JP2015180975A - Manufacturing method of polarizer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a polarizer having high reliability even under an environment having a high temperature or high humidity.SOLUTION: A manufacturing method of a polarizer has a cutting step for obtaining a plurality of polarizers 1 cut into pieces having a prescribed size, by cutting a non-forming area 10 of the polarizers 1 formed on a wafer substrate 16.

Description

  The present invention relates to a method of manufacturing a polarizing plate that separates incident light into transmitted light and reflected light according to the polarization direction.

  In recent years, in a liquid crystal display device or the like, as a thin polarizing plate, a polarizing film in which an iodine compound is adsorbed on a polyvinyl alcohol (PVA) film and stretched and oriented to develop visible light dichroism is often used. . The polarizing film is sandwiched from both sides by a transparent film such as triacetyl cellulose (TAC) to ensure mechanical strength, heat resistance, and moisture resistance, and then hard-coated to prevent scratches and dirt. Has been made.

  Of the light incident on the polarizing film, the light of the polarized component that does not pass is absorbed in the polarizing film and released as heat to the outside of the film. For this reason, when intense light is irradiated, there exists a problem that the temperature of a film rises by heat_generation | fever and a polarization characteristic will deteriorate. This is due to the heat resistance of the organic material itself and is essentially difficult to improve.

  For this problem, a polarizing plate composed entirely of an inorganic material is used. Typical examples of the thin type are a polarizing glass and a wire grid polarizing plate. The polarizing glass is made of metal island-like fine particles deposited in the glass, and exhibits absorption dichroism by anisotropy of plasma resonance absorption of the fine particles. Polarized components that do not pass are absorbed but have high heat resistance because they are composed of an inorganic material.

  On the other hand, in the wire grid polarizer, a wire grid made of fine metal wires having a period equal to or less than the wavelength of light is formed on the surface of the substrate (see Patent Document 1). This wire grid polarizing plate reflects a polarized component that does not pass through free electron plasma oscillation, and thus has an advantage that incident light can be used more effectively.

  Further, as a type similar to a wire grid, there is a fine particle type polarizing plate in which elliptical fine metal particles are arranged on the surface of a substrate (see Patent Document 2). This uses plasma resonance absorption of fine particles and, unlike a wire grid polarizing plate, absorbs a polarized component that does not pass through. For example, the liquid crystal panel is heated or deteriorated by reflected light from the polarizing plate. In order to prevent this, it is used on the emission side of the liquid crystal panel.

  Polarizing plates made of these inorganic materials have been used as polarizing plates for liquid crystal projectors, which do not have the problem of characteristic deterioration due to heat resistance found in organic polarizing films, and are irradiated with strong lamp light.

Special table 2003-502708 gazette JP 2008-216956 A Japanese Patent Laid-Open No. 10-073722 JP 2006-126464 A

Although these inorganic polarizing plates do not contain organic material components that decompose at high temperatures, high heat resistance can be obtained, but polarizing films such as wire grids and fine particles on the substrate surface like wire grid polarizing plates and fine particle type polarizing plates. In a type in which is formed, depending on the polarizing film material, the characteristics may be deteriorated due to oxidation from the surface in a high humidity or high temperature environment. In order to prevent this, it is effective to coat a wire grid made of metal wires or metal fine particles with some protective film. As the protective film, an organic monomolecular layer, an oxide film such as SiO ₂ or Al ₂ O ₃ generally used as a barrier layer of a semiconductor device, or a nitride film such as SiN can be used.

Patent Document 3 describes that the reliability of the wire grid polarizer is improved by coating with a monolayer of a corrosion inhibitor composed of an aluminophosphonate of 10 nm or less. According to this, since the wire grid polarizing plate has a nano-level microstructure, if the materials and forming methods usually used for corrosion resistance are applied as they are, the optical characteristics may be significantly deteriorated. It is described that there is.

