JP6884501B2 - Polarizer - Google Patents

Description

The present invention relates to a polarizer in which the extinction ratio does not change significantly even if the incident angle of light changes.

In order to perform an alignment process on an alignment film generally used in a liquid crystal display device, for example, an exposure process of irradiating ultraviolet rays through a polarizing element is performed.

The polarizer used in such an exposure process is a member designed to selectively pass light only on a plane of polarization in a certain direction. As a conventional polarizer, there is a polarizing film in which a resin film is stretched, but there is a problem in durability when irradiated with strong ultraviolet rays.

On the other hand, as a polarizer having excellent durability, a wire grid type polarizer in which a plurality of thin lines and spaces are alternately arranged has been proposed. In a wire grid type polarizer, a polarizing component (called a P wave) having an electric vector oscillating perpendicular to a thin line is transmitted, and a polarizing component (called an S wave) having an electric vector oscillating parallel to the thin line is reflected or transmitted. By absorbing it, linearly polarized light is obtained. Such a wire grid type polarizer includes a two-beam interferometry method, a photolithography method in which a master plate having a wire grid pattern is optically transferred to a photosensitive resist, an imprint method using a master plate having irregularities, and the like. Manufactured by various manufacturing methods. However, at present, when miniaturization of fine lines is required, each master plate is manufactured by an electron beam drawing device.

By the way, the conventional wire grid type polarizer includes a transparent substrate and a plurality of thin wires provided in parallel with each other on the transparent substrate, and the line width and arrangement pitch of the thin wires are defined to be the same. ..

In the wire grid type polarizer having such a configuration, when the incident angle of light is 0 degrees (when it is vertically incident on the transparent substrate surface), the appropriate P wave transmittance (P wave component / incident in the emitted light). The P-wave component in light) and the extinction ratio (P-wave transmittance / S-wave transmittance) can be obtained, but both the transmittance and the extinction ratio increase as the incident angle of light gradually tilts. It changes, and the angle dependence of transmittance and extinction ratio becomes remarkable.

When the transmittance and the extinction ratio change greatly depending on the incident angle in this way, different alignment treatments are performed depending on the location of the alignment film, and the quality of the alignment film deteriorates. Here, non-uniformity of the intensity distribution of polarized light occurs due to the angle dependence of the transmittance, and such non-uniformity can be reduced by adjusting the arrangement of the light source or the like. On the other hand, the angle dependence of the extinction ratio is a phenomenon in which the ratio of the S wave component to be removed by the polarizing element is changing, and it is difficult to improve it by additional means like the angle dependence of the transmittance. It is desired to improve the angle dependence of the extinction ratio itself.

Japanese Unexamined Patent Publication No. 2009-265290

The present invention has been made in consideration of such a point, and an object of the present invention is to provide a polarizer in which the extinction ratio does not change significantly even if the incident angle changes.

The present invention includes a transparent substrate and a plurality of thin wires provided parallel to each other on the transparent substrate. The plurality of thin wires form a unit fine line region for each desired number of fine wires, and the unit fine wire regions are formed within each unit fine wire region. It is a polarizer characterized in that the arrangement pitch between the thin lines includes thin lines different from each other.

The present invention is a polarizer in which each unit wire region has the same region width as each other.

The present invention is a polarizer characterized in that the arrangement pitch between each thin line in each unit thin line region is changed by changing the width of each thin line.

The present invention is a polarizer characterized in that, within each unit thin line region, the arrangement pitch between the thin lines is different by changing the width of the gap between the thin lines.

As described above, according to the present invention, it is possible to obtain a polarizer in which the extinction ratio does not change significantly even if the incident angle changes.

1 (a) is a perspective view showing a polarizer according to the present invention, FIG. 1 (b) is a plan view thereof, and FIG. 1 (c) is a cross-sectional view thereof. FIG. 2 is a plan view showing a part of a polarizing element having a polarizing region and a light-shielding film according to the present invention. FIG. 3 is a side sectional view showing a polarizer according to the present invention. 4 (a) to 4 (d) are diagrams showing a method for manufacturing a polarizer. 5 (a) to 5 (d) are diagrams showing a method for manufacturing a polarizer. FIG. 6 is a diagram schematically showing a method of irradiating a thin line pattern of a polarizer with an electron beam. FIG. 7 is an overall configuration diagram showing a method of irradiating a thin line pattern of a polarizer with an electron beam. FIG. 8 is a chart showing changes in the shape of the thin wire of the polarizer and the extinction ratio depending on the incident angle. FIG. 9 is a diagram showing a change in P wave transmittance with respect to an incident angle. FIG. 10 is a diagram showing a change in the extinction ratio with respect to the incident angle. FIG. 11 is a diagram showing a drawing method according to a modified example of irradiating a thin line pattern of a polarizer with an electron beam.

<Polarizer>
Hereinafter, the polarizer according to the embodiment of the present invention will be described.

The polarizer according to the present invention is a polarizing element in which a plurality of thin wires are arranged in parallel on a transparent substrate having transparency, and the ultraviolet light is emitted outside the polarizing region in which the thin wires are arranged. A light-shielding film is formed to block light (also called a light-shielding band). Practically, the polarizer preferably has a light-shielding band, but even if it does not have a light-shielding band, it functions as a polarizer and is the polarizer of the present invention.

