JP2004042143A - Method for forming micro flow passage - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for forming a micro flow passage wherein the passage is formed at a high speed and with a high precision, and also the passage having an arbitrary pattern is formed at low cost. <P>SOLUTION: In an exposing process of a photoresist film, laser beam at a wavelength of 350-450 nm is modulated according to the forming pattern of the fine flow passage with a spatial light modulator, and the photoresist film is digitally exposed to the modulated laser beam. When the film is exposed with a higher precision, it is exposed to the laser beam which is emitted from a high-luminance light source and has a deeper focal depth. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for forming a microchannel, and more particularly, to a method for forming a microchannel in a microchip used in the field of microchemistry.
[0002]
[Prior art]
In recent years, there has been a prominent apparatus technology called Laboratory on a Chip that integrates a system that performs mixing, reaction, separation, and detection of solutions on a glass substrate of several centimeters square using micromachining technology. It has been studied. The lab-on-chip is also referred to as a micro TAS (Micro Total Analysis System), a microreactor, or the like depending on the system to be integrated.
[0003]
Usually, a lab-on-chip is provided with a microchannel having a groove width of several tens to several hundreds of μm formed on a substrate having a thickness of about 1 mm, and the solution is mixed in the microchannel. Since the specific interfacial area is increased in the microchannel, it is possible to efficiently mix and react the solutions, such as those that are difficult to react due to the size effect and those that are difficult to mix are mixed. By setting the groove width of the microchannel to 10 μm to 50 μm, the channel resistance can be made relatively small, and a good size effect can be obtained. In addition, since the shape of the micro flow channel has a great influence on the fluid feeding characteristics of the fluid, it is preferable that the micro flow channel has a smooth wall surface and is manufactured with high accuracy.
[0004]
Conventionally, the lab-on-chip micro-channel is a semiconductor processing technology in which the substrate surface is coated with a resist film, the resist film is patterned by photolithography using ultraviolet rays or electron beams, and then the substrate is etched using this as a mask. It is formed using. Photolithography is performed using a contact exposure apparatus used in a semiconductor manufacturing process. The exposure method is an analog exposure method using a mask aligner, and it has been difficult to expose a large area such as 1 square meter at high speed.
[0005]
[Problems to be solved by the invention]
However, the conventional method for forming a microchannel has a problem in that it is difficult to form the microchannel with high accuracy because the patterning is performed by mask exposure, which limits the thickness of the photoresist film. . In other words, if the photoresist film is thin, side etching is likely to occur when the substrate is etched, so that the accuracy of the groove width is lowered and a sufficient groove depth cannot be achieved.
[0006]
Further, in mask exposure, a high-precision glass mask or the like is required for each pattern, so that there is a problem that the cost is increased, and it is difficult to increase the area, and at the same time, it is not suitable for small-quantity multi-product production.
[0007]
On the other hand, it is conceivable that the photolithography process is performed by a digital exposure method. However, since a conventional digital exposure apparatus using ultraviolet rays performs scanning exposure with a single beam, the exposure time is too long. In particular, in the case of high-definition exposure with a beam diameter of 10 μm or less and an addressability of about 1 μm, there is a problem that the exposure time is too long.
[0008]
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a method for forming a microchannel that can form a microchannel with high speed and high accuracy. Another object of the present invention is to provide a method of forming a microchannel that can form a microchannel of an arbitrary pattern at a low cost.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, a method for forming a microchannel according to claim 1, wherein a resist film formed on a substrate is spatially modulated in accordance with microchannel formation pattern data at a wavelength of 350 nm to Using an exposure step of exposing with 450 nm laser light, a patterning step of partially removing the resist film according to an exposure pattern to form a resist film of a predetermined pattern, and using the resist film of the predetermined pattern, And an etching process for removing the substrate by etching from the surface to form a microchannel.
[0010]
In this microchannel forming method, since laser light having a wavelength of 350 nm to 450 nm is used, there is no need to use an optical system of a special material corresponding to ultraviolet rays. A spatial light modulation element can be used. Thereby, it is possible to expose the resist film with the laser beam spatially modulated according to the formation pattern data of the microchannel. That is, high-speed and high-definition digital exposure of the resist film in an arbitrary pattern is possible.
[0011]
Thus, in the exposure process, high-speed and high-definition exposure of the resist film in an arbitrary pattern is possible, and therefore, through the following patterning process and etching process, a minute flow path of an arbitrary pattern is processed at high speed and high. It can be formed with high accuracy. In addition, since it is digital exposure, a mask for each pattern is unnecessary, and a minute flow path can be formed at low cost.
[0012]
In the above exposure process, a laser light source for irradiating a laser beam and a large number of pixel portions whose light modulation states change in response to control signals are arranged in a matrix on the substrate, and the laser irradiated from the laser device. An exposure head including a spatial light modulation element that modulates light and an optical system that forms an image on the exposure surface of laser light modulated by each pixel unit can be used. The resist film formed on the substrate can be scanned and exposed by moving the exposure head relative to the exposure surface of the resist film in a direction crossing a predetermined direction.
[0013]
In order to expose the resist film with higher definition, the spatial light modulator is arranged with a slight inclination so that the arrangement direction of the pixel portions forms a predetermined angle θ with the direction perpendicular to the sub-scanning direction, and multiple exposure is performed. It is preferable. Thereby, high-definition exposure with a beam diameter of 10 μm and addressability of 1 μm is possible. The inclination angle θ is preferably in the range of 1 ° to 5 °.
[0014]
Further, it is more preferable that a microlens array provided with a microlens provided corresponding to each pixel portion of the spatial modulation element and condensing laser light for each pixel is disposed on the emission side of the spatial modulation element. . When the microlens array is arranged, the laser light modulated by each pixel portion of the spatial modulation element is condensed corresponding to each pixel by each microlens of the microlens array. Even when the area is enlarged, the size of each beam spot can be reduced, and high-definition exposure can be performed. By using this reduction optical system, ultrahigh-definition exposure can be performed with a beam diameter of 1 μm and an addressability of 0.1 μm.
