JP2007072171A - Pattern exposure method and apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pattern exposure method and an apparatus for forming a pattern periodical along a conveying direction in a flexible form with a high throughput in a simple equipment with suppressed equipment investment. <P>SOLUTION: A belt-like work 11 having a photosensitive layer formed thereon is conveyed in a work conveying direction F at a work conveying velocity V. An illumination unit 30 illuminates a photomask 29 in an exposure cycle period T synchronizing the work conveying velocity V. The photomask 29 is disposed leaving a proximity gap with respect to the belt-like work 11, and a mask pattern 33 is transferred by exposure as a periodical pattern onto the belt-like work 11. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a pattern exposure method and apparatus, and more particularly to a pattern exposure method and apparatus for exposing a periodic pattern to a strip-shaped workpiece being conveyed.

  As a thin and large screen image display device, a plasma display panel (hereinafter abbreviated as “PDP”) is widely used. In this PDP, an electromagnetic wave shield is provided on the front surface of the panel in order to prevent electromagnetic waves generated from the panel body. Electromagnetic wave shields include metal thin films formed on surface glass and electromagnetic wave shielding films placed on the front of the panel.Currently, electromagnetic wave shielding films with high electromagnetic wave shielding characteristics and light transmittance are the mainstream. It has become. The electromagnetic wave shielding film is a film in which fine metal wires are formed in a lattice shape (mesh shape) on a transparent film.

  A conventional electromagnetic wave shielding film is formed by bonding a transparent film and a metal foil, and photoetching the metal foil to form a metal mesh. On the other hand, the present applicant has developed an electromagnetic wave shielding film in which a fine mesh is formed of silver salt on a transparent film using silver salt photography technology. This electromagnetic wave shielding film can draw a free mesh pattern, and can flexibly respond to the specifications of the panel such as size and definition. In addition, since a complicated and poor yield process of bonding a transparent film and a metal foil is unnecessary, cost reduction and stable supply are possible.

  The electromagnetic wave shielding film irradiates a silver salt sensitive material coated on a transparent film with light through a mask to expose a mesh-like pattern, and develops this to form a silver salt on the transparent film. A mesh is formed. Since the mesh pitch and the line thickness greatly affect the image quality of the PDP, it is desired to expose precisely.

Conventionally, in order to form a light shielding pattern such as a color filter for various display devices and a color pattern, pattern exposure is performed by irradiating light on a work having a photosensitive layer through a mask to expose the pattern on the work. A method and an apparatus have been used, and it was examined whether or not the method and apparatus could be applied to an exposure process of an electromagnetic wave shielding film. For example, in the pattern exposure method described in Patent Document 1, a belt-like workpiece is continuously conveyed, and the pattern is exposed by irradiating light onto the belt-like workpiece through a mask during the conveyance. Further, in the proximity exposure apparatus described in Patent Document 2, positioning, gap setting, and proximity exposure are repeated while the belt-like workpiece is conveyed intermittently to expose the pattern on the belt-like workpiece.
JP 09-274323 A JP 10-171125 A

  However, the pattern exposure method described in Patent Document 1 can only expose a striped pattern parallel to the transport direction of the belt-like workpiece, and has a flexible shape and a periodic pattern in the transport direction, for example, an electromagnetic shield film. The mesh pattern cannot be exposed.

  In addition, the proximity exposure apparatus described in Patent Document 2 can cope with any pattern, not limited to a periodic pattern. However, the accumulated exposure time for each step of positioning, gap setting, and exposure for a fixed time is large during intermittent conveyance. There is a problem that processing capacity (throughput) per hour is low.

  In order to solve the above problems, the present invention provides a pattern exposure method and apparatus capable of forming a periodic pattern in a conveying direction with a flexible shape with a high throughput and a simple facility with reduced capital investment. The purpose is to do.

  In order to solve the above-described problems, the pattern exposure method of the present invention continuously conveys a strip-shaped or sheet-shaped workpiece having a photosensitive layer, and through a photomask arranged with a proximity gap to the workpiece, Proximity exposure is periodically performed for an exposure time ΔT, and a mask pattern provided on the photomask is exposed to a work as a periodic pattern in the transport direction.

In addition, a periodic length of the periodic pattern in the workpiece conveyance direction is defined as a periodic length L ₀ , a workpiece width orthogonal to the workpiece conveyance direction is defined as a workpiece width W _0, and a pattern provided with the mask pattern of the photomask When the length of the area in the workpiece conveyance direction is the pattern length L and the width in the workpiece width direction is the pattern width W, L ₀ <L and W ₀ <W, the workpiece conveyance speed is V, and the periodic pattern Is at least one cycle of the photomask, satisfying L ₀ / V> = T and V · ΔT <Dmin, where T is the exposure cycle for exposure, ΔT is the exposure time, and Dmin is the minimum line width of the mask pattern. Proximity exposure is performed on the exposure area covering the entire area of the mask pattern for the exposure time ΔT for each exposure period T through the photomask.

Further, the light of the exposure light source projected onto the photomask satisfies Lb> L ₀ when the length in the workpiece conveyance direction is Lb, and the quotient of Lb / L ₀ is m (m is a natural number). When a photomask having m or more mask patterns provided in the workpiece conveyance direction is used, the relationship between the workpiece conveyance speed V and the exposure cycle T is (n−1) × (L ₀ / V) = T (n is (Natural number) and 2 = <n <= m, and when the most upstream mask pattern in the workpiece conveyance direction is the first mask pattern, the workpiece is exposed once through the first mask pattern. When the upper latent image pattern passes through the nth mask pattern arranged on the downstream side of the first mask pattern, the workpiece conveyance speed V and the exposure cycle T are synchronized with each other over the nth mask pattern. Multiple exposure is performed.

  The exposure amount at the time of multiple exposure is preferably an exposure amount at which a photosensitive density cannot be obtained by at least one exposure and a desired photosensitive density can be obtained by n multiple exposures.

  Further, it is preferable that the exposure light source exposes the entire width of the workpiece through the photomask by scanning light from one direction in the workpiece width direction during the exposure period T. As the exposure light source, for example, a semiconductor laser is used, and exposure is preferably performed by collimated light obtained by collimating the laser through a lens. Furthermore, two semiconductor lasers are used for polarization multiplexing and collimation, or a plurality of semiconductor lasers are used, and these lasers are individually collimated through a lens. The exposure may be performed with light integrated. The wavelength of the semiconductor laser is preferably about 405 nm in accordance with the sensitive material.

  Furthermore, the speed at which the light from the exposure light source is scanned is the exposure scanning speed Vb, and the amount of the work transported during one scan is (W / Vb) · V. Tilt to

  Further, the exposure light source may be configured such that the exposure amount is constant over the entire width of the workpiece by changing the light amount according to the change in the scanning speed.

  Further, when the proximity gap is Lg, the mask pattern may be formed to be shifted inward by Lg · sin θ in the workpiece width direction in accordance with the change in the incident angle θ of the light from the exposure light source.

  Further, the slit width of the mask pattern may be changed in the scanning width direction so that the line width of the periodic pattern exposed to the workpiece becomes uniform.

  Further, when the length in the workpiece width direction projected onto the photomask is Lw without using scanning light, Lw> W, and the entire width of the workpiece is exposed through the photomask for a set fixed time. An exposure light source may be used.

  Further, the proximity gap is preferably 500 μm or less.

  The photosensitive layer may be a silver salt sensitive material or a photoresist. The silver salt sensitive material preferably has a gradation γ (horizontal axis: light quantity-vertical axis: gradient of density characteristic) of 5 or more.

  The periodic pattern is preferably a seamless pattern that is continuously seamless. Furthermore, it is more suitable for exposure of a periodic pattern having a line width of 20 μm or less. As such a product, it is suitable for producing an electromagnetic shielding material.

  Proximity exposure is preferably performed through a photomask disposed on the outer periphery of the roller in a state where the belt-like workpiece is wound around the roller.

  Furthermore, it is preferable to always monitor the synchronized state between the workpiece conveyance state and the exposure light source state, and not to perform exposure in the asynchronous state.

  In addition, when the belt-shaped workpiece is transported, when the joint portion where the ends of the two belt-shaped workpieces are bonded passes through the vicinity of the photomask, the photomask is released from the workpiece, and after passing, the reproducibility is maintained. Return to the proximity gap.

  In addition, the pattern exposure apparatus of the present invention includes a transport unit that continuously transports a belt-shaped or sheet-shaped workpiece having a photosensitive layer at a workpiece transport speed V, and a photomask that is disposed with a proximity gap Lg therebetween. Illuminating means for performing proximity exposure by irradiating light to the work in the entire width direction perpendicular to the transport direction for each exposure period T through this photomask, work transport speed V, and exposure period And a control means for synchronizing the exposure time ΔT and the mask pattern provided on the photomask is exposed to the workpiece as a periodic pattern periodic in the transport direction.

In addition, a periodic length of the periodic pattern in the workpiece conveyance direction is defined as a periodic length L ₀ , a workpiece width orthogonal to the workpiece conveyance direction is defined as a workpiece width W _0, and a pattern provided with the mask pattern of the photomask When the length of the area in the workpiece conveyance direction is the pattern length L and the width in the workpiece width direction is the pattern width W, L ₀ <L and W ₀ <W. Furthermore, it is preferable that L ₀ / V> = T and V · ΔT <Dmin when the minimum line width of the mask pattern is Dmin.

Further, the photomask is formed by providing a plurality of identical periodic mask patterns in the pattern length L direction. Furthermore, when the length of the light of the exposure light source projected onto the photomask in the workpiece transport direction is Lb, Lb> L ₀ and Lb / L ₀ quotient is m (m is a natural number). , M or more mask patterns are provided in the workpiece conveyance direction.

Further, the control unit satisfies the relationship between the work conveyance speed V and the exposure cycle T such that (n−1) × (L ₀ / V) = T (n is a natural number) and 2 = <n <= m. When the first upstream mask pattern in the workpiece conveyance direction is synchronized to be the first mask pattern, the latent image pattern on the workpiece once exposed through the first mask pattern is the first mask pattern. When passing through the nth mask pattern arranged on the downstream side, the workpiece conveyance speed V and the exposure cycle T are synchronized, and multiple exposure is performed over the nth mask pattern.

  The exposure amount at the time of multiple exposure is such that a photosensitive density cannot be obtained by at least one exposure, but a desired photosensitive density can be obtained by n multiple exposures.

  As the illumination means, an exposure light source that irradiates light toward the photomask, and the light of the exposure light source is scanned from one direction in the workpiece width direction during the exposure period T, and the entire width of the workpiece is exposed through the photomask. And a scanning means.

  The exposure light source may be composed of a semiconductor laser output unit and a collimating lens that collimates the laser beam output from the semiconductor laser output unit to produce parallel light. Also, two systems of semiconductor laser output units, an optical member that polarizes and combines the laser beams output from these semiconductor laser output units, and a collimator that collimates the polarized and combined laser beams into parallel light You may comprise from a lens. Alternatively, a plurality of semiconductor laser output units, a plurality of collimating lenses that collimate the laser beams output from these semiconductor laser output units individually into parallel beams, and a plurality of optical members that integrate the respective parallel beams You may comprise. The output wavelength of the semiconductor laser is preferably 405 nm.

  The scanning means comprises a polygon mirror provided with a plurality of reflecting surfaces for reflecting the light from the exposure light source and irradiating the photomask, and a driving means and a control means for rotating the polygon mirror.

  Further, the light amount of the exposure light source may be changed by the control means in accordance with the change in the scanning speed, and the exposure amount may be adjusted to be constant over the entire width of the workpiece.

  Further, the speed at which the light of the exposure light source is scanned by the scanning means is the exposure scanning speed Vb, and the photomask is moved by the amount (W / Vb) · V that is the amount that the workpiece is conveyed during one scan. You may incline with respect to a workpiece conveyance direction.