1 (a), (b), (c) to 3 are views showing an example of a polarizer according to the present invention, of which FIG. 1 (a) is a perspective view showing a polarizer according to the present invention, FIG. (B) is a plan view thereof, FIG. 1 (c) is a cross-sectional view thereof, FIG. 2 is a plan view showing a polarizing element having a polarizing region and a light-shielding film according to the present invention, and FIG. 3 is a side cross section showing a polarizing element according to the present invention. It is a figure.

As shown in FIGS. 1 to 3, the polarizer 10 has a transparent substrate 1 and a plurality of thin wires 2 provided on the transparent substrate 1 in parallel with each other. The plurality of thin wires 2 form a polarization region 3, and a light-shielding film 4 is formed on the outer periphery of the polarization region 3.

Since it has such a configuration, the polarizer 10 can sandwich the region where the light-shielding film 4 is formed.

That is, in the polarizer 10, the polarizer 10 can be fixed to the photoaligning device without sandwiching the region where the thin wire 2 is formed (polarizing region 3), and therefore, the thin wire 2 can be fixed from the sandwiched portion. It is possible to solve the problem that the damage is caused in a chain reaction and the problem that foreign matter is generated from the damaged thin wire portion.

Further, as described above, since the light-shielding film 4 is formed on the outer periphery of the polarization region 3 in which the thin wire 2 is arranged, in the polarizer 10, incident light, particularly, from the region outside the polarization region 3 It is possible to suppress the transmission of the S wave component of the incident light, and it is possible to suppress the problem that the extinction ratio is significantly lowered.

Hereinafter, each configuration of the polarizer according to the present invention will be described in detail.

(Transparent board)
The transparent substrate 1 is particularly limited as long as it can stably support the thin wire 2, has excellent ultraviolet light transmission, and can be less deteriorated by exposure light. It's not a thing. For example, optically polished synthetic quartz glass, fluorite, calcium fluoride and the like can be used, and among them, 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 1 can be appropriately selected depending on the application, size, and the like of the polarizer 10.

(Thin line)
The thin wire 2 has an effect of efficiently transmitting the P wave component of the incident light having a wavelength of 365 nm, for example, in the polarizer 10 and suppressing the transmittance of the S wave component of the incident light to a low level, and is a transparent substrate. A plurality of linearly formed ones are arranged in parallel.

The material constituting the thin wire 2 is not particularly limited as long as it can obtain a desired extinction ratio and P wave transmission rate, and is, for example, aluminum, titanium, molybdenum, silicon, chromium, tantalum, and ruthenium. , Niobium, hafnium, nickel, gold, silver, platinum, palladium, rhodium, cobalt, manganese, iron, indium and other metals and alloys, and any of these oxides, nitrides or oxynitrides. Materials can be mentioned. Above all, it is preferably composed of a material containing molybdenum silicide.

This is because the extinction ratio and the P wave transmittance can be made excellent even in a short wavelength in the ultraviolet region, and the heat resistance and the light resistance are also excellent. The values of the refractive index and extinction coefficient in the ultraviolet region can be adjusted by the content of elements such as molybdenum (Mo), silicon (Si), nitrogen (N) and oxygen (O) contained in the molybdenum silicide-based material. Because it is. In addition, it has good light resistance to light in the ultraviolet region and is suitable as a material for a polarizer in the ultraviolet region.

Examples of the material containing molybdenum silicide include molybdenum silicide (MoSi), molybdenum silicide oxide (MoSiO), molybdenum silicide nitride (MoSiN), molybdenum silicide oxide nitride (MoSiON), and the like.

The thin wire 2 may be composed of a plurality of types of materials, or may be composed of a plurality of layers having different materials.

As shown in FIG. 3, the thickness t of the thin line 2 is not particularly limited as long as a desired extinction ratio and P wave transmittance can be obtained, but it may be, for example, 60 nm or more. It is preferably in the range of 60 nm to 160 nm, and particularly preferably in the range of 80 nm to 140 nm. This is because the extinction ratio and the P wave transmittance can be made excellent by the above range.

The thickness of the thin wire means the maximum thickness of the thickness in the direction perpendicular to the longitudinal direction and the width direction of the thin wire in a cross-sectional view, and when the thin wire is composed of a plurality of layers, all the thicknesses are used. It refers to the thickness including the layer.

Further, the thickness of the thin wire may include those having different thicknesses in one polarizer, but they are usually formed to have the same thickness.

The number and length of the thin wires 2 are not particularly limited as long as they can obtain a desired extinction ratio and P wave transmittance, and are appropriately set according to the application of the polarizer 10 and the like. Is.

Further, as shown in FIG. 3, the arrangement pitch (hereinafter, also referred to as pitch) of the thin wire 2 is P1, P2, P3, P4, P5 as long as it can obtain a desired extinction ratio and P wave transmittance. It is not particularly limited, and varies depending on the wavelength of light used for generating linearly polarized light, but can be, for example, in the range of 60 nm or more and 140 nm or less, and in particular, in the range of 80 nm or more and 120 nm or less. It is preferably in the range of 90 nm or more and 110 nm or less. This is because the pitch can be excellent in extinction ratio and P wave transmittance.

The pitches P1, P2, P3, P4, and P5 of the thin lines refer to the arrangement pitch between the thin lines adjacent to each other in the width direction, and when the thin lines are composed of a plurality of layers, all the layers are used. It refers to the pitch obtained by including it.