  Patent Document 4 describes that the environmental resistance of a wire grid polarizer is improved by covering the surface of Al constituting the wire grid. Although a surface thermal oxide film by heat treatment of Al is used here, this method has an advantage that the conductive base Al film necessary for electron beam drawing can be thermally oxidized together, and this portion can be made transparent. . Accordingly, it is also described that there is no need to remove the base film using etching, the lift-off method can be used as a patterning method, and the instability of the etching process can be avoided.

  As described above, it is generally recognized that wire grid polarizing plates and fine particle polarizing plates are coated with a protective film in order to enhance environmental resistance. However, when a fine structure exists on the surface, such as a wire grid or fine particles, even when the same material is used as the protective film, there is a problem that the effect of improving the reliability varies significantly depending on the formation method.

  Since the formation of such a protective film on the polarizing film is accompanied by deterioration of polarization characteristics, it is generally desirable to reduce the film thickness. However, since the influence of minute defects inherent in the protective film itself increases, there is a limit to reducing the thickness of the protective film, and the thickness is optimally determined within a range where the protective function does not deteriorate. For example, when a highly reactive material such as Ge is used as a polarizing material, an oxidation reaction may proceed from a pinhole or a minute defect portion of the protective film on the cut-out end face to deteriorate the polarization characteristics. In particular, when a foreign substance such as sebum is present on the defect, it may show significant deterioration. This alteration of the polarizing film tends to proceed along the grid in which the polarizing material is arranged due to the structure of the wire grid polarizing plate and the fine particle type polarizing plate, even if the defect itself is outside the effective range of the polarizing plate. The altered region may expand within the effective range over time.

  Such defects in the protective film include those that occur on the cut end face of the substrate in addition to those inherent in the film itself such as pinholes. When using a process that creates polarizing plates on a large wafer at the same time and separates them at the end for cost reduction, a part of the protective film formed on the polarizing film by dicing or scribing is used. It can be destroyed. Further, the cut end surface portion of the substrate has a high possibility of foreign matter adhering during handling and the like, and this is also one of the reasons that deterioration tends to proceed after the individual pieces.

  Then, an object of this invention is to provide the manufacturing method of a polarizing plate with high reliability also in high temperature and a high humidity environment.

  In order to solve the above-described problems, a method of manufacturing a polarizing plate according to the present invention includes a pattern for forming a grid on a base film formed on the entire surface of a wafer substrate, and the grid on a peripheral portion of the wafer substrate. Providing a resist having a pattern for forming a non-formed region, forming the grid and the non-formed region using the base film, and forming a protective film for protecting the grid and the non-formed region In the manufacturing method of a polarizing plate comprising: a cutting step of further obtaining a plurality of polarizing plates cut and solidified into a predetermined size by cutting in a non-forming region of the polarizing plate formed on the wafer substrate Have

  According to the present invention, since the region where the grid is not formed is provided in the peripheral portion of the substrate, the polarizing film does not deteriorate even when the protective film on the peripheral portion of the substrate is broken.

It is sectional drawing which shows a wire grid polarizing plate. It is sectional drawing which shows a fine particle type polarizing plate. It is a top view which shows a polarizing plate. It is a figure which shows the polarizing plate which permeate | transmitted light. It is a figure which shows the conventional polarizing plate which permeate | transmitted light. It is sectional drawing which shows the peripheral part of a board | substrate. It is a top view which shows another polarizing plate. It is a top view which shows another polarizing plate. It is a figure which shows the manufacturing process of a wire grid polarizing plate. It is a figure which shows the manufacturing process of a fine particle type polarizing plate.

  Hereinafter, a polarizing plate to which the present invention is applied and a method for producing the same will be described in detail with reference to the drawings. In the polarizing plate 1 to which the present invention is applied, for example, as shown in FIG. 1, a wire grid 3 made of fine metal wires having a pitch equal to or smaller than the wavelength of light is formed on a substrate 2. A wire grid polarizer 1A in which a protective film 4 is formed over the entire surface of the substrate 2, or a grid pattern 6 having a pitch less than the wavelength of light is formed on the substrate 5 as shown in FIG. In addition, a fine particle type polarizing plate 1B in which fine particles 7 are arranged on the grid pattern 6 via a metal layer 9 and a protective film 8 is formed over the entire surface of the substrate 5.