  Further, the mask pattern may be formed so as to be shifted inward by Lg · sin θ in the workpiece width direction in accordance with a change in the incident angle θ of light from the exposure light source. Furthermore, the slit width of the mask pattern may be changed in the scanning width direction so that the line width of the periodic pattern exposed to the workpiece is uniform.

The illuminating means may be composed of an exposure light source having an irradiation range of Lw> W, where Lw is the length of light projected onto the photomask in the workpiece width direction.
May be used.

  In addition, it is preferable that a roller around which the belt-shaped workpiece is wound is provided, and the photomask is arranged on the outer periphery of the roller with a proximity gap Lg.

  It is preferable that the control unit constantly monitors the synchronized state between the workpiece transfer unit and the illumination unit, and does not irradiate light from the illumination unit when in the asynchronous state.

  Furthermore, a holding frame that holds the photomask, an exposure position where the photomask held by the holding frame faces the workpiece with a proximity gap therebetween, and a gap that is separated from the workpiece by the proximity gap or more. Provided with a mask holding means comprising a support part for movably supporting the holding frame between a retracted position where the holding frame is formed and a driving part for moving the holding frame between the exposure position and the retracted position. is there. In addition, the holding frame is provided with an adjustment unit that adjusts the proximity gap by moving the photomask in a direction toward and away from the workpiece.

  According to the present invention, since the exposure can be performed while continuously conveying the workpiece, the productivity is improved. Moreover, since it can be realized with simple equipment, capital investment can be suppressed. Further, the light source luminance distribution can be averaged by multiple exposure and scanning exposure, and a uniform line width can be realized. Moreover, since exposure is possible even if the light source intensity is small by multiple exposure, the cost is low. Furthermore, because of the proximity exposure using a photomask, a high-definition pattern can be written, and the area is small, it is easy to use, it can be used multiple times by shifting the position, and the running cost is low, so the cost performance is good. . Furthermore, in order to write a seamless pattern, the joints between patterns can be easily aligned by performing multiple exposure with continuous feeding.

  In addition, in the case of multiple exposure with continuous feeding, it is possible to design so that a latent image can be formed only at a place where many overlaps are made, so that the portion subjected to blur exposure can be designed so that there is insufficient exposure and no image. As a result, blurring has no effect on quality and does not trade off the productivity of continuous feed exposure.

  1 and 2 are a plan view and a sectional view of an electromagnetic wave shielding film formed by the pattern exposure method and apparatus of the present invention. The electromagnetic wave shielding film 2 includes a transparent film 3 and a mesh-like electromagnetic wave shielding pattern 4 formed on the transparent film 3 with a silver salt. The electromagnetic wave shielding pattern 4 includes a periodic pattern 5 formed of a silver salt on the transparent film 3 and a copper plating 6 which is applied to the surface of the periodic pattern 5 and imparts an electromagnetic wave shielding function. As shown in a partially enlarged view in FIG. 1B, in the periodic pattern 5, for example, thin lines having a line width Wp = 10 to 20 μm are orthogonal to each other with a line pitch P = 300 μm and an arrangement angle θp = 45 °. Are arranged as follows.

  FIG. 3 is a schematic diagram showing the configuration of a pattern exposure apparatus used when forming the periodic pattern 5. The pattern exposure apparatus 10 includes a workpiece supply unit 12 that supplies a strip-shaped workpiece 11 serving as a base of the transparent film, and an exposure unit 13 that exposes the shape of the periodic pattern 5 on a silver salt sensitive material provided on the strip-shaped workpiece 11. And a work take-up unit 14 for winding the exposed belt-like workpiece 11, a rear end of the belt-like workpiece 11 that has been previously processed when processing a plurality of belt-like workpieces 11 continuously, and a subsequent belt-like shape. A workpiece joining portion 15 to which the tip of the workpiece 11 is joined, and a control portion 16 for comprehensively controlling them are provided. The belt-like workpiece 11 having the shape of the periodic pattern 5 exposed is developed in the next step to form a silver salt periodic pattern 5 on one surface. Thereafter, the periodic pattern 5 is subjected to copper plating and cut into predetermined lengths, whereby the electromagnetic wave shielding film 2 is obtained.

The periodic pattern 5 is a lattice-like pattern arranged obliquely. However, when the periodic pattern 5 is viewed as a pattern in the transport direction of the strip-shaped workpiece 11, a rhombus having one side of 300 μm and a diagonal of 424 μm is transported. The pattern is arranged in the width direction orthogonal to the. At this time, the cycle length L ₀ which is the length of one cycle of the cycle pattern 5 is 424 μm.

As shown in FIGS. 4A and 4B, which are a plan view and a cross-sectional view of the strip-shaped workpiece 11, the strip-shaped workpiece 11 includes a long film 20 that is a base material of the transparent film 3, and the long film. It consists of a silver salt sensitive material 21 applied on the film 20. The long film 20 is, for example, a transparent PET film having a thickness t ₁ = 100 μm and a work width W ₀ = 650 to 750 mm, and a film having a length of 100 to 1000 m is wound into a roll and is fed to the work supply unit 12. Set to The belt-like workpiece 11 set in the workpiece supply unit 12 is pulled out at its tip, is hooked on a plurality of rollers, and is locked to the winding reel 24 of the workpiece winding unit 14. The belt-like workpiece 11 is wound from the workpiece supply unit 12 to the workpiece winding unit 24 by rotating the winding reel 24 serving as a conveying unit, the exposure roller 28, and a plurality of drive rollers (not shown) in the winding direction by the motor group 25. The workpiece is conveyed along the workpiece conveyance direction F toward the picking section 14. The workpiece conveyance speed V of the strip-shaped workpiece 11 is, for example, 4 m / min, and an optimum value is designed for the workpiece conveyance speed V according to the sensitivity of the photosensitive material and the power of the exposure light source.

  The silver salt sensitive material 21 is designed with a sensitive material having central sensitivity in a wavelength region of 405 nm, for example. The photosensitive material spectral sensitivity characteristic is not limited to the above design, and the center wavelength may be any design, but it is necessary to match both in relation to the light source wavelength. A silver salt sensitive material having a large γ as the exposure amount / density characteristic is used. This is a so-called high-sensitive material in which the density change does not change gently according to the exposure amount, but the density changes at a stroke when the exposure amount exceeds a certain exposure amount.

Hereinafter, a conductive metal film-forming photosensitive material that is the silver salt sensitive material 21 of the belt-like workpiece 11 used in the present invention, and a light-transmitting electromagnetic wave shielding film that is an electromagnetic wave shielding film 2 formed using this photosensitive material. Will be described in detail.
In the present specification, “to” is used as a meaning including numerical values described before and after the lower limit value and the upper limit value.

1. Photosensitive material for forming conductive metal film [emulsion layer]
The light-sensitive material according to the present invention has an emulsion layer (silver salt-containing layer) containing a silver salt emulsion as a photosensor on a support. The swelling ratio of the emulsion layer is 150%. In the present invention, the swelling rate is defined as follows.
Swell rate (%) = 100 × ((b) − (a)) / (a)
In the above formula, (a) shows the film thickness of the emulsion layer at the time of drying, and (b) shows the film thickness of the emulsion layer after being immersed in distilled water at 25 ° C. for 1 minute.
The emulsion layer thickness (a) can be measured, for example, by observing the cross section of the sample with a scanning electron microscope. The film thickness (b) of the emulsion layer after swelling can be measured by observing the sample cross section after lyophilizing the swollen sample with liquid nitrogen using a scanning electron microscope.

In the present invention, the swelling ratio of the emulsion layer of the light-sensitive material needs to be 150% or more, but the swelling ratio in a preferred range depends on the Ag / binder ratio of the emulsion layer. That is, since the binder part in the film can swell but the silver halide grains do not swell, even if the swelling ratio of the binder part is the same, the higher the Ag / binder ratio, the lower the swelling ratio of the whole emulsion layer. is there. In the present invention, the preferred swelling ratio of the emulsion layer is 250% or more when the Ag / binder ratio of the emulsion layer is 4.5 or less, and when the Ag / binder ratio of the emulsion layer is 4.5 or more and less than 6. When the Ag / binder ratio of the emulsion layer is 6 or more, it is 150% or more. In the case of an Ag / binder ratio of 6 to 10 which is the most preferable range of Ag / binder ratio of the present invention, the swelling ratio of the emulsion layer is preferably 150% or more, and more preferably 180% or more.
In the present invention, there is no upper limit on the swelling rate, but if the swelling rate is too high, the film strength during processing decreases and the membrane is liable to be damaged. Therefore, the swelling rate is preferably 350% or less. The swelling ratio of the emulsion layer can be controlled by the addition amount of the hardener, the pH of the emulsion layer after coating, and the water content.

  In addition to the silver salt emulsion, the emulsion layer can contain a dye, a binder, a solvent, and the like, if necessary. Hereinafter, each component contained in the emulsion layer will be described.

<Silver salt emulsion>
Examples of the silver salt emulsion used in the present invention include inorganic silver salts such as silver halide and organic silver salts such as silver acetate. For the silver salt emulsion, it is preferable to use a silver halide having excellent characteristics as an optical sensor. Techniques used in silver halide photographic films, photographic papers, printing plate-making films, emulsion masks for photomasks, etc. relating to silver halide can also be used in the present invention.

  The halogen element contained in the silver halide may be any of chlorine, bromine, iodine and fluorine, or a combination thereof. For example, silver halide mainly composed of AgCl, AgBr, and AgI is preferably used, and silver halide mainly composed of AgBr or AgCl is preferably used. Silver chlorobromide, silver iodochlorobromide and silver iodobromide are also preferably used. More preferred are silver chlorobromide, silver bromide, silver iodochlorobromide and silver iodobromide, and most preferred are silver chlorobromide and silver iodochlorobromide containing 50 mol% or more of silver chloride. Used.

  Here, “silver halide mainly composed of AgBr (silver bromide)” refers to silver halide in which the molar fraction of bromide ions in the silver halide composition is 50% or more. The silver halide grains mainly composed of AgBr may contain iodide ions and chloride ions in addition to bromide ions.

  The silver iodide content in the silver halide emulsion is preferably 1.5 mol% per mole of silver halide emulsion. By setting the silver iodide content to 1.5 mol%, fogging can be prevented and pressure characteristics can be improved. A more preferred silver iodide content is 1 mol% or less per mole of silver halide emulsion.

Silver halide is in the form of solid grains. From the viewpoint of image quality of the patterned metallic silver layer formed after exposure and development, the average grain size of silver halide is 0.1 to 1000 nm in terms of sphere equivalent diameter ( 1 μm) is preferred, 0.1 to 100 nm is more preferred, and 1 to 50 nm is even more preferred.
Incidentally, the sphere equivalent diameter of silver halide grains is the diameter of grains having the same volume and a spherical shape.

The shape of the silver halide grains is not particularly limited, and may be various shapes such as a spherical shape, a cubic shape, a flat plate shape (hexagonal flat plate shape, triangular flat plate shape, tetragonal flat plate shape, etc.), octahedron shape, and tetrahedron shape. There can be a cube and a tetrahedron.
The silver halide grains may be composed of a uniform phase or a different surface layer. Moreover, you may have the localized layer from which a halogen composition differs in a particle | grain inside or the surface.

  Silver halide emulsions are described by P. Glafkides, Chimie etPhysique Photographique (Paul Montel, 1967), GF Dufin, Photographic Emulsion Chemistry (The Forcal Press, 1966), VLZelikman et al, Making and Coating Photographic Emulsion ( The Forcal Press (1964) can be used.

