JP2006308994A - Exposure apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce readjustment work accompanying attachment and detachment of a photodetector provided to a beam position detecting means. <P>SOLUTION: The beam position detecting means to detect exposure positions on the exposure plane of the respective beams projected from a plurality of exposure heads is equipped with a reference plate 170 having a slit to transmit a beam and a photodetector 172 to detect the beam passing through the slit. The photodetector 172 is attached across an attaching plate 190 to a moving base 74 so as to be attached and detached independently of the reference plate 170. Since readjustment of the exposure function by re-attaching the reference plate 170 is made unnecessary when exchanging or detaching the photodetector 172, the readjustment work accompanying the attachment and detachment of the photodetector 172 can be reduced. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an exposure apparatus, and more particularly to a multi-head exposure apparatus that irradiates a photosensitive material with a light beam modulated by a spatial modulation element or the like according to image information from a plurality of exposure heads.

  Conventionally, various exposure apparatuses that use a spatial light modulator (SLM) such as a digital micromirror device (DMD) to perform image exposure with a light beam modulated according to image data have been proposed.

  For example, the DMD is a mirror device in which a number of micromirrors whose reflecting surfaces change in response to a control signal are two-dimensionally arranged on a semiconductor substrate such as silicon. In an exposure apparatus of a scanning exposure system, a light source for irradiating laser light, a lens system for collimating laser light emitted from the light source, DMD arranged at a substantially focal position of the lens system, and laser light reflected by the DMD on the scanning surface An exposure head having a lens system that forms an image on the top modulates each of the DMD micromirrors by a control signal generated according to image data or the like to modulate the laser light. With the modulated laser light, An image (pattern) is scanned and exposed to a photosensitive material such as a printed wiring board and a liquid crystal display element which is set on the stage and moved along the scanning direction.

  In such a digital exposure apparatus, in particular, in an apparatus having a multi-head configuration in which a plurality of exposure heads are arranged along the direction intersecting the conveyance direction of the photosensitive material in order to expose a large area, the images are connected between the heads. A technique for detecting with high accuracy and correcting with high accuracy is required (for example, see Patent Document 1). In addition, in order to form a fine pattern, it is necessary to have a shading technique that measures and uniformly corrects the beam power of each exposure head, and also requires an alignment measurement technique to overlay fine patterns in multiple layers with high accuracy. (For example, refer to Patent Document 2).

Therefore, a beam position comprising a photodetector for detecting an exposure position by each exposure beam and a reference plate for beam position detection in order to correct a connection between exposure areas exposed by each light beam emitted from each exposure head. A detection means, a light quantity measurement means for measuring the light quantity distribution and exposure amount of each light beam emitted from each exposure head, and a calibration reference plate for calibrating the alignment function are provided at the end of the stage, respectively. Sometimes the stage is moved so that, for example, the beam position detecting means or the beam power measuring means is arranged below the exposure head, and the calibration member is an alignment that performs calibration by photographing a reference mark provided on the calibration member. It is arranged below the camera.
Japanese Patent Laid-Open No. 2005-3762 JP 2004-348045 A

  By the way, the above-mentioned beam position detection reference plate and calibration reference plate are reference plates for adjusting (calibrating) functions that are very important for the apparatus performance such as exposure accuracy and alignment accuracy. In addition to being positioned and mounted, it is normally used for the life of the device. At the time of manufacturing the device, each function of the device is adjusted with high accuracy over several hours with reference to these reference plates.

  On the other hand, the photodetector paired with the beam position detection reference plate may be replaced due to a failure, a performance deterioration due to aging, or the like, and may be removed by maintenance of the apparatus. Therefore, if the beam position detection reference plate is removed from the stage due to the replacement or removal of the photodetector, it takes a long time to position the beam position detection reference plate with high accuracy and attach it to the stage. The exposure function must be readjusted, and the work becomes extremely complicated.

  In consideration of the above fact, the present invention reduces the readjustment work associated with the attachment / detachment of the photodetector by enabling the photodetector provided in the beam position detection means to be attached / detached independently of the reference plate. It is an object of the present invention to provide an exposure apparatus capable of performing the above.

  In order to achieve the above object, the invention described in claim 1 is directed to a plurality of exposure heads that scan and expose a photosensitive material by irradiating a light beam modulated according to image information, and the plurality of exposure heads. A stage that moves relative to each other and conveys the photosensitive material along the scanning direction, and an exposure position on the exposure surface of each light beam that is provided at one end of the stage in the moving direction and that is irradiated from the plurality of exposure heads. Beam position detecting means for detecting, wherein the beam position detecting means comprises a reference plate on which a plurality of slit-like light transmitting portions that transmit light beams are formed corresponding to the plurality of exposure heads, and the light transmitting light. And a photodetector that detects the light beam transmitted through the portion and is detachable independently of the reference plate.