  As shown in FIG. 3, the polarizing plate 1 does not form a grid G in which a polarizing film such as fine particles 7 arranged on the wire grid 3 or the grid pattern 6 is formed on the periphery of the substrates 2 and 5. A region (hereinafter referred to as “non-forming region 10”) is provided. As a result, the polarizing plate 1 can be applied to the grid G from the peripheral portion of the substrates 2 and 5 even when defects occur in the protective films 4 and 8 formed on the peripheral portions of the substrates 2 and 5 due to cutting and separating. It is possible to avoid deterioration of the polarizing film traveling along.

  As the substrates 2 and 5 constituting the polarizing plates 1A and 1B, any optically transparent substrate such as glass can be used. In applications such as a liquid crystal projector, a substrate having high heat resistance and heat dissipation is often used in order to prevent the polarizing film from being destroyed by heat generated by absorption.

  For example, a quartz substrate not only has a higher thermal conductivity than glass, but also has the same composition as quartz glass, so it is convenient when etching the substrate itself to improve the optical properties of the polarizing plate. In the case of a sapphire substrate, it has excellent heat dissipation characteristics because it has a higher thermal conductivity than quartz, and even with the same cooling configuration, the substrate temperature can be kept lower than that of quartz, and the temperature of the optical system itself can be suppressed. There is an advantage that can be.

  For the polarizing film such as the fine particles 7 arranged on the wire grid 3 or the grid pattern 6, for example, in the case of the wire grid polarizing plate 1A, Al or AlSi can be used as a polarizing film material. There is no limit. On the other hand, Ge, Si, or the like is used in the case of the fine particle type polarizing plate 1B, but this is not limited to these materials.

  The non-formation region 10 is a region where the grid G on which the polarizing films on the peripheral portions of the substrates 2 and 5 are formed is not formed. For example, when the polarizing plate 1 is separated into pieces by cutting the wafer substrate after the protective films 4 and 8 are formed, a chipping region that is a minute chip of the substrates 2 and 5 may exist in the cut portion. . The protective films 4 and 8 are destroyed in a cutting region that occurs as a result of singulation and a chipping region adjacent to the cutting region.

  Therefore, the polarizing plate 1 is formed on the wire grid 3 or the grid pattern 6 even when the protective films 4 and 8 are broken by forming the non-formed region 10 at the peripheral edge where the protective films 4 and 8 are broken. The arranged fine particles 7 are prevented from being exposed to the outside, and the polarizing film can be prevented from being deteriorated.

  As shown in FIG. 4, the polarizing plate 1 provided with the non-formation region 10 in the peripheral portion does not show the discoloration of the polarizing film over the entire surface and is prevented from being deteriorated. On the other hand, as shown in FIG. 5, in the polarizing plate in which the grid G is formed up to the peripheral portion and the non-forming region 10 is not provided, streaks A starting from the peripheral portion are observed, and the polarizing film is deteriorated. I understand that. In FIG. 5, streaks B starting from foreign matters remaining on the substrate were also observed.

  Moreover, the non-formation area | region 10 has a width | variety far larger than the pitch of the grid G toward the inner side from the peripheral part of the board | substrates 2 and 5, Preferably it is 0.2 mm or more. This is because even when there is a lot of chipping, the possibility of deterioration of the polarizing film due to the destruction of the protective films 4 and 8 can be reduced. That is, the range in which chipping can occur is at most 0.1 mm from the cut surface toward the inside of the substrate, so that the non-formed region 10 is 0.2 mm from the peripheral edge of the substrates 2 and 5 toward the inside of the substrate. By providing the above, the polarizing film is not affected by chipping.

