JP2014180768A - Method for manufacturing mold for antiglare process - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a mold for an antiglare process, by which a high precision pattern can be transferred by exposure in a general-purpose apparatus configuration that can be easily handled.SOLUTION: The method for manufacturing a mold for an antiglare process includes: a photosensitive resin layer forming step of forming a photosensitive resin layer on a mold base material; an exposure step of exposing the photosensitive resin layer so as to project an image of a pattern on an exposure mask onto the surface of the photosensitive resin layer by using a projection exposure apparatus which holds the exposure mask having a reverse Fourier transform image preliminarily formed therein and which includes a light source and a projection optical system, and further moving an exposure position on the surface of the photosensitive resin layer so as to repeat the exposure in an area not subjected to the exposure; a developing step of developing the photosensitive resin layer to obtain the photosensitive resin layer with an opening pattern formed therein; and a first etching step of etching the surface of the mold base material by using the photosensitive resin layer with the opening pattern formed therein as a mask.

Description

  The present invention relates to a method for manufacturing a mold for anti-glare treatment.

  In an image display device such as a liquid crystal display, a plasma display panel, a cathode ray tube (CRT) display, an organic electroluminescence (EL) display, and the like, when external light is reflected on the display surface, visibility is significantly impaired. Conventionally, in order to prevent such reflection of external light, display is performed using a television or personal computer that emphasizes image quality, a video camera or digital camera that is used outdoors with strong external light, and reflected light. In a mobile phone or the like, a process for preventing external light from being reflected on the surface of the image display device is performed. The processing performed on the surface of such an image display device includes antireflection processing using interference by the optical multilayer film and prevention of blurring the reflected image by scattering incident light by forming fine irregularities on the surface. It is roughly divided into dazzling treatment. The former non-reflective treatment increases the cost because it is necessary to form a multilayer film having a uniform optical film thickness. On the other hand, since the latter anti-glare treatment can be performed relatively inexpensively, it is widely used for applications such as large personal computers and monitors.

  The antiglare treatment of the image display device is typically performed by bonding an antiglare film with antiglare properties to the surface of the image display device. Antiglare films are generally produced by forming fine irregularities on the surface.

  As a method of forming irregularities on the surface of the antiglare film, for example, a method of coating the surface with a particle dispersion, a method of forming irregularities on the surface by sandblasting, a laser drawing apparatus, a laser processing apparatus, a precision lathe, etc. And a method of directly processing fine irregularities on the surface of the substrate film, and a method of producing a mold having fine irregularities on the surface and transferring the irregular surface of the mold to a transparent substrate. In particular, the method of transferring the concave / convex surface of the mold to the transparent substrate is advantageous in that it has excellent accuracy and reproducibility when forming fine irregularities on the transparent substrate, and is excellent in productivity.

  In the production of such an antiglare film, as a mold (antiglare mold) used when performing an antiglare treatment for forming irregularities on the surface of a transparent substrate, for example, provided on the side surface of a cylinder An anti-glare mold for use in a roll-to-roll process, in which irregularities are formed on the obtained copper plating layer, can be mentioned. As a method for manufacturing such a mold for anti-glare treatment, Patent Document 1 (Japanese Patent Application Laid-Open No. 2011-118327) discloses that a photosensitive resin on a mold is exposed by a laser direct drawing apparatus, and a resist work is used. A method for producing an anti-glare mold is disclosed.

  However, since the laser direct drawing apparatus requires a special spatial light modulator, the exposure wavelength is limited. For this reason, infrared lasers and the like are widely used. However, since infrared has a long wavelength, it is difficult to expose a high-definition pattern required for a high-definition display device due to a lack of resolution (resolution).

  In addition, in order to modulate the light intensity at high speed, know-how such as noise countermeasures is necessary for handling the electric signal for driving the modulator.

  In addition, when the laser direct drawing apparatus is of a multi-channel type (laser array type), it is necessary to keep the emitted light intensity at the time of exposure with one element one element in order to realize uniform exposure, but adjustment is difficult. Since exposure unevenness occurs due to insufficient stability of exposure intensity, there is a problem that it is difficult to expose a high-definition pattern. On the other hand, when the laser direct drawing apparatus is of a single beam type, uniform exposure can be realized, but there is a problem that the exposure time is remarkably long and sufficient productivity cannot be secured.

