for reducing the S wave transmittance include a method for reducing the pitch of the fine wires and a method for increasing the proportion of the molybdenum silicide-based material layer in the fine wires.

The use of the polarizer is not particularly limited as long as it is used for generating linearly polarized light, but is preferably used for generating linearly polarized light of a short wavelength light such as an ultraviolet region. It is preferably for linearly polarized light generation of light within a wavelength range of 200 nm to 315 nm, and particularly preferably for linearly polarized light generation of light within a wavelength range of 240 nm to 280 nm. This is because the effect of including the molybdenum silicide material layer can be more effectively exhibited.
Moreover, in this invention, it is preferable to use for the orientation control force provision to the optical alignment film for liquid crystal display devices which clamps liquid crystal material in a liquid crystal display device. This is because the alignment regulating force can be effectively applied to the photo-alignment film.

  The method for producing the polarizer is not particularly limited as long as it is a method capable of forming the fine wires with a desired size with high accuracy, and is disclosed in, for example, JP2012-203290A and 2010-191009A. Can be used. Specifically, as shown in FIG. 3, a transparent substrate 1 is prepared (FIG. 3A), and a molybdenum silicide material film 3 ′ is formed on the transparent substrate by sputtering or the like (FIG. 3). (B)), a patterned resist 11 is formed by a photolithographic method, an imprint method, an electron beam drawing method, and the like, and etched using the patterned resist 11 as a mask (FIG. 3C), a molybdenum silicide material layer 3 and a method of obtaining a polarizer 10 including a thin wire 2 having a silicon oxide film 4 formed at the time of forming a molybdenum silicide-based material film or etching (FIG. 3D).

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.

  The present invention will be described more specifically with reference to the following examples.

[Example 1]
A synthetic quartz glass with a film thickness of 10 mm is prepared as a transparent substrate, and molybdenum silicide is formed by reactive sputtering using a mixed target of molybdenum and silicon (Mo: Si = 1: 2 mol%) in a mixed gas atmosphere of argon and oxygen. A molybdenum silicide oxide film (MoSiO) having a film thickness of 60 nm was formed as the system material film.
Next, a patterned resist having openings with a line and space of 60 nm and 60 nm, that is, a pitch of 120 nm, was formed on the molybdenum silicide material film. Thereafter, the molybdenum silicide material film was dry-etched using CF ₆ as an etching gas, and then the patterned resist was peeled off to obtain the polarizer 1.
When the width | variety, the film thickness, and the pitch of the thin line | wire of the obtained polarizer 1 were measured with the SEM measuring apparatus LWM9000 by Vistec, they were 63.7 nm, 63 nm, and 120 nm, respectively.

[Evaluation]
About the polarizer obtained in Example 1, the structural evaluation of thin wires, the P-wave transmittance, and the extinction ratio were measured. In addition, a comparative evaluation with a simulation and a relational evaluation between the P wave transmittance and the pitch of the extinction ratio and the film thickness ratio by the simulation were performed.

(1) Structure evaluation of fine wire About the fine wire of the polarizer 1 obtained in Example 1, the structure was evaluated with the transmission ellipsometer (VUV-VASE made from Woollam).
As a result, the thin wire has a molybdenum silicide material layer made of a molybdenum silicide material having a width and a film thickness of 51.5 nm and 56.9 nm, respectively, and a film thickness on the upper surface and a film thickness on the side surface of the molybdenum silicide material layer. Have a silicon oxide layer made of silicon oxide of 6.1 nm and 6.1 nm, respectively.

(2) Measurement of P-wave transmittance and extinction ratio About the polarizer 1 obtained in Example 1, P-wave transmittance of light within a wavelength range of 200 nm to 380 nm (VUV-VASE manufactured by Woollam Co., Ltd.) The P wave component in the emitted light / the P wave component in the incident light) and the extinction ratio (P wave transmittance / S wave transmittance) were measured. The results are shown in FIG. 4 and FIG.
As shown in FIGS. 4 and 5, the P-wave transmittance and extinction ratio at 250 nm of the polarizer 1 were 0.44 and 19.6, respectively.

(3) Modeling by simulation 1
For model 1 and model 2 below, a simulation model based on RCWA (Regorous Coupled Wave Analysis) described in “Numerical analysis of diffractive optical elements and its application” (Maruzen Publishing, Kashiko Kodate custom) is created. A simulation of P wave transmittance and extinction ratio for light in the range of 380 nm was performed. The results are shown in FIG. 4 and FIG.

(Model 1)
Thin line model consisting only of a molybdenum silicide material layer having a thickness and width of 60 nm and 60 nm and a pitch of 120 nm

(Model 2)
Molybdenum silicide-based material layers having a thickness and width of 56.9 nm and 56.9 nm, and a silicon oxide layer having a thickness and width (side film thickness) of the upper surface of the molybdenum silicide-based material layer of 6.2 nm and 6.2 nm, A thin wire model with a pitch of 120 nm

(4) Modeling by simulation 2
Using the simulation model of model 2 above, the thickness ratio of the molybdenum silicide-based material layer in the thickness direction (thickness of the molybdenum silicide-based material layer / thickness of the thin wire) under the conditions of the following model 3 and model 4; P wave transmittance and extinction ratio were simulated for 250 nm light when the pitch of the thin line was changed. Further, the ratio of the width of the molybdenum silicide-based material layer and the silicon oxide layer was the same as that of the above model 2.
The results are shown in Tables 1 to 4 below. In Tables 1 to 4, the horizontal axis and the vertical axis are the film thickness ratio and the pitch, respectively, and the P wave transmittance for the models 3 and 4 (P wave component in the outgoing light / P wave component in the incident light), respectively. And extinction ratio (P-wave transmittance / S-wave transmittance).

(Model 3)
Thin line model with thin line thickness of 60nm and width 1/2 of the pitch

(Model 4)
A fine line model similar to Model 3, except that the film thickness of the fine line is 80 nm

(Simulation summary)
From FIG. 4 and FIG. 5, it was confirmed that the simulation result of Model 2 was almost the same as the actual P-wave transmittance and extinction ratio of the polarizer 1.
From Tables 1 to 4, it was confirmed that the P wave transmittance was increased by reducing the film thickness ratio of the molybdenum silicide-based material layer, that is, by reducing the proportion of the molybdenum silicide-based material layer in the thin wire. .
It was also confirmed that the extinction ratio was increased when the pitch of the fine wires was reduced and when the film thickness ratio of the molybdenum silicide material layer was increased.

DESCRIPTION OF SYMBOLS 1 ... Transparent substrate 2 ... Fine wire 3 ... Molybdenum silicide type material layer 4 ... Silicon oxide layer 10 ... Polarizer

Claims (3)

A polarizer that have a thin line plural linearly are arranged in parallel,
The fine lines, have a molybdenum silicide-based material layer containing a molybdenum silicide-based material,
The fine wire is formed on the molybdenum silicide-based material layer, and has a silicon oxide layer containing silicon oxide,
The polarizer is for imparting alignment regulating force to the photo-alignment film for liquid crystal display devices,
A polarizer for generating linearly polarized light having a wavelength in the ultraviolet region . The polarizer according to claim 1 , wherein the thin wire has a thickness of less than 100 nm. The polarizer according to claim 1 or 2 , wherein a pitch of the fine wires is in a range of 100 nm to 150 nm.

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