That is, as a method for preparing a silver halide emulsion, either an acidic method or a neutral method may be used. As a method for reacting a soluble silver salt with a soluble halogen salt, a one-side mixing method, a simultaneous mixing method, or the like. Any combination of these may be used.
As a method for forming silver particles, a method of forming particles in the presence of excess silver ions (so-called back mixing method) can also be used. Furthermore, as one type of the simultaneous mixing method, a method of keeping pAg in a liquid phase where silver halide is generated, that is, a so-called controlled double jet method can be used.
It is also preferable to form grains using a so-called silver halide solvent such as ammonia, thioether or tetrasubstituted thiourea. A tetrasubstituted thiourea compound is more preferable as such a method, and is described in JP-A-53-82408 and JP-A-55-77737. Preferred thiourea compounds include tetramethylthiourea and 1,3-dimethyl-2-imidazolidinethione. The addition amount of the silver halide solvent varies depending on the type of compound used, the target grain size, and the halogen composition, but is preferably 10 ⁻⁵ to 10 ⁻² mol per mol of silver halide.
In the controlled double jet method and the grain forming method using a silver halide solvent, it is easy to prepare a silver halide emulsion having a regular crystal type and a narrow grain size distribution, and is preferably used in the present invention. it can.

Further, in order to make the grain size uniform, as described in British Patent No. 1,535,016, Japanese Patent Publication No. 48-36890, and Japanese Patent Publication No. 52-16364, silver nitrate or halogenated A method of changing the alkali addition rate according to the particle growth rate, or a method of changing the concentration of the aqueous solution as described in British Patent No. 4,242,445 and JP-A-55-158124 It is preferable to grow silver quickly in a range not exceeding the critical saturation.
The silver halide emulsion is preferably a monodispersed emulsion, and the coefficient of variation represented by {(standard deviation of grain size) / (average grain size)} × 100 is 20% or less, more preferably 15% or less, and most preferably 10 % Or less is preferable.
The silver halide emulsion may be a mixture of a plurality of types of silver halide emulsions having different grain sizes.

The silver halide emulsion may contain a metal belonging to Group VIII or VIIB. In particular, in order to achieve high contrast and low fog, it is preferable to contain a rhodium compound, an iridium compound, a ruthenium compound, an iron compound, an osmium compound, or the like. These compounds may be compounds having various ligands. Examples of such ligands include cyanide ions, halogen ions, thiocyanate ions, nitrosyl ions, water, hydroxide ions, and such pseudohalogens. In addition to ammonia, organic molecules such as amines (methylamine, ethylenediamine, etc.), heterocyclic compounds (imidazole, thiazole, 5-methylthiazole, mercaptoimidazole, etc.), urea, thiourea and the like can be mentioned.
In order to increase sensitivity, K ₄ [Fe (CN) ₆ ], K ₄ [Ru (CN) ₆ ], K ₃ [Cr
Doping of a metal hexacyanide complex such as (CN) ₆ ] is advantageously performed.

A water-soluble rhodium compound can be used as the rhodium compound. Examples of the water-soluble rhodium compound include a rhodium (III) halide compound, a hexachlororhodium (III) complex salt, a pentachloroacorodium complex salt, a tetrachlorodiacolodium complex salt,
Examples include hexabromorhodium (III) complex salts, hexaaminerhodium (III) complex salts, trizalatrdium (III) complex salts, and K ₃ Rh ₂ Br ₉ .
These rhodium compounds are used by dissolving in water or a suitable solvent, and are generally used in order to stabilize the rhodium compound solution, that is, an aqueous hydrogen halide solution (for example, hydrochloric acid, odorous acid, hydrofluoric acid). Or a method of adding an alkali halide (for example, KCl, NaCl, KBr, NaBr, etc.) can be used. Instead of using water-soluble rhodium, it is also possible to add another silver halide grain previously doped with rhodium and dissolve it at the time of silver halide preparation.

Examples of the iridium compound include hexachloroiridium complex salts such as K ₂ IrCl ₆ and K ₃ IrCl ₆ , hexabromoiridium complex salts, hexaammineiridium complex salts, and pentachloronitrosyliridium complex salts.
Examples of the ruthenium compound include hexachlororuthenium, pentachloronitrosylruthenium, K ₄ [Ru (CN) ₆ ] and the like.
Examples of the iron compound include potassium hexacyanoferrate (II) and ferrous thiocyanate.

The ruthenium and osmium are added in the form of water-soluble complex salts described in JP-A-63-2042, JP-A-1-2855941, JP-A-2-20852, JP-A-2-20855, etc. Preferable examples include hexacoordination complexes represented by the following formula.
[ML ₆ ] ^-n
(Here, M represents Ru or Os, and n represents 0, 1, 2, 3 or 4.)
In this case, the counter ion is not important, and for example, ammonium or alkali metal ions are used. Preferred ligands include halide ligands, cyanide ligands, cyanide oxide ligands, nitrosyl ligands, thionitrosyl ligands, and the like. Although the example of the specific complex used for this invention below is shown, this invention is not limited to this.

[RuCl ₆ ] ⁻³ , [RuCl ₄ (H ₂ O) ₂ ] ⁻¹ , [RuCl ₅ (NO)] ⁻² , [RuBr ₅ (NS)] ⁻² , [Ru (CO) ₃ Cl ₃ ] ^{− 2} , [Ru (CO) Cl ₅ ] ⁻² , [Ru (CO)
Br ₅ ] ⁻² , [OsCl ₆ ] ⁻³ , [OsCl ₅ (NO)] ⁻² , [Os (NO) (CN) ₅ ] ⁻² , [Os (NS) Br ₅ ] ⁻² , [Os ( CN) ₆ ] ⁻⁴ , [Os (O) ₂ (CN) ₅ ] ⁻⁴ .

The amount of these compounds added is preferably 10 ⁻¹⁰ to 10 ⁻² mol / mol Ag per mol of silver halide, more preferably 10 ⁻⁹ to 10 ⁻³ mol / mol Ag.

In addition, in the present invention, silver halide containing Pd (II) ions and / or Pd metal can also be preferably used. Pd may be uniformly distributed in the silver halide grains, but is preferably contained in the vicinity of the surface layer of the silver halide grains. Here, Pd “contains in the vicinity of the surface layer of the silver halide grains” means that the Pd content is higher than the other layers within 50 nm in the depth direction from the surface of the silver halide grains. means.
Such silver halide grains can be prepared by adding Pd in the course of forming silver halide grains. After adding silver ions and halogen ions to 50% or more of the total addition amount, Pd Is preferably added. It is also preferred that Pd (II) ions be present in the surface layer of the silver halide by a method such as addition at the time of post-ripening.
The Pd-containing silver halide grains increase the speed of physical development and electroless plating, increase the production efficiency of a desired electromagnetic shielding material, and contribute to the reduction of production costs. Pd is well known and used as an electroless plating catalyst. However, in the present invention, Pd can be unevenly distributed on the surface layer of silver halide grains, so that extremely expensive Pd can be saved. is there.

The content of Pd ions and / or Pd metal contained in the silver halide is preferably 10 ^{−4 to} 0.5 mol / mol Ag with respect to the number of moles of silver in the silver halide, More preferably, it is -0.3 mol / mol Ag.
Examples of the Pd compound to be used include PdCl ₄ and Na ₂ PdCl ₄ .

  In the present invention, in order to further improve the sensitivity as an optical sensor, chemical sensitization performed with a photographic emulsion can be performed. As the chemical sensitization method, sulfur sensitization, selenium sensitization, chalcogen sensitization such as tellurium sensitization, noble metal sensitization such as gold sensitization, reduction sensitization and the like can be used. These are used alone or in combination. When the above chemical sensitization methods are used in combination, for example, sulfur sensitization method and gold sensitization method, sulfur sensitization method and selenium sensitization method and gold sensitization method, sulfur sensitization method and tellurium sensitization. A combination of a method and a gold sensitization method is preferable.

The sulfur sensitization is usually performed by adding a sulfur sensitizer and stirring the emulsion at a high temperature of 40 ° C. or higher for a predetermined time. As the sulfur sensitizer, known compounds can be used. For example, in addition to sulfur compounds contained in gelatin, various sulfur compounds such as thiosulfates, thioureas, thiazoles, rhodanines, etc. Can be used. Preferred sulfur compounds are thiosulfate and thiourea compounds. The amount of sulfur sensitizer added varies under various conditions such as pH during chemical ripening, temperature, and the size of silver halide grains, and is 10 ⁻⁷ to 10 ⁻² mol per mol of silver halide. It is preferably 10 ⁻⁵ to 10 ⁻³ mol.

  A known selenium compound can be used as the selenium sensitizer used for the selenium sensitization. That is, the selenium sensitization is usually carried out by adding unstable and / or non-labile selenium compounds and stirring the emulsion at a high temperature of 40 ° C. or higher for a predetermined time. As the unstable selenium compound, compounds described in JP-B-44-15748, JP-A-43-13489, JP-A-4-109240, JP-A-4-324855 and the like can be used. In particular, it is preferable to use compounds represented by general formulas (VIII) and (IX) in JP-A-4-324855.

  The tellurium sensitizer used for the tellurium sensitizer is a compound that generates silver telluride presumed to be a sensitization nucleus on the surface or inside of a silver halide grain. The silver telluride formation rate in the silver halide emulsion can be tested by the method described in JP-A-5-313284. Specifically, U.S. Pat. Nos. 1,623,499, 3,320,069, 3,772,031, British Patent 235,211, No. 1,121,496, No. 1,295,462, No. 1,396,696, Canadian Patent No. 800,958, JP-A-4-204640 No. 4-271341, No. 4-3333043, No. 5-303157, Journal of Chemical Society, Chemical Communication (J. Chem. Soc. Chem. Commun.) 635 (1980), ibid 1102 (1979), ibid 645 (1979), Journal of Chemical Society Perkin Transaction (J. Chem. Soc. Perkin. Trans.) 1, 2191 (1980), S.C. Compounds described in S. Patai, The Chemistry of Organic Selenium and Tellunium Compounds, Vol 1 (1986), Vol 2 (1987) Can be used. Particularly preferred are compounds represented by the general formulas (II), (III) and (IV) in JP-A-5-313284.

The amount of selenium sensitizer and tellurium sensitizer used varies depending on the silver halide grains used, chemical ripening conditions, etc., but is generally 10 ⁻⁸ to 10 ⁻² mol, preferably 10 ⁻⁷ mol per mol of silver halide. About 10 ^-3 mol is used. Although there is no restriction | limiting in particular as conditions for chemical sensitization, pH is 5-8, pAg is 6-11, Preferably it is 7-10, As temperature, it is 40-95 degreeC, Preferably it is 45-85 degreeC. is there.

Examples of the noble metal sensitizer include gold, platinum, palladium, iridium and the like, and gold sensitization is particularly preferable. Specific examples of the gold sensitizer used for gold sensitization include chloroauric acid, potassium chloroaurate, potassium aurithiocyanate, gold sulfide, thioglucose gold (I), and thiomannose gold (I). About 10 ⁻⁷ to 10 ⁻² mol per mol of silver halide. In the silver halide emulsion used in the present invention, a cadmium salt, a sulfite salt, a lead salt, a thallium salt or the like may coexist in the process of silver halide grain formation or physical ripening.

  Reduction sensitization can be used for silver halide emulsions. As the reduction sensitizer, stannous salts, amines, formamidinesulfinic acid, silane compounds and the like can be used. A thiosulfonic acid compound may be added to the silver halide emulsion by the method described in European Patent Publication (EP) 293917. There may be only one kind of silver halide emulsion, or two or more kinds (for example, those having different average grain sizes, those having different halogen compositions, those having different crystal habits, those having different chemical sensitization conditions, and different sensitivities. 1). In particular, in order to obtain high contrast, as described in JP-A-6-324426, it is preferable to apply an emulsion with higher sensitivity as it is closer to the support.