JP 2011-118327 A

  An object of the present invention is to provide a method for manufacturing a mold for anti-glare processing, which enables exposure of a high-definition pattern with a general-purpose apparatus configuration that can be handled easily.

The present invention includes a photosensitive resin layer forming step of forming a photosensitive resin layer on a mold base material;
The exposure mask on which the inverse Fourier transform image is printed is held, and the pattern on the exposure mask is formed on the surface of the photosensitive resin layer by using a projection exposure apparatus having a light source and a projection optical system. An exposure step of exposing the photosensitive resin layer, further moving the projection position on the surface of the photosensitive resin layer, and repeating the exposure in a range where the exposure is not performed;
A development step of developing the photosensitive resin layer to obtain the photosensitive resin layer in which an opening pattern is formed;
And a first etching step of etching the surface of the mold base material using the photosensitive resin layer having an opening pattern as a mask.

  Preferably, the manufacturing method further includes a second etching step of removing the photosensitive resin layer and etching the surface of the mold base material after the first etching step.

  In the present invention, by using an exposure mask on which an inverse Fourier transform image is printed, a projection exposure apparatus having a simpler mechanism than that of a conventional laser direct drawing apparatus or the like can be used, and it can be handled more easily than the conventional method. High-definition pattern exposure is possible with a general-purpose apparatus configuration that can be used.

  An exposure mask printed with an inverse Fourier transform image is a general-purpose exposure mask used in semiconductor manufacturing processes, etc., and using such a general-purpose product, a high-definition pattern can be easily exposed on a photosensitive resin. Can do.

  By using a projection exposure apparatus, it is not necessary to handle electrical signals that require know-how to handle such as driving an optical modulator at high speed, and high-definition patterns can be easily exposed.

  Since the transmittance of the transparent portion of the exposure mask can be easily made uniform, uniform pattern exposure can be easily realized by irradiating the exposure mask with a known uniform illumination means such as Koehler illumination.

It is a schematic cross section for demonstrating the manufacturing method of the metal mold | die for a glare-proof process. It is another schematic cross section for demonstrating the manufacturing method of the metal mold | die for glare-proof processing.

(Anti-glare mold)
The antiglare film is a transparent film having predetermined fine irregularities formed on the surface for the purpose of reducing the reflection definition of the surface, and is used in a display device, particularly a liquid crystal display. As one method for producing an antiglare film, there is a method of producing a mold having fine irregularities on the surface and transferring the irregular surface of the mold to a transparent substrate. The “antiglare mold” is a mold used for an antiglare treatment for forming irregularities on the surface of a transparent substrate when producing such an antiglare film. On the surface of the mold for anti-glare treatment, an uneven shape is formed by inverting the uneven shape formed on the surface of the transparent substrate. In recent years, with the increase in devices equipped with display devices with higher definition (about 300 ppi) than conventional devices such as smartphones, it has been desired to realize an anti-glare treatment with a finer uneven shape. The antiglare treatment realized by the mold has an advantage that the definition can be controlled by the processing pattern.

<Exposure mask>
The exposure mask is a translucent member on which a pattern that limits the light irradiation range is drawn, and is also called a photomask. The exposure mask used in the present invention is an exposure mask obtained by printing an inverse Fourier transform image. The inverse Fourier transform image is an image obtained by subjecting a pattern in which a plurality of dots are randomly arranged (random dot pattern) or a pattern in which a brightness distribution is arranged to Fourier transform and further inverse Fourier transform. “Pattern” means an image, image data, a two-dimensional array of discretized information, or an array of openings arranged on a plate.

  Examples of exposure masks include chrome masks and emulsion masks, and companies such as Toppan Printing Co., Ltd., Dai Nippon Printing Co., Ltd., Mitani Micronics Co., Ltd. manufacture exposure masks according to customer request patterns. ing. In the present invention, an exposure mask obtained by printing an inverse Fourier transform image on an exposure mask by a manufacturer can be used. In the present invention, a chrome mask can be suitably used as the exposure mask. This is because an exposure mask can be manufactured with higher definition than an emulsion mask.