  According to the first aspect of the present invention, each light irradiated from the plurality of exposure heads to one end portion in the moving direction of the transport unit that moves relative to the plurality of exposure heads and transports the photosensitive material along the scanning direction. By arranging beam position detection means for detecting the exposure position of the beam on the exposure surface, for example, a plurality of exposures based on the beam position information on the exposure surface of each light beam acquired by the beam position detection means. It is possible to perform high-accuracy image exposure by correcting the connection of exposure regions (images) exposed by each light beam emitted from the head. And in the beam position detection means provided at one end of the moving direction in this stage, the photodetector can be attached and detached independently from the reference plate without removing the reference plate. This eliminates the need to readjust the exposure function by positioning the reference plate with high accuracy and reattaching it to the stage. Thereby, the readjustment work accompanying attachment and detachment of the photodetector can be reduced.

  According to a second aspect of the present invention, a plurality of exposure heads that scan and expose a photosensitive material by irradiating a light beam modulated in accordance with image information, and a relative movement with respect to the plurality of exposure heads, A stage transported along the scanning direction, and a beam position detecting means provided at one end in the moving direction of the stage and detecting an exposure position on an exposure surface of each light beam irradiated from the plurality of exposure heads; The beam position detecting means includes a reference plate in which a plurality of slit-shaped light transmitting portions that transmit a light beam are formed corresponding to the plurality of exposure heads, and a light beam transmitted through the light transmitting portion. It is characterized by having a photodetector to detect, and attachment / detachment means for detachably attaching the photodetector independently of the reference plate.

  According to the second aspect of the present invention, the beam position detecting means provided at one end of the stage in the moving direction can be attached / detached independently of the reference plate through the attaching / detaching means without removing the reference plate. . This eliminates the need for readjustment of the exposure function due to the replacement and removal of the photodetector, eliminating the need for readjustment of the exposure function by positioning the reference plate with high accuracy and reducing the readjustment work. can do.

  According to a third aspect of the present invention, in the exposure apparatus according to the first or second aspect, the reference plate is embedded in the one end of the stage.

  In the invention described in claim 3, by embedding the reference plate in one end portion of the stage, the stability of the reference plate is improved, and a decrease in beam position detection accuracy due to vibration or distortion can be suppressed. Further, even when the reference plate is enlarged to expose a large area, the reference plate can be stably installed on the stage, so that the enlargement of the reference plate can be easily handled.

  According to a fourth aspect of the present invention, in the exposure apparatus according to any one of the first to third aspects, the beam position detecting unit further includes a plurality of light transmitting units corresponding to the light detectors. It has a moving means for moving to the detection position of the light beam.

  In the invention according to claim 4, since the light detector is moved to the detection position of each light beam corresponding to the plurality of light transmitting portions by the moving means, for example, the light detector is replaced with the plurality of light transmitting portions. Even if the same number is not provided, it is possible to detect the light beam at each light-transmitting portion if there is at least one photodetector. As described above, the number of photodetectors can be smaller than that of the light transmitting portions, so that the cost of the beam position detecting means can be reduced.

  According to a fifth aspect of the present invention, in the exposure apparatus according to any one of the first to fourth aspects, the beam position information on the exposure surface of each of the light beams acquired by the beam position detecting means is used. And a connection correction unit that corrects connection of exposure areas exposed by the light beams emitted from the plurality of exposure heads.

  According to the fifth aspect of the present invention, based on the beam position information on the exposure surface of each light beam acquired by the beam position detecting means, the connection correcting means is exposed by each light beam emitted from a plurality of exposure heads. Corrects the connection between exposure areas. Thereby, the connection of the exposure areas (images) between the plurality of exposure heads is corrected with high accuracy.

  Since the exposure apparatus of the present invention has the above-described configuration, the photodetector provided in the beam position detecting means can be attached / detached independently of the reference plate, and the readjustment work accompanying the attachment / detachment of the photodetector can be reduced. Can do.

  An exposure apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

  FIG. 1 shows an exposure apparatus according to an embodiment of the present invention. 2 to 6 show an exposure head and a spatial light modulator applied to the exposure apparatus according to this embodiment.