Further, the pitches P1, P2, P3, P4, and P5 of the fine wire include those having different pitches in one unit fine wire region. Further, the thin line 2 has widths d1, d2, d3, d4, and d5, respectively. When the pitch Pi of the i-th thin line 2 and the width di of the thin line 2 are determined, the width si of the gap between the thin line and the next adjacent thin line is determined as the difference between the pitch Pi of the thin line and the width di of the thin line. Here, the pitch Pi is the pitch of the arrangement of the i-th thin line and the i + 1th thin line, the width di of the thin line is the width of the i-th thin line, and the gap width si is the gap between the i-th thin line and the i + 1th thin line. The width.

The duty ratio of the thin wire, that is, the ratio of the width of the thin wire to the pitch of the thin wire (width / pitch) is not particularly limited as long as a desired extinction ratio and P wave transmittance can be obtained. However, for example, it can be in the range of 0.2 or more and 0.6 or less, and more preferably in the range of 0.25 or more and 0.45 or less. This is because the duty ratio makes it possible to obtain a polarizer having an excellent extinction ratio while maintaining a high P-wave transmittance, and further facilitates fine wire processing.

The width of the thin line means the length in the direction perpendicular to the longitudinal direction of the thin line in a plan view, and when the thin line is composed of a plurality of layers, the width including all the layers (that is, the maximum width). Width).

Further, the width of the thin line includes those having different widths in one polarizer.

(Polarized region)
The polarizing region 3 is a region in which a large number of thin lines are arranged, and the polarizing element 10 shown in FIGS. 2 and 3 is surrounded by a light-shielding film 4. Further, the region defined by the light-shielding film 4 is a region through which the incident light is transmitted, and in the polarizer 10 shown in FIGS. 2 and 3, the region through which the incident light is transmitted and the polarizing region 3 coincide with each other in a plan view. There is.

In the present invention, the region through which the incident light is transmitted can be set to be a region larger than the polarization region 3. More specifically, the thin wire 2 may not be connected to the light-shielding film 4 in the longitudinal direction thereof.

Further, in the arrangement direction of the thin wires 2 (in the plan view, the direction perpendicular to the longitudinal direction of the thin wires 2), the distance between the thin wires 2 at the end and the light-shielding film 4 is larger than the distance si between the thin wires 2. May be good.

However, in order to obtain a high extinction ratio, it is preferable that the thin wire 2 is connected to the light-shielding film 4 in the longitudinal direction thereof. The region where the thin line 2 outside the polarization region 3 does not exist, that is, the region through which the incident light is transmitted but not polarized can be made smaller, and the transmission of the S wave component of the incident light can be further suppressed. Because.

Further, the distance between the thin wire 2 at the end and the light-shielding film 4 in the arrangement direction of the thin wire 2 is preferably the same as the distance between the thin wires 2.

In the present invention, for example, by making the step of forming the thin wire 2 and the step of forming the light-shielding film 4 the same step, the positional relationship between the light-shielding film 4 and the thin wire 2 can be accurately produced, and the edge of the light-shielding film 4 can be manufactured. The direction and the direction of the thin line 2 can be manufactured in parallel or vertically with high accuracy.

As described above, in the form in which the thin wire 2 is connected to the light-shielding film 4, the heat accumulated in the thin wire 2 due to the light applied to the polarizing element is dispersed in the light-shielding film 4, and antistatic is prevented. It can also be effective.

Further, in the form in which the thin wire 2 is connected to the light-shielding film 4, in the manufacturing process of the polarizer 10, a thin resist pattern (thin wire pattern) for forming the thin wire 2 is used to form the light-shielding film 4. It can be connected to a large-area resist pattern (light-shielding film pattern), and it is possible to suppress the problem that the thin resist pattern (thin line pattern) for forming the fine wire 2 collapses or peels off during the manufacturing process. You can also.

(Shading film)
The light-shielding film 4 is formed on the outside of the polarizing region 3 and suppresses the transmission of incident light, particularly the S wave component of the incident light.

In the present invention, the light-shielding film 4 preferably has a light-shielding property having an optical density of 2.8 or more with respect to ultraviolet light having a wavelength of 240 nm or more and 380 nm or less.

This is because the light-shielding film 4 has a high light-shielding property in the wavelength range of ultraviolet light irradiated to impart an orientation-regulating force to the photo-alignment film, so that a polarizer having an excellent extinction ratio can be provided. ..

The material constituting the light-shielding film 4 is not particularly limited as long as it can obtain a desired optical density, and for example, aluminum, titanium, molybdenum, silicon, chromium, tantalum, ruthenium, niobium, hafnium, etc. Metals and alloys such as nickel, gold, silver, platinum, palladium, rhodium, cobalt, manganese, iron, indium, and materials containing any of these oxides, nitrides, or oxynitrides can be mentioned. it can. Among them, a material containing molybdenum silicide can be preferably mentioned.

When the material constituting the light-shielding film 4 is made of a material containing molybdenum silicide, if the thickness of the light-shielding film 4 is 60 nm or more, the optical density is 2 with respect to ultraviolet light having a wavelength of 240 nm or more and 380 nm or less. This is because it can have a light-shielding property of 8.8 or more.

The light-shielding film 4 may be composed of a plurality of types of materials, or may be composed of a plurality of layers having different materials.

Further, the material constituting the light-shielding film 4 preferably contains the material constituting the thin wire 2.