(Fourier transform)
The Fourier transform is a method of converting into a frequency domain function. In the present invention, Fourier transform is used as a mathematical method for generating a light / dark pattern of a mask.

  Since the pattern handled in the present invention cannot always be handled by an appropriate function, a discrete Fourier transformation (hereinafter referred to as DFT) that can be numerically calculated using a computer can be suitably used.

  The DFT is defined by Equation (1).

According to Equation (1), Nx complex sequences F (u) are obtained for Nx complex sequences f (x). In Equation 1, e is the number of Napiers, j is an imaginary unit (j ² = −1), and π is a circular ratio.

  In the method of giving a light / dark pattern, for example, a numerical value representing lightness is substituted for the real part of the complex number f (x), and zero is given to the imaginary part. This is an example, and a numerical value representing lightness may be given to the imaginary part, or a complex number sequence representing lightness change may be obtained by other methods.

  Equation (1) is an equation that defines a one-dimensional DFT and must be expanded to two dimensions to be applied to a pattern. Equation (2) is an equation that defines a two-dimensional DFT.

The two-dimensional complex number sequence F (u, v) is obtained for the two-dimensional complex number sequence f (x, y) by the mathematical formula (2). In Equation 2, e is a Napier number, j is an imaginary unit (j ² = −1), and π is a circumference ratio.

  DFT has a huge amount of calculation. For this reason, in order to perform processing at higher speed, various algorithms collectively referred to as Fast Fourier Transform (FFT) may be used. As a typical FFT algorithm, for example, there is a Cooley-Tukey type algorithm. In this algorithm, Nx and Ny are limited to powers of 2, unlike the case of calculating with equations (1) and (2), but the amount of calculation is reduced compared to the case of calculating equations (1) and (2). Widely used.

(Inverse Fourier transform)
The inverse Fourier transform is a mathematical technique for obtaining a function expressed with a spatial coordinate as a variable from a function expressed with a frequency as a variable. In the present invention, since the pattern to be handled is not always expressed by a function, an inverse discrete Fourier transform (hereinafter abbreviated as “IDFT”) that can be calculated numerically is preferably used. it can. IDFT is defined by Equation (3).

By Expression (3), Nx complex sequences f (x) are obtained for Nx complex sequences F (u). In Equation 1, e is the number of Napiers, j is an imaginary unit (j ² = −1), and π is a circular ratio.

  Since the pattern has a two-dimensional brightness distribution, processing in two dimensions is necessary. The two-dimensional IDFT is defined by Equation (4).

The two-dimensional complex number sequence f (x, y) is obtained with respect to the two-dimensional complex number sequence F (u, v) by the equation (4). In Equation (4), e is the number of Napiers, j is an imaginary unit (j ² = −1), and π is a circumference ratio.

(Inverse Fourier transform image)
Formula (4) is a form in which f (x, y) is obtained by multiplying a periodic function whose phase is the same by the number of elements Nx, Ny in the sequence and multiplying this by a complex coefficient F (u, v). taking it. That is, f (x, y) obtained by inverse transformation can be connected with the same value at both ends of the array. Therefore, it has a feature suitable for manufacturing a mold for anti-glare treatment using a projection exposure apparatus, in which small unit patterns are arranged without gaps so that a continuous pattern can be formed. With this feature, even with a small-sized mask having a projection area of about 8 mm × 1 mm, a pattern can be formed without a seam that allows the entire display device to be visually observed by performing multiple exposures.

  Since f (x, y) is obtained as a complex number, it is necessary to use lightness information (real number) of the exposure mask. A means often used is a method in which an absolute value of a complex number sequence f (x, y) is a real number sequence I (x, y) representing lightness. Furthermore, since the light shielding part and the transmission part are formed on the exposure mask, it is necessary to binarize the real number sequence I (x, y). As a binarization method for the exposure pattern of the anti-glare processing mold, for example, a method disclosed in Patent Document 1 (Japanese Patent Application Laid-Open No. 2011-118327) can be used.