[0015]
Thus, by exposing the resist film with high definition, it is possible to form a very smooth wall surface of the minute flow path, and to reduce the flow path resistance and obtain a good size effect.
[0016]
In order to form the microchannel with high accuracy, the resist film is preferably thick. When forming a micro flow channel having a groove width of 10 μm to 50 μm, the thickness of the resist film is preferably 10 μm to 50 μm, and more preferably 10 μm to 100 μm. In particular, it is more preferable to expose the resist film in two layers. Since the resist film is digitally exposed, it is possible to correct the elongation at the time of exposure by the digital scaling function, and the alignment of the exposure position of the first layer and the exposure position of the second layer can be realized with high accuracy. As a result, it is possible to perform patterning with a high accuracy and a high aspect ratio with a resist film having a thickness twice that of the prior art, and it is possible to form a deep microchannel with high accuracy by etching. The aspect ratio is the ratio a / b of the groove depth b to the groove width a of the groove formed in the resist film.
[0017]
In the exposure step of the above forming method, the resist film can be exposed with higher accuracy by performing exposure at a deep focal depth using a high-intensity light source. As the high-intensity light source, a combined laser light source that combines a plurality of laser beams and enters each of the optical fibers is suitable. In addition, a high-power laser light source is necessary for exposure of the thickened resist film. A semiconductor laser having an oscillation wavelength of 350 to 450 nm is difficult to increase the output with a single element, but can increase the output by multiplexing.
[0018]
The combined laser light source, for example, (1) condenses laser light emitted from each of the plurality of semiconductor lasers, one optical fiber, and the plurality of semiconductor lasers, and collects the condensed beam of the optical fiber. A condensing optical system coupled to the incident end, (2) a multi-cavity laser having a plurality of light emitting points, one optical fiber, and laser light emitted from each of the light emitting points And (3) a plurality of multi-cavity lasers, a single optical fiber, and the plurality of multi-fibers. And a condensing optical system that condenses laser light emitted from each of the plurality of light emitting points of the cavity laser and couples the condensing beam to the incident end of the optical fiber.
[0019]
The light emitting points at the emission end of the optical fiber of the above combined laser light source can be arranged in an array to form a fiber array light source, or the light emitting points can be arranged in a bundle to form a fiber bundle light source. Higher output can be achieved by bundling or arraying. From the viewpoint of increasing the brightness, it is preferable to use an optical fiber having a uniform core diameter and a cladding diameter at the exit end smaller than that at the entrance end.
[0020]
The cladding diameter at the exit end of the optical fiber is preferably smaller than 125 μm, more preferably 80 μm or less, and particularly preferably 60 μm or less from the viewpoint of reducing the diameter of the light emitting point. An optical fiber having a uniform core diameter and a cladding diameter at the output end smaller than the cladding diameter at the input end can be configured by, for example, combining a plurality of optical fibers having the same core diameter but different cladding diameters. Further, by configuring the plurality of optical fibers so as to be detachable with connectors, the replacement becomes easy when the light source module is partially damaged.
[0021]
In particular, in the case where the spatial light modulator is tilted as described above and ultra-high-definition exposure is performed using a reduction optical system, the above-described high-intensity fiber array light source or fiber bundle light source is used, so that Thus, there is no beam thickening on the resist surface and in the resist, and patterning with higher accuracy and higher aspect ratio becomes possible. In addition, smooth patterning is also possible when forming an oblique channel with inclined wall surfaces.
[0022]
In the above exposure process, for example, the laser light is irradiated to the spatial light modulation elements arranged on the substrate with a large number of pixel portions whose light modulation states change according to the control signals. Modulated in the pixel portion.
[0023]
As the spatial modulation element, a micromirror device (DMD) configured by two-dimensionally arranging a large number of micromirrors each capable of changing the angle of the reflecting surface according to a control signal on a substrate (for example, a silicon substrate). A digital micromirror device). In addition, the spatial modulation element is configured by arranging in parallel a large number of movable gratings each having a ribbon-like reflecting surface and movable in accordance with a control signal and fixed gratings having a ribbon-like reflecting surface. A one-dimensional grating light valve (GLV) may be used. Alternatively, a liquid crystal shutter array in which a large number of liquid crystal cells capable of blocking transmitted light according to each control signal are two-dimensionally arranged on a substrate may be used.
[0024]
On the emission side of these spatial modulation elements, it is preferable to arrange a microlens array provided with a microlens provided corresponding to each pixel portion of the spatial modulation element and condensing laser light for each pixel. When the microlens array is arranged, the laser light modulated by each pixel portion of the spatial modulation element is condensed corresponding to each pixel by each microlens of the microlens array. Even when the area is enlarged, the size of each beam spot can be reduced, and even when the area is increased, high-definition exposure can be performed.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment for producing a microchip for synthesis reaction using the method for forming a microchannel of the present invention will be described in detail with reference to the drawings.
[Microchip for synthesis reaction]
As shown in FIG. 1, the microchip for synthesis reaction is configured by superposing a protective substrate 202 on a flat substrate 150 made of glass or the like. The thickness of the substrate 150 is usually about 0.5 mm to 2.0 mm, and the thickness of the protective substrate 202 is usually about 0.1 mm to 2.0 mm. The protective substrate 202 is provided with inlets 204a and 204b for injecting the reagent and an outlet 206 for discharging the reaction liquid obtained by the reaction of the reagent so as to penetrate the protective substrate 202, respectively. Yes. The substrate 150 is provided with a microchannel 208 through which a reagent or reaction solution flows. The microchannel 208 is arranged so that the reagent injected from each of the injection ports 204 a and 204 b merges at the merge point 210 and then is discharged to the discharge port 206. The groove width of the microchannel is several tens to several hundreds μm, and 10 μm to 50 μm is particularly preferable. A micro-channel with a groove width of 10 μm to 50 μm has a relatively small channel resistance and can provide a good size effect.