When the material constituting the light-shielding film 4 contains the material constituting the thin wire 2, the apparatus and material used in the process of forming the thin wire 2 can also be used in the process of forming the light-shielding film 4, and the manufacturing cost This is because it will reduce the cost. Further, by making the step of forming the thin wire 2 and the step of forming the light-shielding film 4 the same step, the relative position accuracy of the thin wire 2 and the light-shielding film 4 can be improved.

Further, when the material constituting the light-shielding film 4 and the material constituting the thin wire 2 are both made of a material containing molybdenum silicide, the light-shielding film 4 has a high light-shielding property and has a dimming ratio and an extinction ratio. It can be a polarizer having excellent P-wave transmittance.

Next, the shape of the thin wire 2 of the polarizer 10 will be further described with reference to FIGS. 1 to 3.

The polarizer 10 includes a transparent substrate 1 and a plurality of thin wires 2 provided on the transparent substrate 1 as described above, of which the thin wires 2 are a desired number, for example, a unit fine wire region 2A for every five wires. It forms 2A. However, the number of thin wires 2 included in the unit thin wire region 2A is not limited to five, and can be appropriately determined depending on manufacturing conditions and the like.

The unit thin line regions 2A and 2A have the same region widths PL and PL.

Further, in the unit thin line regions 2A and 2A, the arrangement pitches (also simply referred to as pitches) P1, P2, P3, P4, and P5 between the thin lines 2 and 2 are different from each other as described later. For example, in FIG. 3, the arrangement pitches P1, P2, P3, P4, and P5 may be different by changing the width of the gaps s1, s2, s3, s4, and s5 between the thin lines 2 and 2. Alternatively, in FIG. 3, the arrangement pitches P1, P2, P3, P4, and P5 may be different by changing the widths d1, d2, d3, d4, and d5 of the thin lines 2 and 2. Further, even if the arrangement pitches P1, P2, P3, P4, and P5 are different by changing both the fine line gaps s1, s2, s3, s4, s5 and the thin line widths d1, d2, d3, d4, and d5 at the same time. Good. Here, as a special example, if the increase / decrease in the gap si of the thin line and the increase / decrease in the width di of the thin line are set to cancel each other, the pitch Pi is apparently constant, and P1, P2, P3, P4, and P5 are not different. Although it is a setting, in the present application, it is assumed that the pitch is different as an exception to such a special example. That is, in the present application, the fact that the pitch is constant and does not differ means that the width di of the thin line and the gap si of the thin line are constant and do not differ from each other.

In any case, since the arrangement pitches P1, P2, P3, P4, and P5 of the thin wire 2 of the polarizer 10 are different from each other, the extinction ratio of light does not change significantly even if the incident angle changes.

The reason for this is that when the arrangement pitches P1, P2, P3, P4, and P5 of the thin wire 2 are the same, the optical characteristics with respect to the incident light are realized by a single periodic structure, and thus a steep characteristic is exhibited (for example, a diffraction grating). Since the spectral characteristics of the above are remarkable in angle dependence), it is presumed that the extinction ratio of the incident light becomes large in angle dependence, and the extinction ratio changes greatly according to the change in the incident angle.

On the other hand, when the arrangement pitches P1, P2, P3, P4, and P5 of the thin wire 2 are different, different optical characteristics corresponding to different pitches are added to the incident light to obtain an averaged optical characteristic, so that the incident light is extinguished. It is presumed that the ratio becomes less angle-dependent and does not change significantly in response to changes in incident light.

By the way, as shown in FIGS. 1 to 3, the unit wire region 2A composed of the five wire 2 has the same region width PL. By repeatedly moving and exposing such a pattern of the unit fine line region 2A by the region width PL, it is possible to form a pattern of a wire grid polarizer 10 having a predetermined optical characteristic and having a required size.

Therefore, if the combination of the width di of the thin wire 2 and the gap si of the thin wire 2 or the combination of the width di of the thin wire 2 and the pitch Pi of the thin wire 2 is determined within the range of the unit thin wire region 2A, the entire wire grid polarizer 10 can be used. The pattern of the thin line 2 is determined.

Next, with reference to FIGS. 8 to 10, the specific shape of the thin wire 2 of the polarizer 10 and its optical characteristics, particularly the angle dependence of the extinction ratio will be described.

As the polarizer, the polarizers A to G as shown in the table of FIG. 8 were prepared. Next, the changes in the P wave transmittance and the extinction ratio when the incident light having a wavelength of 365 nm with respect to the polarizers A to G is irradiated with the incident angle changed from 0 degrees to 60 degrees are obtained by electromagnetic field simulation. , P wave transmittance and angle dependence of extinction ratio were confirmed (FIGS. 9 and 10). In the electromagnetic field simulation, a simulation model based on the strict coupling wave theory (also called RCWA method (Rigorous Coupled Wave Analysys)) was created, the P wave transmittance and the S wave transmittance were obtained, and the extinction ratio was obtained. The exact coupling wave theory (RCWA method) is described in, for example, "Numerical analysis of diffractive optical elements and its application" (Maruzen Publishing Co., Ltd., supervised by Kashiiko Kodate).

FIG. 9 is a graph showing the change in the P wave transmittance when the incident angle of the incident light changes from 0 degrees to 60 degrees, and shows the tendency that the P wave transmittance decreases as the incident angle increases. There is. FIG. 10 is a graph showing a change in the quenching ratio when the incident angle of the incident light changes from 0 degrees to 60 degrees, and shows a tendency that the quenching ratio increases as the incident angle increases. Curves A to G show changes in P-wave transmittance corresponding to the wire grid polarizers A to G evaluated this time.

