JP2004062157A - Method of manufacturing optical wiring circuit and optical wiring board provided with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a method of manufacturing an optical wiring board, which easily forms a slope shape to be provided in an end part of a core layer constituting an optical waveguide, by maskless exposure. <P>SOLUTION: An exposure device which exposes an image with a light beam modulated by a spatial modulation element in accordance with image information is used, and a prescribed area of a photosensitive material 150 (photoresist) applied on a core layer 206 being an optical wiring board material is exposed and patterned with a light beam (UV) to form an etching mask 150A. An area corresponding to a slope 208 to be formed in the end part of the core layer 206 is exposed and patterned with a light beam which has the exposure controlled in accordance with the sloped shape of the slope 208 to give a sloped structure to the end part of the etching mask 150A. When the core layer 206 is etched with the etching mask 150A, the slope 208 is formed because etching progresses in proportion to the thickness of the etching mask 150A in the end part of the core layer 206. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of manufacturing an optical wiring circuit and an optical wiring substrate provided with the optical wiring circuit, and more specifically, a digital that performs image exposure with a light beam modulated by a spatial light modulation element or the like according to image data. The present invention relates to a method for manufacturing an optical wiring circuit using a maskless exposure apparatus, and an optical wiring substrate including the optical wiring circuit.
[0002]
[Prior art]
An optical wiring circuit having a circuit configuration using an optical waveguide, for example, an optical wiring board having an optical wiring circuit for transmitting light between a surface-mounted light-emitting element and a light-receiving element, is provided on the surface-mounted element side. In order to convert the optical path from the optical path to the optical path on the optical waveguide side of the optical wiring board by 90 °, and to make the light enter or exit the optical waveguide, the end of the optical waveguide is formed at an oblique angle of 45 °, Some have a reflecting mirror on the inclined end face.
[0003]
Conventionally, in such an optical wiring substrate, in order to form an inclined surface at the end of the optical waveguide, a photomask in which the density of the mask pattern in the region corresponding to the inclined surface changes (increases or decreases) in the longitudinal direction of the optical waveguide. Is used to form an etching mask with a tilted structure by changing the amount of UV transmitted light that exposes the photoresist, and the mask pattern is transferred by reactive ion etching, etc. Thickness having slanted side surfaces using a photomask having a simple structure having a mask pattern having a boundary between light transmission and light shielding near the end of a portion to be a mirror (see, for example, Patent Document 1) There is one that forms a film resist pattern and processes the core diagonally by dry etching the resist pattern together (for example, See Patent Document 2).
[0004]
In recent years, a polymer material such as polysilane whose refractive index is changed by light irradiation or BP-PMA (polymethacrylic acid (PMA) polymer having a photofunctional group consisting of benzophenone residues (BP groups)) is used as a core material. An optical wiring substrate (large area waveguide film, optical waveguide) can be manufactured without an etching process by a photo bleaching method (for example, see Patent Documents 3 and 4) or a direct exposure method using a photocurable resin. Thus, the manufacturing is simplified.
[0005]
[Patent Document 1]
JP-A-6-265738 (page 3-4, FIG. 1)
[Patent Document 2]
JP 2002-82242 A (page 3-4, FIG. 2)
[Patent Document 3]
JP-A-6-265738 (Pages 6-7, FIGS. 5 and 6)
[Patent Document 4]
JP 2002-14241 (page 4)
[0006]
[Problems to be solved by the invention]
However, in the example of Patent Document 1 described above, since the photomask has a special structure, it takes time to manufacture. With respect to Patent Document 2, since the photolithography process is required twice for processing the mirror forming portion, the manufacturing process becomes complicated.
[0007]
Further, in these conventional examples in which a photolithography process is performed, when manufacturing an optical wiring substrate having a multi-stage structure in which a plurality of optical wiring circuits are provided in the thickness direction (stacking direction) of the substrate, the photolithography process is repeatedly performed. However, in this case, in a substrate material such as polyimide having a high hygroscopic property and a large dimensional change, the position accuracy of the mirror forming portion is lowered due to the expansion and contraction. Therefore, in order to realize highly accurate alignment, it is necessary to prepare a plurality of types of photomasks with different dimensions. This causes a problem that the manufacturing process is complicated and the manufacturing cost is increased.
[0008]
On the other hand, a photolithographic process is also required in a photo bleaching method and a direct exposure method that do not require an etching process. Therefore, the same is true for high-precision alignment and mirror formation when forming a multistage circuit as described above. Issues remain.
[0009]
By the way, in recent years, various exposure apparatuses that perform image exposure with a light beam modulated in accordance with image data using a spatial light modulation element such as a digital micromirror device (DMD) have been proposed.
[0010]
For example, the DMD is a mirror device in which a number of micromirrors whose reflection surfaces change in response to a control signal are two-dimensionally arranged on a semiconductor substrate such as silicon. An exposure apparatus using this DMD is , A light source that emits laser light, a lens system that collimates the laser light emitted from the light source, a DMD that is arranged at a substantially focal position of the lens system, and a lens system that forms an image of the laser light reflected by the DMD on the scanning surface Each of the DMD micromirrors is on / off controlled by a control signal generated according to image data or the like to modulate the laser beam, and image exposure is performed with the modulated laser beam. Further, in this exposure apparatus, since the exposure amount (light intensity) can be controlled for each pixel in units of micromirrors of the spatial light modulator, it is considered suitable for manufacturing the above-described optical wiring board without a mask.
[0011]
In consideration of the above facts, the present invention can easily form an optical wiring circuit by maskless exposure, in particular, an inclined surface shape for providing a reflection mirror at the end of an optical waveguide, or an optical wiring circuit. It is an object of the present invention to provide a method for manufacturing an optical wiring circuit that can be easily formed even in a circuit configuration in which a plurality of stages are formed in the stacking direction, and an optical wiring substrate including the optical wiring circuit.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, an invention according to claim 1 is a method of manufacturing an optical wiring circuit configured by an optical waveguide, wherein an image is generated by a light beam modulated by a spatial light modulator according to image information. The method has a step of exposing and patterning a predetermined region of the optical material for forming the optical waveguide with the light beam by using an exposure means for performing exposure.
[0013]
According to the first aspect of the present invention, a predetermined region of the optical material for forming the optical waveguide is exposed and patterned by image exposure using a light beam modulated by a spatial light modulation element such as DMD. Then, an optical waveguide is formed, and an optical wiring circuit constituted by the optical waveguide is manufactured. Thereby, manufacture of the optical wiring circuit by maskless exposure is implement | achieved, and the manufacturing method can be made easy. Further, since a photomask is not used, it is possible to easily cope with a change in a circuit or an optical wiring circuit having a complicated circuit configuration.
[0014]
Moreover, since high-definition image exposure can be performed with a light beam in contrast to conventional mask exposure using light from a lamp light source or the like, the pattern shape of the optical waveguide can be smoothly formed with high accuracy. For this reason, it is possible to manufacture an optical wiring circuit with reduced propagation loss.
[0015]
According to a second aspect of the present invention, an optical device having an inclined surface for providing a reflection mirror that allows light to enter the core layer or emit light from the core layer at an end of the core layer that constitutes the optical waveguide. A method of manufacturing an optical wiring circuit configured by a waveguide, wherein an optical device for forming the optical waveguide using an exposure unit that performs image exposure with a light beam modulated by a spatial light modulator in accordance with image information The method includes a step of exposing and patterning a predetermined region of the material with the light beam whose exposure amount is controlled according to the inclined shape of the inclined surface.
[0016]
According to the second aspect of the present invention, the predetermined region of the optical material for forming the optical waveguide, which corresponds to the inclined surface formed at the end portion of the core layer constituting the optical waveguide, is determined according to the image information. Using exposure means for performing image exposure with a light beam modulated by a spatial light modulator, exposure is performed with a light beam whose exposure amount is controlled according to the inclined shape of the inclined surface, and patterning is performed. Since the pattern shape (film thickness) of the optical material changes according to the exposure amount, an inclined surface is formed in a predetermined region of the optical material exposed by the light beam whose exposure amount is controlled as described above.
[0017]
For example, in the case of a photoresist in which an optical material is formed on an optical waveguide material, a slope structure etching mask is formed in a predetermined region of the photoresist. When the core layer is etched using this etching mask, the etching mask is also etched as the material to be etched (core layer) is etched. Therefore, the pattern of the etching mask is formed at the end of the core layer. Accordingly, an inclined surface inclined (transferred) is formed. When a reflecting mirror is formed on this inclined surface by metal vapor deposition or the like, an optical wiring circuit having an optical waveguide provided with a reflecting mirror on the inclined surface at the end of the core layer is manufactured.
[0018]
Thereby, an optical wiring circuit can be easily manufactured without using a special photomask as in the prior art.
[0019]
According to a third aspect of the present invention, in the method for manufacturing an optical wiring circuit according to the second aspect, the exposure unit performs image exposure by scanning the light beam and overlaps two or more pixels in the scanning. And the exposure amount is controlled by the multiple exposure.
[0020]
According to a third aspect of the present invention, the light beam by the exposure means is modulated and scanned by the spatial light modulator, and the exposure amount is adjusted by using multiple exposure in which two or more pixels are overlapped and exposed by the scanning of the light beam. By controlling, it becomes easy to control the exposure amount by the light beam. Further, since high-definition exposure with improved gradation is possible, for example, when the optical material is a photoresist, the inclined shape of the etching mask to be formed can be made smooth. The multiple exposure function for exposing two or more pixels in an overlapping manner includes a function for exposing a plurality of pixels by overlapping them at the same point, and a function for exposing a plurality of pixels by overlapping the centers of the pixels instead of the same point. , And a combination of both.
[0021]
According to a fourth aspect of the present invention, in the optical wiring circuit manufacturing method according to any one of the first to third aspects, the resolution of image exposure by the light beam is 0.1 μm to 2.5 μm. It is characterized by being.
[0022]
In the invention according to claim 4, the pattern shape of the optical waveguide can be more favorably formed by the very high-definition light beam exposure with a resolution of 0.1 μm to 2.5 μm, for example, propagation in a branch circuit or the like. Loss can be reduced.
[0023]
The invention according to claim 5 is the optical wiring circuit manufacturing method according to any one of claims 1 to 4, wherein the optical material is a photoresist formed on an optical waveguide material, An etching mask is formed from the photoresist in the step of exposing and patterning with the light beam, and then the optical waveguide material is etched using the etching mask.
[0024]
In the invention according to claim 5, an etching mask is formed from the photoresist by exposing and patterning a predetermined region of the photoresist formed on the optical waveguide material with a light beam modulated by a spatial light modulator. Then, the core layer constituting the optical waveguide is formed by etching the optical waveguide material using the etching mask. Thereby, the core layer can be formed by maskless exposure, and the manufacture of the optical wiring circuit is facilitated.
[0025]
According to a sixth aspect of the present invention, in the optical wiring circuit manufacturing method according to the fifth aspect, the photoresist is a positive type.
[0026]
According to the sixth aspect of the present invention, by using a positive photoresist, a pattern shape having the above inclined structure can be easily formed in the etching mask.
[0027]
The invention according to claim 7 is the optical wiring circuit manufacturing method according to any one of claims 1 to 4, wherein the optical material is an optical waveguide material whose refractive index changes by light irradiation, The optical waveguide is formed by changing the refractive index of a predetermined region of the optical waveguide material in the step of exposing and patterning with the light beam.