[0026]
When a reagent is injected into each of the inlets 204a and 204b of the reaction microchip and sucked from the outlet 206 side, the reagent flows through the microchannel 208 and is mixed and reacted at the junction 210. Thereby, a desired substance can be synthesized. The obtained reaction liquid flows through the microchannel 208 and is discharged from the discharge port 206. By analyzing the reaction solution obtained from the discharge port 206, the reaction product can be identified and quantified in the same manner as the reaction on a normal scale.
[0027]
[Microchip manufacturing method]
Next, a method for producing the microchip for synthesis reaction will be described with reference to FIG. This manufacturing method includes an exposure process for exposing a photoresist film, a patterning process for partially removing the photoresist film and patterning, an etching process for etching a substrate to form a microchannel, A bonding step of bonding the substrate on which the path is formed and the protective substrate. Hereinafter, each process will be described.
[0028]
As shown in FIG. 2A, after a photoresist film 212 is formed on the substrate 150 by spin coating or the like, the photoresist film 212 is formed according to the pattern of the microchannel 208 as shown in FIG. After exposure, as shown in FIG. 2C, the exposed portion 214 is dissolved in a developing solution and removed. Here, the microchannel 208 can be formed with high accuracy by patterning the photoresist film 212 with high positional accuracy. The exposure process for the photoresist film 212 will be described later.
[0029]
Then, as shown in FIG. 2 (D), the patterned photoresist film 212 is used to etch the substrate 150 from the surface to form a micro flow path 208, and the remaining as shown in FIG. 2 (E). The photoresist film 212 removed is removed. Although the substrate 150 can be etched by either dry etching or wet etching, dry etching such as fast atomic beam (FAB) etching is preferable because of fine processing.
[0030]
Next, as shown in FIG. 2F, through holes to be the inlets 204a and 204b and the outlet 206 are formed in the protective substrate 202 by ultrasonic processing or the like. Then, as shown in FIG. 2 (G), both the substrates are overlapped and fixed in close contact so that the protective substrate 202 and the surface of the substrate 150 on which the micro flow path 208 is formed are opposed to each other. For example, a UV adhesive can be used for fixing. A UV adhesive is applied to the surface of the protective substrate 202 on which the microchannels 208 are formed by a spin coating method or the like, and the substrate 150 and the protective substrate 202 are brought into close contact with each other, and then bonded by irradiation with ultraviolet rays.
[0031]
Note that in the case where the substrate 150 and the protective substrate 202 are formed of glass, the surfaces of both the substrates may be dissolved and bonded with hydrofluoric acid.
[0032]
[Exposure of photoresist film]
Next, the exposure process of the photoresist film will be described in detail. In this exposure step, a spatial light modulation element is used to modulate laser light having a wavelength of 350 nm to 450 nm in accordance with micro-channel formation pattern data, and the photoresist film 212 is digitally exposed with the modulated laser light. In order to perform exposure with higher accuracy, it is preferable to perform exposure with laser light having a deep focal depth emitted from a high-intensity light source.
[0033]
(Photoresist film)
As the photoresist film 212, a dry film resist (DFR) or an electrodeposition resist used in a manufacturing process of a printed wiring board (PWB) can be used. These DFRs and electrodeposition resists can be made thicker than resists used in the semiconductor manufacturing process, and a film having a thickness of 10 μm to 40 μm can be formed.
[0034]
Further, by stacking a plurality of photoresist films, a further increase in thickness can be achieved. In this case, as shown in FIG. 3A, a first photoresist film 212a is formed, and a predetermined region 214a is exposed. Then, as shown in FIG. 3B, on the first photoresist film 212a. Then, a second photoresist film 212b is formed, and a region 214b corresponding to the predetermined region 214a is exposed using a digital exposure scaling function. As shown in FIG. 3C, when the exposed region 214a and region 214b are removed, a deep groove made of resist is formed. In this example, an example in which two layers of resist films are stacked has been described. However, a deeper groove can be formed by exposing the same position by a digital exposure scaling function by stacking three or four layers of resist films. it can.
[0035]
Further, by thickening the photoresist film 212 in this way, a deep groove made of resist can be formed, and a deep groove (microchannel) can be accurately formed in the substrate 202 by etching. For example, as can be seen from FIGS. 4A and 4B, when a microchannel having the same groove width is formed by FAB etching, if the photoresist film 212 is thin, the substrate 150 is easily side-etched by oblique light. If the photoresist film 212 is thick, it is difficult for oblique light to enter due to kicking, and the substrate 150 is difficult to be side-etched. Thereby, a deep groove can be formed in the substrate 150 with high accuracy.
[0036]
When forming a micro flow channel having a groove width of 10 μm to 50 μm, the thickness of the photoresist film 212 is preferably 10 μm to 50 μm, and more preferably 10 μm to 100 μm.
[0037]
Further, in the case where the microchannel is formed by wet etching using an etching solution, as shown in FIG. 5, an opening 216 that is widened in a tapered shape may be formed in a pattern in the photoresist film 212. Since the opening 216 expands in a taper shape, the etching solution can easily enter.
[0038]
(Exposure equipment)
As an exposure apparatus used in the exposure process of the photoresist film, for example, an apparatus shown in FIG. 6 can be used. As shown in FIG. 6, this apparatus includes a flat stage 152 for adsorbing and holding a substrate 150 on which a photoresist film is formed. Two guides 158 extending along the stage moving direction are installed on the upper surface of the thick plate-shaped installation table 156 supported by the four legs 154. The stage 152 is arranged so 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 is provided with a drive device (not shown) for driving the stage 152 along the guide 158.
[0039]
A U-shaped gate 160 is provided at the center of the installation table 156 so as to straddle the movement path of the stage 152. Each of the ends of the U-shaped gate 160 is fixed to both side surfaces of the installation table 156. A scanner 162 is provided on one side of the gate 160, and a plurality of (for example, two) detection sensors 164 for detecting the front and rear ends of the substrate 150 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. 7 and 8B, 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 substrate 150. In the case where individual exposure heads arranged in the m-th row and the n-th column are shown, the exposure head 166 is used. _mn Is written.
[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 region 170 is formed for each exposure head 166 in the photoresist film formed on the substrate 150. In addition, when showing the exposure area by each exposure head arranged in the mth row and the nth column, the exposure area 168 is shown. _mn Is written.