<Manufacturing method of mold>
Below, an example of the manufacturing method of the metal mold | die for anti-glare processing of this invention is demonstrated. FIG. 1 is a schematic cross-sectional view showing a preferred example of the first half of a method for manufacturing a mold. FIG. 2 is a schematic cross-sectional view showing a preferred example of the latter half of the method for manufacturing a mold. In addition, the manufacturing method of the metal mold | die for anti-glare processing demonstrated below is [1] 1st plating process, [2] Polishing process, [3] Photosensitive resin layer formation process, [4] Exposure process, [5] A development step, [6] a first etching step, and [7] a photosensitive resin layer peeling step are included in this order. Hereafter, each process of the manufacturing method of the metal mold | die of this invention is demonstrated in detail, referring FIG. 1, FIG.

[1] First Plating Step First, a die base material is obtained by performing copper plating or nickel plating on the surface of a substrate (mold substrate) used for a mold. Thus, by performing copper plating or nickel plating on the surface of the mold base, it is possible to improve the adhesion and gloss of chromium plating in the subsequent second plating step. In other words, when chrome plating is applied to the surface of iron or the like, or when chrome plating is applied again after forming irregularities on the chrome plating surface by the sandblasting method or the bead shot method, the surface tends to be rough and fine cracks occur. This makes it difficult to control the uneven shape on the surface of the mold. On the other hand, such inconvenience can be eliminated by first performing copper plating or nickel plating on the substrate surface. This is because copper plating or nickel plating has a high covering property and a strong smoothing action, so that a flat and glossy surface is formed by filling minute irregularities and voids of the mold base. is there. Due to these copper plating or nickel plating characteristics, even if chrome plating is applied in the second plating step, which will be described later, the rough surface of the chrome plating that appears to be caused by minute irregularities and voids that existed on the substrate is eliminated. In addition, the occurrence of fine cracks is reduced due to the high coverage of copper plating or nickel plating.

  The copper or nickel used in the first plating step may be a pure metal, or may be an alloy mainly composed of copper or an alloy mainly composed of nickel. “Copper” means to include copper and copper alloy, and “nickel” means to include nickel and nickel alloy. Copper plating and nickel plating may be performed by electrolytic plating or electroless plating, respectively, but electrolytic plating is usually employed.

  When copper plating or nickel plating is performed, if the plating layer is too thin, the influence of the underlying surface cannot be completely eliminated. Therefore, the thickness is preferably 50 μm or more. Although the upper limit of the plating layer thickness is not critical, the upper limit of the plating layer thickness is preferably about 500 μm in view of cost and the like.

  Examples of the metal material suitably used for forming the mold base include aluminum and iron from the viewpoint of cost. From the viewpoint of handling convenience, it is more preferable to use lightweight aluminum. The aluminum and iron here may be pure metals, respectively, or may be an alloy mainly composed of aluminum or iron.

  Moreover, the shape of the mold base material may be an appropriate shape conventionally employed in the field, and may be, for example, a plate-like shape, a columnar shape, or a cylindrical roll. If a die is produced using a roll-shaped substrate, there is an advantage that the anti-glare treatment can be continuously performed and the anti-glare film can be produced in a continuous roll shape.

[2] Polishing Step In the polishing step, the surface of the substrate that has been subjected to copper plating or nickel plating in the first plating step described above is polished. It is preferable that the base material surface is grind | polished in the state close | similar to a mirror surface through the said process. This is because metal plates and metal rolls that serve as base materials are often subjected to machining such as cutting and grinding in order to achieve the desired accuracy, and as a result, machine marks remain on the base material surface. This is because even if copper plating or nickel plating is applied, those processed marks may remain, and the surface may not be completely smooth in the plated state. That is, even if a process described later is performed on the surface where such deep processed marks remain, unevenness such as processed marks may be deeper than the unevenness formed after each process is performed. Such effects may remain, and when an antiglare treatment is performed using such a mold or an antiglare film is produced, the optical characteristics may be unexpectedly affected. In FIG. 1 (a), the mold base 1 is subjected to copper plating or nickel plating on the surface in the first plating step (the copper plating or nickel plating layer formed in the step is not shown). Furthermore, the state made to have the surface 11 further mirror-polished by the grinding | polishing process is shown typically.