[0028]
According to the seventh aspect of the present invention, a predetermined region of the optical waveguide material whose refractive index is changed by light irradiation is exposed and patterned by a light beam modulated by a spatial light modulator, thereby forming a high refractive index constituting the optical waveguide. An index core layer and a low index cladding layer are formed. Thereby, the core layer and the clad layer can be formed by maskless exposure, and the manufacture of the optical wiring circuit is facilitated.
[0029]
According to an eighth aspect of the present invention, in the optical wiring circuit manufacturing method according to the seventh aspect, the optical waveguide material has a property that a refractive index is lowered by light irradiation.
[0030]
In the invention described in claim 8, the optical waveguide material is a polymer material or the like having a property that the refractive index is lowered by light irradiation, and by this, the region where the cladding layer is formed is exposed and patterned by the light beam. A clad layer having a refractive index lower than that of the core layer can be formed.
[0031]
The invention according to claim 9 is the method for manufacturing an optical wiring circuit according to any one of claims 2 to 4, wherein the optical waveguide is in the method for manufacturing an optical wiring circuit according to claim 7 or 8. The core layer formed of a material has a refractive index of the patterned inclined surface in a substantially vertical direction with respect to the inclined surface in the step of exposing and patterning with the light beam whose exposure amount is controlled according to the inclined shape of the inclined surface. It is characterized by a distribution that changes stepwise or substantially continuously.
[0032]
In the invention according to claim 9, the refractive index of the inclined surface provided at the end of the core layer is incident on the inclined surface by a distribution that changes stepwise or substantially continuously in a direction substantially perpendicular to the inclined surface. It is possible to increase the reflectance of light. Since the inclined surface substantially functions as a reflecting mirror, light can be efficiently bent without providing a reflecting mirror separately on the inclined surface.
[0033]
According to a tenth aspect of the present invention, in the method for manufacturing an optical wiring circuit according to any one of the first to fourth aspects, the optical material is an optical waveguide material that is cured by light irradiation, and the light beam In the step of exposing and patterning, after curing a predetermined region of the optical waveguide material, an uncured portion of the optical waveguide material is removed by development processing.
[0034]
In the invention according to claim 10, the predetermined region of the optical waveguide material that is cured by light irradiation is exposed and patterned by the light beam modulated by the spatial light modulator, thereby curing the predetermined region of the optical waveguide material. The uncured portion of the optical waveguide material is removed by development processing to form a core layer constituting the optical waveguide. Thereby, the core layer can be formed by maskless exposure, and the manufacture of the optical wiring circuit is facilitated.
[0035]
The invention according to claim 11 is characterized by an optical wiring substrate including an optical wiring circuit manufactured by the manufacturing method according to any one of claims 1 to 10. According to a twelfth aspect of the present invention, there is provided an optical wiring substrate including a plurality of optical wiring circuits manufactured by the manufacturing method according to any one of the first to tenth aspects in a stacking direction.
[0036]
In the inventions according to claims 11 and 12, if an optical wiring board is provided with an optical wiring circuit formed by digital maskless exposure using the above light beam, the manufacturing becomes easy, and the optical wiring circuit is arranged in the stacking direction. Even an optical wiring board having a plurality of stages is easily manufactured.
[0037]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0038]
(First embodiment)
[Configuration of exposure apparatus]
As shown in FIG. 1, an exposure apparatus 100 according to the first embodiment of the present invention uses an optical wiring board material (optical wiring board 200) in which a photosensitive material (photoresist) 150 is formed on an optical waveguide material. A flat plate-like stage 152 is provided which is sucked and held on the surface. Two guides 158 are extended on the upper surface of the thick plate-shaped installation base 156 supported by the four legs 154 along the stage moving direction (the arrow Y direction in the figure). The stage 152 is disposed such that the longitudinal direction thereof faces the stage moving direction, and is supported by a guide 158 so as to be reciprocally movable. The exposure apparatus 100 is provided with a drive device (not shown) for driving the stage 152 along the guide 158.
[0039]
A gate 160 formed in a U-shape is disposed at the center of the installation table 156 so as to straddle the movement path of the stage 152, and both ends of the gate 160 are fixed to both side surfaces of the installation table 156. A scanner 162 is disposed on one side of the gate 160, and a plurality of (for example, two) detection sensors 164 for detecting the front end and the rear end of the optical wiring board 200 are provided on the other side. The scanner 162 and the detection sensor 164 are respectively attached to the gate 160 and fixedly arranged above the moving path of the stage 152. The scanner 162 and the detection sensor 164 are connected to a controller (not shown) that controls them.
[0040]
As shown in FIGS. 2 and 3B, the scanner 162 includes a plurality of (for example, 14) exposure heads 166 arranged in an approximately matrix of m rows and n columns (for example, 3 rows and 5 columns). ing. In this example, four exposure heads 166 are arranged in the third row in relation to the width of the photosensitive material 150 (optical wiring board 200). In addition, when showing each exposure head arranged in the m-th row and the n-th column, it is expressed as an exposure head 166 mn.
[0041]
An exposure area 168 by the exposure head 166 has a rectangular shape with a short side in the sub-scanning direction. Therefore, as the stage 152 moves, a strip-shaped exposed area 170 is formed for each exposure head 166 in the photosensitive material 150. In addition, when showing the exposure area by each exposure head arranged in the nth column of the m-th row, it is expressed as an exposure area 168mn.
[0042]
Further, as shown in FIGS. 3A and 3B, each of the exposure heads in each row arranged in a line so that the strip-shaped exposed areas 170 are arranged without gaps in the direction orthogonal to the sub-scanning direction. In the arrangement direction, they are shifted by a predetermined interval (natural number times the long side of the exposure area, twice in this embodiment). For this reason, the part which cannot be exposed between the exposure area 16811 of the 1st line and the exposure area 16812 can be exposed by the exposure area 16821 of the 2nd line and the exposure area 16831 of the 3rd line.
[0043]
As shown in FIGS. 4, 5A and 5B, each of the exposure heads 16611 to 166mn is a digital light / semiconductor device that modulates an incident light beam for each pixel in accordance with image data. A micromirror device (DMD) 50 is provided. The DMD 50 is connected to a controller (not shown) including a data processing unit and a mirror drive control unit. The data processing unit of this controller generates a control signal for driving and controlling each micromirror in the region to be controlled by the DMD 50 for each exposure head 166 based on the input image data. The area to be controlled will be described later. The mirror drive control unit controls the angle of the reflection surface of each micromirror of the DMD 50 for each exposure head 166 based on the control signal generated by the image data processing unit. The control of the angle of the reflecting surface will be described later.
[0044]
On the light incident side of the DMD 50, a fiber array light source 66 including a laser emitting section in which emission ends (light emitting points) of an optical fiber are arranged in a line along a direction corresponding to the long side direction of the exposure area 168, a fiber A lens system 67 that corrects the laser light emitted from the array light source 66 and collects it on the DMD, and a mirror 69 that reflects the laser light transmitted through the lens system 67 toward the DMD 50 are arranged in this order.
[0045]
The lens system 67 includes a pair of combination lenses 71 that collimate the laser light emitted from the fiber array light source 66 and a pair of combination lenses that correct the light quantity distribution of the collimated laser light to be uniform. 73 and a condensing lens 75 that condenses the laser light whose light quantity distribution is corrected on the DMD. With respect to the arrangement direction of the laser emitting ends, the combination lens 73 spreads the light beam at a portion close to the optical axis of the lens and contracts the light beam at a portion away from the optical axis, and with respect to a direction orthogonal to the arrangement direction. Has a function of allowing light to pass through as it is, and corrects the laser light so that the light quantity distribution is uniform.
[0046]
Further, on the light reflection side of the DMD 50, lens systems 54 and 58 for forming an image of the laser light reflected by the DMD 50 on the scanning surface (exposed surface) 56 of the photosensitive material 150 are arranged. The lens systems 54 and 58 are arranged so that the DMD 50 and the exposed surface 56 are in a conjugate relationship.
[0047]
As shown in FIG. 6, the DMD 50 is configured such that a micromirror 62 is supported by a support column on an SRAM cell (memory cell) 60, and a large number of (pixels) (pixels) are formed. For example, the mirror device is configured by arranging 600 × 800 micromirrors in a lattice pattern. Each pixel is provided with a micromirror 62 supported by a support column at the top, and a material having a high reflectance such as aluminum is deposited on the surface of the micromirror 62. The reflectance of the micromirror 62 is 90% or more. A silicon gate CMOS SRAM cell 60 manufactured on a normal semiconductor memory manufacturing line is disposed directly below the micromirror 62 via a support including a hinge and a yoke, and is entirely monolithic (integrated type). ).
[0048]
When a digital signal is written in the SRAM cell 60 of the DMD 50, the micromirror 62 supported by the support is inclined within a range of ± α degrees (for example, ± 10 degrees) with respect to the substrate side on which the DMD 50 is disposed with the diagonal line as the center. It is done. FIG. 7A shows a state in which the micromirror 62 is tilted to + α degrees in the on state, and FIG. 7B shows a state in which the micromirror 62 is tilted to −α degrees in the off state. Therefore, by controlling the inclination of the micromirror 62 in each pixel of the DMD 50 as shown in FIG. 6 according to the image signal, the light incident on the DMD 50 is reflected in the inclination direction of each micromirror 62. .
[0049]
FIG. 6 shows an example of a state in which a part of the DMD 50 is enlarged and the micromirror 62 is controlled to + α degrees or −α degrees. On / off control of each micromirror 62 is performed by a controller (not shown) connected to the DMD 50. A light absorber (not shown) is arranged in the direction in which the light beam is reflected by the micromirror 62 in the off state.
[0050]
The DMD 50 is preferably arranged with a slight inclination so that the short side forms a predetermined angle θ (for example, 1 ° to 5 °) with the sub-scanning direction. 8A shows the scanning trajectory of the reflected light image (exposure beam) 53 by each micromirror when the DMD 50 is not tilted, and FIG. 8B shows the scanning trajectory of the exposure beam 53 when the DMD 50 is tilted. Show.
[0051]
In the DMD 50, a number of micromirror arrays in which a large number (for example, 800) of micromirrors are arranged in the longitudinal direction are arranged in a large number (for example, 600 sets) in the short direction. As shown, by tilting the DMD 50, the pitch P2 of the scanning trajectory (scanning line) of the exposure beam 53 by each micromirror becomes narrower than the pitch P1 of the scanning line when the DMD 50 is not tilted, and the resolution is greatly improved. Can be made. On the other hand, since the tilt angle of the DMD 50 is very small, the scan width W2 when the DMD 50 is tilted and the scan width W1 when the DMD 50 is not tilted are substantially the same.
[0052]
Further, the same scanning line is overlapped and exposed (multiple exposure) by different micromirror rows. By such multiple exposure, a very small amount of exposure position can be controlled, and high-definition exposure can be realized. Further, joints between a plurality of exposure heads arranged in the main scanning direction can be connected without a step by controlling a very small amount of exposure position. Further, by using the above-described multiple exposure function and performing exposure by overlapping two or more pixels, that is, by changing the number of exposures for each pixel or for each scanning line, the exposure amount control for each pixel or scanning line. Is possible. The multiple exposure function that exposes two or more pixels in an overlapped manner has a function of exposing a plurality of pixels at the same point (exposure on the same scanning line), and a plurality of pixels at the center of each other instead of the same point. And a function of overlapping and exposing, and a function combining both of them.