[0042]
Also, as shown in FIGS. 8A and 8B, each of the exposure heads in each row arranged in a line so that the strip-shaped exposed regions 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). Therefore, the exposure area 168 in the first row ₁₁ And exposure area 168 ₁₂ The portion that cannot be exposed between the exposure area 168 and the exposure area 168 in the second row ₂₁ And exposure area 168 in the third row ₃₁ And can be exposed.
[0043]
Exposure head 166 ₁₁ ~ 166 _mn As shown in FIGS. 9, 10 (A) and (B), each is a spatial light modulation element that modulates an incident light beam for each pixel in accordance with image data representing a formation pattern of minute dew. A digital 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 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 for correcting the laser light emitted from the array light source 66 and condensing it on the DMD, and a mirror 69 for reflecting 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 that image the laser light reflected by the DMD 50 on a scanning surface (exposed surface) 56 of a photoresist film formed on the substrate 150 are arranged. ing. 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. 11, the DMD 50 is configured such that a micromirror 62 is supported on a SRAM cell (memory cell) 60 by supporting columns, and a large number of (for example, pixels) (for example, pixels) are formed. , 600 × 800) micromirrors arranged 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. 12A shows a state in which the micromirror 62 is tilted to + α degrees when the micromirror 62 is in the on state, and FIG. 12B shows a state in which the micromirror 62 is tilted to −α degrees when the micromirror 62 is in the off state. Therefore, by controlling the tilt of the micromirror 62 in each pixel of the DMD 50 according to the image signal as shown in FIG. 11, the light incident on the DMD 50 is reflected in the tilt direction of each micromirror 62. .
[0049]
FIG. 11 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]
Further, it is preferable that the DMD 50 is disposed with a slight inclination so that the short side forms a predetermined angle θ (for example, 1 ° to 5 °) with the sub-scanning direction. 13A shows the scanning trajectory of the reflected light image (exposure beam) 53 by each micromirror when the DMD 50 is not tilted, and FIG. 13B 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, the pitch P of the scanning trajectory (scanning line) of the exposure beam 53 by each micromirror is obtained by inclining the DMD 50. ₂ However, the pitch P of the scanning line when the DMD 50 is not inclined. ₁ It becomes narrower and the resolution can be greatly improved. On the other hand, since the tilt angle of the DMD 50 is very small, the scanning width W when the DMD 50 is tilted. ₂ And the scanning width W when the DMD 50 is not inclined. ₁ Is substantially the same.
[0052]
Further, the same scanning line is overlapped and exposed (multiple exposure) by different micromirror rows. In this way, by performing multiple exposure, it is possible to control a minute amount of the exposure position and to realize high-definition exposure. 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.
[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. 14A, 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 emission ends (light emission points) of the optical fiber 31 in a line along a main scanning direction orthogonal to the sub-scanning direction. As shown in FIG. 14D, the light emitting points can be arranged in two rows along the main scanning direction.
[0055]
As shown in FIG. 14B, 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 protective plate 63 may be disposed in close contact with the end surface of the optical fiber 31, and is disposed so that the end surface of the optical fiber 31 is sealed with an inert gas such as nitrogen gas or an inert gas containing a small amount of oxygen gas. May be. The exit end of the optical fiber 31 has a high light density and is easy to collect dust and easily deteriorate. However, the protective plate 63 is disposed to reduce the light density and prevent dust from adhering to the end face and deteriorate. Can be delayed.
[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. 15, 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. 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]
In general, in laser light in the infrared region, propagation loss increases as the cladding diameter of the optical fiber is reduced. For this reason, a suitable cladding diameter is determined according to the wavelength band of the laser beam. However, the shorter the wavelength, the smaller the propagation loss. In the case of laser light having a wavelength of 405 nm emitted from a GaN-based semiconductor laser, the cladding thickness {(cladding diameter−core diameter) / 2} is set to infrared light in the wavelength band of 800 nm. The propagation loss hardly increases even if it is about ½ of the case of propagating infrared light and about ¼ of the case of propagating infrared light in the 1.5 μm wavelength band for communication. Therefore, the cladding diameter can be reduced to 60 μm.
[0061]
However, the cladding diameter of the optical fiber 31 is not limited to 60 μm. The clad diameter of an optical fiber used in a conventional fiber light source is 125 μm, but the depth of focus becomes deeper as the clad diameter becomes smaller. Therefore, the clad diameter of a multimode optical fiber is preferably 80 μm or less, more preferably 60 μm or less. Preferably, it is 40 μm or less. On the other hand, since the core diameter needs to be at least 3 to 4 μm, the cladding diameter of the optical fiber 31 is preferably 10 μm or more.
[0062]
The laser module 64 is configured by a combined laser light source (fiber light source) shown in FIG. This combined laser light source includes a plurality of (for example, seven) chip-like lateral multimode or single mode GaN-based 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 GaN-based semiconductor lasers LD1 to LD7, one condenser lens 20, and one multi-lens. Mode optical fiber 30. The number of semiconductor lasers is not limited to seven. A multimode optical fiber having a clad diameter = 60 μm, a core diameter = 50 μm, and NA = 0.2 can receive as many as 20 semiconductor laser beams. The number of fibers can be further reduced.
[0063]
The GaN-based semiconductor lasers LD1 to LD7 all have the same oscillation wavelength (for example, 405 nm), and the maximum output is also all the same (for example, 100 mW for the multimode laser and 30 mW for the single mode laser). As the GaN-based semiconductor lasers LD1 to LD7, lasers having an oscillation wavelength other than the above 405 nm in a wavelength range of 350 nm to 450 nm may be used.
[0064]
As shown in FIGS. 17 and 18, 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 created so as to close the opening thereof. After the deaeration process, a sealing gas is introduced, and the package 40 and the package lid 41 are closed by closing the opening of the package 40 with the package lid 41. The combined laser light source is hermetically sealed in a closed space (sealed space) formed by 41.
[0065]
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.
[0066]
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 driving current to the GaN-based semiconductor lasers LD1 to LD7 is drawn out of the package through the opening.