  In addition, the non-formation area | region 10 is formed to the range of 2 mm-3 mm toward the inner side from the peripheral part of the board | substrates 2 and 5. FIG. This is because the boundary of the effective area of the polarizing plate 1 on which the light beam is incident is often located at a position 2 mm to 3 mm from the edge of the substrate, so that the non-formed area 10 is 0.2 mm or more in width from the peripheral edge of the substrates 2 and 5. By providing in the range of 2 mm to 3 mm, it is possible to prevent the polarizing film from being deteriorated due to the destruction of the protective films 4 and 8 without reducing the effective area as the polarizing plate 1.

  Further, the non-forming region 10 is effective even when the protective films 4 and 8 are formed on the substrates 2 and 5 that have been separated into pieces in advance. That is, in the polarizing plate 1, defects are likely to occur in the vicinity of the peripheral portions of the substrates 2 and 5 due to disorder of the grid structure of the protective films 4 and 8 and disorder of the substrate shape. In addition, the polarizing plate 1 has a high possibility of foreign matter adhering to the vicinity of the periphery when the substrates 2 and 5 are handled, and the degree of deterioration given to the polarizing film even with a slight defect depending on the type of foreign matter and the type of polarizing film is low. May be large. For this reason, even if the polarizing plate 1 does not include a cutting step after the formation of the protective films 4 and 8 by providing the non-formation region 10 in which the grid G is not formed in the vicinity of the peripheral portions of the substrates 2 and 5, It has a great effect on improving reliability.

  Here, the non-formation region 10 means a region where a fine lattice-like pattern (grid G) is not formed. As shown in FIG. 6, a metal such as an Al film is interposed through the protective films 4 and 8. In addition to the case where the film 15 is exposed, the case where the flat surfaces of the substrates 2 and 5 are exposed as they are or the case where the flat film covering the surfaces of the substrates 2 and 5 is exposed is also included.

  When the grid G is a wire grid polarizing plate 1A formed of a metal material such as Al or a polarizing plate having a similar structure, the non-formed region 10 is in a state where the metal film 15 remains as it is. Become. In this case, the metal film in the non-formation region 10 optically functions as a reflection film or a light-shielding film, and the non-formation region 10 serves as a light-shielding portion.

  The non-forming region 10 is a region that does not function at all in terms of polarization characteristics. When the polarizing plate 1 is desired to have a large effective region, the non-forming region 10 is preferably small. Furthermore, when the light that has passed through this ineffective portion is adversely affected as leakage light, a light-shielding film (a film that shields part of it, such as a reflection film or an absorption film) is formed on this portion. Preferably, the metal film 15 formed in the non-forming region 10 is suitable for this purpose. On the other hand, in the case where the reflected film has an adverse effect, the light shielding film can be removed by etching so as to have transparency.

  Further, the protective film 4, 8 is formed on the polarizing plate 1 up to the non-formation region 10 at the periphery of the substrates 2, 5. If the protective film is formed except for the peripheral edge of the substrates 2 and 5 according to the region of the grid G where the fine particles 7 arranged on the wire grid 3 or the grid pattern 6 are formed, the protective film is formed. There is a possibility that the protective performance of the peripheral portion of the film region becomes insufficient due to the decrease in the film thickness. Therefore, the protective film is preferably formed larger than the formation region of the grid G, and is preferably formed on the entire surface of the substrate including the peripheral portion of the substrate.

  And since the protective films 4 and 8 are formed in the polarizing plate 1 to the non-formation area | region 10 of the peripheral part of the board | substrates 2 and 5, the protection performance of the microparticles | fine-particles 7 arranged on the wire grid 3 or the grid pattern 6 is provided. In addition, the defect of the protective films 4 and 8 at the peripheral portions of the substrates 2 and 5 does not overlap with the formation region of the fine particles 7 arranged on the wire grid 3 or the grid pattern 6, thereby affecting the protection performance. There is nothing.