[0053]
Note that the same effect can be obtained by arranging the micromirror rows in a staggered manner by shifting the micromirror rows by a predetermined interval in a direction orthogonal to the sub-scanning direction instead of tilting the DMD 50.
[0054]
As shown in FIG. 9A, the fiber array light source 66 includes a plurality of (for example, six) laser modules 64, and one end of the multimode optical fiber 30 is coupled to each laser module 64. Yes. The other end of the multimode optical fiber 30 is coupled with an optical fiber 31 having the same core diameter as the multimode optical fiber 30 and a cladding diameter smaller than the multimode optical fiber 30, as shown in FIG. A laser emission portion 68 is configured by arranging the emission end portions (light emission points) of the optical fiber 31 in one row along the main scanning direction orthogonal to the sub-scanning direction. As shown in FIG. 9D, the light emitting points can be arranged in two rows along the main scanning direction.
[0055]
As shown in FIG. 9B, the emission end of the optical fiber 31 is sandwiched and fixed between two support plates 65 having a flat surface. Further, a transparent protective plate 63 such as glass is disposed on the light emitting side of the optical fiber 31 in order to protect the end face of the optical fiber 31. The protection plate 63 may be disposed in close contact with the end surface of the optical fiber 31 or may be disposed so that the end surface of the optical fiber 31 is sealed. The exit end portion of the optical fiber 31 has a high light density and is likely to collect dust and easily deteriorate. However, the protective plate 63 can prevent the dust from adhering to the end face and can also delay the deterioration.
[0056]
In this example, in order to arrange the emission ends of the optical fibers 31 with a small cladding diameter in a line without any gaps, the multimode optical fiber 30 is placed between two adjacent multimode optical fibers 30 at a portion with a large cladding diameter. Two exit ends of the optical fiber 31 coupled to two adjacent multi-mode optical fibers 30 where the exit ends of the optical fibers 31 coupled to the stacked multi-mode optical fibers 30 are adjacent to each other at a portion where the cladding diameter is large. Are arranged so as to be sandwiched between them.
[0057]
For example, as shown in FIG. 10, an optical fiber 31 having a length of 1 to 30 cm and having a small cladding diameter is coaxially connected to the tip of the multimode optical fiber 30 having a large cladding diameter on the laser light emission side. Can be obtained by linking them together. In the two optical fibers, the incident end face of the optical fiber 31 is fused and joined to the outgoing end face of the multimode optical fiber 30 so that the central axes of both optical fibers coincide. As described above, the diameter of the core 31 a of the optical fiber 31 is the same as the diameter of the core 30 a of the multimode optical fiber 30.
[0058]
In addition, a short optical fiber in which an optical fiber having a short cladding diameter and a large cladding diameter is fused to an optical fiber having a short cladding diameter and a large cladding diameter may be coupled to the output end of the multimode optical fiber 30 via a ferrule or an optical connector. Good. By detachably coupling using a connector or the like, the tip portion can be easily replaced when an optical fiber having a small cladding diameter is broken, and the cost required for exposure head maintenance can be reduced. Hereinafter, the optical fiber 31 may be referred to as an emission end portion of the multimode optical fiber 30.
[0059]
The multimode optical fiber 30 and the optical fiber 31 may be any of a step index type optical fiber, a graded index type optical fiber, and a composite type optical fiber. For example, a step index type optical fiber manufactured by Mitsubishi Cable Industries, Ltd. can be used. In the present embodiment, the multimode optical fiber 30 and the optical fiber 31 are step index type optical fibers, and the multimode optical fiber 30 has a cladding diameter = 125 μm, a core diameter = 25 μm, NA = 0.2, an incident end face. The transmittance of the coat is 99.5% or more, and the optical fiber 31 has a cladding diameter = 60 μm, a core diameter = 25 μm, and NA = 0.2.
[0060]
The laser module 64 is configured by a combined laser light source (fiber light source) shown in FIG. The combined laser light source includes a plurality of (for example, seven) chip-like lateral multimode or single mode UV semiconductor lasers LD1, LD2, LD3, LD4, LD5, LD6, arrayed and fixed on the heat block 10. And LD7, collimator lenses 11, 12, 13, 14, 15, 16, and 17 provided corresponding to each of the UV semiconductor lasers LD1 to LD7, one condenser lens 20, and one multi-lens. Mode optical fiber 30. The UV-based semiconductor lasers LD1 to LD7 all have the same oscillation wavelength and maximum output. The number of semiconductor lasers is not limited to seven.
[0061]
As shown in FIGS. 12 and 13, the above-described combined laser light source is housed in a box-shaped package 40 having an upper opening together with other optical elements. The package 40 includes a package lid 41 manufactured so as to close the opening. By introducing a sealing gas after the deaeration process and closing the opening of the package 40 with the package lid 41, the package 40, the package lid 41, The combined laser light source is hermetically sealed in a closed space (sealed space) formed by the above.
[0062]
A base plate 42 is fixed to the bottom surface of the package 40, and the heat block 10, a condensing lens holder 45 that holds the condensing lens 20, and the multimode optical fiber 30 are disposed on the top surface of the base plate 42. A fiber holder 46 that holds the incident end is attached. The exit end of the multimode optical fiber 30 is drawn out of the package from an opening formed in the wall surface of the package 40.
[0063]
Further, a collimator lens holder 44 is attached to the side surface of the heat block 10, and the collimator lenses 11 to 17 are held. An opening is formed in the lateral wall surface of the package 40, and wiring 47 for supplying a drive current to the UV semiconductor lasers LD1 to LD7 is drawn out of the package through the opening.
[0064]
In FIG. 13, in order to avoid complication of the drawing, only the UV semiconductor laser LD 7 among the plurality of UV semiconductor lasers is numbered, and only the collimator lens 17 among the plurality of collimator lenses is numbered. doing.
[0065]
FIG. 14 shows the front shape of the attachment part of the collimator lenses 11-17. Each of the collimator lenses 11 to 17 is formed in a shape obtained by cutting a region including the optical axis of a circular lens having an aspherical surface into a long and narrow plane. This elongated collimator lens can be formed, for example, by molding resin or optical glass. The collimator lenses 11 to 17 are closely arranged in the arrangement direction of the light emitting points so that the length direction is orthogonal to the arrangement direction of the light emitting points of the UV semiconductor lasers LD1 to LD7 (left and right direction in FIG. 14).
[0066]
On the other hand, each of the UV-based semiconductor lasers LD1 to LD7 includes an active layer having a light emission width of 2 μm, and each of the laser beams B1 in a state in which the divergence angles in the direction parallel to and perpendicular to the active layer are 10 ° and 30 °, respectively. A laser emitting ~ B7 is used. These UV-based semiconductor lasers LD1 to LD7 are arranged so that the light emitting points are arranged in a line in a direction parallel to the active layer.
[0067]
Accordingly, in the laser beams B1 to B7 emitted from the respective light emitting points, the direction in which the divergence angle is large coincides with the length direction and the divergence angle is small with respect to the elongated collimator lenses 11 to 17 as described above. Incident light is incident in a state where the direction coincides with the width direction (direction perpendicular to the length direction). That is, the collimator lenses 11 to 17 have a width of 1.1 mm and a length of 4.6 mm, and the horizontal and vertical beam diameters of the laser beams B1 to B7 incident thereon are 0.9 mm and 2. 6 mm. Each of the collimator lenses 11 to 17 has a focal length f1 = 3 mm, NA = 0.6, and a lens arrangement pitch = 1.25 mm.
[0068]
The condensing lens 20 is formed by cutting a region including the optical axis of a circular lens having an aspheric surface into a long and narrow shape in parallel planes, and is long in the arrangement direction of the collimator lenses 11 to 17, that is, in a horizontal direction and short in a direction perpendicular thereto. Is formed. The condenser lens 20 has a focal length f2 = 23 mm and NA = 0.2. This condensing lens 20 is also formed by molding resin or optical glass, for example.
[0069]
[Operation of exposure apparatus]
Next, the operation of the exposure apparatus will be described.
[0070]
In each exposure head 166 of the scanner 162, laser beams B1, B2, B3, B4, B5, and B6 emitted in a divergent light state from each of the UV semiconductor lasers LD1 to LD7 that constitute the combined laser light source of the fiber array light source 66. , And B7 are collimated by corresponding collimator lenses 11-17. The collimated laser beams B <b> 1 to B <b> 7 are collected by the condenser lens 20 and converge on the incident end face of the core 30 a of the multimode optical fiber 30.
[0071]
In this example, the collimator lenses 11 to 17 and the condenser lens 20 constitute a condensing optical system, and the condensing optical system and the multimode optical fiber 30 constitute a multiplexing optical system. That is, the laser beams B1 to B7 condensed as described above by the condenser lens 20 enter the core 30a of the multimode optical fiber 30 and propagate through the optical fiber to be combined with one laser beam B. The light is emitted from the optical fiber 31 coupled to the output end of the multimode optical fiber 30.
[0072]
In each laser module, when the coupling efficiency of the laser beams B1 to B7 to the multimode optical fiber 30 is 0.85 and each output of the UV semiconductor lasers LD1 to LD7 is 30 mW, the light arranged in an array For each of the fibers 31, a combined laser beam B with an output of 180 mW (= 30 mW × 0.85 × 7) can be obtained. Therefore, the output from the laser emitting unit 68 in which the six optical fibers 31 are arranged in an array is about 1 W (= 180 mW × 6).
[0073]
In the laser emitting portion 68 of the fiber array light source 66, light emission points with high luminance are arranged in a line along the main scanning direction as described above. A conventional fiber light source that couples laser light from a single semiconductor laser to a single optical fiber has a low output, so a desired output could not be obtained unless multiple rows are arranged. Since the combined laser light source used in the form has a high output, a desired output can be obtained even with a small number of columns, for example, one column.
[0074]
For example, in a conventional fiber light source in which a semiconductor laser and an optical fiber are coupled on a one-to-one basis, a laser having an output of about 30 mW (milliwatt) is usually used as the semiconductor laser, and the core diameter is 50 μm and the cladding diameter is 125 μm. Since a multimode optical fiber having a numerical aperture (NA) of 0.2 is used, if an output of about 1 W (watt) is to be obtained, 48 multimode optical fibers (8 × 6) must be bundled. Since the area of the light emitting region is 0.62 mm 2 (0.675 mm × 0.925 mm), the luminance at the laser emitting portion 68 is 1.6 × 10 6 (W / m 2), and the luminance per optical fiber. Is 3.2 × 10 6 (W / m 2).
[0075]
On the other hand, in this embodiment, as described above, an output of about 1 W can be obtained with six multimode optical fibers, and the area of the light emitting region at the laser emitting portion 68 is 0.0081 mm 2 (0.325 mm × 0.025 mm), the luminance at the laser emitting portion 68 is 123 × 10 6 (W / m 2), and about 80 times higher luminance can be achieved compared to the conventional case. Further, the luminance per optical fiber is 90 × 10 6 (W / m 2), and the luminance can be increased by about 28 times compared with the conventional one.