  There is no particular limitation on the method for polishing the surface of the substrate on which copper plating or nickel plating has been applied, and any of mechanical polishing, electrolytic polishing, and chemical polishing can be used. Examples of the mechanical polishing method include super finishing, lapping, fluid polishing, and buff polishing. As for the surface roughness after polishing, the center line average roughness Ra in accordance with the provisions of JIS B 0601 is preferably 0.1 μm or less, and more preferably 0.05 μm or less. If the centerline average roughness Ra after polishing is greater than 0.1 μm, the final unevenness of the mold surface may remain affected by the surface roughness after polishing. In addition, the lower limit of the center line average roughness Ra is not particularly limited, and there is no limit in particular because there is a natural limit from the viewpoint of processing time and processing cost.

[3] Photosensitive resin layer forming step In the photosensitive resin layer forming step, as a solution obtained by dissolving the photosensitive resin in a solvent on the polished surface 11 of the mold base material 1 that has been mirror-polished by the polishing step described above. The photosensitive resin layer is formed by coating, heating and drying. FIG. 1B schematically shows a state in which the photosensitive resin layer 2 is formed on the polished surface 11 of the mold base material 1.

  A conventionally known photosensitive resin can be used as the photosensitive resin. Examples of the negative photosensitive resin having a property of curing the photosensitive part include, for example, a monomer or prepolymer of an acrylate ester having an acrylic group or a methacrylic group in the molecule, a mixture of bisazide and a diene rubber, polyvinyl Cinnamate compounds and the like can be used. Further, as a positive photosensitive resin having such a property that a photosensitive part is eluted by development and only an unexposed part remains, for example, a phenol resin type or a novolac resin type can be used. Moreover, you may mix | blend various additives, such as a sensitizer, a development accelerator, an adhesiveness modifier, and a coating property improving agent, with a photosensitive resin as needed. Since photosensitive resins corresponding to each exposure wavelength such as ultraviolet rays, visible rays, and infrared rays are developed and sold by various companies, they can be selected according to the required resolution.

  When these photosensitive resins are applied to the polished surface 11 of the mold base material 1, it is preferable to dilute and apply in an appropriate solvent in order to form a good coating film. As the solvent, cellosolve solvents, propylene glycol solvents, ester solvents, alcohol solvents, ketone solvents, highly polar solvents, and the like can be used.

  As a method for applying the photosensitive resin solution, known methods such as meniscus coating, fountain coating, dip coating, spin coating, roll coating, wire bar coating, air knife coating, blade coating, and curtain coating may be used. it can. The thickness of the coating film is preferably in the range of 1 to 6 μm after drying.

[4] Exposure Step In the exposure step, the pattern on the exposure mask on which the inverse Fourier transform image is baked is formed on the surface of the photosensitive resin layer 2 formed in the photosensitive resin layer formation step. The photosensitive resin layer is exposed. The exposure is performed using a projection exposure apparatus that holds an exposure mask and includes a light source and a projection optical system. Further, the projection position is moved on the surface of the photosensitive resin layer 2, and the exposure is repeated in a range where the exposure is not performed.

  FIG. 1C schematically shows a state in which the pattern is exposed to the photosensitive resin layer 2. When the photosensitive resin layer is formed of a negative photosensitive resin, the exposed region 21 undergoes a crosslinking reaction of the resin by exposure, and the solubility in a developing solution described later decreases. Therefore, the unexposed area 22 in the developing process is dissolved by the developer, and only the exposed area 21 remains on the substrate surface as a mask. On the other hand, in the case where the photosensitive resin layer is formed of a positive photosensitive resin, the exposed region 21 is cut by the bond of the resin by the exposure, and the solubility in the developer described later increases. Therefore, the area 21 exposed in the developing process is dissolved by the developer, and only the unexposed area 22 remains on the substrate surface as a mask.

(Projection exposure equipment)
The projection exposure apparatus is an apparatus that projects a pattern on an exposure mask onto the surface of a photosensitive resin layer via a projection optical system. The projection exposure apparatus is preferably a reduced projection exposure apparatus that projects an exposure mask pattern on the surface of the photosensitive resin layer through a lens system. As the reduction projection exposure apparatus, various known apparatuses can be used (see, for example, JP-A-1-54205 and JP-A-63-100722). Reduction projection exposure apparatuses are manufactured and sold by Nikon Engineering Co., Ltd. and Canon Inc., for example.