There is no particular limitation on the coating amount of the silver salt emulsion. If the coating amount of the emulsion is too large, there will be problems such as an increase in the cost of the light-sensitive material and an increase in the development time. However, increasing the coating amount of the silver salt emulsion is effective for forming a developed silver having a lower resistance value. The coating amount of a silver salt emulsion preferable as a silver salt photosensitive material for forming a conductive film is in the range of ² g / m ² to 15 g / m ^{2 in} terms of silver amount, and 4 g / m ² to 10 g / m ^2. Is more preferable.

<Binder>
In the emulsion layer, a binder can be used for the purpose of uniformly dispersing silver salt grains and assisting the adhesion between the emulsion layer and the support. In the present invention, as the binder, both water-insoluble polymers and water-soluble polymers can be used as binders, but it is preferable to use water-soluble polymers.
Examples of the binder include polysaccharides such as gelatin, polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP), starch, cellulose and derivatives thereof, polyethylene oxide, polysaccharides, polyvinylamine, chitosan, polylysine, polyacrylic acid, polyacrylic acid, and the like. Examples include alginic acid, polyhyaluronic acid, and carboxycellulose. These have neutral, anionic, and cationic properties depending on the ionicity of the functional group.

The content of the binder contained in the emulsion layer is not particularly limited and can be appropriately determined within a range in which dispersibility and adhesion can be exhibited. However, the higher the binder ratio in the emulsion layer, the lower the resistance value. Development silver formation is possible and preferable. However, if the Ag / binder ratio is too high, aggregation of silver halide grains and deterioration of coatability become problems. In the present invention, the Ag / binder weight ratio is preferably 3 or more, more preferably 4.5 or more and 12 or less, and most preferably 6 or more and 10 or less.
Further, gelatin is the most preferable type of binder.

<Hardener>
The emulsion layer and other hydrophilic colloid layers of the light-sensitive material according to the present invention are preferably hardened with a hardener.
As the hardener, inorganic or organic gelatin hardeners can be used alone or in combination. For example, active vinyl compounds (1,3,5-triacryloyl-hexahydro-s-triazine, bis (vinylsulfonyl) methyl ether, N, N′-methylenebis- [β- (vinylsulfonyl) propionamide], etc.) active halogen compounds (Such as 2,4-dichloro-6-hydroxy-s-triazine), mucohalogen acids (such as mucochloric acid), N-carbamoylpyridinium salts (such as (1-morpholinyl, carbonyl-3-pyridinio) methanesulfonate) haloamidinium salts (1- (1-chloro-1-pyridinomethylene) pyrrolidinium, 2-naphthalenesulfonate, etc.) can be used alone or in combination. Of these, the active vinyl compounds described in JP-A-53-41220, 53-57257, 59-162546, and 60-80846 and the active halogen compounds described in US Pat. No. 3,325,287 are preferred. The following are examples of typical compounds of gelatin hardeners.

As described above, the swelling ratio of the emulsion layer can be arbitrarily controlled by adjusting the addition amount of the hardener in the emulsion layer.
The preferred range of the amount of the hardener added to the emulsion layer varies depending on the storage temperature and humidity of the photosensitive material after the addition of the hardener, the storage period, the film pH of the photosensitive material, the amount of binder contained in the photosensitive material, etc. Is not decided. In particular, since the hardener can diffuse over all layers located on the same side of the photosensitive material before reacting with the binder, the preferred addition amount of the hardener is the total amount of binder on the same side of the photosensitive material including the emulsion layer. Depends on. The preferable content of the hardener in the light-sensitive material of the present invention is in the range of 0.2% by weight to 15% by weight with respect to the total binder amount on the same side of the light-sensitive material including the emulsion layer, and more preferably. It is in the range of 0.5% to 6% by weight.
Further, as described above, since the hardener can diffuse, the addition position of the hardener does not need to be in the emulsion layer and can be preferably added to any layer on the same side as the emulsion layer. It is also preferable to add in portions.

<Dye>
The light-sensitive material may contain a dye at least in the emulsion layer. The dye is contained in the emulsion layer as a filter dye or for various purposes such as prevention of irradiation. The dye may contain a solid disperse dye. Examples of the dye preferably used in the present invention include dyes represented by general formula (FA), general formula (FA1), general formula (FA2), and general formula (FA3) described in JP-A-9-179243. Specifically, compounds F1 to F34 described in the publication are preferable. Further, (II-2) to (II-24) described in JP-A-7-152112, (III-5) to (III-18) described in JP-A-7-152112, and JP-A-7-152112. (IV-2) to (IV-7) described in the publication are also preferably used.

In addition, as dyes that can be used in the present invention, solid fine particle dispersed dyes to be decolored during development or fixing processing include cyanine dyes, pyrylium dyes, and aminium dyes described in JP-A-3-138640. Can be mentioned. Further, as dyes that do not decolorize during processing, cyanine dyes having a carboxyl group described in JP-A-9-96891, cyanine dyes not containing an acidic group described in JP-A-8-245902, and those described in JP-A-8-333519 Lake type cyanine dyes, cyanine dyes described in JP-A-1-266536, holopolar cyanine dyes described in JP-A-3-136638, pyrylium dyes described in JP-A-62-299959, JP-A-7-253039 Polymer-type cyanine dyes described in JP-A No. 2-282244, solid fine particle dispersions described in JP-A No. 2-282244, light scattering particles described in JP-A No. 63-131135, Yb ³ described in JP-A No. 9-5913 ⁺ compounds and ITO powder or the like of JP-a 7-113072 JP and the like In addition, dyes represented by general formula (F1) and general formula (F2) described in JP-A-9-179243, specifically, compounds F35 to F112 described in the same publication can also be used.

  Moreover, as said dye, a water-soluble dye can be contained. Such water-soluble dyes include oxonol dyes, benzylidene dyes, merocyanine dyes, cyanine dyes and azo dyes. Of these, oxonol dyes, hemioxonol dyes and benzylidene dyes are particularly useful in the present invention. Specific examples of water-soluble dyes that can be used in the present invention include British Patent Nos. 584,609, 1,177,429, JP-A-48-85130, 49-99620, No. 49-114420, No. 52-20822, No. 59-154439, No. 59-208548, US Pat. No. 2,274,782, No. 2,533,472, No. 2 No. 3,956,879, No. 3,148,187, No. 3,177,078, No. 3,247,127, No. 3,540,887, No. 3 , 575,704 specification, 3,653,905 specification, and 3,718,427 specification.

  The content of the dye in the emulsion layer is preferably 0.01 to 10% by mass with respect to the total solid content, from the viewpoint of preventing irradiation and the like, and from the viewpoint of lowering sensitivity due to an increase in the amount added. More preferred is mass%.

<Solvent>
The solvent used for forming the emulsion layer is not particularly limited. For example, water, organic solvents (for example, alcohols such as methanol, ketones such as acetone, amides such as formamide, sulfoxides such as dimethyl sulfoxide, etc. , Esters such as ethyl acetate, ethers, etc.), ionic liquids, and mixed solvents thereof.
The content of the solvent used in the emulsion layer of the present invention is in the range of 30 to 90% by mass and in the range of 50 to 80% by mass with respect to the total mass of silver salt, binder and the like contained in the emulsion layer. Preferably there is.

[Support]
As the support of the photosensitive material according to the present invention, a plastic film, a plastic plate, a glass plate, or the like can be used.
Examples of the raw material for the plastic film and plastic plate include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate; polyolefins such as polyethylene (PE), polypropylene (PP), polystyrene, EVA; polyvinyl chloride, Vinyl resins such as polyvinylidene chloride; polyether ether ketone (PEEK), polysulfone (PSF), polyether sulfone (PES), polycarbonate (PC), polyamide, polyimide, acrylic resin, triacetyl cellulose (TAC) Etc. can be used.
In the present invention, the plastic film is preferably a polyethylene terephthalate film from the viewpoint of transparency, heat resistance, ease of handling and cost.

When the conductive metal film obtained by the present invention is used as an electromagnetic shielding material for a display, the support is preferably a transparent substrate such as a transparent plastic. In this case, the total visible light transmittance of the plastic film or plastic plate is preferably 70 to 100%, more preferably 85 to 100%, and particularly preferably 90 to 100%.
The support may be colored. The support may be a single layer or a multilayer film composed of two or more layers.

  When a glass plate is used as the support, the type is not particularly limited, but when the conductive metal film obtained by the present invention is used as an electromagnetic shielding film for a display, a tempered glass provided with a tempered layer on the surface is used. It is preferable to use it. There is a high possibility that tempered glass can prevent damage compared to glass that has not been tempered. Furthermore, the tempered glass obtained by the air cooling method is preferable from the viewpoint of safety because even if it is broken, the crushed pieces are small and the end face is not sharp.

[Formation of photosensitive material]
The light-sensitive material according to the present invention can be formed by coating an emulsion layer coating solution containing the above components on a support. Any coating means may be used as the coating means.
The pH of the emulsion layer after coating is preferably in the range of 3.0 to 9.0, and preferably in the range of 4.0 to 7.0, in order to achieve the aforementioned swelling rate. Here, the pH of the emulsion layer is defined as a value obtained by reading the pH value after 1 minute at 25 ° C. after dropping 20 μl of distilled water on the surface of the coating film and contacting the surface electrode. The water content of the emulsion layer is preferably in the range of 50% by weight or less, more preferably in the range of 5 to 30% by weight, based on the total binder amount in the emulsion layer.

The light-sensitive material according to the present invention may have other functional layers in addition to the emulsion layer. As other functional layers, for example, a protective layer, a UL layer, an undercoat layer and the like can be provided on the emulsion layer side, and a back layer and the like can be provided on the side having no emulsion layer.
In addition, it is preferable that the emulsion layer is substantially disposed in the uppermost layer. Here, “the emulsion layer is substantially the uppermost layer” not only means that the emulsion layer is actually disposed on the uppermost layer, but also the total thickness of the layers provided on the emulsion layer is 0. .5 μm or less. The total thickness of the layers provided on the emulsion layer is preferably 0.2 μm or less. The film thickness of the emulsion layer is not particularly limited, but is preferably 0.2 to 20 μm, and more preferably 0.5 to 5 μm.

The exposure unit 13 includes, for example, an exposure roller 28 having a diameter De = 150 mm, a photomask 29 disposed on the top of the exposure roller 28, and an illumination unit 30 that is illumination means for irradiating the photomask 29 with light. Has been. As shown in FIG. 5, the photomask 29 is formed of, for example, transparent soda glass having a thickness t ₂ = 4.5 mm, a mask length L ′ = 200 mm in the workpiece conveyance direction F, and a mask width W ′ = 800 mm. The mask substrate 32 and a plurality of mask patterns 33 formed along the workpiece transfer direction F on one surface of the mask substrate 32.

  The mask pattern 33 is formed by forming a slit having the shape of the mask pattern 33 in a black light shielding pattern, for example, so that light can be transmitted. Originally, the light shielding pattern should be drawn on a black background and the mask pattern 33 made of slits should be drawn on a white background. However, since the drawing becomes complicated, in FIG. 5, the light shielding pattern is drawn on a white background and the mask pattern 33 is drawn with a black line. ing.

As shown in FIG. 5C, the mask pattern 33 has the same shape and the same size as the mesh-shaped periodic pattern 5 described above, and is formed on the mask substrate 32 by chromium vapor deposition along the workpiece width direction. . A plurality of mask patterns 33 are formed along the workpiece conveyance direction F in a pattern area 35 provided on the mask substrate 32. In the pattern area 35, for example, the pattern length L in the workpiece conveyance direction F is 200 mm, and the pattern width W in the workpiece width direction is 760 mm. As described above, the pattern width W of the pattern area 35 is larger than the workpiece width W _0. Even if the belt-like workpiece 11 meanders during conveyance, the shape of the periodic pattern 5 is surely formed in the entire width direction. This is for exposure. Therefore, the workpiece width W ₀ and the pattern width W are not limited to the above values, but preferably have a relationship of W ₀ <W.