[0067]
In FIG. 18, in order to avoid complication of the drawing, only the GaN semiconductor laser LD7 is numbered among the plurality of GaN semiconductor lasers, and only the collimator lens 17 is numbered among the plurality of collimator lenses. doing.
[0068]
FIG. 19 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 light emitting point arrangement direction so that the length direction is orthogonal to the light emitting point arrangement direction of the GaN-based semiconductor lasers LD1 to LD7 (left and right direction in FIG. 19).
[0069]
On the other hand, each of the GaN-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 parallel to the active layer and a divergence angle in a direction perpendicular to the active layer, respectively, for example A laser emitting ~ B7 is used. These GaN-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.
[0070]
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 f. ₁ = 3 mm, NA = 0.6, and lens arrangement pitch = 1.25 mm.
[0071]
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 f. ₂ = 23 mm, NA = 0.2. This condensing lens 20 is also formed by molding resin or optical glass, for example.
[0072]
Next, the operation of the exposure apparatus will be described.
[0073]
In each exposure head 166 of the scanner 162, laser beams B1, B2, B3, B4, B5, B6 emitted in a divergent light state from each of the GaN-based semiconductor lasers LD1 to LD7 constituting 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.
[0074]
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.
[0075]
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 GaN-based 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).
[0076]
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.
[0077]
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. The area of the light emitting region is 0.62 mm ² (0.675 mm × 0.925 mm), the luminance at the laser emission unit 68 is 1.6 × 10 6. ⁶ (W / m ² ) The brightness per optical fiber is 3.2 × 10 ⁶ (W / m ² ).
[0078]
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 emission unit 68 is 123 × 10. ⁶ (W / m ² Thus, the brightness can be increased by about 80 times compared to the conventional case. In addition, the luminance per optical fiber is 90 × 10 ⁶ (W / m ² The brightness can be increased by about 28 times compared to the conventional case.
[0079]
Here, with reference to FIGS. 20A and 20B, 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 emission region of the bundled fiber light source of the conventional exposure head is 0.675 mm, and the diameter of the light emission region of the fiber array light source of the exposure head according to the present embodiment is 0.025 mm. is there. As shown in FIG. 20A, 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 beam 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).
[0080]
On the other hand, as shown in FIG. 20B, in the exposure head of the present embodiment, the diameter of the light emitting region of the fiber array light source 66 in the sub-scanning direction is small, 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. This effect on the depth of focus is more prominent and effective as the required light quantity of the exposure head is larger. 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. 20A and 20B are developed views for explaining the optical relationship.
[0081]
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).
[0082]
The stage 152 that adsorbs the substrate 150 on which the photoresist film is formed to the surface 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 substrate 150 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 each of a plurality of lines. 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.
[0083]
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 is covered with a photoresist film formed on the substrate 150 by the lens systems 54 and 58. An image is formed on the exposure surface 56. In this manner, the laser light emitted from the fiber array light source 66 is turned on and off for each pixel, and the photoresist film is exposed in a pixel unit (exposure area 168) that is approximately the same number as the number of pixels used in the DMD 50. Further, when the substrate 150 is moved together with the stage 152 at a constant speed, the photoresist film formed on the substrate 150 is sub-scanned in the direction opposite to the stage moving direction by the scanner 162, and a strip shape is formed for each exposure head 166. The exposed area 170 is formed.
[0084]
When the sub-scanning of the photoresist film by the scanner 162 is completed and the rear end of the substrate 150 is detected by the detection sensor 164, the stage 152 is moved to the uppermost stream side of the gate 160 along the guide 158 by a driving device (not shown). It returns to a certain origin, and again moves along the guide 158 from the upstream side to the downstream side of the gate 160 at a constant speed.
[0085]
As described above, in this embodiment, since a spatial light modulation element such as DMD is used in the exposure process of the photoresist film, the laser light is modulated for each pixel in accordance with the formation pattern of the microchannel. And the photoresist film can be exposed at high speed and with high definition by the modulated laser beam. Thus, in the exposure process, high-speed and high-definition exposure of the photoresist film in an arbitrary pattern is possible. It can be formed with high accuracy.
[0086]
As described above, since exposure with an arbitrary pattern is possible, a minute flow path with a complicated pattern can be easily formed. Moreover, since high-speed exposure is possible, a microchannel can be formed in a short time on a large-area glass substrate. Furthermore, since it is digital exposure, a mask for each pattern is unnecessary, and a micro flow path can be formed at low cost.
[0087]
Further, since DFR or electrodeposition resist is used for the photoresist film, it can be made thicker than the resist used in the semiconductor manufacturing process, and a photoresist film having a thickness of 10 μm to 40 μm can be formed. . In this way, by increasing the thickness of the photoresist film, it is possible to accurately form a minute groove having a deep groove by etching.
[0088]
Further, a plurality of photoresist films can be stacked to further increase the thickness. In this case, the same position of a plurality of stacked photoresist films can be exposed using the scaling function of digital exposure.
[0089]
In the present embodiment, the exposure apparatus uses a combined laser light source to form a fiber array light source, and the cladding diameter of the exit end of the optical fiber is made smaller than the cladding diameter of the entrance end. The diameter of the part becomes smaller, and the brightness of the fiber array light source can be increased. As a result, the photoresist film can be exposed with higher definition with a laser beam having a deep focal depth. For example, it is possible to perform exposure with an ultra-high resolution with a beam diameter of 1 μm or less and a resolution of 0.1 μm or less, which is sufficient to accurately form a microchannel having a groove width of 10 μm to 50 μm.
[0090]
Hereinafter, modifications of the present embodiment will be described.
[High-speed driving method]
Usually, in the DMD, 600 micromirror arrays in which 800 micromirrors are arranged in the main scanning direction are arranged in the subscanning direction, but some micromirror arrays (for example, 800 × 10 6) are arranged by the controller. It may be controlled so that only the column is driven. Since the data processing speed of the DMD 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. Thereby, the exposure time can be shortened. On the other hand, in the scanning method in which the irradiation head is continuously moved relative to the exposure surface, it is not necessary to use all the pixels in the sub-scanning direction.