[0076]
Here, with reference to FIGS. 15A and 15B, the difference in depth of focus between the conventional exposure head and the exposure head of the present embodiment will be described. The diameter of the light emitting region of the bundled fiber light source of the conventional exposure head is 0.675 mm, and the diameter of the light emitting region of the fiber array light source of the exposure head of this embodiment is 0.0025 mm. is there. As shown in FIG. 15A, in the conventional exposure head, since the light emitting area of the light source (bundle-shaped fiber light source) 1 is large, the angle of the light beam incident on the DMD 3 increases, and as a result, the light enters the scanning surface 5. The angle of the light beam increases. For this reason, the beam diameter tends to increase with respect to the light condensing direction (shift in the focus direction).
[0077]
On the other hand, as shown in FIG. 15B, in the exposure head of the present embodiment, the diameter of the light emitting region of the fiber array light source 66 is small in the sub-scanning direction, so that the light flux that passes through the lens system 67 and enters the DMD 50 , And as a result, the angle of the light beam incident on the scanning surface 56 is reduced. That is, the depth of focus becomes deep. In this example, the diameter of the light emitting region in the sub-scanning direction is about 30 times that of the conventional one, and a depth of focus substantially corresponding to the diffraction limit can be obtained. Therefore, it is suitable for exposure of a minute spot. In this example, the size of one pixel projected on the exposure surface is 10 μm × 10 μm. DMD is a reflective spatial modulation element, but FIGS. 15A and 15B are developed views for explaining the optical relationship.
[0078]
Image data corresponding to the exposure pattern is input to a controller (not shown) connected to the DMD 50 and temporarily stored in a frame memory in the controller. This image data is data representing the density of each pixel constituting the image by binary values (whether or not dots are recorded).
[0079]
The stage 152 on which the optical wiring substrate 200 is set is moved at a constant speed from the upstream side to the downstream side of the gate 160 along the guide 158 by a driving device (not shown). When the leading edge of the optical wiring board 200 is detected by the detection sensor 164 attached to the gate 160 when the stage 152 passes under the gate 160, the image data stored in the frame memory is sequentially read out for a plurality of lines. Then, a control signal is generated for each exposure head 166 based on the image data read by the data processing unit. Then, each of the micromirrors of the DMD 50 is controlled on and off for each exposure head 166 based on the generated control signal by the mirror drive control unit.
[0080]
When the DMD 50 is irradiated with laser light from the fiber array light source 66, the laser light reflected when the micromirror of the DMD 50 is in the on state forms an image on the exposed surface 56 of the photosensitive material 150 by the lens systems 54 and 58. Is done. In this manner, the laser light emitted from the fiber array light source 66 is turned on and off for each pixel, and the photosensitive material 150 is exposed in pixel units (exposure area 168) that is approximately the same number as the number of pixels used in the DMD 50. Further, when the photosensitive material 150 (optical wiring board 200) is moved at a constant speed together with the stage 152, the photosensitive material 150 is sub-scanned in the direction opposite to the stage moving direction by the scanner 162, and each exposure head 166 has a strip shape. The exposed area 170 is formed.
[0081]
As shown in FIGS. 16A and 16B, in this embodiment, the DMD 50 has 600 sets of micromirror arrays in which 800 micromirrors are arranged in the main scanning direction, which are arranged in the subscanning direction. However, in the present embodiment, control is performed so that only a part of micromirror rows (for example, 800 × 100 rows) are driven by the controller.
[0082]
As shown in FIG. 16A, a micromirror array arranged at the center of the DMD 50 may be used, and as shown in FIG. 16B, the micromirror array arranged at the end of the DMD 50 is used. May be used. In addition, when a defect occurs in some of the micromirrors, the micromirror array to be used may be appropriately changed depending on the situation, such as using a micromirror array in which no defect has occurred.
[0083]
Since the data processing speed of the DMD 50 is limited and the modulation speed per line is determined in proportion to the number of pixels used, the modulation speed per line can be increased by using only a part of the micromirror rows. Get faster. On the other hand, in the case of an exposure method in which the exposure head is continuously moved relative to the exposure surface, it is not necessary to use all the pixels in the sub-scanning direction.
[0084]
For example, when only 300 sets are used in 600 micromirror rows, modulation can be performed twice as fast per line as compared to the case of using all 600 sets. Further, when only 200 sets of 600 micromirror arrays are used, modulation can be performed three times faster per line than when all 600 sets are used. That is, an area of 500 mm in the sub-scanning direction can be exposed in 17 seconds. Further, when only 100 sets are used, modulation can be performed 6 times faster per line. That is, an area of 500 mm in the sub-scanning direction can be exposed in 9 seconds.
[0085]
The number of micromirror rows to be used, that is, the number of micromirrors arranged in the sub-scanning direction is preferably 10 or more and 200 or less, and more preferably 10 or more and 100 or less. Since the area per micromirror corresponding to one pixel is 15 μm × 15 μm, when converted to the use area of DMD50, an area of 12 mm × 150 μm or more and 12 mm × 3 mm or less is preferable, and 12 mm × 150 μm or more and 12 mm A region of × 1.5 mm or less is more preferable.
[0086]
If the number of micromirror rows to be used is within the above range, as shown in FIGS. 17A and 17B, the laser light emitted from the fiber array light source 66 is made into substantially parallel light by the lens system 67, and the DMD 50 Can be irradiated. It is preferable that the irradiation area where the laser beam is irradiated by the DMD 50 coincides with the use area of the DMD 50. When the irradiation area is wider than the use area, the utilization efficiency of the laser light is lowered.
[0087]
On the other hand, the diameter of the light beam condensed on the DMD 50 in the sub-scanning direction needs to be reduced according to the number of micromirrors arranged in the sub-scanning direction by the lens system 67, but the number of micromirror rows to be used. Is less than 10, it is not preferable because the angle of the light beam incident on the DMD 50 increases and the depth of focus of the light beam on the scanning surface 56 becomes shallow. Further, the number of micromirror rows to be used is preferably 200 or less from the viewpoint of modulation speed. DMD is a reflective spatial modulation element, but FIGS. 17A and 17B are developed views for explaining the optical relationship.
[0088]
When the sub scanning of the photosensitive material 150 by the scanner 162 is completed and the rear end of the optical wiring board 200 is detected by the detection sensor 164, the stage 152 is moved along the guide 158 by the driving device (not shown) to the uppermost stream of the gate 160. It returns to the origin on the side and is moved again along the guide 158 from the upstream side to the downstream side of the gate 160 at a constant speed.
[0089]
As described above, the exposure apparatus of the present embodiment includes a DMD in which 600 micromirror arrays in which 800 micromirrors are arranged in the main scanning direction are arranged in 600 sets in the subscanning direction. Since the control is performed so that only the micromirror array is driven, the modulation speed per line becomes faster than when all the micromirror arrays are driven. This enables high-speed exposure.
[0090]
Further, since a high-intensity fiber array light source in which output ends of optical fibers of a combined laser light source are arranged in an array is used as a light source for illuminating the DMD, an exposure apparatus having a high output and a deep focal depth Can be realized. Furthermore, since the output of each fiber light source is increased, the number of fiber light sources necessary to obtain a desired output is reduced, and the cost of the exposure apparatus can be reduced.
[0091]
In particular, in the present embodiment, since the cladding diameter of the output end of the optical fiber is made smaller than the cladding diameter of the incident end, the diameter of the light emitting section is further reduced, and the brightness of the fiber array light source can be increased. Thereby, an exposure apparatus having a deeper depth of focus can be realized. For example, even in the case of ultra-high resolution exposure with a beam diameter of 1 μm or less and a resolution of 0.1 μm or less, a deep depth of focus can be obtained, high-speed and high-definition exposure is possible, and, for example, high resolution is required. It is also suitable for an exposure process such as a thin film transistor (TFT). In the exposure apparatus 100 of the present embodiment, the image exposure resolution is set to fall within the range of 0.1 μm to 2.5 μm.
[0092]
[Manufacture of optical wiring board]
Next, a method for manufacturing an optical wiring substrate (optical wiring circuit) using the exposure apparatus will be described.
[0093]
18 to 21 show the manufacturing process of the optical wiring board by the etching method. First, in FIG. 18A, a clad layer (fluorinated polyimide layer) 204 is formed by applying and baking a fluorinated polyamic acid solution to the temporary substrate 202. In FIG. 18B, a core layer (fluorinated polyimide layer) 206 having a refractive index larger than that of the cladding layer 204 is similarly applied and baked on the cladding layer 204.
[0094]
Next, in FIG. 18C, a positive photoresist (photosensitive epoxy resin or the like) as the photosensitive material 150 is applied on the core layer 206 with a thick film (laminate in the case of a dry film), and then the optical wiring is formed. The substrate material is set on the stage 152 of the exposure apparatus 100 of this embodiment.
[0095]
When the exposure operation is started by operating the apparatus, the exposure pattern is exposed to the photosensitive material 150 by the laser light emitted from the scanner 162 as the stage 152 moves as described above. In this embodiment, the amount of exposure at the edge of the pattern to be exposed is changed by multiple exposure in which two or more pixels are overlapped for exposure. As shown in FIG. 19D, in a predetermined region corresponding to the reflection mirror arrangement portion of the core layer 206, the number of overlaps is reduced stepwise from the tip side to the inside, and the exposure amount distribution (arrow UV) is illustrated. The exposure amount is controlled so as to have an inclination (about 45 °) as shown in FIG. In the figure, the depth direction is the main scanning direction, and the horizontal direction is the sub-scanning direction.
[0096]
After the exposure process of the photosensitive material 150 by the exposure apparatus 100 is completed, the exposed optical wiring board material is removed from the stage 152 and the photosensitive material 150 is developed. Here, since the pattern shape (film thickness) of the photosensitive material 150 changes in accordance with the exposure amount, an etching mask having a trapezoidal cross-section with an inclined end as shown in FIG. 150A is made.
[0097]
In FIG. 19F, the core layer 206 is processed by dry etching such as reactive ion etching. In this etching process, as the core layer 206 is etched, the etching mask 150A is also etched. The amount of processing at the end of the core layer 206 is proportional to the film thickness of the etching mask 150A, that is, the amount of processing reaching the material to be etched is larger in the thinner part than in the thicker part. An inclined surface 208 inclined according to the pattern shape of the etching mask 150A is formed at the end of the layer 206.
[0098]
In FIG. 20G, the etching mask 150A is peeled off, and in FIG. 20H, in order to increase the light reflectance at the inclined surface 208 of the core layer 206, a metal is deposited on the inclined surface 208 to form a thin film. A reflection mirror 210 is formed.
[0099]
Finally, in FIG. 20I, a fluorinated polyamic acid solution is applied and baked, the core layer 206 is covered with the clad layer 204, and peeled off from the temporary substrate 202, thereby completing the optical wiring substrate 200 (FIG. 21 (J )).
[0100]
As described above, in the method for manufacturing an optical wiring board according to the present embodiment, after the photosensitive material 150 (photoresist) is formed on the core layer 206, an image is formed with a light beam modulated by the DMD 50 in accordance with image information. Using an exposure apparatus 100 that performs exposure, a predetermined region of the photosensitive material 150 is exposed and patterned by a light beam, thereby forming an etching mask 150A and further corresponding to the inclined surface 208 formed at the end of the core layer 206. The core layer 206 is etched by setting the end of the etching mask 150A as a slope structure by exposing and patterning the etched area with a light beam whose exposure amount is controlled according to the slope shape of the slope 208. Even without using a special photomask as in the prior art, the light L is incident on the core layer 206 at the end of the core layer 206. That or optical wiring circuits and optical wiring board having a circuit constituted by an optical waveguide having an inclined surface 208 for providing a reflecting mirror 210 from the core layer 206 to emit light L can be easily manufactured.