  As shown in FIG. 1, the exposure apparatus 10 includes a rectangular thick plate-shaped installation base 12 supported by four legs 14. Two guides 16 extend along the longitudinal direction on the upper surface of the installation table 12, and a rectangular flat plate-like stage 18 is provided on the two guides 16. The stage 18 is disposed such that the longitudinal direction thereof is directed to the extending direction of the guide 16, and is supported by the guide 16 so as to be reciprocally movable on the installation table 12. The stage 18 is driven by a driving device (not shown) to reciprocate along the guide 16. Move (in the direction of arrow Y in FIG. 1).

  On the upper surface of the stage 18, a rectangular plate-shaped photosensitive material 20 serving as an exposure object is placed in a state of being positioned at a predetermined placement position by a positioning unit (not shown). A plurality of grooves (not shown) are formed on the upper surface (photosensitive material placement surface) of the stage 18, and the photosensitive material 20 is placed on the stage 18 by applying a negative pressure inside the grooves by a negative pressure supply source. It is adsorbed and held on the upper surface. In addition, the photosensitive material 20 is provided with a plurality of alignment marks 21 indicating the reference of the exposure position. In this embodiment, the alignment marks 21 formed by circular through holes are each in the vicinity of the four corners of the photosensitive material 20. A total of four are arranged.

  A U-shaped gate 22 is provided at the center of the installation table 12 so as to straddle the movement path of the stage 18. Both ends of the gate 22 are fixed to both sides of the upper surface of the installation table 12, and a scanner 24 for exposing the photosensitive material 20 is provided on one side across the gate 22, and the photosensitive material is provided on the other side. An alignment unit 100 including a plurality of (for example, two) CCD cameras 26 for photographing the alignment mark 21 provided at 20 is provided.

  As shown in FIG. 7, the alignment unit 100 includes a rectangular unit base 102 attached to the gate 22. A pair of guide rails 104 are extended on the camera mounting surface side of the unit base 102 along a direction (arrow X direction) orthogonal to the moving direction (arrow Y direction) of the stage 18. Is slidably guided by the pair of guide rails 104 and driven by a drive source such as a ball screw mechanism 106 prepared individually and a stepping motor (not shown) for driving the mechanism, It moves independently in the direction orthogonal to the moving direction. Each CCD camera 26 is arranged in such a posture that the lens portion 26B provided at the tip of the camera body 26A is directed downward and the optical axis of the lens is substantially vertical, and a ring is provided at the tip of the lens portion 26B. A strobe light source (LED strobe light source) 26C is attached.

  Each CCD camera 26 is moved in the direction of the arrow X by the drive source and the ball screw mechanism 106 when the alignment mark 21 of the photosensitive material 20 is photographed, and is arranged at a predetermined photographing position, that is, lens light. The shaft is arranged so as to match the passing position of the alignment mark 21 of the photosensitive material 20 that moves with the movement of the stage 18, and the strobe light source 26C is caused to emit light at the timing when the alignment mark 21 reaches a predetermined photographing position. The alignment mark 21 is photographed by causing the reflected light of the strobe light irradiated on the photosensitive material 20 to be input to the camera body 26A via the lens portion 26B.

  The stage 18 drive device, the scanner 24, the CCD camera 26, a drive source for moving the CCD camera 26, and a measurement unit 70 provided on the stage 18 are connected to a controller 28 for controlling them. Yes. The controller 28 controls the stage 18 to move at a predetermined speed during the exposure operation of the exposure apparatus 10 to be described later, and the CCD camera 26 is placed at a predetermined position and aligned with the alignment mark 21 of the photosensitive material 20 at a predetermined timing. The scanner 24 is controlled to expose the photosensitive material 20 at a predetermined timing. Further, during each measurement operation by the measurement unit 70, the measurement unit 70 is controlled by the controller 28 to perform each predetermined measurement operation.

  As shown in FIGS. 1 and 2, a plurality of (for example, eight) exposure heads 30 arranged in a matrix of m rows and n columns (for example, 2 rows and 4 columns) are installed in the scanner 24. ing.

  As shown in FIGS. 2 and 11, the exposure area 32 exposed by the exposure head 30 has a rectangular shape having a short side in the scanning direction, and is inclined at a predetermined inclination angle θ with respect to the scanning direction. As the stage 18 moves, a strip-shaped exposed region 34 is formed on the photosensitive material 20 for each exposure head 30.