In order to expose the strip-shaped workpiece 11 with the mask pattern 33 as the periodic pattern 5, it is preferable that the pattern length L of the pattern area 35 and the periodic length L ₀ have a relationship of L ₀ <L. In the present embodiment, the pattern length L = 200 mm is sufficiently larger than the period length L ₀ = 424 μm, but this is intended to ensure rigidity in consideration of image torsion due to photomask deflection. And is not determined from the necessity of forming the mask pattern 33. Therefore, if the structure can ensure the rigidity of the photomask 29, the L dimension may be smaller, which is an advantage that leads to cost reduction in that a large photomask is not required. For example, if a mask with the same periodic pattern is cut on a soda glass substrate of 800 × 1000 mm and then divided into strips, a single mask is manufactured and cut into a plurality of masks. Can be produced.

Note that by making the pattern length L of the mask pattern 33 sufficiently larger than the minimum period length L ₀ necessary for the exposure of the periodic pattern 5, even if the photomask 29 is damaged due to a work mistake or the like, If assembled with a shift of L ₀ or more in the workpiece conveyance direction F, it can be used as a new photomask 29. Thus, the spare photomask 29 is not necessarily required in that it can be reused a plurality of times, and the cost performance is also good in this respect.

  The line width of the mask pattern 33 is preferably set to be thinner than the finished dimension Ws in consideration of the line width increase caused by proximity exposure. Further, the angle θp, the pitch P, and the line width Ws of the pattern are not limited, but it is essential that the pattern is a periodic pattern in the feeding direction of the belt-like workpiece 11.

  The photomask 29 is held by a mask holding unit 40 shown in FIG. The mask holding unit 40 includes a holding frame 41 that holds the photomask 29, and an exposure position at which the photomask 29 held by the holding frame 41 faces the band-shaped workpiece 11 with a proximity gap Lg therebetween. A support portion 42 that movably supports the holding frame 41 between a retraction position (indicated by a two-dot chain line in the figure) separated from the belt-like workpiece 11 by a proximity gap Lg or more and forming a gap; Is composed of an actuator 43 that is a drive unit that moves the lens between the exposure position and the retracted position. In this embodiment, the proximity gap Lg is, for example, 50 μm.

  The holding frame 41 holds the outer periphery of the photomask 29 sandwiched from the front and rear. The holding frame 41 is provided with a plurality of adjustment screws 46 in the width direction that are screwed from the back side and come into contact with the photomask 29. The adjustment screw 46 is an adjustment unit that performs fine adjustment with respect to the minute strain in the width direction of the proximity gap Lg. By adjusting the amount of tightening to the holding frame 41, the photomask 29 is pushed by the adjustment screw 46 and held. The proximity gap Lg is adjusted so that it moves within the frame 41 and the gap is the same across the entire width.

  The support portion 42 includes a slide guide 49 attached to the holding frame 41, a slide rail 50 that slidably supports the slide guide 49, and the like, and the holding frame 41 is slidably supported between the exposure position and the retracted position. To do. For example, a motor, a solenoid, an air cylinder, or the like is used as the actuator 43, and the holding frame 41 is slid on the slide rail 50 to move between the exposure position and the retracted position. The proximity gap Lg is determined by fine adjustment of a stopper that determines the exposure position on the slide rail 50.

  The actuator 43 is attached to the support portion 42, the moving element 43 a is connected to the slide guide 49, and is controlled by the control unit 16. The actuator 43 moves the holding frame 41 to the exposure position by projecting the mover 43a downward during exposure. Further, when the joint portion of the belt-like workpiece 11 passes under the first photomask 29, the moving element 43a is pulled in to move the holding frame 41 to the retracted position, and interference between the first photomask 29 and the joint portion. To prevent. The retracted position is set, for example, approximately 50 mm above the exposure position in order to reliably avoid interference between the first photomask 29 and the joint portion. In addition, since the support part 42 is a highly accurate one having high position reproducibility when moved to the exposure position, the proximity gap Lg is not shifted by the movement of the holding frame 41.

  FIG. 7 is a schematic diagram illustrating the configuration of the illumination unit 30. The illumination unit 30 includes a laser output device 55 that is an exposure light source, a collimating lens 56 that collimates the laser light S output from the laser output device 55 into parallel light, and a reflection mirror 59 that reflects the laser light S. And a polygon mirror 57 as a scanning means and a motor 58.

The laser output device 55 is, for example, a single mode semiconductor laser output device having an output of 60 mw, and outputs a laser beam S having a wavelength of 405 nm. The collimating lens 56 has a focal length of 3 mm, for example, and as shown in FIG. 8, the input laser light S has a parallel projection shape having an elliptical projection shape with a major axis Lb = 3.6 mm and a minor axis Wb = 1.2 mm. Convert to light. The laser beam S is applied to the photomask 29 so that the long axis Lb is along the workpiece conveyance direction F and the short axis Wb is along the workpiece width direction. The projected shape and size of the laser light S is a 1 / e ² equivalent beam diameter, but is not limited to this, and can be freely set by the collimating lens 56. Although a 60 mw single-mode semiconductor laser was used, it does not define the laser rated output, and it can be said that it is more preferable because the design margin is increased as the light source power is increased.

  The polygon mirror 57 is provided with a plurality of flat reflecting surfaces 61 on a substantially disc-shaped outer peripheral surface. The polygon mirror 57 reflects the laser light S incident on the reflecting surface 61 toward the photomask 29, and at that time, a motor. The laser beam S is scanned on the photomask 29 by being rotated by 58. The polygon mirror 57 of this embodiment is provided with 18 reflecting surfaces 61. Although the scanning angle that can be scanned by the reflecting surface 61 is 20 °, in this embodiment, 10 ° is used for exposure scanning as the scanning angle θs. In order to scan the entire width direction of the photomask 29 at a scanning angle θs of 10 °, the distance Ls from the reflecting surface 61 of the polygon mirror 57 to the photomask 29 is 2250 mm.

  The reason why the scanning angle θs used for the exposure scanning is set to 10 ° is to reduce the variation in the exposure time due to the reflection of the polygon mirror 57. Since the reflection surface 61 of the polygon mirror 57 has different radii from the center at the central portion and the end portion in the rotation direction, the scanning speed changes due to the difference in angular velocity at the time of rotation, the exposure time varies, and the exposure quality is reduced. descend. For example, when the scanning angle is 10 °, the difference in scanning speed between the central portion and the end portion of the reflecting surface 61 is as small as 3.1%, so that the influence on the exposure of the periodic pattern 5 is small. However, when the scanning angle is 20 °, the difference in scanning speed is 13.2%, and when the scanning angle is 45 °, the difference is 50%. Occurs.

  In order to reduce the size of the pattern exposure apparatus 10, when the distance between the illumination unit 30 and the photomask 29 is shortened, the power of the laser beam S changes in accordance with the change in scanning speed by the polygon mirror 57. It is preferable to control in such a manner. The silver salt sensitive material 21 has a photosensitive density defined according to the total amount of light exposed, that is, the integrated exposure amount, and this integrated exposure amount has a relationship of “integrated exposure amount = total exposure time × light amount”. Therefore, if the power (light quantity) of the laser beam S is varied so that the integrated exposure amount is constant, the periodic pattern 5 can be exposed without deteriorating the exposure quality.

  The reason why the number of reflecting surfaces of the polygon mirror 57 is 18 is to suppress the diameter of the polygon mirror 57 to about 100 mm. Originally, when the polygon mirror 57 having a scanning angle of 20 ° uses only a scanning angle of 10 °, the use efficiency of the exposure light source is 50%. Further, in order to obtain a necessary exposure amount with the use efficiency of 50%, it is necessary to increase the light amount of the exposure light source, which is disadvantageous in terms of cost. However, if the number of reflecting surfaces of the polygon mirror 57 is set to 36 in order to increase the use efficiency of the exposure light source, the diameter of the polygon mirror 57 becomes 600 mm or more, and the part processing cost becomes impractical. It was adopted. Since the number of reflection surfaces of the polygon mirror 57 and the amount of light of the exposure light source are in a corresponding relationship, the optimum number of reflection surfaces may be selected according to the combination of the power of the exposure light source and the sensitivity of the exposure light-sensitive material.

  The beam scanning is not limited to the polygon mirror, and various actuators such as a galvano and resonant scanner can be used. However, laser scanning must always be performed from one direction, as will be described later, and an actuator that performs reciprocating scanning requires modulation control to turn off one direction.

Next, a method for exposing the mesh-shaped periodic pattern 5 by the pattern exposure apparatus 10 having the above configuration will be described. FIG. 9 is a conceptual diagram showing the pattern exposure method of the present invention. The belt-like workpiece 11 is conveyed in the workpiece conveyance direction indicated by an arrow F in the figure, and the laser beam S is irradiated from the illumination unit 30 to the photomask 29 during the conveyance. The laser beam S applied to the photomask 29 passes through the slit of the mask pattern 33 and reaches the strip-shaped workpiece 11, and the rhombic periodic pattern 5 having a periodic length L ₀ = 424 μm is exposed along the carrying direction. A proximity gap Lg of 50 μm, for example, is provided between the belt-like workpiece 11 and the photomask 29, and there is no deviation by performing proximity exposure in synchronization with the workpiece conveyance for the period length L _0. The periodic pattern 5 is exposed.

  In the present invention, the entire area of the mask pattern 33 corresponding to at least one period of the photomask 29 is kept in a state where the photomask 29 provided with the mask pattern 33 is stationary while continuously transporting the belt-like workpiece 11 without stopping. Proximity exposure is characterized in that the exposure area to be covered is periodically exposed (period in accordance with the feed of 424 μm). Therefore, the exposure area covering the entire area of the mask pattern 33 for at least one period of the photomask 29 is an area of 424 μm in the transport direction and 750 mm in the width direction necessary for exposing the periodic pattern 5 for one period. The minimum exposure area including.

The periodic length L ₀ of the periodic pattern 5 in the conveying direction is 424 μm, the workpiece conveying speed of the strip-shaped workpiece 11 is V = 4 m / min, the exposure period for exposing the periodic pattern 5 is T, the exposure time is ΔT, and the mask pattern 33 When the minimum line width Dmin is 10 μm, the time required for the belt-like workpiece 11 to be conveyed by the period length L ₀ is L ₀ /V=6.36 msec. If designed to perform laser scanning once in this time, the exposure cycle T = 6.36 msec, and the rotation speed of the 18-sided polygon mirror 57 is ω = 524 rpm. Since the distance Ls from the polygon mirror 57 to the photomask 29 is 2250 mm, the beam scanning speed Vb at this time is Vb = Ls · ω = 123 m / sec, and the size in the width direction of the projected shape of the laser light is 1. Since it is 2 mm, the exposure time during which the laser beam S is exposed at this scanning speed is ΔT = 1.2 / vb = 9.8 μsec, and during this time, the conveyance amount Lm that the strip-like workpiece 11 moves in the feeding direction is V · ΔT = 0. .65 μm.

  The transport amount Lm is an amount by which the belt-like workpiece 11 is shifted in the transport direction F with respect to the photomask 29 during exposure. Therefore, when the carry amount Lm becomes larger than the minimum line width Dmin of the mask pattern 33, the line width Ws of the periodic pattern 5 becomes thick and the exposure quality deteriorates. In order to ensure the exposure quality, V · ΔT <Dmin must be satisfied. In the present embodiment, since V · ΔT = 0.65 μm <Dmin = 10 μm is satisfied, there is little deterioration in exposure quality.