  Moreover, the non-formation area | region 10 may be formed over the perimeter of the board | substrates 2 and 5, as shown in FIG. 3, and the direction of the wire grid 3 of the board | substrates 2 and 5 as shown in FIG. Or formed only on the sides 2A and 5A orthogonal to the arrangement direction of the fine particles 7, or as shown in FIG. 8, the sides 2A and 5A orthogonal to the direction of the wire grid 3 of the substrates 2 and 5 and the arrangement direction of the fine particles 7. The non-formation region 10 may be formed larger than the sides 2B and 5B parallel to the direction of the wire grid 3 and the arrangement direction of the fine particles 7.

  The deterioration of the polarizing film easily proceeds in the direction of the grid G along the wire grid 3 and the fine particles 7. Therefore, when the protective films 4 and 8 are broken at the cut end faces perpendicular to the direction of the wire grid 3 and the arrangement direction of the fine particles 7, the protection is performed at the cut end faces parallel to the direction of the wire grid 3 and the arrangement direction of the fine particles 7. Compared to the case where the films 4 and 8 are broken, there is a high possibility that the deterioration of the polarizing film spreads from the peripheral portions of the substrates 2 and 5 to the inside.

  Accordingly, the non-forming region 10 is formed only on the sides 2A and 5A orthogonal to the direction of the wire grid 3 and the arrangement direction of the fine particles 7, or the size of the orthogonal sides 2A and 5A is determined from the parallel sides 2B and 5B. Also, the polarizing plate 1 has a large deterioration in the polarizing film while keeping the effective area large with respect to the sides parallel to the direction of the wire grid 3 and the arrangement direction of the fine particles 7. It is possible to prevent the progression to 1 effective region and to secure the performance of the protective film.

  Next, a manufacturing method of the wire grid polarizer 1A will be described with reference to FIG. A plurality of wire grid polarizing plates 1A are formed on the wafer substrate 11 and then cut into pieces by cutting into a predetermined size. First, after forming an antireflection film (ARC) 12 on the back surface of the wafer substrate 11 (FIG. 9A), an Al thin film 13 is formed on the surface of the wafer substrate 11 by sputtering or the like (FIG. 9B). . Next, an antireflection film (BARC) and a chemical catalyst type photoresist are applied in this order by a spin coater. Next, after performing two-beam interference exposure using a DUV (far ultraviolet) laser and developing, a resist grid pattern having a predetermined pitch, width, and height is formed. At this time, a rectangular light-shielding aperture mask is provided on the surface of the wafer substrate 11, and a region that is not exposed at the time of two-beam interference exposure is formed in the peripheral portion of the substrate 2 formed on the wafer substrate 11 (FIG. 9C).

Next, in order to form an Al grid pattern by RIE etching, after first performing Al etching with Cl ₂ gas (FIG. 9D), the remaining resist is removed with Ar gas (FIG. 9E). Thereby, the wire grid 3 and the non-formation area | region 10 are formed in the peripheral part of each board | substrate 2. As shown in FIG. In FIG. 9E, the Al thin film is left in the non-formed region 10 to function as a light shielding portion, but the light shielding portion is not provided by removing the Al thin film in the non-formed region 10 in the Al etching process. You can also.

Next, a protective film 14 made of SiO ₂ or the like is formed on the entire surface of the wafer substrate 11 by chemical vapor deposition (CVD) or the like (FIG. 9F). Finally, the wire grid polarizing plate 1A formed on the wafer substrate 11 is cut into a predetermined size by a general-purpose glass scriber or the like and separated into individual pieces. Note that the wire grid polarizing plate 1 </ b> A may be divided into pieces before forming the protective film 14, and finally the protective film 14 may be formed. Moreover, you may form the wire grid polarizing plate 1A by giving the process mentioned above to the board | substrate 2 separated into pieces previously.