  Further, as shown in FIG. 11, the exposure heads 30 in each row arranged in a line form such that the strip-shaped exposed regions 34 are arranged without gaps in the direction orthogonal to the scanning direction. The exposure area is shifted by a natural number times the long side of the exposure area (1 time in the present embodiment). For this reason, for example, the non-exposure area between the exposure area 32A located on the leftmost side of the first row and the exposure area 32C located on the right side of the exposure area 32A is the exposure area located on the leftmost side of the second row. It is exposed by 32B. Similarly, a non-exposure area between the exposure area 32B and the exposure area 32D located on the right side of the exposure area 32B is exposed by the exposure area 32C.

  As shown in FIG. 3, each exposure head 30 includes a digital micromirror device (DMD) 36 as a spatial light modulation element that modulates an incident light beam for each pixel in accordance with image data. Yes. The DMD 36 is connected to the above-described controller 28 including a data processing unit and a mirror drive control unit (see FIG. 1).

  The data processing unit of the controller 28 generates a control signal for driving and controlling each micromirror in the area to be controlled by the DMD 36 for each exposure head 30 based on the input image data. The area to be controlled will be described later. Further, the mirror drive control unit as the DMD controller controls the angle of the reflection surface of each micromirror in the DMD 36 for each exposure head 30 based on the control signal generated by the data processing unit. The control of the angle of the reflecting surface will be described later.

  On the light incident side of the DMD 36 in each exposure head 30, as shown in FIG. 1, a bundle-like shape drawn out from an illumination device 38 that emits a multi-beam extending in one direction including an ultraviolet wavelength region as laser light. An optical fiber 40 is connected.

  Although not shown, the illuminating device 38 includes a plurality of multiplexing modules that multiplex laser beams emitted from a plurality of semiconductor laser chips and input them to the optical fiber. The optical fiber extending from each multiplexing module is a multiplexing optical fiber that propagates the combined laser beam, and a plurality of optical fibers are bundled into one to form a bundle-shaped optical fiber 40.

  Further, on the light incident side of the DMD 36 in each exposure head 30, as shown in FIG. 3, a uniform illumination optical system 41 that converts the laser light emitted from the connection end of the optical fiber 40 into uniform illumination light, and uniform illumination A mirror 42 that reflects the laser light transmitted through the optical system 41 toward the DMD 36 is disposed.

  The projection optical system provided on the light reflection side of the DMD 36 in each exposure head 30 projects a light source image onto the photosensitive material 20 on the exposure surface on the light reflection side of the DMD 36, and therefore sequentially from the DMD 36 toward the photosensitive material 20. The optical members for exposure of the lens system 50, the microlens array 54, and the objective lens system 56 are arranged.

  Here, as shown in FIG. 3, the lens system 50 and the objective lens system 56 are configured as a magnifying optical system in which a plurality of lenses (such as a convex lens and a concave lens) are combined, and a laser beam (light beam) reflected by the DMD 36. By enlarging the cross-sectional area of the bundle, the area of the exposure area 32 on the photosensitive material 20 by the laser beam reflected by the DMD 36 is expanded to a predetermined size. The photosensitive material 20 is disposed at the rear focal position of the objective lens system 56.

  As shown in FIG. 3, the microlens array 54 includes two microlenses 60 corresponding one-to-one to each micromirror 46 of the DMD 36 that reflects the laser light emitted from the illumination device 38 through each optical fiber 40. The microlenses 60 are arranged in a dimensional shape and are integrally formed to form a rectangular flat plate. Each microlens 60 is arranged on the optical axis of each laser beam (exposure beam) that has passed through the lens system 50. Has been.

  Further, as shown in FIG. 5, the DMD 36 includes a micromirror (micromirror) 46 supported by a support column on an SRAM cell (memory cell) 44, and has a large number of pixels (pixels). It is configured as a mirror device in which minute mirrors (for example, 600 × 800) are arranged in a lattice pattern. Each pixel is provided with a micromirror 46 supported by a support column at the top, and a material having high reflectance such as aluminum is deposited on the surface of the micromirror 46.

  A silicon gate CMOS SRAM cell 44 manufactured on a normal semiconductor memory manufacturing line is disposed directly below the micromirror 46 via a post including a hinge and a yoke (not shown). (Integrated type).