[0101]
Further, such maskless exposure can easily cope with circuit changes and manufacture of complicated circuit configurations. Furthermore, since a large area can be exposed at high speed by line exposure, an optical wiring circuit can be formed at a high speed and in a large area on a film supplied in a roll shape, and the optical waveguide is formed into a plurality of buses. Even circuit patterns such as optical sheet buses can be mass-produced.
[0102]
In the present embodiment, the light beam by the exposure apparatus 100 is modulated and scanned by the DMD 50, and the exposure amount is controlled by using multiple exposure in which two or more pixels are overlapped and exposed by the scanned light beam. The exposure amount by the light beam can be easily controlled, and the inclined shape of the etching mask formed thereby can be made smooth.
[0103]
Furthermore, by realizing very high-definition light beam exposure with a resolution of 0.1 μm to 2.5 μm, it is possible to improve the pattern shape of the optical waveguide to be formed and to suppress circuit propagation loss. ing. For example, when exposing and forming a Y-shaped branch circuit, as schematically shown in FIG. 22, the (Y) branch circuit YH exposed with a light beam at a higher resolution than the (X) branch circuit YL. However, the pattern shape at the circuit inclined portion becomes better. Thereby, the branch circuit YH becomes a circuit with a smaller propagation loss.
[0104]
In the present embodiment, by using a positive photoresist, a pattern shape having an inclined structure can be easily formed on the etching mask 150A.
[0105]
(Second Embodiment)
Next, a method for manufacturing an optical wiring board having a plurality of optical wiring circuits will be described.
[0106]
23 and 24 show an exposure apparatus for forming a multi-stage optical wiring circuit according to the second embodiment of the present invention. In this exposure apparatus 171, a stage 172 is formed of a transparent glass plate having a predetermined thickness (for example, 10 mm), and is arranged above and below the stage 172 in parallel along the longitudinal direction of the stage 172. A pair of rails 176 is laid (in the figure, the upper rail 176 is omitted). On each pair of rails 176, linear scanners 162A and 162B having a plurality of the above-described exposure heads 166 are installed across the width direction (main scanning direction) of the stage 172. The scanners 162A and 162B are not shown. It is configured to move in the sub-scanning direction along the rail 176 under drive control by a driving device.
[0107]
Further, the optical wiring board material (optical wiring board 220) placed on the stage 172 is fixed so that both end portions in the longitudinal direction are pressed by a pair of rollers 186, and each roller 186 is fixed. The both ends of the roller shaft are respectively supported by an actuator 190 such as an air cylinder disposed above, and the optical wiring board 220 is fixed and released by moving up and down by driving the actuator 190.
[0108]
With the above configuration, in the exposure operation of the exposure apparatus 171, as shown in FIG. 24, the laser beam UVA emitted from the upper scanner 162 </ b> A over the main scanning direction is formed on the upper surface (front surface) 220 </ b> A of the optical wiring board 220. The laser beam UVB emitted from the lower scanner 162B is irradiated through the stage 172, and each scanner moves along the rail 176 in the sub-scanning direction. Thus, both sides can be exposed simultaneously by one scan without inverting the substrate.
[0109]
Next, a method for manufacturing an optical wiring board having a plurality of stages of optical wiring circuits using the exposure apparatus 171 will be described. First, the core layer (fluorinated polyimide) having a refractive index larger than that of the clad layer (fluorinated polyimide layer) 204 and the clad layer 204 on the temporary substrate 202 by the steps of FIGS. Layer) 206 and photosensitive material (positive photoresist) 150 are formed in this order. Moreover, the temporary board | substrate 202 here is formed with the transparent material (a glass plate, a transparent resin board, etc.) which has a light transmittance.
[0110]
When the optical wiring substrate 220 is set on the stage 172 of the exposure apparatus 171 and the apparatus is operated, the actuator 190 is driven to move the roller 186 downward, the both ends of the substrate are fixed to the roller 186, and the exposure operation starts. As described above, as the scanners 162A and 162B move in the sub-scanning direction, an exposure pattern corresponding to the image data is exposed to the photosensitive material 150 by the laser light emitted from each scanner.
[0111]
Again, the amount of exposure at the pattern edge exposed by multiple exposure is changed. However, as an exposure pattern, as shown in FIG. 25K, one of the pattern ends (left side in the figure) is exposed with the laser beam UVA from the scanner 162A disposed above, and the other end of the pattern ends. (Right side of the figure) is exposed by laser light UVB emitted from the scanner 162B disposed below and transmitted through the stage 172, the temporary substrate 202, the cladding layer 204, and the core layer 206. As for the light quantity distribution of each laser beam, as in the above-described manufacturing method, a predetermined region corresponding to the reflection mirror arrangement part of the core layer 206 is gradually decreased from the front end side to the inside, and the number of overlaps is reduced stepwise. The exposure amount is controlled so that the distribution (arrow UVA and arrow UVB) has an inclination (about 45 °) as shown. In the figure, the depth direction is the main scanning direction, and the horizontal direction is the sub-scanning direction.
[0112]
After the exposure process of the photosensitive material 150 by the exposure device 171 is completed, the photosensitive material 150 is developed. In this development processing, as shown in FIG. 25L, an etching mask 150B having a parallelogram cross section having a slope structure with a reverse taper (undercut) at the right end is formed.
[0113]
In FIG. 25M, when dry etching is performed to process the core layer 206, the core layer 206 is etched together with the etching mask 150B by the same action as the etching process described above. The state of the processing is shown in FIGS. 29 (U) to (W). As shown in the drawing, in the reverse taper portion of the etching mask 150B, as the etching of the core layer 206 and the etching mask 150B progresses due to etching, the core layer 206 is eroded downward and the inside of the inclined surface (in the left direction in the figure). Erosion to) proceeds at the same time. As a result, the mask pattern is transferred to the core layer 206 while the parallelogram shape of the etching mask 150B is gradually reduced. Therefore, the cross-sectional parallelogram as shown in FIG. A shaped core layer 206A is formed.
[0114]
Then, after removing the etching mask 150B, a thin reflective mirror 210 is formed on the inclined surfaces 208 at both ends of the core layer 206A by metal vapor deposition or the like, and the core layer 206A is covered with the clad layer 204. FIG. As described above, a first-stage optical wiring circuit configured by an optical waveguide including the core layer 206A having reflection mirrors at both ends and the clad layer 204 covering the core layer 206A is formed.
[0115]
Next, in order to form a second-stage optical wiring circuit, a core layer 206 and a photosensitive material (positive photoresist) 150 are sequentially formed on the cladding layer 204 in FIG. P), the exposure process is performed again by the exposure apparatus 171. In the second exposure, as shown in the figure, the upper and lower exposure directions at the end of each pattern are performed from the opposite direction, and the other end of the pattern end is exposed with the laser beam UVA from the upper scanner 162A. One end of the pattern is exposed by laser light UVB emitted from the lower scanner 162B and transmitted through the stage 172, the temporary substrate 202, the cladding layer 204, and the core layer 206. Each exposure area is a substantially adjacent area outside the end of the first-stage core layer 206A, and the light amount distribution of the laser light is the same as that of the first time.
[0116]
As a result, when the photosensitive material 150 is developed after the exposure step, an etching mask 150C having a parallelogram cross section with the left end portion as an inversely tapered surface is formed as shown in FIG. When dry etching is performed using this etching mask 150C, the mask pattern of the etching mask 150C is transferred to the core layer by the same action as described in FIGS. 29 (U) to (W), and FIG. The second-stage core layer 206B shown is formed. The core layer 206B has a parallelogram shape obtained by inverting the first-stage core layer 206A up and down, and the inclined surface positions at both ends of each core layer are arranged so as to substantially overlap each other.
[0117]
Then, the remaining etching mask 150C is peeled off, the reflection mirror 210 is formed on the inclined surfaces 208 at both ends of the core layer 206B by metal vapor deposition or the like, and the core layer 206B is covered with the cladding layer 204. FIG. Thus, the second-stage optical wiring circuit is formed. Finally, when peeled from the temporary substrate 202, an optical wiring substrate 220 having a plurality of optical wiring circuits as shown in FIG. 28T is completed.
[0118]
Further, when this optical wiring board 220 is used, for example, as shown in the figure, light is emitted from the upper light emitting element 214 to the reflection mirror 210 at the left end of the optical wiring circuit (core layer 206B) arranged in the upper stage. L is incident. Then, the light L reflected by the reflection mirror 210 is guided to the core layer 206B and reaches the reflection mirror 210 at the opposite end, where it is reflected and emitted downward. Further, the light L enters the reflection mirror 210 at the right end of the optical wiring circuit (core layer 206A) located in the lower stage, is reflected, and enters the core layer 206A. Then, the light is guided by the core layer 206 </ b> A, reflected by the reflection mirror 210 at the left end, and emitted to the lower side of the optical wiring substrate 220.
[0119]
Incidentally, in the manufacture of the optical wiring board by the above-described two photolithography processes, a well-known alignment technique and scaling function can be used in order to increase the relative positional accuracy of the first and second exposure patterns. In addition, for the alignment mark necessary for that purpose, for example, a method of using the reflection mirror 210 formed on the core layer 206A or a mark pattern corresponding to the alignment mark is exposed separately from the optical waveguide pattern in the first exposure. -The method etc. of forming are mentioned. These alignment marks are imaged with a CCD camera or the like equipped in the exposure apparatus, the position of the alignment mark is obtained from the image data, and scaling is performed based on the position data, so that the alignment is performed with high accuracy. An optical wiring board provided with a three-dimensional optical wiring circuit is obtained. Further, even two or more stages of optical wiring circuits can be easily formed by repeating the same photolithography process as described above.
[0120]
In addition, the method of forming the reverse tapered surface at the end of the etching mask may be other than the double-sided exposure as described above. For example, it can be formed in a desired shape by changing the exposure conditions and the etching conditions.
[0121]
As described above, in the manufacture of an optical wiring substrate including a plurality of stages of optical wiring circuits, the substrate can be formed more easily than conventional mask exposure by digital maskless exposure using a light beam. In addition, it becomes easy to use alignment and scaling, whereby the three-dimensional optical wiring circuit can be aligned with higher accuracy.
[0122]
(Third embodiment)
Next, a method for manufacturing an optical wiring substrate (optical wiring circuit) by the photobleaching method using the exposure apparatus 100 described in the first embodiment will be described.
[0123]
30 to 32 show a manufacturing process of an optical wiring board by a photo bleaching method. First, in FIG. 30A, the clad layer 222 is formed by applying and baking polyvinylidene fluoride (PVDF) to the temporary substrate 202. In FIG. 30B, a polymer material for photobleaching has a property that the refractive index is higher on the clad layer 222 than the clad layer 222 and the molecular structure changes in response to UV light to lower the refractive index. The core layer 224 is formed by applying and baking polysilane.
[0124]
Next, this optical wiring board material is set on the stage 152 of the exposure apparatus 100, and the core layer 224 is exposed with a predetermined exposure pattern by laser light (UV light) irradiated from the scanner 162. As shown in FIG. 31 (C), in this case as well, in a predetermined region corresponding to the inclined surface formed at the end of the core layer 224, multiple exposure is performed in which two or more pixels are overlapped and exposed from the tip side to the inside. By reducing the number of overlaps in stages, the exposure amount is controlled so that the exposure amount distribution (arrow UV) has an inclination (about 45 °) as shown.