  Next, a manufacturing method of the particulate polarizing plate 1B will be described with reference to FIG. A plurality of fine particle type polarizing plates 1B are also formed on a wafer substrate 16 made of a quartz substrate or the like, and then cut into a predetermined size. First, after forming an antireflection film 17 on the back surface of the wafer substrate 16 (FIG. 10A), an Al thin film 18 is formed on the surface of the wafer substrate 16 by sputtering or the like (FIG. 10B). Next, an antireflection film and a chemical catalyst type photoresist are applied in this order by a spin coater. Next, after performing two-beam interference exposure using a DUV laser and developing, a resist grid pattern having a predetermined pitch, width, and height is formed. At this time, a rectangular light-shielding aperture mask is provided on the surface of the wafer substrate 16, and regions that are not exposed at the time of two-beam interference exposure are formed in each peripheral portion of the substrate 5 formed on the wafer substrate 16 (FIG. 10C). ).

Then, after performing Al etching with Cl ₂ gas ((FIG. 10D)), the remaining resist is removed with Ar gas (FIG. 10E). Here, the Al film partially functions as an etching mask, and as a result, the uneven grid pattern 6 having a predetermined pitch is formed on the quartz substrate. Further, it is not always necessary to provide an Al film on the grid pattern 6, and the Al film may be removed as appropriate. Fine particles 7 made of Ge or the like are formed on the substrate by sputtering (FIG. 10 (f)). Thereby, the grid G and the non-formation area | region 10 are formed in the peripheral part of each board | substrate 5. FIG. In FIG. 10E, the Al thin film is left in the non-formed region 10 to function as a light shielding portion. However, the light shielding portion is not provided by removing the Al thin film in the non-formed region 10 in the Al etching process. You can also.

Next, a protective film 19 made of SiO ₂ or the like is formed on the entire surface of the wafer substrate 16 by chemical vapor deposition (CVD) or the like. Finally, the particulate polarizing plate 1B formed on the wafer substrate 16 is cut into a predetermined size and separated into individual pieces (FIG. 10G). Also in the fine particle type polarizing plate 1B, the protective film 19 may be separated into pieces before forming the protective film 19, and finally the protective film 19 may be formed. Further, the above-described steps are performed on the substrate 5 that has been individually separated. May be formed.

Experimental example 1

  In Experimental Example 1, the change of the polarizing film was observed for the wire grid polarizing plate 1A provided with the non-forming region 10, the wire grid polarizing plate not provided with the non-forming region 10, and the wire grid polarizing plate not formed with the protective film. did.

In Experimental Example 1, an Al thin film having a thickness of 230 nm is formed on the surface of a 4-inch quartz substrate having an antireflection film (ARC) formed of a dielectric multilayer film on the back surface by a DC sputtering apparatus. Next, an antireflection film (BARC) having a thickness of 28 nm and a chemical catalyst type photoresist having a thickness of 230 nm are applied in this order by a spin coater. Next, after performing two-beam interference exposure using a DUV (far ultraviolet) laser and developing, a resist grid pattern having a pitch of 150 nm, a width of 70 nm, and a height of 180 nm is formed. Next, in order to form an Al grid pattern by RIE etching, Al etching with Cl ₂ gas was first performed, and then the remaining resist was removed with Ar gas. The wire grid polarizing plate formed on this 4-inch wafer was cut into a size of 25 mm × 25 mm with a general-purpose glass scriber to obtain Comparative Example 1.

In Comparative Example 1, a protective film made of SiO ₂ formed by chemical vapor deposition (CVD) with a thickness of about 20 nm was used as Comparative Example 2, and after the protective film was formed under the same conditions in the state of a 4-inch substrate before cutting. What was cut | disconnected by 25 mm x 25 mm with the scribe was made into the comparative example 3. Next, a comparative example 2 and a comparative example 3 are provided except that a square light-shielding aperture mask is provided on the substrate surface during interference exposure to form a 24.5 mm × 24.5 mm outside area that is not exposed and a non-formed area 10 is provided. Examples produced under the same conditions were designated as Example 1 and Example 2, respectively. The completed five types of wire grid polarizing plates were each left in an environment of 60 ° C. and 90% humidity for 100 hours to observe changes in the polarizing film.