  When a digital signal is written in the SRAM cell 44 of the DMD 36, the micromirror 46 supported by the support is tilted in a range of ± α degrees (for example, ± 10 degrees) with respect to the substrate side on which the DMD 36 is disposed with the diagonal line as the center. It is done. FIG. 6 shows an example of a state in which a part of the DMD 36 is enlarged and the micromirror 46 is controlled to + α degrees or −α degrees. FIG. 6A shows that the micromirror 46 is in an on state. FIG. 6B shows a state in which the micromirror 46 is inclined to −α degrees, which is in an off state. Therefore, by controlling the inclination of the micromirror 46 in each pixel of the DMD 36 as shown in FIG. 6 according to the image signal, the light incident on the DMD 36 is reflected in the inclination direction of each micromirror 46. .

  On / off control of each micromirror 46 is performed by the mirror drive control unit of the controller 28 connected to the DMD 36, and the light reflected by the on-state micromirror 46 is modulated into an exposure state, and the DMD 36 Is incident on a projection optical system (see FIG. 3) provided on the light exit side. The light reflected by the micromirror 46 in the off state is modulated into a non-exposure state and is incident on a light absorber (not shown).

  Further, it is preferable that the DMD 36 is disposed slightly inclined so that the short side direction forms a predetermined angle (for example, 0.1 ° to 0.5 °) with the scanning direction. 4A shows the scanning trajectory of the reflected light image (exposure beam) 48 by each micromirror when the DMD 36 is not tilted, and FIG. 4B shows the scanning trajectory of the exposure beam 48 when the DMD 36 is tilted. Show.

In the DMD 36, a number of micromirror arrays in which a large number (for example, 800) of micromirrors 46 are arranged along the longitudinal direction (row direction) are arranged in a short direction (for example, 600 sets). as shown in FIG. 4 (B), by inclining the DMD 36, the pitch P of the scanning lines when the pitch P ₂ is not tilted the DMD 36 of the scanning locus of the exposure beam 48 by the micromirrors 46 (scanning line) Narrower than _{1 and} can greatly improve the resolution. On the other hand, since the tilt angle of the DMD 36 is very small, the scan width W ₂ when the DMD 36 is tilted and the scan width W ₁ when the DMD 36 is not tilted are substantially the same.

  Further, substantially the same position (dot) on 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, the joints between the plurality of exposure heads arranged in the scanning direction can be connected without any step by controlling a very small amount of exposure position.

  Note that the same effect can be obtained by arranging the micromirror rows in a staggered manner at a predetermined interval in the direction orthogonal to the scanning direction instead of inclining the DMD 36.

  In the exposure head 30 configured as described above, incident light (laser light) from the illumination device 38 is modulated by the DMD 36 and the exposure beam (laser beam) is irradiated onto the surface of the photosensitive material 20 for exposure (image formation). ), However, the exposure light beam reflected and emitted from the DMD 36 is non-uniform in the light beam distribution in the direction perpendicular to the scanning direction due to disturbance generated during the operation, change over time, or the like. In some cases, the exposure amount of each portion to be exposed with a predetermined exposure value on 20 changes from the predetermined exposure value.

  In view of this, the exposure apparatus 10 is provided with a light amount measuring means for measuring the light amount distribution and the exposure amount in the exposure beam emitted from the DMD 36 side in order to adjust the shading and the exposure amount to make the light amount distribution uniform. Yes.

  Furthermore, since this exposure head 30 is provided with a large number of optical members, mechanism members, and the like from the light source to the image formation surface, thermal expansion and contraction due to temperature changes, and accumulation over time due to long-term use. As a result, the image formed by the exposure beam from each exposure head 30 (exposed region 34) may cause a shift that cannot be ignored at the joints, and the image quality may deteriorate.

  Therefore, in this exposure apparatus 10, in order to correct the connection between the images (exposure areas 32) formed by the exposure beams emitted from the plurality of exposure heads 30, beam position detection means for detecting the exposure position of each exposure beam is provided. Provided.

  These light quantity measuring means and beam position detecting means are integrally formed in the measuring unit 70 and unitized.

  As shown in FIG. 1, a plurality of exposure heads 30 are mounted on the stage 18 of the exposure apparatus 10 at the stop position (state shown in FIG. 1) of the stage 18 where the photosensitive material 20 is stopped. A measurement unit 70 is attached to an end on the downstream side in the stage moving direction, which is an end near the scanner 24. As shown in FIGS. 2 and 8, the measurement unit 70 includes a box-shaped unit frame 71 attached to the stage 18, and the unit frame 71 is orthogonal to the scanning direction of the exposure beam emitted from the DMD 36 side. A light amount measuring device 72 as a light amount measuring means for measuring the light amount distribution and the exposure amount with respect to the direction (arrow X direction), and a moving base 74 with the light amount measuring device 72 attached to the upper surface are arranged.