The table of FIG. 8 shows the dimensions of each part of the wire grid polarizer evaluated this time and the calculation result of the extinction ratio by the electromagnetic field simulation. The polarizer A is a conventional example in which both the fine line width and the fine line gap are constant (and therefore the fine line pitch is also constant). The polarizers B, C, and D are examples in which the fine line width is constant and the fine line gap si is changed. The polarizers F and G are examples in which the thin line gap is constant and the fine line width di is changed. The polarizer E is an example in which both the fine line width di and the fine line gap si are changed.

In the table of FIG. 8, in order to evaluate the angle dependence of the extinction ratio, the difference between the extinction ratio when the incident angle is 0 degrees (directly incident to the wire grid polarizer) and the extinction ratio when the incident angle is 60 degrees. The value obtained by dividing the absolute value by the extinction ratio at an incident angle of 0 degrees and displaying it as a percentage was defined as the "extinguishing ratio change rate". The smaller the rate of change in the extinction ratio, the less the angle dependence of the extinction ratio. Below, the rate of change in the extinction ratio when the width of the thin wire of the wire grid polarizer and the gap between the thin wires are changed will be investigated.

The polarizer A is a wire grid polarizer based on the conventional design, and the arrangement pitches P1, P2, P3, P4, and P5 of the thin wire 2 are the same 100 nm, and the width of the thin wire 2 is also the same 30 nm. There is. Therefore, the gap between the thin lines 2 is also constant at 70 nm. The extinction ratio change rate of the polarizer A (conventional example) was 48.4%.

The polarizer B is an example, in which the gap between the thin wires 2 changes to 70 to 74 nm, the width of the thin wires 2 is fixed at 30 nm, and the arrangement pitches P1, P2, P3, P4, and P5 change to 100 to 104 nm. doing. The extinction ratio change rate of the polarizer B is 40.2%, the extinction ratio change rate is reduced by 8.2% as compared with the conventional example, and the angle dependence is improved (that is, the angle dependence is small).

The polarizer C is an example, in which the gap between the thin wires 2 changes to 71 to 75 nm, the width of the thin wires 2 is fixed at 30 nm, and the arrangement pitches P1, P2, P3, P4, and P5 change to 101 to 105 nm. doing. The extinction ratio change rate of the polarizer C is 36.5%, the extinction ratio change rate is reduced by 11.5% as compared with the conventional example, and the angle dependence is further improved.

The polarizer D is an example, in which the gap between the thin wires 2 changes to 70 to 78 nm, the width of the thin wires 2 is fixed at 30 nm, and the arrangement pitches P1, P2, P3, P4, and P5 change to 100 to 108 nm. doing. The extinction ratio change rate of the polarizer D is 32.4%, the extinction ratio change rate is reduced by 16% as compared with the conventional example, and the angle dependence is further improved.

The polarizer E is an example, in which the gap between the thin wires 2 changes to 70 to 74 nm, the width of the thin wires 2 changes to 30 to 34 nm, and the arrangement pitches P1, P2, P3, P4, and P5 are 100 to 108 nm. Has changed to. The extinction ratio change rate of the polarizer E is 25.6%, the extinction ratio change rate is reduced by 22.8% as compared with the conventional example, and the angle dependence is satisfactorily improved.

The polarizer F is an example, in which the gap between the thin wires 2 is fixed at 70 nm, the width of the thin wires 2 changes from 30 to 34 nm, and the arrangement pitches P1, P2, P3, P4, and P5 change from 100 to 104 nm. doing. The extinction ratio change rate of the polarizer F is 33.2%, the extinction ratio change rate is reduced by 15.4% from the conventional example, and the angle dependence is improved to the same extent as that of the polarizer D.

The polarizer G is an example, in which the gap between the thin wires 2 is fixed at 70 nm, the width of the thin wires 2 changes from 30 to 38 nm, and the arrangement pitches P1, P2, P3, P4, and P5 change from 100 to 108 nm. ing. The extinction ratio change rate of the polarizer G is 20.0%, the extinction ratio change rate is reduced by 28.4% from the conventional example, and the angle dependence is the best improved in the examples simulated this time. ..

Each of the polarizers A to G has a unique region width PL of the unit thin line region. In this case, the region width PL of the unit wire region 2A of the polarizers A to G is 500 nm, 510 nm, 515 nm, 520 nm, 520 nm, 510 nm, and 520 nm, respectively.

As shown in FIG. 10, the polarizers B to G having different thin wire arrangement pitches have different incident angles of incident light as compared with the conventional polarizing elements A having the same thin wire arrangement pitch and the same thin line width. However, it was found that the change in the extinction ratio was small, and therefore the angle dependence of the extinction ratio of the polarizers B to G was small and improved.

In particular, the polarization elements E, F, and G, whose fine line widths are changed, have a smaller angle dependence of the extinction ratio than the polarizers B, C, and D, which change only the fine line gaps. found. On the other hand, in the polarizer F and the polarizer G in which only the fine line width is changed, the angle dependence of the extinction ratio is reduced, but at the same time, the P wave transmittance tends to be significantly reduced. On the other hand, the polarizer E changes both the fine line width and the fine line gap, and the angle dependence of the extinction ratio is improved to the same extent as that of the polarizers F and G. It can be reduced as compared with the polarizers F and G, which is advantageous in the design of the wire grid polarizer.