  The results are shown in Table 1. In Comparative Example 1 in which the protective film was not formed, a slight unevenness of the polarizing film, which was considered to be caused by alteration such as Al surface oxidation, occurred on the entire surface of all the samples.

  Although the protective film is formed after the substrate is cut, in the comparative example 2 in which the wire grid is formed up to the peripheral portion of the separated substrate without providing the non-forming region 10 at the peripheral portion of the substrate, However, there was a sample in which a streak-colored region extending from the periphery of the substrate toward the center was observed. In Comparative Example 3 in which the wire grid was formed up to the periphery of the substrate without providing the non-formation region 10 at the periphery of the substrate, and the substrate was cut after forming the protective film, the number of samples in which the discoloration region was observed was compared. More than in Example 2. When Comparative Example 2 and Comparative Example 3 were evaluated for the polarization characteristics of the discoloration region, a part of the polarization component that should be reflected was transmitted, and deterioration of the polarization characteristics was observed.

  On the other hand, in Comparative Example 2 and Comparative Example 3 in which the protective film is provided and the non-formation region 10 is provided in the peripheral portion of the substrate, the protective film is formed before the substrate is cut. Regardless of whether or not it was later, no discoloration region or the like was observed over the entire surface including the center of the substrate and the peripheral edge of the substrate.

Experimental example 2

  In Experimental Example 2, the change of the polarizing film was observed for the fine particle type polarizing plate 1B provided with the non-formed region 10, the fine particle type polarizing plate not provided with the non-formed region 10, and the fine particle type polarizing plate not formed with the protective film. did.

In Experimental Example 2, an Al thin film is deposited by sputtering on the surface of a 25 mm square quartz substrate having an antireflection film (ARC) formed on the back surface by a dielectric multilayer film by sputtering. Next, an antireflection film (BARC) and a chemical catalyst type photoresist are applied in this order to a thickness of 28 nm and 230 nm, respectively, with a spin coater. Next, after performing two-beam interference exposure using a DUV (far ultraviolet) laser and developing, a resist grid pattern having a pitch of 150 nm, a width of 70 nm, and a height of 230 nm is formed. Thereafter, Al etching with Cl ₂ gas was performed, and then the remaining resist was removed with Ar gas. Here, the Al film partially functions as an etching mask, and as a result, an uneven grid pattern with a pitch of 150 nm is formed on the quartz substrate. Comparative Example 4 of a fine particle type polarizing plate was obtained by forming Ge fine particles on this substrate by sputtering. Next, Comparative Example 5 was obtained by forming a protective film made of SiO ₂ with a thickness of about 20 nm by chemical vapor deposition (CVD).

  Further, a light-shielding mask was provided on the entire surface of the substrate during interference exposure, and an unexposed area of about 1 mm from the end was formed only in the direction orthogonal to the grid, and the non-formed area 10 was provided, and the same conditions as in Comparative Example 5 were provided. This was designated as Example 3. As an extreme example that occurs during handling of these three types of fine particle type polarizing plates, ten sheets of artificially adhered sebum on the four surfaces around the substrate are each in an environment with a temperature of 60 ° C. and a humidity of 90%. For 100 hours, and the change in polarization characteristics was observed.

  The results are shown in Table 2. In Comparative Example 4 in which no protective film was formed, Ge oxidation occurred on the entire substrate surface and the polarizing film was completely transparent for all samples. In Comparative Example 5 in which the protective film is formed but the non-formation region 10 is not provided and the grid is also formed in the peripheral portion of the substrate, there is no discoloration or characteristic deterioration in the center of the substrate, but the substrate moves from the periphery to the center. There was a sample in which a streak-like discolored region extending was observed. When the polarization characteristics of the discoloration region were evaluated, a part of the polarization component that should be reflected and absorbed was transmitted, and deterioration of the polarization characteristics was observed.

  On the other hand, compared with Comparative Example 5, in Example 3 where the protective film was provided and the non-formed region 10 was provided in the vicinity of the side orthogonal to the grid pattern, no discoloration region or omission occurred around the substrate. .