  Between the side plate portions 88A and 88B erected opposite to both side portions of the unit frame 71, two guides are provided along a direction (arrow X direction) orthogonal to the moving direction of the stage 18 (arrow Y direction). Shafts 90A and 90B and a ball screw 92 are installed. In the moving base 74, a guide hole 94 formed at one end on the stage 18 side is inserted into one guide shaft 90A, and a cam follower 96 rotatably attached to a lower portion at the other end is disposed on the other guide shaft 90B. A ball screw nut 98 mounted on and supported on the lower surface is screwed into the ball screw 92. When the ball screw 92 is driven by a driving source such as a stepping motor (not shown), the moving base 74 and the light amount measuring device 72 are guided by the guide shafts 90A and 90B and moved in the X direction.

  The light quantity measuring device 72 includes a rectangular box-shaped housing 76, and a slit plate 78 is fitted and attached to a rectangular opening 77 formed on the upper surface of the housing 76. As shown in FIG. 9, the slit plate 78 is formed with a slit 80 of a through groove having an I-shape (straight line) in plan view. The slit 80 is exposed from the exposure head 30. The direction is parallel to the scanning direction of the beam (the moving direction of the stage 18).

  As shown in FIG. 10, a condensing lens 82 is arranged in the housing 76 of the light quantity measuring device 72 immediately below the slit plate 78 and on the optical path of the exposure beam incident from the slit 80, and if necessary. An optical filter (ND filter) 84 is disposed directly below the condenser lens 82, and a light receiving element (photodetector) 86 is disposed directly below the optical filter 84.

  The optical filter 84 is used to match the spectral sensitivity characteristic of the photosensitive material 20 or to match the optical wavelength characteristic of the light beam emitted from the exposure head 30. The DMD 36 and the light receiving element 86 are used. Can be arranged at any position on the optical path.

  The light receiving element 86 is connected to the controller 28 and is configured to output an electrical signal corresponding to the amount of received light to the controller 28.

  As described above, the light amount measuring device 72 is attached to the moving base 74 and mounted on the measuring unit 70. In this embodiment, the upper surface of the slit plate 78 is the surface of the photosensitive material 20 placed on the stage 18. It is arranged so as to coincide with the exposure surface position (a state where it is flush with the exposure surface of the photosensitive material 20).

  When the light amount measuring device 72 measures the light amount of the light beam, the light beam that has passed through the slit 80 enters the condensing lens 82, and the optical filter 84 is collected on the optical path that is collected by the condensing lens 82. The light beam having a predetermined wavelength passes through the optical filter 84 and is collected and received on the light receiving element 86. The light receiving element 86 outputs a signal of a voltage level corresponding to the measured value of the amount of received light to the controller 28. To do. Further, in the measurement of the light amount of the light beam, as described above, the slit plate 78 is arranged so as to coincide with the exposure surface position of the photosensitive material 20, so that the level is substantially the same as the actual exposure on the photosensitive material 20. Can be measured and the measurement accuracy can be improved.

  In addition, as described above, the measurement unit 70 of the present embodiment is provided with the beam position detection means, and the beam position detection means is configured such that the upper plate portion of the unit frame 71 as shown in FIGS. A reference plate 170 fitted and attached to 99 and a light receiving element (photodetector) 172 attached to the upper surface of the moving base 74 and disposed below the reference plate 170 are provided.

  As shown in the drawing, the reference plate 170 and the light receiving element 172 constituting the beam position detecting means are arranged on the stage 18 side (upstream side in the stage moving direction) from the light quantity measuring device 72.

  The reference plate 170 is formed of a rectangular glass plate that is longer than the full width dimension in the arrangement direction of the plurality of exposure heads 30 provided in the scanner 24, and detects the beam position downstream in the stage moving direction. 170A is provided, and a camera position detector 170B is provided on the upstream side (see FIG. 2).

  In the beam position detection unit 170A, a plurality of slits 120 formed in a transparent portion (translucent portion) in the shape of a “<” are opened in the X direction by patterning with a metal film such as chrome plating in the X direction. Are arranged at predetermined intervals along.

  As shown in FIG. 9, the slit 120 includes a linear slit portion 120a having a predetermined length located on the upstream side in the stage moving direction (camera position detecting unit 170B side) and the downstream side in the stage moving direction (light quantity). A linear slit portion 120b having a predetermined length located in the measuring device 72) is formed in a shape in which each end portion is connected at a right angle. That is, the slit part 120a and the slit part 120b are orthogonal to each other, and the slit part 120a has an angle of 135 degrees and the slit part 120b has an angle of 45 degrees with respect to the Y axis.