<Manufacturing method of polarizer>
Next, a method for producing a polarizer according to the present invention will be described.

The method for producing an etchant according to the present invention is a method for producing a polarizer having a plurality of thin wires and a light-shielding film that blocks ultraviolet light on a transparent substrate having transparency. A step of preparing a laminate having a thin wire material layer formed on it, a step of forming a resist layer on the fine wire material layer, a step of forming a resist pattern having a fine wire pattern and a light-shielding film pattern, and the above-mentioned steps. It includes a step of etching the laminated body using a resist pattern as an etching mask.

In the present invention, the manufacturing process is shortened by forming a resist pattern having a thin wire pattern and a light-shielding film pattern and etching, and making the step of forming the thin wire 2 and the step of forming the light-shielding film 4 the same step. And the relative positional accuracy between the thin wire 2 and the light-shielding film 4 can be improved.

Further, by forming the thin wire 2 and the light-shielding film 4 from the same material, the manufacturing cost can be kept low.

4 and 5 are schematic process diagrams showing an example of a method for manufacturing a polarizer according to the present invention.

For example, in order to manufacture the polarizer 10 by using the method for manufacturing a polarizing element according to the present invention, first, as shown in FIG. 4A, a thin wire 2 and a light-shielding film 4 are formed on the transparent substrate 1. A laminate 1A is prepared in which a polarizing material layer (material layer for fine wires) 31 made of the material to be formed and a hard mask material layer 32 acting as a hard mask when etching the polarizing material layer 31 are sequentially formed.

Next, a resist layer 33 is formed on the laminate 1A by the resist film forming apparatus (FIG. 4 (b)), and the electron beam 40 is irradiated by the electron beam irradiating apparatus (FIG. 4 (c)). To form a resist pattern 34 having a thin line pattern 34a and a light-shielding film pattern 34b (FIG. 4 (d)).

In the present invention, as will be described later, for example, an electron beam drawing apparatus used for manufacturing a photomask for semiconductor lithography is used to produce a fine line pattern 34a, a light-shielding film pattern 34b, the above-mentioned alignment mark, and the like in the same process. Therefore, their relative positions can be controlled under the highly accurate position accuracy control of the electron beam drawing apparatus.

Next, in the etching apparatus, the hard mask material layer 32 is etched by using the resist pattern 34 as the etching mask to form the hard mask pattern 32P (FIG. 5 (e)). For example, when chromium is used as the material of the hard mask material layer 32, the hard mask pattern 32P can be formed by dry etching using a mixed gas of chlorine and oxygen.

Next, in the etching apparatus, the resist pattern 34 and the hard mask pattern 32P are used as the etching mask, and the polarizing material layer 31 is etched to form the polarizing material pattern 31P having the fine wire 2 and the light-shielding film 4 (FIG. 5). (F)). For example, when molybdenum silicide is used as the material of the polarizing material layer 31, the polarizing material pattern 31P can be formed by dry etching using SF6 gas.

Next, in the peeling device, the resist pattern 34 is removed (FIG. 5 (g)), then the hard mask pattern 32P is removed, and a plurality of thin wires 2 and a light-shielding film 4 are provided on the transparent substrate 1. A polarizer 10 is obtained (FIG. 5 (h)).

Although omitted in the examples shown in FIGS. 4 and 5, in the present invention, a plurality of thin wires 2 and a light-shielding film 4 are formed on a large-area transparent substrate 1, and then the thin wires 2 are arranged. The outside of the polarized light region 3 may be cut to obtain a polarizing element 10 cut out to a desired size and shape.

Further, in the above, the polarizing material layer 31 is etched while the resist pattern 34 remains, but in the present invention, the resist is formed after the step of forming the hard mask pattern 32P shown in FIG. 5 (e). The pattern 34 may be removed and only the hard mask pattern 32P may be used as the etching mask to etch the polarizing material layer 31 to form the polarizing material pattern 31P.

Further, in the above, the form in which the hard mask pattern 32P is removed as the obtained polarizer 10 has been described, but in the present invention, the hard mask pattern 32P may be left in whole or in part as needed. good.

For example, as in the form shown in FIG. 5 (g), a form in which the hard mask pattern 32P is left on the entire surface may be used as the form of the finally obtained polarizer. In this case, the step of removing the hard mask pattern 32P can be omitted, and the effect of shortening the step can be obtained.

Further, in the above, the mode in which the hard mask material layer 32 is provided on the polarizing material layer 31 has been described, but in the present invention, the resist layer is provided on the polarizing material layer 31 without providing the hard mask material layer 32. 33 may be formed, and the polarizing material layer 31 may be etched by using the resist pattern 34 as an etching mask to form the polarizing material pattern 31P having the fine wire 2 and the light-shielding film 4.

<Electron beam irradiation method>
Here, the method used for forming the resist pattern 34 shown in FIG. 4C is used as long as it can form a resist pattern 34 having a desired fine line pattern 34a and a light-shielding film pattern 34b. However, among them, the method of irradiating an electron beam is preferable.

The resist pattern formation by the method of irradiating an electron beam has a proven track record in the manufacture of photomasks for semiconductors, and for example, a fine line pattern having a pitch in the range of 60 nm or more and 140 nm or less can be formed in a desired region with high accuracy. Because. Further, the relative position accuracy of the thin line pattern 34a and the light-shielding film pattern 34b can also be set to the nanometer level accuracy required for manufacturing a photomask for semiconductors.