[0125]
Here, due to the nature of the polysilane used for the core layer 224, the exposed region of the core layer 224 exposed by the laser light is exposed to light and the refractive index is lowered. This low refractive index portion becomes the cladding layer 226, and the unexposed high refractive index portion becomes the core layer 224. Further, an inclined surface 228 that is inclined according to the distribution of the exposure dose is formed at the boundary with the cladding layer 226 at the end of the core layer 224 (left and right side ends in FIG. 31C).
[0126]
After the exposure process of the core layer 224 by the exposure apparatus 100 is completed, the exposed optical wiring board material is removed from the stage 152, and polyvinylidene fluoride (PVDF) is applied and baked in FIG. The core layer 224 and the cladding layer 226 are covered with 222. Finally, when peeled off from the temporary substrate 202, the optical wiring substrate 230 is completed (FIG. 32E).
[0127]
Further, the refractive index of the optical wiring board 230 changes near the inclined surface 228, and FIG. 33 schematically shows the distribution of refractive index near the inclined surface 228. In the case of polysilane, the refractive index can be changed by about 6%, but the refractive index of the inclined surface 228 here has a distribution that changes stepwise in a direction substantially perpendicular to the inclined surface 228 within the range of physical properties. ing. In FIG. 33, the inclined surface 228 is schematically shown as an inclined surface first layer 228A having a high refractive index on the core layer 224 side, and an inclined surface second layer 228B having a low refractive index on the cladding layer 226 side. The relationship between the refractive index of the core layer 224 and the clad layer 226, the inclined surface 228 of the two-step (two-layer) structure composed of the inclined surface first layer 228A and the inclined surface second layer 228B is as follows. The first surface layer 228A> the inclined second surface layer 228B> the cladding layer 226.
[0128]
As shown in FIGS. 32 (F) and 33, the light L emitted from the light emitting element 214 is incident on the inclined surface 228 at an incident angle i. ₁ = 45 °, the light L is refracted at the interface 229A between the core layer 224 and the inclined surface first layer 228A and at the interface 229B between the inclined surface first layer 228A and the inclined surface second layer 228B. The angle of refraction is refracted toward the side where the angle increases, and the incident angle i is incident on the interface 229C between the inclined second layer 228B and the cladding layer 226. ₂ Incident at. This incident angle i ₂ Is the incident angle i ₁ Therefore, the reflectance of the light L reflected by the interface 229C is increased. The light L reflected by the interface 229C is refracted to the side where the refraction angle becomes smaller at the interface 229B and the interface 229A, and the refraction angle i ₃ Is incident on the core layer 224 at 45 °.
[0129]
Thus, the incident angle i is applied to the inclined surface 228. ₁ The light L incident at 45 ° is reflected with a high reflectivity by the inclined surface 228 including the interface 229A, the interface 229B, and the interface 229C, and the optical path is converted by 90 ° (in FIG. 32 (F) and FIG. 33, the upper side). Therefore, the inclined surface 228 functions as a reflecting mirror.
[0130]
Then, the light L reflected by the inclined surface 228 is transmitted through the core layer 224 and reaches the inclined surface 228 at the opposite end portion, and the inclined surface 228 is similarly reflected at a high reflectivity so that the optical path is 90 °. It is converted and emitted upward.
[0131]
As described above, in the method for manufacturing an optical wiring board by the photobleaching method according to the present embodiment, the exposure apparatus 100 that performs image exposure with the light beam modulated by the DMD 50 according to the image information is used, and UV light is emitted. A predetermined region of the core layer 224 made of a photobleaching polymer material (polysilane) whose refractive index is lowered by irradiation is exposed and patterned by a light beam, whereby the cladding layer 226 whose refractive index is lowered with respect to the core layer 224. Further, at the end of the core layer 224, the inclined surface 228 functioning as a reflecting mirror is formed by performing exposure and patterning with a light beam whose exposure amount is controlled according to the inclined shape of the inclined surface 228. .
[0132]
As a result, even in the production of the optical wiring substrate by the photo bleaching method, the core layer and the clad layer constituting the optical waveguide can be formed by maskless exposure, and the production of the optical wiring circuit and the optical wiring substrate is facilitated. .
[0133]
In addition, as with the etching method, maskless exposure enables easy adaptation to circuit changes and complicated circuit configuration production. Furthermore, because of line exposure, films supplied in rolls can be used. Even with a circuit pattern such as an optical sheet bus, an optical wiring circuit can be formed at a high speed and in a large area. In addition, since the exposure is performed with a very high-definition light beam having a resolution of about 0.1 μm, an optical waveguide and an optical branch circuit with a good pattern shape and reduced propagation loss can be formed. Since the exposure amount of the inclined surface 228 provided at the end can be easily controlled by multiple exposure, the inclined shape can be made smooth.
[0134]
In addition, the refractive index distribution of the inclined surface 228 shown in FIG. 33 schematically shows an example, but in addition to this, for example, the refractive index has three steps in a direction substantially perpendicular to the inclined surface 228 ( Even in the case where the three layers are changed stepwise or when the refractive index change width is very small and substantially continuously changed, the light L incident on the inclined surface 228 is obtained by the same action. Can be reflected with high reflectivity. Therefore, the inclined surface 228 functioning as the reflecting mirror can bend the light L efficiently without providing a reflecting mirror separately.
[0135]
(Fourth embodiment)
Next, a method for manufacturing an optical wiring substrate having a plurality of optical wiring circuits by the photobleaching method using the exposure apparatus 171 described in the second embodiment will be described.
[0136]
First, the core having a higher refractive index than the clad layer (polyvinylidene fluoride layer) 222 and the clad layer 222 is formed on the temporary substrate 202 such as a glass plate by the steps of FIGS. 30A to 30B in the third embodiment. A layer (a polymer material layer for photobleaching) 224 is sequentially formed.
[0137]
This optical wiring board material is set on the stage 172 of the exposure apparatus 171, and one end (left side in the figure) of the core layer 224 is exposed with the laser light UVA from the scanner 162 A disposed above, and the other (see FIG. The right end of the substrate is exposed by laser light UVB emitted from a scanner 162B disposed below and transmitted through the stage 172, the temporary substrate 202, and the cladding layer 222. As for the light amount distribution of each laser beam, as shown in FIG. 34 (G), in this case as well, in a predetermined region corresponding to the inclined surface formed at the end of the core layer 224, two pixels or more are formed from the tip side to the inside. By gradually reducing the number of overlaps of multiple exposures that are exposed in an overlapping manner, the exposure amount is controlled so that the exposure amount distribution (arrow UVA and arrow UVB) has an inclination (about 45 °) as shown in the figure. doing.
[0138]
As a result, the exposed region of the core layer 224 is exposed to light and the refractive index decreases to become the clad layer 226A. The unexposed region has a parallel-parallel core layer 224A having a slope structure with a reverse end taper on the right side. Thus, an inclined surface 228 inclined according to the exposure dose distribution is formed at the boundary with the cladding layer 226A at the end of the core layer 224A (the left and right side ends in FIG. 34G).
[0139]
After the exposure of the first core layer, the exposed optical wiring board material is removed from the stage 172, and the core layer 224A and the clad layer 226A are covered with the clad layer 222 in FIG. . As a result, a first-stage optical wiring circuit constituted by an optical waveguide including the core layer 206A provided with the inclined surfaces 228 at both ends and the clad layers 222 and 226A covering the core layer 206A is formed.
[0140]
Next, after forming the core layer 224 on the cladding layer 222 in FIG. 35I in order to form the second stage optical wiring circuit, the exposure apparatus 171 again exposes the light in FIG. 35J. Perform the process. In this second exposure, as shown in the figure, the upper and lower exposure directions at each pattern end are performed in the reverse direction, and the other end of the core layer 224 is irradiated with the laser beam UVA from the upper scanner 162A. The one end of the core layer 224 is exposed by laser light UVB emitted from the lower scanner 162B and transmitted through the stage 172, the temporary substrate 202, the clad layer 222, the clad layer 226A, and the clad layer 222. The exposure area by the laser beam UVB is a substantially adjacent area outside the end of the first-stage core layer 224A, and the light quantity distribution of each laser beam is the same as the first time.
[0141]
As a result, the exposed region of the core layer 224 is exposed to light and the refractive index decreases to become the cladding layer 226B, and the unexposed region becomes the core layer 224B having a parallelogram cross section with the left end portion being an inversely tapered surface. An inclined surface 228 that is inclined in accordance with the distribution of the exposure dose is formed at the boundary with the cladding layer 226B at the end of the core layer 224B (left and right side ends in FIG. 35J). In addition, the inclined surface 228 on the right side of the core layer 224B is disposed so as to substantially overlap the inclined surface 228 of the core layer 224A.
[0142]
In FIG. 36K, the core layer 224B and the clad layer 226B are covered with the clad layer 222 to form a second-stage optical wiring circuit. Finally, when peeled from the temporary substrate 202, an optical wiring substrate 240 including a plurality of optical wiring circuits as shown in FIG. 36L is completed.
[0143]
As an example of use of this optical wiring board 240, as shown in FIG. 36 (L), when the light L is incident on the left inclined surface 228 of the upper core layer 224B from the upper light emitting element 214, the light L is The light is reflected by the inclined surface 228 and guided to the core layer 224B to reach the inclined surface 228 on the opposite side, where it is reflected and emitted downward. Further, the light L is incident on and reflected by the right inclined surface 228 of the lower core layer 224A, is guided by the core layer 224A, is reflected by the left inclined surface 228, and is emitted below the optical wiring board 240. .
[0144]
As described above, even when an optical wiring substrate having a plurality of stages of optical wiring circuits is manufactured by the photobleaching method, the substrate can be formed more easily than conventional mask exposure by digital maskless exposure using a light beam. be able to. Similarly to the second embodiment, alignment and scaling can be performed to align a plurality of stages of optical wiring circuits with high accuracy.
[0145]
(Fifth embodiment)
Next, a method for manufacturing an optical wiring substrate (optical wiring circuit) by the direct exposure method using the exposure apparatus 100 will be described.
[0146]
37 to 40 show the manufacturing process of the optical wiring board by the direct exposure method. First, in FIG. 37A, the clad layer 242 is formed by applying and baking polyimide or the like to the temporary substrate 202. In FIG. 37B, a core layer 244 is formed on the clad layer 242 by applying and baking a photo-curing material (UV acrylate, UV epoxy resin, etc.) having a refractive index larger than that of the clad layer 242.
[0147]
Next, this optical wiring board material is set on the stage 152 of the exposure apparatus 100, and the core layer 244 is exposed with a predetermined exposure pattern by laser light (UV light) irradiated from the scanner 162. As shown in FIG. 38C, here, the pattern formation (wiring) region of the optical wiring circuit constituted by the core layer 244 is exposed with laser light. Further, in a predetermined region corresponding to the inclined surface formed at the end of the core layer 224, the exposure amount distribution (arrow UV) is illustrated by gradually reducing the number of overlaps due to multiple exposure from the inside to the tip side. The exposure amount is controlled so as to have an inclination (about 45 °) as shown in FIG.