  In the present embodiment, the size of the projected shape of the laser beam S by the laser scanning described above is set to the long axis Lb = 3.6 mm × the short axis L1.2 mm, and the length of the laser beam S is on the back surface of the photomask 29. A light shielding mask 67 provided with a slit 65 having a width Ws substantially equal to the axis Lb is disposed so that no more light strikes the photomask 29. Therefore, the exposure area by one scanning of the laser beam S is 3.6 mm × width direction 750 mm, and 3.6 / 0.424 = 8.5 mask patterns 33 are irradiated, and multiple exposure is performed. It will be.

Thereby, the length Lb of the exposure light source projected onto the photomask satisfies Lb = 3.6 mm, Lb = 3.6> L ₀ = 0.424, and the quotient m of Lb / L ₀ is m = 8. Become. Therefore, the relationship between the workpiece conveyance speed V and the exposure cycle T satisfies (n−1) × (L ₀ / V) = T (n is a natural number) and 2 = <n <= m = 8. In this case, an arbitrary number of n = 2 to 8 can be selected, and the number of times of multiple exposure can be maximized when n = 2. In the present embodiment, as described above, the time L ₀ /V=6.36 msec required for the belt-shaped workpiece to be conveyed by the length of one cycle of the periodic pattern is set, and laser scanning is performed once in this time. Therefore, the relationship between T and V is determined so that n = 2 and T = 6.36 msec.

FIG. 10 schematically shows an exposure state of the silver salt sensitive material by laser scanning. As shown in a to e of FIG. 6A, by one scan of the laser beam S, 8.5 rows of periodic patterns 5 are sequentially exposed from the left to the right through the photomask 29 with the full width. That is, as shown to a of the figure (B), the strip | belt-shaped workpiece | work 11 is exposed to 8.5 rows of rhombuses in the workpiece conveyance direction F. FIG. In the meantime, since the belt-like workpiece 11 is conveyed in the workpiece conveyance direction F by the periodic length L ₀ , this portion passes through the photomask 29 from the portion on the belt-like workpiece 11 where the periodic pattern 5 has already been exposed. In this case, the same pattern is over-exposed through the photomask 29. If the workpiece conveyance speed V and the exposure cycle T at this time are synchronized, the exposure is performed on the latent image so that the periodic pattern 5 is not disturbed. By repeating this in sequence, 8.5 multiple exposures are always performed for one periodic pattern 5 as shown in FIGS. Since the number of exposures is gradually reduced at the start and end of operation of the pattern exposure apparatus 10, this portion is extracted as NG.

When the required exposure amount is calculated, the width of the photosensitive material 750 mm is exposed at a speed of 4 m / min, so the exposure area per unit time is 66.7 mm / sec (4 m / min) × 750 mm = 500 cm ² , and the photosensitive material sensitivity. Is 10 μj / cm ² , for example, an exposure power of 10 μj / cm ² × 500 cm ² = 5 mw is required. Further, assuming that the slit width (minimum line width) of the mask pattern is 15 μm and the pitch P is 300 μm, the aperture ratio is 9.75%, the scanning efficiency is 50%, and the optical system efficiency is 50%. Efficiency η = 0.5 × 0.5 × 0.0975 = 2.4%. In order to obtain the above-mentioned 5 mw with a single exposure with this efficiency, the light source power needs 5 / 2.4% = 208 mw.

In the multiple exposure according to the above-described embodiment, the exposure amount determined by the integral value corresponding to the number of multiple exposures can be irradiated more than the single exposure, so that the light source power can be reduced accordingly. Higher power can be achieved by selecting a light-sensitive material sensitivity (about ² to 10 μj / cm ² ) and a light source power (50 mw to 200 mw), and by combining and exposing a plurality of light sources, so that a flexible design is possible.

  The advantage of multiple exposure is that the number of exposures can be increased as in the above calculation, so that the shortage of the light amount of the light source can be compensated. In addition to this, the multiple exposure has an effect of averaging the non-uniformity of the luminance distribution of the light source, and can suppress the non-uniform exposure amount due to the luminance variation in the feed direction. Similarly, the horizontal scanning has the effect of averaging the non-uniformity of the luminance distribution of the light source in the scanning direction, and the non-uniform exposure amount due to the luminance variation in the scanning direction can be suppressed by the scanning. Therefore, by the combination of multiple exposure and horizontal scanning, a uniform exposure amount can be obtained at any time by an integration effect in design regardless of the light source luminance distribution. This is an advantage that greatly reduces the cost in that it is not necessary to worry about the luminance variation of the light source.

  In the pattern exposure method of the present invention, it is the relationship between the exposure cycle T and the work conveyance speed V that greatly contributes to variations in the exposure line width. If the synchronization is shifted, exposure is performed by the amount of synchronization shift. Will shift. The deviation affects the major axis Lb of the laser light S, and 8.5 periodic patterns are effective as the accumulation of deviation.

FIG. 11 shows the result of calculation of the accumulated exposure shift amount due to the synchronization shift under simulation under the following conditions.
Premise of calculation ・ Work transfer speed V = 4m / min ・ Scan frequency 1 / 6.36msec = 157Hz
Premise of drive system ・ After the motor, it is further decelerated to 1: 2 with a 1/50 worm reducer and pulley to drive the exposure roller. ・ Gear mark (component per gear tooth: (Same frequency component as one rotation of input shaft)
・ Simulation of the maximum deviation of the scanning position (work transfer direction) that can occur during eight scans ・ Assuming that the speed variation of the gear mark component is 1%

  As a result of the above calculation, it has been found that if there is a speed variation due to 1% gear mark in 8.5 multiple exposures, a maximum deviation of 37 μm is caused. Therefore, it is preferable that the equipment side speed synchronization and speed unevenness suppression design be performed so as to minimize the synchronization shift due to speed unevenness, and be suppressed to about 0.1%. If the projected shape of the laser beam is designed to be small, the influence on the speed unevenness can be reduced by that amount, but the number of multiple exposures is reduced by that amount, so that exposure power is required. Therefore, it is necessary to design with a good balance from the viewpoint of sensitivity of the photosensitive material and equipment cost.

  In this embodiment, the photosensitive density is almost zero by the first exposure of the multiple exposure, reaches a density of almost half or more by the second exposure, and is almost designed by the third and fourth exposures. The exposure amount is determined so that the density can be obtained. This is deeply related to the use of a light sensitive material having a large γ and a high contrast. Generally, γ of the light-sensitive material for performing such exposure is 5 or more, preferably 10 or more. The light-sensitive material used in this embodiment uses 20 or more. This photosensitive material exhibits a large γ characteristic (hard tone) in a region where the number of exposures is small, and is a preferable photosensitive material as described above.

  The luminance distribution of the exposure light source generally shows a Gaussian distribution, and an area having a luminance sufficient to contribute to the exposure is, for example, about four times in the central portion of 8.5 multiple exposures. Therefore, the process is substantially close to four times of multiple exposure, and a latent image is formed when the cumulative exposure amount of four times reaches a certain level during this time. However, since the exposure amount due to the exposure deviation is designed not to appear as a latent image once, the design has a wide tolerance for the deviation. That is, an image appears only when the accumulated exposure amount at the overlapped position reaches a certain level or more. Since exposure is performed while the belt-like work 11 is conveyed, blur exposure is always performed. However, if the cumulative exposure amount for this blur is designed to be sufficiently small, the exposure amount for forming a latent image can be prevented from being reached. It is also possible to hide it.

  On the other hand, the influence of the fluctuation of the laser light S is the exposure amount fluctuation because the exposure is performed through the photomask 29, but the mask pattern 33 is always exposed without affecting the pattern shape. . Moreover, because of the multiple exposure, the total exposure amount fluctuation due to the fluctuation of the laser beam S is averaged, and the design is such that the line width is hardly affected. Therefore, even if the surface blur of the polygon mirror 57 and the angle accuracy of each surface 61 are slightly sweet, the effect of the exposure shape is small and stable quality can be maintained.

  In the above-described proximity exposure, the proximity gap Lg is preferably 500 μm or less. As a result of the experiment, the contact exposure has almost the same line width as that of the photomask, whereas the proximity exposure has a line slightly thicker than the mask line width even when a parallel light source is used due to light diffraction. This is because it becomes a width. FIGS. 12A to 12F show the simulation results of the light intensity distribution by light diffraction when the proximity gap Lg is changed from 50 to 550 μm. As can be seen from the simulation results, the light intensity distribution becomes wider as the proximity gap Lg increases. Further, when the exposure pattern shape was checked when the gap was widened, it was found from the mask pattern shape that the deformation at the orthogonal points of the lines increased greatly. Therefore, it was determined that 500 μm or less was preferable. In this embodiment, the smaller the proximity gap Lg is, the more advantageous the exposure quality is. Therefore, it is set to 50 μm (the reason why the proximity gap Lg cannot be further approached will be described later).

In the present embodiment, the exposure unit 13 is on the exposure roller 28 having a diameter of 150 mm, and the belt-like workpiece 11 is continuously conveyed while being exposed while the belt-like workpiece 11 is wrapped on the exposure roller 28. At this time, the irradiation direction of the laser beam S is adjusted so that the center of the laser beam S is directed toward the center of the exposure roller 28. As shown in FIG. 13, the proximity gap Lg varies between the end portion and the center portion of the laser beam S because of the curvature of the exposure roller 28. If the difference in proximity gap between the exposure roller radius R, the laser beam radius r, and the center and end of the laser beam S is h,
^{h = R- (R 2 -r 2} ) 1/2
If the diameter Lb of the laser beam S is 3 mm, the difference is h = 15 μm. If the diameter Lb of the laser beam S is 3.6 mm, a difference of h = 21.6 μm is obtained. As described above, the larger the roller diameter of the exposure roller 28, the smaller the difference in the proximity gap Lg between the center and the end due to the relationship of curvature, which is preferable. Since it becomes a large-scale apparatus, it is preferable to perform an optimum design in accordance with the diameter Lb of the laser beam S.

  Further, the proximity gap Lg varies with the rotation period of the exposure roller 28 depending on the eccentricity of the exposure roller 28, the processing accuracy of the exposure roller 28 itself, the backlash of the shaft, and the like. In this embodiment, the blur of the proximity gap Lg is suppressed to about 20 μm. However, if the roller processing and assembly are performed precisely, it can be suppressed to the order of several microns. Note that the merit of exposing on the exposure roller 28 is that fluttering of the strip-shaped workpiece 11 can be suppressed. For example, the fluttering on the flat surface of the belt-like work 11 hung between the rollers has a vibration of the order of 100 μm, which is one digit higher, and can be suppressed much smaller than that. These are variations in the proximity gap Lg, which are factors affecting the line width. In the experiment, blurring in the range of several tens of microns does not significantly affect the exposure quality. If Lg is too small as described above, the web and the mask come into contact with each other due to mechanical variations, and there is a possibility that the mask and the product may be scratched. Therefore, Lg = 50 μm including some margins. Set.

Next, the outline of the exposure process of the electromagnetic wave shielding film 2 will be described with reference to the flowchart of FIG. The strip-shaped workpiece 11 is composed of a long film 20 having a thickness t1 = 100 μm and a width W ₀ = 650 to 750 mm coated with an unexposed silver salt photosensitive material 21, and 100 to 1000 m is wound on a reel and the workpiece supply unit 12 is wound. Set to On the other hand, a reel 24 for winding is set in the workpiece winding unit 14, and the tip of the strip-shaped workpiece 11 is locked. In this state, the illuminating unit 30 rotates the polygon mirror 57 while the laser output device 55 is in the off state, and starts to convey the belt-like workpiece 11 when the set number of rotations is reached.