[0091]
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, the laser irradiation can be performed in 17 seconds for a 500 mm region in the sub-scanning direction. Further, when only 100 sets are used, modulation can be performed 6 times faster per line. That is, the laser irradiation can be performed in 9 seconds in an area of 500 mm in the sub-scanning direction.
[0092]
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 DMD use region, a region of 12 mm × 150 μm or more and 12 mm × 3 mm or less is preferable, 12 mm × 150 μm or more and 12 mm A region of × 1.5 mm or less is more preferable.
[0093]
If the number of micromirror arrays to be used is within the above range, the laser light emitted from the fiber array light source 66 can be made substantially parallel by the lens system 67 and irradiated to the DMD 50 as shown in FIG. Accordingly, the DMD 50 can be illuminated efficiently and uniformly, and a long focal depth can be achieved. In addition, it is preferable that the irradiation area | region which irradiates a laser beam with DMD50 corresponds with the use area | region of DMD50. When the irradiation area is wider than the use area, the utilization efficiency of the laser light is lowered.
[0094]
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.
[0095]
[Other microchip manufacturing methods]
In the above embodiment, the example in which the microchannel is formed directly on the substrate constituting the microchip has been described. However, the mold is manufactured by forming the microchannel on the substrate for mold production, and this mold is used. A microchip having a microchannel can also be manufactured by the stamping or glass mold used.
[0096]
[Microchip with microchannel]
In the above embodiment, an example of producing a microchip for synthesis reaction has been described. However, the method for forming a microchannel of the present invention is also applicable to the case of manufacturing other types of microchips having microchannels. can do.
[0097]
Examples of other types of microchips include cancer diagnostic chips, cell biochemical chips, environmental measurement chips, chromatography chips, electrophoresis chips, protein chips, and immunoanalysis chips. These chips have different microchannel formation patterns depending on the function of each chip. However, according to the microchannel formation method of the present invention, an etching mask is formed by digital exposure according to the microchannel formation pattern. Therefore, it is easy to handle multi-product production. It is also easy to form a microchannel having a plurality of functions.
[0098]
The method for forming a microchannel of the present invention is not limited to the microchannel of a lab-on-chip, and can be widely used as a method for forming a micro groove on a substrate.
[0099]
[Other spatial modulation elements]
In the above-described embodiment, an example in which an exposure head including a DMD is used as a spatial modulation element has been described. For example, another MEMS (Micro Electro Mechanical Systems) type space such as a grating light valve (GLV) is used. Spatial modulators other than the MEMS type, such as a modulator (SLM; Spatial Light Modulator), an optical element (PLZT element) that modulates transmitted light by an electro-optic effect, and a liquid crystal optical shutter (FLC) can be used.
[0100]
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.
[0101]
[Other laser devices (light sources)]
In the above embodiment, an example using a fiber array light source including a plurality of laser light sources has been described. However, the laser device is not limited to a fiber array light source in which combined laser light sources are arrayed. For example, a fiber array light source obtained by arraying fiber light sources including one optical fiber that emits laser light incident from a single semiconductor laser having one light emitting point can be used.
[0102]
(Laser array)
As a light source having a plurality of light emitting points, for example, as shown in FIG. 21, a laser array in which a plurality of (for example, seven) chip-shaped semiconductor lasers LD1 to LD7 are arranged on a heat block 100 is used. Can be used.
[0103]
(Multi cavity laser)
Further, a chip-shaped multicavity laser 110 in which a plurality of (for example, five) light emitting points 110a shown in FIG. 22A is arranged in a predetermined direction is known. Since the multicavity laser 110 can arrange the light emitting points with higher positional accuracy than the case where the chip-shaped semiconductor lasers are arranged, it is easy to multiplex laser beams emitted from the respective light emitting points. However, as the number of light emitting points increases, the multicavity laser 110 is likely to be bent at the time of laser manufacturing. Therefore, the number of light emitting points 110a is preferably 5 or less.
[0104]
In the exposure head of the present embodiment, as shown in FIG. 22B, the multi-cavity laser 110 and a plurality of multi-cavity lasers 110 are arranged on the heat block 100 in the arrangement direction of the light emitting points 110a of each chip. A multi-cavity laser array arranged in the same direction can be used as a laser device (light source).
[0105]
(Combined laser light source using multi-cavity laser)
The combined laser light source is not limited to one that combines laser beams emitted from a plurality of chip-shaped semiconductor lasers. For example, as shown in FIG. 23, a combined laser light source including a chip-shaped multicavity laser 110 having a plurality of (for example, three) light emitting points 110a can be used. This combined laser light source is configured to include a multi-cavity laser 110, one multi-mode optical fiber 130, and a condensing lens 120. The multi-cavity laser 110 can be composed of, for example, a GaN-based laser diode having an oscillation wavelength of 405 nm.
[0106]
In the above configuration, each of the laser beams B emitted from each of the plurality of light emitting points 110 a of the multicavity laser 110 is collected by the condenser lens 120 and enters the core 130 a of the multimode optical fiber 130. The laser light incident on the core 130a propagates in the optical fiber, is combined into one, and is emitted.
[0107]
A plurality of light emitting points 110 a of the multi-cavity laser 110 are juxtaposed within a width substantially equal to the core diameter of the multi-mode optical fiber 130, and a focal point substantially equal to the core diameter of the multi-mode optical fiber 130 is used as the condenser lens 120. By using a convex lens of a distance or a rod lens that collimates the outgoing beam from the multicavity laser 110 only in a plane perpendicular to the active layer, the coupling efficiency of the laser beam B to the multimode optical fiber 130 can be increased. it can.
[0108]
(Multiple laser source using multi-cavity laser array)
Further, as shown in FIG. 24, a multi-cavity laser 110 having a plurality of (for example, three) emission points is used, and a plurality of (for example, nine) multi-cavity lasers 110 are equally spaced from each other on the heat block 111. A combined laser light source including the laser array 140 arranged in (1) can be used. The plurality of multi-cavity lasers 110 are arranged and fixed in the same direction as the arrangement direction of the light emitting points 110a of each chip.