  The light source used in the exposure process may be appropriately selected according to the photosensitive wavelength and sensitivity of the coated photosensitive resin. For example, the g-line (wavelength: 436 nm) of the high-pressure mercury lamp, the h-line (wavelength: 405 nm) of the high-pressure mercury lamp. ), I-line (wavelength: 365 nm), high-pressure mercury lamp, semiconductor laser (wavelength: 830 nm, 532 nm, 488 nm, 405 nm, etc.), YAG laser (wavelength: 1064 nm), KrF excimer laser (wavelength: 248 nm), ArF excimer laser (wavelength) 193 nm), F2 excimer laser (wavelength: 157 nm), or the like. From the viewpoint of designing the optical system of the exposure projection apparatus, the light source wavelength is preferably in a wavelength range in which general BK7 or synthetic quartz can be used as the material of the optical lens. The specific wavelength of the light source is preferably 200 to 2000 nm, and more preferably 350 to 440 nm from the viewpoint of availability and resolution of the light source and the optical lens. In the exposure projection apparatus, the degree of freedom of light source selection is higher than in a laser direct drawing apparatus, and by selecting a light source with a shorter wavelength, the exposure resolution becomes higher, so that exposure of a higher definition pattern becomes possible. .

(Projection position moving means)
Since the projection position of the pattern projected onto the surface of the photosensitive resin layer 2 using the exposure projection device is usually a part of the photosensitive resin layer 2 on the mold base material 1, It is necessary to move the projection position on the surface and repeat the exposure in a range where the exposure is not performed. In order to move the projection position, the exposure apparatus may be moved, or the projection position may be relatively moved by moving the mold base 1. When the exposure apparatus is moved, a linear actuator equipped with a linear encoder can be suitably used. Commercially available from various companies, for example, GLM series sold by THK Corporation.

  When the mold base 1 is columnar or cylindrical, it is preferable to move the projection position by rotating the mold base 1 about its axis. As a means for rotating the mold base 1, a servo motor or a stepping motor can be used. In the present invention, a step-less backlashless geared stepping motor can be preferably used. An example of such a motor is AR98AA-H100-3 sold by Oriental Motor Co., Ltd.

[5] Development Step In the development step, when a negative photosensitive resin is used for the photosensitive resin layer 2, the unexposed area 22 is dissolved by the developer, and only the exposed area 21 is molded. And remains as a mask in the subsequent first etching step. On the other hand, when a positive photosensitive resin is used for the photosensitive resin layer 2, only the exposed region 21 is dissolved by the developer, and the unexposed region 22 remains on the mold base. It acts as a mask in the subsequent first etching step.

  A conventionally well-known thing can be used about the developing solution used for a image development process. For example, inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, primary amines such as ethylamine and n-propylamine, diethylamine, di-n-butylamine and the like Secondary amines, tertiary amines such as triethylamine, methyldiethylamine, alcohol amines such as dimethylethanolamine, triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, trimethylhydroxyethylammonium hydroxide, etc. Examples include alkaline aqueous solutions such as quaternary ammonium salts, cyclic amines such as pyrrole and piperidine; and organic solvents such as xylene and toluene.

  The development method in the development step is not particularly limited, and methods such as immersion development, spray development, brush development, and ultrasonic development can be used.

  FIG. 1D schematically shows a state in which a development process is performed using a negative photosensitive resin for the photosensitive resin layer 2. In FIG. 1C, the unexposed area 22 is dissolved by the developer, and only the exposed area 21 becomes the remaining mask 3 on the substrate surface. FIG. 1E schematically shows a state in which a development process is performed using a positive photosensitive resin for the photosensitive resin layer 2. In FIG. 1C, the exposed region 21 is dissolved by the developer, and only the unexposed region 22 remains on the substrate surface as the mask 3.