[0148]
Here, due to the property of the photo-curing material used for the core layer 244, the exposed region of the core layer 244 exposed by the laser beam of the exposure apparatus 100 is exposed and cured.
[0149]
After the exposure process of the core layer 244 by the exposure apparatus 100 is completed, the exposed optical wiring board material is removed from the stage 152, and the core layer 244 is developed. By this development processing, the unexposed portion of the core layer 224 is removed, and as shown in FIG. 38D, a core layer 224B having a trapezoidal cross section with an end portion having a reverse tapered surface (inclined surface 246) is formed.
[0150]
Subsequently, in FIG. 39E, in order to increase the light reflectivity at the inclined surface 246 of the core layer 244, metal is vapor-deposited on the inclined surface 246 to form a thin-film reflective mirror 248. Finally, in FIG. 39F, polyimide or the like is applied and baked, the core layer 244 is covered with the clad layer 242, and peeled off from the temporary substrate 202, the optical wiring substrate 250 is completed (FIG. 40G). In addition, although the usage example of this optical wiring board 250 is shown in FIG.40 (G), the description is abbreviate | omitted.
[0151]
As described above, in the method for manufacturing an optical wiring board by the direct exposure method according to the present embodiment, the exposure apparatus 100 that performs image exposure with the light beam modulated by the DMD 50 according to the image information is used and cured by light irradiation. The predetermined region of the core layer 244 made of a photo-curing material is exposed and patterned with a light beam to cure the predetermined region of the core layer 244, and at the end of the core layer 244, the inclined surface 246 is inclined. By exposing and patterning with a light beam whose exposure amount is controlled according to the shape, an inclined structure (inclined surface 246) for providing the reflection mirror 248 is formed.
[0152]
As a result, even in the production of an optical wiring board by the direct exposure method, the core layer and the inclined surface provided at the end of the core layer can be formed by maskless exposure, and the production of the optical wiring circuit and the optical wiring board is easy. It becomes.
[0153]
In addition, as with etching and photobleaching methods, maskless exposure makes it possible to easily handle circuit changes and manufacture of complicated circuit configurations.Furthermore, since line exposure is used, it can be rolled. Even with a circuit pattern such as a supplied film or optical sheet bus, an optical wiring circuit can be formed at a high speed and in a large area. In addition, since the exposure is performed with a very high-definition light beam with a resolution of about 0.1 μm, an optical waveguide and an optical branch circuit with a good pattern shape and reduced propagation loss can be formed. Since the exposure amount of the inclined surface 246 provided at the end can be easily controlled by multiple exposure, the inclined shape can be made smooth.
[0154]
(Sixth embodiment)
Next, a method for manufacturing an optical wiring board having a plurality of optical wiring circuits by the direct exposure method using the exposure apparatus 171 will be described.
[0155]
First, the core layer (refractive index higher than the cladding layer (polyimide layer) 242 and the cladding layer 242 is formed on the temporary substrate 202 such as a glass plate by the steps of FIGS. 37A to 37B in the fifth embodiment. Photo-curing material layer) 244 is formed in order.
[0156]
This optical wiring board material is set on the stage 172 of the exposure apparatus 171, and one end (left side in the figure) of the core layer 244 is emitted from the scanner 162 </ b> B disposed below, and the stage 172, the temporary substrate 202, Exposure is performed with laser light UVB that has passed through the cladding layer 242, and the pattern forming region of the optical wiring circuit and the other end (right side in the figure) of the core layer 244 are exposed with laser light UVA from the scanner 162A disposed above. To do. As for the light amount distribution of each laser beam, as shown in FIG. 41 (H), in a predetermined region corresponding to the inclined surface formed at the end of the core layer 244, the overlap number by multiple exposure is given from the inside to the tip side. By decreasing in steps, the exposure amount is controlled so that the exposure amount distribution (arrow UVA and arrow UVB) has an inclination (about 45 °) as shown. As a result, the exposed region of the core layer 224 is exposed and cured.
[0157]
After the exposure process of the first core layer is completed, the exposed optical wiring board material is removed from the stage 172, and the core layer 244 is developed. By this development processing, the unexposed portion of the core layer 224 is removed, and as shown in FIG. 41 (I), a core layer 244A having a parallelogram cross section having a sloped structure with a reverse taper at the right end is formed. It is done.
[0158]
Subsequently, in FIG. 42J, metal is vapor-deposited on the inclined surfaces 246 at both ends of the core layer 244A to form a thin-film reflective mirror 248, and the core layer 244A is covered with the clad layer 242. As in (K), a first-stage optical wiring circuit is formed which is constituted by an optical waveguide (core layer 244A) provided with reflection mirrors at both ends.
[0159]
Next, in order to form a second-stage optical wiring circuit, after forming the core layer 244 on the cladding layer 242 in FIG. 42L, the exposure apparatus 171 in FIG. An exposure process is performed. In this second exposure, as shown in the drawing, the pattern formation region of the optical wiring circuit and one end of the core layer 244 are exposed by the laser beam UVA from the scanner 162A disposed above. Regarding the light amount distribution of the laser beam UVA, in a predetermined region corresponding to the inclined surface formed at the end of the core layer 244, the number of overlaps by multiple exposure is reduced stepwise from the inside to the tip side, thereby reducing the exposure amount. The exposure amount is controlled so that the distribution (arrow UVA) has an inclination (about 45 °) as shown.
[0160]
The other end of the core layer 244 is exposed by laser light UVB from the scanner 162B disposed below. Here, a reflection mirror 248 formed at the left end of the first-stage core layer 244A and The corresponding region is irradiated with laser light UVB. Further, regarding the light amount distribution of the laser beam UVB, the exposure amount distribution (arrow UVB) is illustrated by gradually reducing the number of overlaps due to multiple exposure from the tip side to the inside of the core layer 244A (inclined surface 246). The exposure amount is controlled so as to have an inclination (about 45 °) as shown in FIG.
[0161]
The laser beam UVB passes through the stage 172, the temporary substrate 202, and the cladding layer 242, and enters the reflection mirror 248 at the left end of the core layer 244A. Then, the laser beam UVB is reflected by the reflection mirror 248 and enters the core layer 244A. Further, it is guided by the core layer 244A, reflected by the reflecting mirror 248 at the right end, and emitted upward, and the other end of the core layer 244 is irradiated from below. Further, the distribution of the exposure amount of the laser beam UVB at the other end of the core layer 244 is a distribution in which the exposure amount gradually decreases from the inner side to the front end side.
[0162]
As a result, the exposed area of the second-stage core layer 224 is exposed to light and cured, and when the core layer 244 is developed to remove the unexposed portion, as shown in FIG. A core layer 244B having a parallelogram cross-section with a reverse taper surface is formed. The core layer 244B has a parallelogram shape obtained by inverting the first-stage core layer 244A up and down, and the inclined surface positions at both ends of each core layer are arranged so as to substantially overlap each other.
[0163]
43 (O), a reflecting mirror 248 is formed on the inclined surfaces 246 at both ends of the core layer 244B by metal vapor deposition or the like, and in FIG. 44 (P), the core layer 244B is covered with the cladding layer 242. A stage optical wiring circuit is formed. Finally, when peeled from the temporary substrate 202, an optical wiring substrate 260 having a plurality of optical wiring circuits as shown in FIG. 44 (Q) is completed. An example of use of this optical wiring board 260 is shown in FIG. 44 (Q), but since it is the same as the optical wiring board 220 shown in FIG. 28 (T), its description is omitted.
[0164]
As described above, even when an optical wiring substrate having a plurality of stages of optical wiring circuits is manufactured by a direct exposure method, the substrate can be formed more easily than conventional mask exposure by digital maskless exposure using a light beam. Can do. Similarly to the second and fourth embodiments, alignment and scaling can be performed to align a plurality of stages of optical wiring circuits with high accuracy.
[0165]
The present invention has been described in detail with reference to the first to sixth embodiments. However, the present invention is not limited thereto, and various other embodiments are possible within the scope of the present invention. .
[0166]
For example, in the first to sixth embodiments, the exposure amount of the light beam for exposing the photosensitive material is controlled by multiple exposure in which two or more pixels are overlapped, but the light intensity is changed for each pixel. The amount of exposure can be similarly changed by intensity modulation. The optical wiring board is not limited to a structure in which the core layer (optical waveguide) is covered with the cladding layer, and the core layer may be laminated on the cladding layer.
[0167]
Further, in the manufacture of each optical wiring board, the temporary substrate 202 is used. However, when a plastic film or the like having a refractive index smaller than that of the core layer is used instead of the temporary substrate 202, the first cladding layer is used. The core layer can be formed directly on the plastic film by omitting the forming step.
[0168]
In addition, an exposure head having a DMD as a spatial modulation element has been described. For example, a MEMS (Micro Electro Mechanical Systems) type spatial modulation element (SLM) or an optical that modulates transmitted light by an electro-optical effect is used. Similar effects can be obtained when a spatial modulation element other than the MEMS type, such as an element (PLZT element) or a liquid crystal optical shutter (FLC), is used.
[0169]
Note that MEMS is a general term for micro systems that integrate micro-sized sensors, actuators, and control circuits based on micro-machining technology based on the IC manufacturing process. It means a spatial modulation element that is driven by the electromechanical operation used.
[0170]
【The invention's effect】
Since the present invention has the above-described configuration, an optical wiring circuit can be easily formed by maskless exposure, and in particular, an inclined surface shape for providing a reflection mirror at the end of an optical waveguide, or an optical wiring circuit is laminated. An optical wiring circuit manufacturing method that can be easily formed even in a circuit configuration in which a plurality of stages are formed in the direction, and an optical wiring board including the optical wiring circuit are obtained.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an external appearance of an exposure apparatus according to a first embodiment of the present invention.
FIG. 2 is a perspective view showing a configuration of a scanner of the exposure apparatus according to the first embodiment of the present invention.
FIG. 3A is a plan view showing an exposed area formed on a photosensitive material, and FIG. 3B is a view showing an arrangement of exposure areas by each exposure head.
FIG. 4 is a perspective view showing a schematic configuration of an exposure head of the exposure apparatus according to the first embodiment of the present invention.
5A is a cross-sectional view in the sub-scanning direction along the optical axis showing the configuration of the exposure head shown in FIG. 4, and FIG. 5B is a side view of FIG.
FIG. 6 is a partially enlarged view showing a configuration of a digital micromirror device (DMD).
7A and 7B are explanatory diagrams for explaining the operation of the DMD. FIG.
FIGS. 8A and 8B are plan views showing the arrangement of exposure beams and scanning lines in a case where the DMD is not inclined and in a case where the DMD is inclined. FIG.
9A is a perspective view showing the configuration of a fiber array light source, FIG. 9B is a partially enlarged view of A, and FIGS. 9C and 9D show the arrangement of light emitting points in a laser emitting section. FIG.
FIG. 10 is a diagram showing a configuration of a multimode optical fiber.
FIG. 11 is a plan view showing a configuration of a combined laser light source.
FIG. 12 is a plan view showing the configuration of a laser module.
13 is a side view showing the configuration of the laser module shown in FIG. 12. FIG.
14 is a partial side view showing the configuration of the laser module shown in FIG. 12. FIG.
FIGS. 15A and 15B are cross-sectional views along the optical axis showing the difference between the depth of focus in a conventional exposure apparatus and the depth of focus in an exposure apparatus according to an embodiment of the present invention. FIGS.