[0109]
This combined laser light source includes a laser array 140, a plurality of lens arrays 114 arranged corresponding to each multi-capability laser 110, and a single lens arranged between the laser array 140 and the plurality of lens arrays 114. A rod lens 113, one multimode optical fiber 130, and a condenser lens 120 are provided. The lens array 114 includes a plurality of microlenses corresponding to the emission points of the multi-capability laser 110.
[0110]
In the above configuration, each of the laser beams B emitted from each of the plurality of light emitting points 10a of the plurality of multi-cavity lasers 110 is condensed in a predetermined direction by the rod lens 113 and then each microlens of the lens array 114. Is collimated. The collimated laser beam L is condensed by the condenser lens 120 and enters the core 130a of the multimode optical fiber 130. The laser light incident on the core 130a propagates in the optical fiber, is combined into one, and is emitted.
[0111]
(Multi-stage combined laser light source)
Still another example of the combined laser light source will be described. In this combined laser light source, as shown in FIGS. 25A and 25B, a heat block 182 having an L-shaped cross section in the optical axis direction is mounted on a substantially rectangular heat block 180, and two heats are provided. A storage space is formed between the blocks. On the upper surface of the L-shaped heat block 182, a plurality of (for example, two) multi-cavity lasers 110 in which a plurality of light emitting points (for example, five) are arranged in an array form the light emitting points 110a of each chip. It is arranged and fixed at equal intervals in the same direction as the arrangement direction.
[0112]
A concave portion is formed in the substantially rectangular heat block 180, and a plurality of (for example, two) light emitting points (for example, five) are arranged in an array on the upper surface of the space side of the heat block 180. The multi-cavity laser 110 is arranged such that its emission point is located on the same vertical plane as the emission point of the laser chip arranged on the upper surface of the heat block 182.
[0113]
On the laser beam emission side of the multi-cavity laser 110, a collimator lens array 184 in which collimator lenses are arranged corresponding to the light emission points 110a of the respective chips is arranged. In the collimating lens array 184, the length direction of each collimating lens coincides with the direction in which the divergence angle of the laser beam is large (the fast axis direction), and the width direction of each collimating lens is in the direction in which the divergence angle is small (slow axis direction). They are arranged to match. Thus, by collimating and integrating the collimating lenses, the space utilization efficiency of the laser light can be improved, the output of the combined laser light source can be increased, and the number of parts can be reduced and the cost can be reduced. .
[0114]
Further, on the laser beam emitting side of the collimating lens array 184, there is one multimode optical fiber 130, and a condensing lens 120 that condenses and combines the laser beam at the incident end of the multimode optical fiber 130. Has been placed.
[0115]
In the above configuration, each of the laser beams B emitted from each of the plurality of light emitting points 10a of the plurality of multi-cavity lasers 110 arranged on the laser blocks 180 and 182 is collimated by the collimating lens array 184, The light is condensed by the condensing lens 120 and enters the core 130 a of the multimode optical fiber 130. The laser light incident on the core 130a propagates in the optical fiber, is combined into one, and is emitted.
[0116]
As described above, this combined laser light source can achieve particularly high output by the multi-stage arrangement of multi-cavity lasers and the array of collimating lenses. By using this combined laser light source, a higher-intensity fiber array light source or bundle fiber light source can be formed, which is particularly suitable as a fiber light source constituting the laser light source of the exposure apparatus of the present invention.
[0117]
It should be noted that a laser module in which each of the above combined laser light sources is housed in a casing and the emission end portion of the multimode optical fiber 130 is pulled out from the casing can be configured.
[0118]
In the above embodiment, another optical fiber having the same core diameter as the multimode optical fiber and a cladding diameter smaller than the multimode optical fiber is coupled to the output end of the multimode optical fiber of the combined laser light source. However, for example, a multimode optical fiber having a cladding diameter of 125 μm, 80 μm, 60 μm, or the like can be used without coupling another optical fiber to the output end. Good.
[0119]
[Other imaging optics]
In the above embodiment, two sets of lenses are arranged as the imaging optical system on the light reflection side of the DMD used for the exposure head. However, the imaging optical system that forms an image by enlarging the laser beam is arranged. Also good. By expanding the cross-sectional area of the light beam reflected by the DMD, the exposure area area (image area) on the exposed surface can be expanded to a desired size.
[0120]
For example, as shown in FIG. 26A, the exposure head is configured to illuminate DMD 50, illumination device 144 that irradiates the laser beam to DMD 50, lens systems 454, 458, and DMD 50 that expand the laser beam reflected by DMD 50 to form an image. A microlens array 472 in which a large number of microlenses 474 are arranged corresponding to each of the pixels, an aperture array 476 in which a large number of apertures 478 are provided corresponding to each microlens of the microlens array 472, and a laser that has passed through the aperture It can be configured by lens systems 480 and 482 that form an image of light on the exposed surface 56.
[0121]
In this exposure head, when laser light is irradiated from the illumination device 144, the cross-sectional area of the light beam reflected by the DMD 50 in the ON direction is enlarged several times (for example, twice) by the lens systems 454 and 458. . The expanded laser light is condensed corresponding to each pixel of the DMD 50 by each microlens of the microlens array 472, and passes through the corresponding aperture of the aperture array 476. The laser light that has passed through the aperture is imaged on the exposed surface 56 by the lens systems 480 and 482.
[0122]
In this imaging optical system, the laser light reflected by the DMD 50 is magnified several times by the magnifying lenses 454 and 458 and projected onto the exposed surface 56, so that the entire image area is widened. At this time, if the microlens array 472 and the aperture array 476 are not arranged, as shown in FIG. 26 (B), one pixel size (spot size) of each beam spot BS projected onto the exposed surface 56 is exposed. MTF (Modulation Transfer Function) characteristics representing the sharpness of the exposure area 468 are reduced depending on the size of the area 468.