[6] First Etching Step In the first etching step, the mold base material mainly in the absence of the mask is used by using the photosensitive resin layer remaining on the mold base surface after the development step as a mask. Are etched to form irregularities on the polished plated surface. FIG. 2 is a diagram schematically showing a preferred example of the latter half of the method for producing a mold of the present invention. FIG. 2A schematically shows a state in which the mold base material 1 mainly in a portion 12 without a mask is etched by the first etching process. Although the mold base material 1 below the mask 3 is not etched from the surface of the mold base, the etching from the portion 12 without the mask proceeds with the progress of etching. Therefore, in the vicinity of the boundary between the mask 3 and the portion 12 without the mask, the mold base material 1 below the mask 3 is also etched. Etching the mold base material 1 below the mask 3 in the vicinity of the boundary between the mask 3 and the portion 12 without the mask is called side etching.

  The etching process in the first etching step usually involves corroding the metal surface using ferric chloride (FeCl3) solution, cupric chloride (CuCl2) solution, alkaline etching solution (Cu (NH3) 4Cl2), etc. However, a strong acid such as hydrochloric acid or sulfuric acid can be used, or reverse electrolytic etching by applying a potential opposite to that during electrolytic plating can be used. The concave shape formed on the mold base material when the etching process is performed differs depending on the type of the base metal, the type of the photosensitive resin layer, the etching technique, and the like. In the following cases, the etching is performed isotropically from the metal surface in contact with the etching solution. The etching amount here is the thickness of the base material to be cut by etching.

  The etching amount in the first etching step is preferably 1 to 50 μm. When the etching amount is less than 1 μm, the unevenness shape is hardly formed on the metal surface, and the die is almost flat, so that the antiglare property is not exhibited. In addition, when the etching amount exceeds 50 μm, the height difference of the concavo-convex shape formed on the metal surface becomes large, and in the image display device to which the antiglare film produced using the obtained mold is applied, it is white. There is a risk of injury. The etching process in the first etching step may be performed by one etching process, or the etching process may be performed twice or more. In the case where the etching process is performed twice or more, the total etching amount in the two or more etching processes is preferably 1 to 50 μm.

[7] Photosensitive resin layer peeling step In the subsequent photosensitive resin layer peeling step, the remaining photosensitive resin layer used as a mask in the first etching step is completely dissolved and removed. In the photosensitive resin layer peeling step, the photosensitive resin layer is dissolved using a peeling solution. As the stripper, the same developer as that described above can be used. When a negative photosensitive resin layer is used by changing pH, temperature, concentration, immersion time, etc., the exposed portion is exposed. When the positive type photosensitive resin layer is used, the photosensitive resin layer in the non-exposed portion is completely dissolved and removed. There is no particular limitation on the peeling method in the photosensitive resin layer peeling step, and methods such as immersion development, spray development, brush development, and ultrasonic development can be used.

  FIG. 2B schematically shows a state in which the photosensitive resin layer used as the mask 3 in the first etching process is completely dissolved and removed by the photosensitive resin layer peeling process. A surface irregularity shape 13 is formed on the surface of the mold substrate by etching using the mask 3 made of a photosensitive resin layer.

[8] Second Etching Step In the mold manufacturing method of the present invention, after the above-described [7] photosensitive resin layer peeling step, the uneven surface formed by the first etching step is further blunted by an etching process. It is preferable to include a second etching step. In the second etching step, the surface uneven shape 13 formed by the first etching step using the photosensitive resin layer as a mask is blunted by an etching process. By this second etching process, there is no portion with a steep surface inclination in the surface uneven shape 13 formed by the first etching process, and an anti-glare process such as an anti-glare film manufactured using the obtained mold is performed. The optical properties of the transparent substrate thus made change in a preferred direction.

Similarly to the first etching process, the etching process of the second etching process is usually ferric chloride (FeCl ₃ ) liquid, cupric chloride (CuCl ₂ ) liquid, alkaline etching liquid (Cu (NH ₃ ) ₄ Cl ₂ ) or the like, and by corroding the surface, strong acid such as hydrochloric acid or sulfuric acid can be used, or reverse electrolytic etching by applying a potential opposite to that during electrolytic plating can also be used. The bluntness of the unevenness after the etching process varies depending on the type of the underlying metal, the etching technique, and the size and depth of the unevenness obtained by the first etching process. The largest factor in controlling the amount is the etching amount. The etching amount here is also the thickness of the base material to be cut by etching, as in the first etching step. If the etching amount is small, the effect of dulling the surface shape of the unevenness obtained by the first etching step is insufficient, and the antiglare treatment obtained by transferring the uneven shape onto a transparent substrate such as a transparent film The optical properties of the applied transparent substrate (such as an antiglare film) are not so good. On the other hand, when the etching amount is too large, the uneven shape is almost lost and the die is almost flat, so that the antiglare property is not exhibited. Therefore, the etching amount is preferably in the range of 1 to 50 μm, and more preferably in the range of 4 to 20 μm. Similarly to the first etching process, the etching process in the second etching process may be performed by one etching process, or the etching process may be performed twice or more. In the case where the etching process is performed twice or more, the total etching amount in the two or more etching processes is preferably 1 to 50 μm.

  EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

<Example 1>
(Photosensitive resin layer forming step)
First, the photosensitive resin layer is formed on the mold base material by applying a negative photosensitive resin whose cross-linking reaction proceeds with i-line to a 200 mm diameter copper plating roll (mold base material) and drying. To do. At this time, the thickness after drying is set to about 2 μm.

(Exposure process)
Next, a chrome mask having a pattern region size of 40 mm × 5 mm is prepared. In the pattern area of the chrome mask, an inverse Fourier transform image is printed with a dot size of 10 μm. For the exposure mask, based on the real number sequence I (x, y) obtained from the absolute value of the complex number sequence f (x, y), a threshold is set so that the aperture ratio is 0.5, and the light shielding portion and the transmission portion And this is printed as an inverse Fourier transform image.

  Using this chrome mask as an exposure mask, it is held in a projection exposure apparatus having a reduction projection optical system with NA (numerical aperture) of 0.45 and 1/5 magnification, and exposure is performed with a light source having a peak wavelength of 365 nm.

  At this time, the size of the pattern projected on the resist exposure surface is 8 mm × 1 mm. On the projection plane, the side of 8 mm is made parallel to the axis of the copper plating roll (die base material). This is because the depth of focus of the reduction projection optical system is about 1.8 μm, and exposure is performed so as to be within the focus depth range on the curved surface of the cylinder (copper plating roll). The difference in height of the roll surface in the exposure surface is about 1 μm. When the photosensitive resin has been irradiated with the prescribed light amount, the shutter is closed to stop projection, and the exposure apparatus is moved 8 mm in the axial direction of the roll to perform exposure again. When the exposure in the width direction is completed, the roll is rotated so that the projection position on the roll moves 1 mm, and exposure is performed in the same manner.

(Development process)
After exposure to a desired area is completed, development is performed with a developer designated by the photosensitive resin to form an opening in the photosensitive resin layer.

(First etching process)
Etching is performed using a cupric chloride aqueous solution through the photosensitive resin layer having the opening. The etching depth is 5 μm.

(Second etching process)
Next, after all the photosensitive resin layer is removed, etching using a cupric chloride aqueous solution is performed. The etching depth is 8 μm.

  Then, in order to provide hardness, a 4 μm-thick chromium plating process is performed to manufacture an anti-glare mold.

  According to the present invention, it becomes possible to expose a photosensitive resin with a uniform strength, and it is possible to manufacture a mold for anti-glare treatment in which a pattern seam is hardly visible.

  DESCRIPTION OF SYMBOLS 1 Mold base material, 11 Surface, 12 Location without mask, 13 Surface uneven | corrugated shape, 2 Photosensitive resin layer, 21 Exposed area | region, 22 Unexposed area | region, 3 Mask

Claims (2)

A photosensitive resin layer forming step of forming a photosensitive resin layer on the mold base material;
The exposure mask on which the inverse Fourier transform image is printed is held, and the pattern on the exposure mask is formed on the surface of the photosensitive resin layer by using a projection exposure apparatus having a light source and a projection optical system. An exposure step of exposing the photosensitive resin layer, further moving the projection position on the surface of the photosensitive resin layer, and repeating the exposure in a range where the exposure is not performed;
A development step of developing the photosensitive resin layer to obtain the photosensitive resin layer in which an opening pattern is formed;
And a first etching step of etching the surface of the mold base material with the photosensitive resin layer having an opening pattern formed as a mask.   2. The antiglare treatment mold according to claim 1, further comprising a second etching step of removing the photosensitive resin layer and etching the surface of the mold base material after the first etching step. Production method.

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