Further, in the present invention, the resist layer 33 is composed of a positive electron beam resist, and the step of forming the resist pattern 34 having the fine wire pattern 34a and the light-shielding film pattern 34b is a step of forming the desired thin wire and the desired light-shielding. It is preferable that the step is to irradiate the resist layer 33 other than the position where the film is formed with an electron beam.

More specifically, it is preferable that the thin line pattern 34a constitutes a line and space pattern, and the resist layer 33 at a position serving as the space pattern portion of the line and space pattern is irradiated with an electron beam.

This is because if the method of irradiating the electron beam at the above position, the area for irradiating the electron beam can be reduced, and the time required for the electron beam irradiation step can be shortened.

The above will be described in more detail.

For example, as shown in FIG. 3, when the width of the thin wire 2 of the polarizer 10 is half the pitch of the thin wire 2, a negative electron beam resist is used to block the thin wire pattern of the polarizer 10 and to block light. When trying to obtain a film pattern, the area irradiated with electron beams is the area obtained by adding the area of the light-shielding film 4 to the area of all the thin wires 2.

On the other hand, when a positive electron beam resist is used, the area to be irradiated with the electron beam is the total area of all the space portions (gap portions) of the thin wire 2, that is, the total area of all the thin wire 2. The time required to irradiate the area of the light-shielding film 4 can be reduced.

Next, the electron beam irradiation method will be further described with reference to FIGS. 6 and 7. As shown in FIGS. 6 and 7, an electron beam irradiation method using an electron beam irradiation device is used to form a resist pattern 34 having a thin line pattern 34a and a light shielding film pattern 34b on the resist layer 33.

As shown in FIGS. 6 and 7, such an electron beam irradiating device 11 has an electron gun 12 that generates an electron beam 40 and a rectangular opening 13a through which the electron beam 40 generated from the electron gun 12 passes. A first deflector 14 having a first aperture 13 and a first deflector 14 for deflecting the electron beam 40 passing through the first aperture 13, and a plurality of linear openings 15a for passing the electron beam 40 deflected by the first deflector 14. The second deflection that deflects the 2 aperture 15 and the electron beam 40 that has passed through the second aperture 15 and irradiates the deflected electron beam 40 on the resist layer 33 provided on the polarizing material layer 31 of the above-mentioned laminate 1A. It is equipped with a vessel 16.

Of these, the first aperture 13 has a single rectangular opening 13a, and the second aperture 15 has a plurality of linear openings 15a and a linear mask 15b between the linear openings 15a.

Generally, the electron beam 40 generated from the electron gun 12 has a large energy near the center and a small energy near the periphery.

Therefore, the electron beam 40 generated from the electron gun 12 passes through the first aperture 13 having a rectangular opening 13a, so that only the electron beam 40 near the center having a large energy is used among the electron beams 40. Can be done.

Next, the electron beam 40 that has passed through the first aperture 13 passes through the second aperture 15 having a plurality of linear openings 15a, so that the second aperture 15 can obtain a plurality of linear electron beams 40a. The linear electron beam 40a thus obtained can be applied to the resist layer 33 provided on the laminated body 1A.

Next, an electron beam irradiation method using the electron beam irradiation device 11 having such a configuration will be described.

As shown in FIGS. 6 and 7, the electron beam 40 generated from the electron gun 12 passes through the rectangular opening 13a of the first aperture 13, and only the electron beam 40 near the center of the electron beam 40 having a large energy. Is selected.

Next, the electron beam 40 that has passed through the first aperture 13 is deflected by the first deflector 14 and enters the second aperture 15. Next, the electron beam 40 passes through the linear opening 15a of the second aperture 15 to form a plurality of linear electron beams 40a. Next, the linear electron beam 40a is deflected through the second deflector 16 and irradiates the resist layer 33 provided on the laminated body 1A.

At this time, the linear electron beam 40a irradiates the resist layer 33 for each shot, and the linear electron beam 40a irradiated for each shot includes a predetermined number of linear electron beams 40a on the resist layer 33. A unit region 40A of a rectangular electron beam is formed.

In this case, the linear electron beam 40a included in the unit region 40A of the electron beam corresponds to the space between the thin wire 2 or the thin wire 2 depending on the type of the electronic resist of the resist layer 33.

In FIG. 6, the linear electron beam 40a included in the unit region 40 of the electron beam formed on the resist layer 33 is shown corresponding to the thin wire 2 of the polarizer 10.

As described above, according to the present embodiment, since the arrangement pitches P1, P2, P3, P4, and P5 of the thin wire 2 of the polarizer 10 are different from each other, the quenching ratio changes significantly even if the incident angle changes. There is no such thing. Generally, when light emitted from a point light source at a predetermined position is applied to an alignment film via a polarizer 10, the angle of incidence of the incident light on the polarizer changes depending on the location of the alignment film. In addition, since the extinction ratio does not change significantly even if the incident angle changes, it is possible to perform an orientation treatment with improved uniformity over the entire alignment film regardless of a specific location. As a result, the alignment treatment can be performed on the alignment film with high accuracy.

<Modified example of the present invention>
Next, a modification of the present invention will be described. In the above embodiment, the electron beam irradiation device 11 shown in FIGS. 6 and 7 is shown, but the present invention is not limited to this, and the electron beam irradiation device 11 shown in FIGS. 11 (a) and 11 (b) is used as the electron beam irradiation device. You may use it.