  As described above, in order to perform multiple exposure without deviation, a certain synchronization relationship is required between the exposure cycle T and the work conveyance speed V. Further, in order to synchronize the exposure cycle T and the work conveyance speed V, it is easiest to synchronize the rotation speed ω of the polygon mirror 57 and the work conveyance speed V. Specifically, for example, a quartz oscillator 80 is provided externally as a reference clock to synchronize the work conveyance speed V and the exposure cycle T, and the control unit 17 refers to this clock and all speeds are set to a desired constant speed. Control to become. As a result, accurate synchronization can be achieved. As a scan start signal of the polygon mirror 57, a signal obtained by detecting a laser beam scanned by the mirror by a photodetector such as a photodiode is used, or a rising edge of a pulse signal output once per surface by a mirror control signal Is used.

  The reason why the exposure is started after the rotational speed ω of the polygon mirror 57 and the work conveyance speed V are synchronized is to facilitate the discrimination between the appropriately exposed portion and the NG portion. Even if exposure is performed in a state where the rotational speed ω of the polygon mirror 57 and the work conveyance speed V are asynchronous, the periodic pattern is exposed, so that it may appear to be a good product at first glance. When extracting, human error always occurs and there is a risk of NG contamination. For this reason, whether or not the synchronization state has been reached is monitored in advance by the control unit 16, and the laser output device 55 is not operated in the asynchronous state. Therefore, the laser does not automatically emit light in the asynchronous start / stop band.

  When the rotational speed ω of the polygon mirror 57 and the workpiece conveyance speed V are in a synchronized state, the control unit 16 outputs the laser beam S from the laser output device 55 and exposes the periodic pattern 5 on the belt-like workpiece 11 through the photomask 29. To do. This exposure is performed by multiple exposures as described above. The exposed strip-shaped workpiece 11 is wound around the workpiece winding unit 14. When the belt-like workpiece 11 of the workpiece supply unit 12 disappears, an end signal is input from the workpiece supply unit 12 to the control unit 16, the conveyance of the belt-like workpiece 11 is stopped, and the terminal of the belt-like workpiece 11 is cut at the joint 15. The workpiece supply unit 12 is tape-bonded to the tip of a new strip-shaped workpiece 11 to be set.

  After the belt-like workpiece 11 is joined, the workpiece conveyance is started again. However, since the mask holding unit 40 moves the photomask 29 to the retracted position when the joining portion passes the exposure roll 28, the photomask 29 and the belt-like workpiece 11 are moved. There is no damage due to contact with the joints. After passing through the joint portion, the photomask 29 is returned to the exposure position with good reproducibility, and a predetermined proximity gap Lg is set. Note that it is preferable to keep the laser output device 55 in the off state even when the joint portion passes.

  When the joined portion is wound up by the workpiece winding unit 14 by the workpiece conveyance, the workpiece is temporarily stopped, the winding end portion is fixed, cut, and the terminal after winding is fixed to the terminal tape. After the wound product is taken out and the reel 24 is newly supplied and chucked, the leading end of the cut strip-shaped workpiece 11 is locked to the reel 24. The exposure process is completed as described above, and a product is produced by repeating this process.

  Although the above description has been made taking the example of single-axis feeding and winding as an example, the feeding and winding may be set to two axes, respectively, so that a switching time can be obtained, or a reservoir or the like can be configured to completely stop. Loss can be minimized if it is configured to perform switching.

  The strip-shaped work 11 exposed in the exposure process is conveyed to the development process and developed to form a mesh-like periodic pattern 5 of silver salt. In the next plating step, copper plating is performed by electrolytic plating using the periodic pattern as a core of plating, and the electromagnetic wave shielding film 2 is completed.

  In this embodiment, an electromagnetic wave shielding film using a silver salt sensitive material has been described as an example. However, a copper foil is laminated on a PET base material and a photoresist is applied thereto, or a DFR (dry film resist) is laminated. It is also preferable to apply the above exposure method and exposure apparatus to the above. However, it is necessary to adapt the light source wavelength in accordance with the spectral sensitivity of the light-sensitive material. In that case, an unnecessary portion of the copper foil is removed by an etching process after exposure and development, thereby forming a copper mesh to obtain an electromagnetic wave shielding film product.

  The photosensitive material may be not only a silver salt sensitive material but also a photoresist, or a commercially available dry film resist. In this case, the sensitivity is slightly lower than that of the silver salt sensitive material, but the light source power may be increased correspondingly, and even a photoresist can be sufficiently applied. In this case also, it is necessary to adapt the light source wavelength in accordance with the spectral sensitivity of the photosensitive material.

  Further, although a 60 mw single mode semiconductor laser was used, it does not define the laser rated output, and it can be said that the larger the light source power, the greater the design margin, which is more preferable. In addition, as shown in FIG. 15, the two laser beams S 1 and S 2 output from the two laser output devices 70 and 71 are polarized and combined by the prism 73 to increase the power, and the collimator lens 74 converts the light into parallel beams. It may be used for exposure. Also, a 200 mw multimode semiconductor laser may be used. Furthermore, as shown in FIG. 16, a laser output device 77, a collimating lens 78, and a prism 79 are installed as a set on each stage 81 of a pedestal base 80, and a plurality of laser beams S4 to S7 are reduced. You may concentrate on an area.

  Further, in the exposure by scanning, light is incident on the photomask 29 obliquely, so that the scanning pattern is increased at both ends in the width direction of the belt-like work 11 and the periodic pattern 5 is shifted to the outside and exposed. In order to solve this, the mask pattern formed on the photomask 29 may be formed in advance by shifting inward in the width direction. For example, when the incident angle is 20 ° and the proximity gap Lg is 50 μm, the deviation of the periodic pattern 5 exposed on the strip-shaped workpiece 11 is 50 · sin 20 = 17.1 μm. This is because the image forming position gradually shifts outward from the center in the width direction of the photomask 29 and shifts by 17.1 μm at the outermost part. If this cannot be ignored, the rhombus shape of the mask pattern may be formed by shifting inward by 50 · sin θ in the width direction in advance.

  Further, as the scanning angle increases, the line width of the periodic pattern 5 exposed to the strip-shaped workpiece 11 becomes thicker. To prevent this, the lines of the mask pattern 33 become closer to both ends of the photomask 29. It is good to narrow the width. According to this, the line width of the periodic pattern 5 to be exposed can be made uniform.

  Also, when pattern exposure is performed by laser scanning, the workpiece feed speed V, exposure width W, and beam scan speed Vb are equivalent to V · W / Vb, which is the amount that the belt-like workpiece 11 moves in the feed direction during one scan. It is preferable to incline the mask pattern 33 in advance. This is because the actual pattern is not exactly the same as the mask pattern 33, and the periodic pattern 5 is inclined and exposed by the amount of continuous feeding of the belt-like work 11. In order to correct this, the same periodic pattern 5 as the mask pattern 33 can be exposed by inclining the mask pattern 33 in the opposite direction to the direction in which the periodic pattern 5 is inclined in advance. In the case of the above-described embodiment, (66.7 mm / sec ÷ 123 m / sec) × 750 mm = 0.407 mm with respect to the total width 750 mm of the strip-shaped workpiece 11, that is, from the position where the mask pattern 33 is installed at a right angle on the strip-shaped workpiece 11. If the downstream side of the beam scanning is shifted and fixed by 0.407 mm in the workpiece conveyance direction, the completed periodic pattern 5 can be made perpendicular to the strip-shaped workpiece 11.

  In addition, the combination of the polygon mirror and the parallel light beam of the semiconductor laser is preferable because it is simple, inexpensive, but there are cases where it is not always effective to perform beam scanning as a light source, such as when the size of a periodic pattern becomes very large. . In this case, it is preferable to use a parallel light source having a large area and perform exposure for a specified time within a specified range using a shutter device. In this case, since the luminance distribution affects the exposure amount, it is necessary to use an exposure light source that is made as uniform as possible.

  FIG. 17 is a front view of an exposure unit in which the belt-like workpiece 11 is hung on the exposure roller 28. As an exposure light source 85, an ultraviolet mercury lamp or metal halide lamp used in a so-called proximity exposure machine is used as a concave mirror. And a simple parallel light source having a large area, for example, a diameter Dn = φ800 mm, which is collimated using a collimator lens. At this time, since the length of the light projected onto the photomask 29 in the width direction of the belt-like workpiece 11 is Lw = 800 mm, if the pattern width in the workpiece width direction of the photomask 29 is set to W = 750 mm, Lw > W can be realized. Further, a light shielding mask 87 having a slit 86 of 3.6 mm × 800 mm and a shutter device 88 are arranged between the exposure light source 85 and the photomask 29 so that a long and narrow area can be exposed for the exposure time ΔT. Good. As the shutter device 88, a mechanical shutter, a liquid crystal shutter, or the like can be used.

  The pattern exposure method and apparatus of the present invention can be used for exposure of various periodic patterns. However, it is a continuous seamless pattern such as a mesh pattern constituting a magnetic shield film for plasma display. It is more suitable when the workpiece is exposed seamlessly. This is because several periodic patterns adjacent to each other are continuously overwritten by multiple exposure, and therefore, the design is such that joint defects such as missing patterns in the case of disturbances are difficult to occur.

  Moreover, it is more suitable when exposing to 20 micrometers or less as the pattern minimum line width Dmin which draws a periodic pattern. In direct drawing with a normal exposure beam, the beam diameter is about 50 μm, and when the beam diameter is designed to be smaller, the equipment cost becomes a heavy burden. However, according to the present method, since a mask is used, it is easy to expose even a thin line width, and high exposure can be expected because continuous exposure can be performed.

  Furthermore, the pattern exposure method of the present invention can be applied not only to pattern exposure but also to photographic exposure. Although proximity exposure is adopted, projection exposure can also be used. Furthermore, in the present embodiment, the belt-like workpiece has been described as an example, but the present invention can be easily applied to continuous exposure while conveying a sheet-like workpiece.

It is a top view of the electromagnetic wave shield film manufactured using this invention. It is sectional drawing of an electromagnetic wave shield film. It is the schematic which shows the structure of the pattern exposure apparatus of this invention. It is the top view and sectional drawing of the strip | belt-shaped workpiece | work used as the base material of an electromagnetic wave shield film. It is the top view and side view of a photomask. It is the schematic which shows the structure of a mask holding | maintenance part. It is the schematic which shows the structure of an illumination part. It is explanatory drawing which shows the projection shape of a laser beam. It is a conceptual diagram showing the pattern exposure method of this invention. It is a schematic diagram which shows a pattern exposure state. It is a graph showing the amount of exposure shift by synchronous shift. It is a graph showing the relationship between a proximity gap and light intensity distribution. It is explanatory drawing showing the difference of the proximity gap by the position of an exposure roller. It is a flowchart which shows the exposure process of an electromagnetic wave shield film. It is explanatory drawing which shows the exposure light source which uses two laser output apparatuses. It is explanatory drawing which shows the exposure light source which uses multiple laser output apparatuses. It is a front view of the exposure part which uses a surface emitting light source.