  In addition, although the slit part 120a in the slit 120 and the slit part 120b illustrated what was formed so that an angle of 45 degrees might be formed with respect to the moving direction (scanning direction) of the stage 18, these slit parts 120a, If the slit portion 120b can be tilted with respect to the pixel arrangement of the exposure head 30 and at the same time tilted with respect to the stage moving direction (arranged so that they are not parallel to each other), the angle with respect to the stage moving direction can be arbitrarily set. May be set. Further, a diffraction grating may be used instead of the slit 120.

  On the other hand, the light receiving element 172 is attached to one end portion on the upper surface of the moving base 74 and is positioned below the beam position detecting unit 170A, and the ball screw 92 is driven and controlled by the controller 28. As it moves, it moves in the X direction and is arranged directly below each slit 120. The light receiving element 172 is connected to the controller 28 and is configured to output an electrical signal corresponding to the amount of received light to the controller 28.

  Further, as shown in FIG. 9, the camera position detection unit 170B of the reference plate 170 has a detection mark 177A formed in a circular shape by patterning with a metal film such as chrome plating, and a detection mark formed in a cross shape. 177B and a plurality of detection marks 177C formed in a square are arranged in order at predetermined intervals along the X direction.

  As shown in FIGS. 20A to 20D, the width dimension of the detection mark 177A: MA and the width dimension of the detection mark 177B: MB and the width dimension of the detection mark 177C: MC are equal (MA = MB = MC), the arrangement pitch P1 of the detection marks 177A, 177B, and 177C is determined from the length dimension L in the X direction of the field of view (imaging field of view) V of the CCD camera 26: 177A, 177B, 177C. Is set to a value obtained by subtracting ½ of the width dimension (P1 = L− (MA / 2) = L− (MB / 2) = L− (MC / 2)). Here, the unit of movement of the CCD camera 26 in the X direction: U1 is set to ½ of the width dimension of the detection marks 177A, 177B, 177C (U1 = MA / 2 = MB / 2 = MC / 2).

  Further, in the measurement unit 70 of the present embodiment, the light receiving element 86 of the light amount measuring means and the light receiving element 172 of the beam position detecting means attached to the moving base 74 can be attached and detached independently of the reference plate 170, respectively. Has been.

  As shown in FIGS. 21 and 22, the light receiving element 86 is integrated with the mounting plate 180 by fixing one end portion to the lower portion of the mounting plate 180 formed in a rectangular flat plate shape. Two through holes 182 are formed in the upper portion of the mounting plate 180, and screws 184 are respectively inserted into these through holes 182, and two screw holes 186 formed in the side surface 74 A of the moving base 74. Threaded onto. The light receiving element 86 is screwed and fixed to the moving base 74 via the attachment plate 180 and is detachably attached independently of the reference plate 170.

  In addition, the light receiving element 172 is integrated with the mounting plate 190 by fixing one end portion to the base end portion of the mounting plate 190 formed in a rectangular long shape. The mounting plate 190 extends forward from the base end portion to which the light receiving element 172 is fixed, and the distal end portion thereof is located above the mounting plate 180 of the light receiving element 86. In addition, two through holes 192 are formed at the distal end portion of the mounting plate 190, and screws 194 are respectively inserted into these through holes 192, and two pieces formed on the side surface 74 </ b> A of the moving base 74. Screwed into the screw hole 196. The light receiving element 172 is screwed to the moving base 74 via the mounting plate 190 and is detachably mounted independently from the reference plate 170.

  Next, by using the light quantity measuring device 72 of the measurement unit 70 equipped in the exposure apparatus 10, shading adjustment and exposure amount adjustment for making the light quantity distribution of the exposure beam emitted from each exposure head 30 of the scanner 24 uniform. A procedure for performing the adjustment will be described.

  First, in carrying out each of the above adjustments, the light amount distribution and exposure amount of the exposure beam are measured by the light amount measuring device 72. In this measurement, the controller 28 controls the illumination device 38 and the DMD 36 of the exposure head 30 that is symmetrical to the measurement, and the first column of the DMD 36 (for example, on the right side in FIG. 2, the direction orthogonal to the scanning direction). An operation of sequentially lighting each column from the first column) to the last column located on the initial position side of the light amount measuring device 72 is performed.