[0123]
On the other hand, when the microlens array 472 and the aperture array 476 are arranged, the laser light reflected by the DMD 50 is condensed corresponding to each pixel of the DMD 50 by each microlens of the microlens array 472. Accordingly, as shown in FIG. 26C, even when the exposure area is enlarged, the spot size of each beam spot BS can be reduced to a desired size (for example, 10 μm × 10 μm), and the MTF characteristics are obtained. It is possible to perform high-definition exposure while preventing a decrease in the image quality. The exposure area 468 is tilted because the DMD 50 is tilted and arranged in order to eliminate a gap between pixels.
[0124]
In addition, even if the beam is thick due to the aberration of the microlens, the beam can be shaped by the aperture so that the spot size on the exposed surface 56 becomes a constant size, and corresponding to each pixel. By passing the provided aperture, it is possible to prevent crosstalk between adjacent pixels.
[0125]
Furthermore, by using a high-intensity light source for the illumination device 144 as in the above embodiment, the angle of the light beam incident on each microlens of the microlens array 472 from the lens 458 is reduced, so that the light flux of adjacent pixels can be reduced. Part of the incident can be prevented. That is, a high extinction ratio can be realized.
[0126]
【The invention's effect】
According to the method for forming a microchannel of the present invention, an effect that the microchannel can be formed at high speed and with high accuracy is obtained. Moreover, the effect that the micro flow path of arbitrary patterns can be formed at low cost is acquired.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a configuration of a synthesis reaction microchip.
2 (A) to (G) are cross-sectional views sequentially showing the manufacturing steps of the synthesis reaction microchip shown in FIG.
FIGS. 3A to 3C are cross-sectional views showing examples of thickening a resist film. FIGS.
FIGS. 4A and 4B are explanatory views for explaining that the etching accuracy is improved as the resist film is thickened. FIGS.
FIG. 5 is a cross-sectional view showing a resist film patterned in a tapered shape.
FIG. 6 is a perspective view showing an external appearance of an exposure apparatus used in the embodiment of the present invention.
7 is a perspective view showing a configuration of a scanner of the exposure apparatus shown in FIG. 6. FIG.
FIG. 8A is a plan view showing an exposed region formed on a photoresist film, and FIG. 8B is a diagram showing an arrangement of exposure areas by each exposure head.
9 is a perspective view showing a schematic configuration of an exposure head of the exposure apparatus shown in FIG. 6. FIG.
10A is a cross-sectional view in the sub-scanning direction along the optical axis showing the configuration of the exposure head shown in FIG. 9, and FIG. 10B is a side view of FIG.
FIG. 11 is a partially enlarged view showing a configuration of a digital micromirror device (DMD).
FIGS. 12A and 12B are explanatory diagrams for explaining the operation of the DMD.
FIGS. 13A and 13B 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.
14A is a perspective view showing the configuration of a fiber array light source, FIG. 14B is a partially enlarged view of A, and FIGS. 14C and 14D show the arrangement of light emitting points in a laser emitting section. FIG.
FIG. 15 is a diagram showing a configuration of a multimode optical fiber.
FIG. 16 is a plan view showing a configuration of a combined laser light source.
FIG. 17 is a plan view showing a configuration of a laser module.
18 is a side view showing the configuration of the laser module shown in FIG.
19 is a partial side view showing the configuration of the laser module shown in FIG.
20A and 20B are cross-sectional views along the optical axis showing the difference between the depth of focus in the conventional exposure apparatus and the depth of focus in the exposure apparatus used in the present embodiment.
FIG. 21 is a perspective view showing a configuration of a laser array.
22A is a perspective view showing a configuration of a multi-cavity laser, and FIG. 22B is a perspective view of a multi-cavity laser array in which the multi-cavity lasers shown in FIG.
FIG. 23 is a plan view showing another configuration of the combined laser light source.
FIG. 24 is a plan view showing another configuration of the combined laser light source.
25A is a plan view showing another configuration of the combined laser light source, and FIG. 25B is a sectional view taken along the optical axis of FIG.
FIG. 26A is a cross-sectional view along the optical axis showing the configuration of another exposure head having a different coupling optical system, and FIG. 26B is projected onto the exposure surface when a microlens array or the like is not used. FIG. 6C is a plan view showing a light image projected on an exposed surface when a microlens array or the like is used.
[Explanation of symbols]
LD1-LD7 GaN semiconductor laser
10 Heat block
11-17 Collimator lens
20 Condensing lens
30 Multimode optical fiber
50 Digital Micromirror Device (DMD)
53 Reflected light image (exposure beam)
54, 58 Lens system
56 Scanning surface (exposed surface)
64 laser module
66 Fiber array light source
68 Laser emitting part
73 Combination lens
150 substrates
152 stages
162 Scanner
166 Exposure head
168 Exposure area
170 Exposed area
202 Protection board
204a, 204b inlet
206 outlet
208 Microchannel
210 Junction
212 photoresist film
214 Exposed part

Claims (5)

An exposure step of exposing the resist film formed on the substrate with laser light having a wavelength of 350 nm to 450 nm spatially modulated in accordance with the formation pattern data of the microchannel;
The resist film is partially removed according to the exposure pattern, and a patterning step of forming a resist film having a predetermined pattern;
Using the resist film of the predetermined pattern, the substrate is etched away from the surface, and an etching step for forming a micro flow path;
A method of forming a microchannel having The method for forming a microchannel according to claim 1, wherein when forming a microchannel with a groove width of 10 μm to 50 μm, the thickness of the resist film is set to 10 μm to 100 μm. The laser light collects a plurality of semiconductor lasers, a single optical fiber, and laser light emitted from each of the plurality of semiconductor lasers, and couples a focused beam to an incident end of the optical fiber. The method for forming a microchannel according to claim 1 or 2, which is emitted from a combined laser light source including an optical optical system. 4. The method of forming a micro flow channel according to claim 3, wherein an optical fiber having a uniform core diameter and a cladding diameter at the output end smaller than the cladding diameter at the input end is used as the optical fiber. The laser light is applied to a spatial light modulation element in which a large number of pixel portions whose light modulation states change according to a control signal are arranged on a substrate, and is modulated by each pixel portion of the spatial light modulation element. Item 5. The method for forming a microchannel according to any one of Items 1 to 4.

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