Explanation of symbols

2 Electromagnetic Shield Film 5 Periodic Pattern 10 Pattern Exposure Device 11 Strip Work 13 Exposure Unit 16 Control Unit 28 Exposure Roller 29 Photo Mask 30 Illumination Unit 33 Mask Pattern 40 Mask Holding Unit 41 Holding Frame 42 Supporting Unit 43 Actuator 55, 70, 71, 77 Laser output device 56, 74, 78 Collimator lens 57 Polygon mirror 73, 79 Prism

Claims (51)

  A belt-like or sheet-like work having a photosensitive layer is continuously conveyed, and the photomask is periodically exposed for exposure time ΔT through a photomask arranged with a proximity gap therebetween. A pattern exposure method comprising exposing a workpiece with a mask pattern provided on the substrate as a periodic pattern that is periodic in the transport direction. A pattern area in which a periodic length of the periodic pattern in the workpiece conveyance direction is defined as a periodic length L ₀ , a workpiece width orthogonal to the workpiece conveyance direction is defined as a workpiece width W _0, and a mask pattern of the photomask is provided When the length in the workpiece conveyance direction is the pattern length L and the width in the workpiece width direction is the pattern width W,
L ₀ <L and W ₀ <W
And
When the workpiece conveyance speed is V, the exposure cycle for exposing the periodic pattern is T, the exposure time is ΔT, and the minimum line width of the mask pattern is Dmin,
L ₀ / V> = T and V · ΔT <Dmin
The filling,
2. The pattern according to claim 1, wherein the exposure area covering the entire mask pattern for at least one period of the photomask is subjected to proximity exposure through the photomask for each exposure period T for the exposure time ΔT. Exposure method. The light from the exposure light source projected onto the photomask satisfies Lb> L ₀ when the length in the workpiece conveyance direction is Lb, and m is the quotient of Lb / L ₀ (m is a natural number). , Using a photomask provided with m or more mask patterns in the workpiece conveyance direction,
The relationship between the workpiece transfer speed V and the exposure cycle T is
(N−1) × (L ₀ / V) = T (n is a natural number) and 2 = <n <= m
And when the most upstream mask pattern in the workpiece transfer direction is the first mask pattern,
When the latent image pattern on the workpiece once exposed through the first mask pattern passes through the nth mask pattern arranged on the downstream side of the first mask pattern, the workpiece conveyance speed V and the exposure cycle T 3. The pattern exposure method according to claim 2, wherein multiple exposure is performed through the nth mask pattern in synchronization with each other.   4. The pattern according to claim 3, wherein the exposure amount at the time of the multiple exposure is an exposure amount at which a photosensitive density cannot be obtained by at least one exposure and a desired photosensitive density can be obtained by n multiple exposures. Exposure method.   5. The pattern exposure method according to claim 3, wherein the exposure light source scans light from one direction in the workpiece width direction during the exposure period T to expose the entire width of the workpiece through a photomask. .   6. The pattern exposure method according to claim 5, wherein the exposure light source is a semiconductor laser, and exposure is performed with parallel light obtained by collimating the laser through a lens.   6. The pattern exposure method according to claim 5, wherein the exposure light source is a two-system semiconductor laser, and the exposure is performed by parallel light obtained by polarization-multiplexing these lasers and collimating through a lens. .   6. The exposure light source according to claim 5, wherein the exposure light source is a plurality of semiconductor lasers, and these lasers are individually collimated through a lens, and exposure is performed using light obtained by integrating the plurality of parallel lights. Pattern exposure method.   9. The pattern exposure method according to claim 6, wherein the semiconductor laser has a wavelength of 405 nm.   The speed at which the light from the exposure light source is scanned is the exposure scanning speed Vb, and the photomask is moved in the workpiece conveyance direction by the amount (W / Vb) · V that is the amount by which the workpiece is conveyed during one scan. The pattern exposure method according to claim 5, wherein the pattern exposure method is inclined with respect to the surface.   11. The pattern exposure method according to claim 5, wherein the exposure light source changes the light amount in accordance with a change in scanning speed and makes the exposure amount constant over the entire width of the workpiece.   The proximity gap is Lg, and the mask pattern is formed to be shifted inward by Lg · sin θ in the workpiece width direction in accordance with a change in an incident angle θ of light from an exposure light source. The pattern exposure method according to any one of 5 to 11.   12. The pattern exposure according to claim 5, wherein a slit width of the mask pattern is changed in a scanning width direction so that a line width of a periodic pattern exposed to the workpiece is uniform. Method.   The light from the exposure light source is Lw> W, where Lw is the length in the workpiece width direction projected onto the photomask, and the entire width of the workpiece is exposed through the photomask for a set fixed time. The pattern exposure method according to claim 3 or 4.   The pattern exposure method according to claim 1, wherein the proximity gap is 500 μm or less.   The pattern exposure method according to claim 1, wherein the photosensitive layer is a silver salt sensitive material or a photoresist.   The pattern exposure method according to claim 16, wherein the silver salt sensitive material has a gradation γ (horizontal axis: light quantity—vertical axis: gradient of density characteristic) of 5 or more.   The pattern exposure method according to claim 1, wherein the periodic pattern is a seamless pattern that is continuously seamless and is exposed to a strip-shaped workpiece seamlessly.   The pattern exposure method according to claim 1, wherein a line width of the periodic pattern is 20 μm or less.   The pattern exposure method according to claim 1, wherein the periodic pattern is a mesh pattern constituting an electromagnetic wave shielding material.   21. The pattern exposure method according to claim 1, wherein proximity exposure is performed through a photomask disposed on an outer periphery of the roller in a state where the belt-like workpiece is wound around the roller.   The pattern exposure method according to any one of claims 1 to 21, wherein a synchronization state between the work conveyance state and the exposure light source state is constantly monitored, and exposure is not performed in an asynchronous state.   When the belt-shaped workpiece is transported, when the joining portion that joins the ends of the two belt-shaped workpieces passes through the vicinity of the photomask, the photomask is released from the workpiece, and after passing, the proxy is maintained with reproducibility. The pattern exposure method according to any one of claims 1 to 22, wherein the pattern returns to the miti gap. Conveying means for continuously conveying a strip-shaped or sheet-shaped workpiece having a photosensitive layer at a workpiece conveying speed V;
A photomask disposed with a proximity gap Lg separated from the workpiece;
Illumination means that performs proximity exposure by irradiating the work with light in the entire width direction perpendicular to the transport direction for an exposure time ΔT for each exposure period T through the photomask;
A control means for synchronizing the work conveyance speed V with the exposure period T and the exposure time ΔT;
A pattern exposure apparatus, wherein a mask pattern provided on the photomask is exposed onto a workpiece as a periodic pattern periodic in a transport direction. A pattern area in which a periodic length of the periodic pattern in the workpiece conveyance direction is defined as a periodic length L ₀ , a workpiece width orthogonal to the workpiece conveyance direction is defined as a workpiece width W _0, and a mask pattern of the photomask is provided When the length in the workpiece conveyance direction is the pattern length L and the width in the workpiece width direction is the pattern width W,
L ₀ <L and W ₀ <W
25. The pattern exposure apparatus according to claim 24, wherein: When the minimum line width of the mask pattern is Dmin,
L ₀ / V> = T and V · ΔT <Dmin
26. The pattern exposure apparatus according to claim 25, wherein:   27. The pattern exposure apparatus according to claim 25 or 26, wherein the photomask is provided with a plurality of mask patterns having the same cycle in the pattern length L direction. When the length of the light of the exposure light source projected onto the photomask in the workpiece conveyance direction is Lb, when Lb> L ₀ and the quotient of Lb / L ₀ is m (m is a natural number), 28. The pattern exposure apparatus according to claim 27, wherein m or more mask patterns are provided in a workpiece conveyance direction. The control unit has a relationship between the workpiece conveyance speed V and the exposure cycle T.
(N−1) × (L ₀ / V) = T (n is a natural number) and 2 = <n <= m
When the first upstream mask pattern in the workpiece conveyance direction is used as the first mask pattern, the latent image pattern on the workpiece once exposed through the first mask pattern is the first mask pattern. The multiple exposure through the nth mask pattern is performed by synchronizing the work conveyance speed V and the exposure cycle T when passing through the nth mask pattern arranged on the downstream side of the mask pattern. Item 28. The pattern exposure apparatus according to Item 28.   30. The pattern according to claim 29, wherein the exposure amount at the time of the multiple exposure is an exposure amount at which a photosensitive density is not obtained by at least one exposure and a desired photosensitive density is obtained by n multiple exposures. Exposure device. The illumination means includes an exposure light source that irradiates light toward a photomask;
31. Scanning means for scanning the light from an exposure light source in one direction in the workpiece width direction during the exposure period T and exposing the entire width of the workpiece through a photomask. The pattern exposure apparatus as described.   32. The pattern exposure apparatus according to claim 31, wherein the exposure light source comprises a semiconductor laser output unit and a collimating lens for collimating the laser beam output from the semiconductor laser output unit to produce parallel light. .   The exposure light source includes two systems of semiconductor laser output units, an optical member that polarizes and combines the laser beams output from these semiconductor laser output units, and collimated and collimated with the polarized and combined laser beams. 32. The pattern exposure apparatus according to claim 31, comprising a collimating lens.   The exposure light source includes a plurality of semiconductor laser output units, a plurality of lenses individually collimating laser beams output from these semiconductor laser output units, and a plurality of optical units for integrating the parallel lights. 32. The pattern exposure apparatus according to claim 31, comprising a member.   35. The pattern exposure apparatus according to claim 32, wherein the semiconductor laser has a wavelength of 405 nm.   The scanning means comprises a polygon mirror provided with a plurality of reflection surfaces for reflecting light from an exposure light source and irradiating the photomask, and driving means and control means for rotating the polygon mirror. Item 36. The pattern exposure apparatus according to any one of Items 31 to 35.   The pattern according to any one of claims 31 to 36, wherein the control means changes the light amount of the exposure light source in accordance with the change in the scanning speed and adjusts the exposure amount to be constant over the entire width of the workpiece. Exposure device.   The speed at which the light of the exposure light source is scanned by the scanning means is the exposure scanning speed Vb, and the photomask is moved by the amount of (W / Vb) · V that is the amount that the work is conveyed during one scan. 38. The pattern exposure apparatus according to claim 31, wherein the pattern exposure apparatus is inclined with respect to the transport direction.   The pattern according to any one of claims 31 to 3811, wherein the mask pattern is formed to be shifted inward by Lg · sin θ in the workpiece width direction in accordance with a change in incident angle θ of light from an exposure light source. Exposure device.   40. The pattern exposure according to claim 31, wherein a slit width of the mask pattern is changed in a scanning width direction so that a line width of a periodic pattern exposed to the workpiece is uniform. apparatus.   31. The light source according to claim 24, wherein the illumination unit comprises an exposure light source having an irradiation range of Lw> W, where Lw is a length of light projected onto the photomask in the workpiece width direction. The pattern exposure apparatus as described.   42. The pattern exposure apparatus according to claim 24, wherein the proximity gap Lg is 500 [mu] m or less.   43. The pattern exposure apparatus according to claim 24, wherein the photosensitive layer is a silver salt sensitive material or a photoresist.   44. The pattern exposure apparatus according to claim 43, wherein the silver salt sensitive material has a gradation [gamma] (horizontal axis: light quantity-vertical axis: gradient of density characteristic) of 5 or more.   45. The pattern exposure apparatus according to any one of claims 24 to 44, wherein the periodic pattern is a seamless pattern that is continuous and seamlessly exposed to a strip-shaped workpiece.   46. The pattern exposure apparatus according to claim 24, wherein a line width of the periodic pattern is 20 [mu] m or less.   47. The pattern exposure apparatus according to claim 24, wherein the periodic pattern is a mesh pattern constituting an electromagnetic shielding material.   48. The pattern exposure apparatus according to claim 24, wherein a roller around which the belt-like workpiece is wound is provided, and the photomask is arranged on the outer periphery of the roller with a proximity gap Lg.   49. The pattern exposure apparatus according to claim 24, wherein the control means constantly monitors the synchronized state of the workpiece conveying means and the illumination means, and does not irradiate light from the illumination means when in an asynchronous state. A holding frame for holding the photomask;
Between the exposure position where the photomask held by the holding frame faces the workpiece with a proximity gap therebetween, and the retreat position where a gap is formed by being separated from the workpiece by the proximity gap or more. A support part for movably supporting the holding frame;
50. The pattern exposure apparatus according to claim 24, further comprising a mask holding unit including a driving unit that moves the holding frame between an exposure position and a retracted position. 51. The pattern exposure apparatus according to claim 50, wherein the holding frame includes an adjustment unit that adjusts the proximity gap by moving the photomask in a direction toward and away from the workpiece.

Images