FIGS. 16A and 16B are diagrams showing examples of DMD usage areas; FIGS.
FIG. 17A is a side view when the DMD use area is appropriate, and FIG. 17B is a cross-sectional view in the sub-scanning direction along the optical axis of FIG.
18A and 18B are views for explaining a method of manufacturing the optical wiring substrate according to the first embodiment of the present invention by etching, wherein FIG. 18A shows a state in which a cladding layer is formed on a temporary substrate, and FIG. In this state, a core layer is formed on the cladding layer, and (C) shows a state in which a photosensitive material is applied on the core layer.
FIG. 19 is a diagram for explaining the manufacturing process and subsequent steps in FIG. 18, wherein (D) shows the exposure of the photosensitive material by changing the exposure amount by the light beam, and (E) shows the etching mask after developing the photosensitive material. (F) is a state where the core layer is dry-etched.
FIG. 20 is a diagram for explaining the manufacturing process and subsequent steps in FIG. 19, where (G) shows a state in which the etching mask is peeled off, and (H) shows a state in which a reflecting mirror is formed on the inclined surface of the core layer end; (I) is a state in which the core layer is covered with a clad layer.
FIG. 21J is a diagram showing a completed state of the optical wiring board manufactured by the etching method.
FIG. 22 is a plan view schematically showing a difference in pattern shape due to a difference in resolution when a branch circuit is exposed to a light beam, where (X) is a low resolution case and (Y) is a high resolution case. It is.
FIG. 23 is a perspective view showing an exposure apparatus according to a second embodiment of the present invention.
FIG. 24 is a front view showing an exposure apparatus according to a second embodiment of the present invention.
FIG. 25 is a view for explaining a manufacturing method by an etching method of an optical wiring substrate having a plurality of optical wiring circuits according to the second embodiment of the present invention, wherein (K) is a photosensitivity by changing an exposure amount by a light beam; The material is exposed from both sides, (L) is a state where the photosensitive material is developed to form an etching mask, and (M) is a state where the first core layer is dry-etched.
FIG. 26 is a diagram for explaining the manufacturing process and subsequent steps in FIG. 25, in which (N) is a state in which a reflecting mirror is formed on the inclined surface at the end of the first-stage core layer and the core layer is covered with a clad layer; (O) shows a state in which a second core layer is formed on the clad layer and a photosensitive material is applied, and (P) shows that the photosensitive material is exposed from both sides by changing the exposure amount by the light beam. .
FIG. 27 is a diagram for explaining the manufacturing process and subsequent steps in FIG. 26, where (Q) is a state in which the photosensitive material is developed to form an etching mask, and (R) is a state in which the second core layer is dry-etched. (S) is a state in which a reflecting mirror is formed on the inclined surface at the end of the second-stage core layer, and the core layer is covered with a clad layer.
FIG. 28T is a diagram showing a completed state of an optical wiring board including a plurality of stages of optical wiring circuits manufactured by an etching method and an example of use thereof.
FIG. 29 is a diagram for explaining step (M) in FIG. 25 in detail, and (U), (V), and (W) show how the core layer and the etching mask are gradually processed by dry etching. It is a schematic diagram.
FIG. 30 is a diagram for explaining a manufacturing method by an optical bleaching method for an optical wiring board according to a third embodiment of the present invention, in which (A) shows a state in which a cladding layer is formed on a temporary substrate; ) Is a state in which a core layer is formed on the cladding layer.
FIG. 31 is a diagram for explaining the manufacturing process and subsequent steps in FIG. 30, in which (C) shows the exposure of the core layer by changing the exposure amount by the light beam, and (D) shows the core layer covered with the cladding layer. State.
FIG. 32 is a diagram for explaining the manufacturing process and subsequent steps in FIG. 31, in which (E) shows a state in which the optical wiring board is peeled off from the temporary substrate 202, and (F) shows an optical wiring board manufactured by the photobleaching method. It is a figure which shows a completion state and its usage example.
FIG. 33 is an enlarged schematic cross-sectional view showing the refractive index distribution of the core layer, the clad layer, and the inclined surface of the optical wiring board manufactured by the photobleaching method, and the state of light reflection by the inclined surface.
FIG. 34 is a view for explaining a manufacturing method by an optical bleaching method of an optical wiring board including a plurality of optical wiring circuits according to the fourth embodiment of the present invention, and FIG. The first stage core layer is exposed from both sides, and (H) shows a state where the first stage core layer is covered with a clad layer.
FIG. 35 is a diagram for explaining the manufacturing process and subsequent steps in FIG. 34, in which (I) shows a state in which a second-stage core layer is formed on the cladding layer, and (J) shows that the exposure amount by the light beam is changed. It is a mode that the 2nd step | paragraph core layer is exposed from both surfaces.
FIG. 36 is a diagram for explaining the manufacturing process and subsequent steps in FIG. 35, in which (K) shows a state in which the second-stage core layer is covered with a clad layer, and (L) shows an optical wiring manufactured by a photobleaching method. It is a figure which shows the completion state of the optical wiring board provided with a multistage circuit, and its usage example.
FIG. 37 is a view for explaining a manufacturing method of an optical wiring board according to the fifth embodiment of the present invention by a direct exposure method, in which (A) shows a state in which a cladding layer is formed on a temporary substrate; Is a state in which a core layer is formed on the cladding layer.
FIG. 38 is a diagram for explaining the manufacturing process and subsequent steps in FIG. 37, in which (C) shows a state in which the core layer is exposed by changing the exposure amount by the light beam, and (D) shows a state in which the core layer is developed. .
FIG. 39 is a diagram for explaining the manufacturing process and subsequent steps in FIG. 38, where (E) shows a state in which a reflecting mirror is formed on the inclined surface at the end of the core layer, and (F) shows the core layer covered with a clad layer. State.
FIG. 40G is a diagram showing a completed state of an optical wiring board manufactured by the direct exposure method and an example of its use.
FIG. 41 is a diagram for explaining a manufacturing method by a direct exposure method of an optical wiring board provided with a plurality of stages of optical wiring circuits according to the sixth embodiment of the present invention. The first core layer is exposed from both sides, and (I) shows a state in which the first core layer is developed.
FIG. 42 is a diagram for explaining the manufacturing process and subsequent steps in FIG. 41, in which (J) shows a state in which a reflecting mirror is formed on the inclined surface at the end of the first layer core layer, and (K) shows the first step. The core layer is covered with the cladding layer, and (L) is the state where the second-stage core layer is formed on the cladding layer.
FIG. 43 is a diagram for explaining the manufacturing process and subsequent steps in FIG. 42, in which (M) shows the exposure of the second-stage core layer from both sides by changing the exposure amount by the light beam, and (N) shows 2 A state in which the core layer of the stage is developed, and (O) is a state in which a reflecting mirror is formed on the inclined surface at the end of the core layer of the second stage.
44 is a diagram for explaining the manufacturing process and subsequent steps in FIG. 43, in which (P) is a state in which the second-stage core layer is covered with a cladding layer, and (Q) is an optical wiring circuit manufactured by the direct exposure method. FIG. 2 is a view showing a completed state of an optical wiring board having a plurality of stages and an example of its use.
[Explanation of symbols]
50 DMD (Spatial Light Modulator)
100 Exposure apparatus (exposure means)
150 Photosensitive material (optical material / photoresist)
150A etching mask
150B etching mask
150C etching mask
171 Exposure apparatus (exposure means)
200 Optical circuit board
204 Clad layer (optical waveguide / optical wiring circuit)
206 Core layer (optical waveguide / optical wiring circuit)
208 inclined surface
210 Reflection mirror
220 Optical circuit board
222 Clad layer (optical waveguide / optical wiring circuit)
224 Core layer (optical waveguide / optical wiring circuit / optical material / optical waveguide material according to claim 7)
226 Cladding layer (optical waveguide / optical wiring circuit / optical material / optical waveguide material according to claim 7)
228 Inclined surface (Inclined surface / Reflective mirror)
228A Inclined surface first layer
228B inclined surface second layer
230 Optical circuit board
240 Optical wiring board
242 Clad layer (optical waveguide / optical wiring circuit)
244 Core layer (optical waveguide / optical wiring circuit / optical material / optical waveguide material according to claim 10)
246 Inclined surface
248 reflection mirror
250 Optical circuit board
260 Optical wiring board
UV laser light (light beam)
UVA laser light (light beam)
UVB laser light (light beam)
L light

Claims (12)

A method of manufacturing an optical wiring circuit configured by an optical waveguide,
Using an exposure unit that performs image exposure with a light beam modulated by a spatial light modulation element according to image information, and exposing and patterning a predetermined region of the optical material for forming the optical waveguide with the light beam. An optical wiring circuit manufacturing method characterized by the above. An optical wiring circuit configured by an optical waveguide having an inclined surface for providing a reflection mirror for allowing light to enter or exit from the core layer at the end of the core layer constituting the optical waveguide A manufacturing method of
Using an exposure means that performs image exposure with a light beam modulated by a spatial light modulation element according to image information, a predetermined area of the optical material for forming the optical waveguide is exposed according to the inclined shape of the inclined surface A method of manufacturing an optical wiring circuit, comprising the step of exposing and patterning with the light beam controlled. The exposure means scans the light beam to perform image exposure and has a multiple exposure function in which exposure is performed by overlapping two or more pixels in the scan, and the exposure amount is controlled by the multiple exposure. The method for manufacturing an optical wiring circuit according to claim 2. 4. The method of manufacturing an optical wiring circuit according to claim 1, wherein a resolution of image exposure by the light beam is 0.1 [mu] m to 2.5 [mu] m. The optical material is a photoresist formed on an optical waveguide material, and after forming an etching mask from the photoresist in the step of exposing and patterning with the light beam, the optical waveguide material is formed using the etching mask. The method of manufacturing an optical wiring circuit according to claim 1, further comprising a step of etching the substrate. 6. The method of manufacturing an optical wiring circuit according to claim 5, wherein the photoresist is a positive type. The optical material is an optical waveguide material whose refractive index is changed by light irradiation, and an optical waveguide is formed by changing a refractive index of a predetermined region of the optical waveguide material in a process of exposing and patterning with the light beam. The method for manufacturing an optical wiring circuit according to claim 1, wherein the optical wiring circuit is a manufacturing method. 8. The method of manufacturing an optical wiring circuit according to claim 7, wherein the optical waveguide material has a property that a refractive index is lowered by light irradiation. 9. The core layer formed of the optical waveguide material in the method of manufacturing an optical wiring circuit according to claim 7 or claim 8, wherein the core layer is exposed and patterned by the light beam whose exposure amount is controlled according to the inclined shape of the inclined surface. 5. The distribution according to claim 2, wherein the refractive index of the patterned inclined surface is changed in a stepwise or substantially continuous manner in a direction substantially perpendicular to the inclined surface. Manufacturing method of optical wiring circuit. The optical material is an optical waveguide material that is cured by light irradiation, and after a predetermined region of the optical waveguide material is cured in the process of exposure and patterning with the light beam, an uncured portion of the optical waveguide material is developed by a development process. The method for manufacturing an optical wiring circuit according to claim 1, further comprising a step of removing. An optical wiring board provided with the optical wiring circuit manufactured by the manufacturing method of any one of Claims 1-10. An optical wiring board comprising a plurality of optical wiring circuits manufactured by the manufacturing method according to claim 1 in a stacking direction.

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