  In Comparative Example 5, since there is no cutting treatment after the formation of the protective film, this deterioration is not due to partial destruction of the protective film due to the cutting, but any alteration of the polarizing film by sebum from the protective film defect portion present at the substrate edge. It is thought that the phenomenon progressed along the grid pattern. From the results of Example 3, in the non-formation region 10 where the grid pattern is not formed, the progress of deterioration along the grid pattern does not occur regardless of such a defect of the protective film, so that a sufficient protection function is maintained. it seems to do.

  As described above, in the wire grid polarizing plate and the fine particle type polarizing plate, when the non-formation region 10 in which the grid is not formed is provided in the vicinity of the substrate end, the polarizing film is not deteriorated and is excellent in the high humidity test. It has been verified that it has high reliability.

  The present invention is not limited to the wire grid polarizing plate 1A and the fine particle type polarizing plate 1B described here, but may be a device that depends on polarized light having a fine grid and a structure similar to the grid. But it can be applied. In this case, the fine grid is assumed to have a structure with an uneven cross section mainly having a pitch of about ½ or less of the wavelength used. The cross-sectional shape of the grid is appropriately determined within a range having a desired polarization characteristic, but when the “concave / convex depth / pitch” is 1/2 or more, it is suitable for producing a good polarization characteristic.

  DESCRIPTION OF SYMBOLS 1 Polarizing plate, 1A Wire grid polarizing plate, 1B Fine particle type polarizing plate, 2 Substrate, 3 Wire grid, 4 Protective film, 5 Substrate, 6 Grid pattern, 7 Fine particle, 8 Protective film, 9 Antireflection film, 10 Non-formation region 11 Wafer substrate, 12 Antireflection film, 13 Al thin film, 14 Protective film, 16 Wafer substrate, 17 Antireflection film, 18 Al thin film, 19 Grid pattern, 20 Ge fine particle, 21 Protective film

Claims (9)

A resist having a pattern for forming a grid and a pattern for forming a non-formation region not forming the grid on the peripheral edge of the wafer substrate is provided on the base film formed on the entire surface of the wafer substrate, and the base film is used. Forming the grid and the non-forming region;
In the manufacturing method of a polarizing plate provided with the process of forming the protective film which protects the grid and the non-formation region,
Furthermore, the manufacturing method of the polarizing plate which has the cutting process which obtains several polarizing plates cut | disconnected by the predetermined magnitude | size by cut | disconnecting in the non-formation area | region of the said polarizing plate formed on the said wafer substrate.   The method for producing a polarizing plate according to claim 1, wherein the cutting step is performed before the step of forming the protective film.   The method for producing a polarizing plate according to claim 1, wherein the cutting step is performed after the step of forming the protective film.   The manufacturing method of the polarizing plate of any one of Claims 1-3 in which the light-shielding part is formed in the said non-formation area | region.   The said non-formation area | region is a manufacturing method of the polarizing plate of any one of Claims 1-4 provided 0.2 mm or more toward the inner side from the peripheral part of the said wafer substrate.   The said non-formation area | region is a manufacturing method of the polarizing plate of Claim 5 provided from the peripheral part of the said wafer substrate to the position of 2-3 mm. The wafer substrate is formed in a substantially rectangular shape,
The said non-formation area | region is a manufacturing method of the polarizing plate of any one of Claims 1-6 provided in the peripheral part of the side substantially orthogonal to the longitudinal direction of the said grid of the said wafer substrate.   Furthermore, the said non-formation area | region is a manufacturing method of the polarizing plate of Claim 7 provided in the peripheral part of the side substantially parallel to the longitudinal direction of the said grid of the said wafer substrate.   The non-formation region provided in the peripheral portion of the side substantially orthogonal to the longitudinal direction of the grid is formed larger than the non-formation region provided in the peripheral portion of the side substantially parallel to the longitudinal direction of the grid. The method for producing a polarizing plate according to claim 8.