As shown in FIGS. 11A and 11B, such an electron beam irradiating device 11 includes an electron gun 12 that generates an electron beam 40, a first concentrator 17, and electrons generated from the electron gun 12. A first aperture 13 having a rectangular opening 13a through which the wire 40 passes, a first deflector 14 that deflects the electron beam 40 that has passed through the first aperture 13, and a second condenser deflected by the first deflector 14. The second aperture 15 having a rectangular opening 15c through which the electron beam 40 focused by the vessel 18 passes, and the point-shaped electron beam 40b passing through the second aperture 15 are deflected, and the deflected electron beam 40 is described above. The resist layer 33 provided on the polarizing material layer 31 of the laminate 1A is provided with a second deflector 16 that irradiates the resist layer 33 via the third condenser 19.

Of these, the first aperture 13 has a rectangular opening 13a, and the second aperture 15 has a rectangular opening 15c.

Generally, the electron beam 40 generated from the electron gun 12 has a large energy near the center and a small energy near the periphery.

Therefore, the electron beam 40 generated from the electron gun 12 passes through the first aperture 13 having a rectangular opening 13a, so that only the electron beam 40 near the center having a large energy is used among the electron beams 40. Can be done.

Next, the electron beam 40 that has passed through the rectangular opening 13a of the first aperture 13 passes through the corner of the rectangular opening 15c of the second aperture 15, so that the point-shaped electron beam 40a can be obtained by the second aperture 15. The point-shaped electron beam (more accurately, the electron beam shaped into a minute rectangular shape) 40b thus obtained can be irradiated to the resist layer 33 provided on the laminated body 1A. That is, as shown in FIGS. 11A and 11B, the rectangular opening 13a of the first aperture 13 and the rectangular opening 15c of the second aperture 15 have a relationship of overlapping each other at their corners, and thus the rectangular opening A point-shaped electron beam 40b can be obtained from the corner portion of 13a and the corner portion of the rectangular opening 15c.

Next, an electron beam irradiation method using the electron beam irradiation device 11 having such a configuration will be described.

As shown in FIGS. 11A and 11B, the electron beam 40 generated from the electron gun 12 passes through the first condenser 17 and the rectangular opening 13a of the first aperture 13, and the electron beam. Of the 40, only the electron beam 40 near the center having a large energy is selected.

Next, the electron beam 40 that has passed through the first aperture 13 is deflected by the first deflector 14, passes through the second condenser 18, and enters the second aperture 15. Next, the electron beam 40 passes through the corner of the rectangular opening 15c of the second aperture 15 to form a point-shaped electron beam 40b. Next, the point-shaped electron beam 40b is deflected through the second deflector 16 and the third condenser 19 and irradiates the resist layer 33 provided on the laminated body 1A.

At this time, the point-shaped electron beam 40b travels on the laminated body 1A by the second deflector 16 and the third condenser 19, whereby the desired pattern by the electron drawing method, that is, the thin wire 2 or A pattern corresponding to the gap between the thin lines 2 can be formed. If such a pattern forming method using the point-shaped electron beam 40b is used, an exposure pattern in which the pitch of the thin wire 2 prepared in advance is changed as the unit fine wire region 2A is used in manufacturing, and the entire polarizing region 3 is exposed by repeated exposure. No need to expose. That is, when the pattern forming method by the electron drawing method using the point-shaped electron beam 40b is used, the pattern in which the pitch of the thin wire 2 is randomly changed within a certain value range is drawn by the point-shaped electron beam 40b. Therefore, a polarizer having an effect of reducing the angle dependence of the extinction ratio can be obtained as in the case of repeated exposure of the pattern by the unit thin line region 2A. Such an embodiment is a case where the size of the unit thin wire region 2A matches the polarization region 3, but the polarizer is formed by a pattern in which the pitch of the thin wire 2 is changed, and within the scope of the rights of the present application. is there.

Furthermore, an example in which the resist pattern 34 is formed on the resist layer 33 by an electron beam irradiation method is shown, but the present invention is not limited to this, and the uneven pattern of the mold is formed on the resist layer 33 by using a flexible mold in which the uneven pattern is formed. A resist pattern may be formed on the resist layer 33 by using a nyimprint method for transferring the above.

1 Transparent substrate 1A Laminated body 2 Fine wire 2A Unit fine wire region 3 Polarizing region 4 Shading film 10 Polarizer 11 Electron beam irradiator 12 Electron gun 13 1st aperture 13a Rectangular opening 14 1st deflector 15 2nd aperture 15a Linear opening 15b Linear mask 15c Rectangular opening 16 Second deflector 40 Electron beam 40a Linear electron beam 40b Dot electron beam

Claims (3)

With a transparent board
A plurality of thin wires provided parallel to each other on this transparent substrate are provided.
The plurality of thin lines form a unit thin line region for each desired number of thin lines, and within each unit thin line region, the gap between the thin lines increases or decreases, and the width of each thin line increases or decreases, and the gap between the thin lines and each thin line increase or decrease. Both widths change at the same time,
A polarizer characterized in that the plurality of thin wires are made of a material containing molybdenum silicide. The polarizer according to claim 1, wherein the plurality of thin wires form a polarizing region, and a light-shielding film made of a material containing molybdenum silicide is provided on the outer periphery of the polarizing region on the transparent substrate. .. The polarizer according to claim 1 or 2, wherein each unit wire region has the same region width as each other.

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