  Further, the controller 28 turns on the micromirrors 46 in the first row of the DMD 36 and turns on all the other micromirrors 46 before starting the control of the illumination device 38 and the DMD 36. The ball screw 92 is driven and controlled to move the light quantity measuring device 72 to the initial position and stop so that the central portion of the slit 80 is correspondingly disposed at a predetermined position on the exposure surface irradiated with the exposure beam.

  After the light quantity measuring device 72 is placed at the initial position, the controller 28 starts light quantity measurement, turns on only the first row of micromirrors 46 of the DMD 36 to be measured, and turns on this first light. The exposure amount of the scanning area corresponding only to the micromirrors 46 in the row is measured. Subsequently, the controller 28 drives and controls the ball screw 92 so that the central portion of the slit 80 is located in the scanning region on the exposure surface exposed by the second row of micromirrors 46 of the DMD 36 to measure the light amount. After the movement is stopped, only the second row of micromirrors 46 in the DMD 36 are turned on (lighted), and exposure of the scanning region corresponding to the second row of micromirrors 46 is performed. Measure the amount.

  The controller 28 sequentially repeats the series of light quantity measurement operations described above from the first row of micromirrors 46 to the last row of micromirrors 46. As a result, the light amount distribution and the exposure amount of the exposure beam modulated and emitted by one DMD 36 that is the measurement target are measured, and the controller 28 uses these measured values as exposure by one DMD 36 that is the measurement target. In order to adjust the shading and the exposure amount to make the light quantity distribution of the beam uniform, it is stored in the memory.

  As described above, when the light quantity of a certain group of micromirrors 46 corresponding to the exposure scanning direction is measured using the slit 80, the DMD 36 of the exposure head 30 is turned on as shown in FIG. A plurality of predetermined exposure beams 48 emitted from the group of micromirrors 46 in one row pass through the central portion in the longitudinal direction of the slit 80, are collected by the condenser lens 82, and are received by the exposure beam 48 that has passed through the optical filter 84. The light is received by the element 86 and the amount of light is measured.

  At this time, light that is not subject to light quantity measurement such as stray light and other exposure beams emitted from places other than the one row of micromirrors 46 in the on state in the DMD 36 is other than the slit 80 of the slit plate 78. It is reflected and cut off by the flat part. For this reason, light that is not subject to light quantity measurement is not received by the light receiving element 86 as indicated by a three-dot chain line in FIG.

  Therefore, when the light amount is measured using the slit plate 78 provided with the slits 80 in this way, the light is emitted from the micromirrors 46 in a predetermined row in an on state, eliminating the influence of stray light and the like. It is possible to measure the amount of light in the scanning region in accordance with the actual exposure state with a predetermined plurality of exposure beams.

  Further, in this light amount measurement, as shown in FIG. 11, for example, after the light amount measurement for the DMD 36A in the first row and the first column located on the leftmost side in the figure is completed, the next row located on the right next The light amount measurement for the DMD 36C in the second column is performed in the same manner, and the light amount measurement for all DMDs 36 (36A, 36C, 36E, 36G) in the first row is performed. Further, after the light amount measurement for each DMD 36 in the first row is completed, the stage 18 is moved to sequentially measure the light amount of each DMD 36 (36B, 36D, 36F, 36H) in the second row.

  The light amount distribution and exposure amount of the exposure beam measured by each DMD 36 measured in this way are data as indicated by a solid line (with slits) in the graph of FIG. 12, for example. In the light quantity data illustrated in FIG. 12, as described above, stray light or the like is excluded by the slit 80 of the slit plate 78 when measuring the light quantity. The accuracy is improved as compared with the case of using a light amount measuring means that makes incident light.

  Here, when light amount data with non-uniform light amount distribution as illustrated in FIG. 12 is obtained, shading adjustment and exposure amount adjustment for making the light amount distribution of the exposure beam uniform by each DMD 36 are performed.

  This shading adjustment and exposure amount adjustment are performed by, for example, reducing the number of micromirrors 46 that are subjected to multiple exposure with respect to a pixel with an increased exposure amount, or reducing the on-time of the micromirrors 46, thereby reducing the light amount distribution. Correction is performed to make the light amount distribution uniform along the lowest exposure amount line.

  The exposure beam for each pixel has a normal distribution state as shown in FIG. 13, so that the exposure area of the pixel increases as the exposure amount increases, and the exposure area of the pixel decreases as the exposure amount decreases. Using the properties, rewrite the image data corresponding to the pixel portion where the exposure amount increases to a small area, and rewrite the image data corresponding to the pixel portion where the exposure amount decreases to a large area. Correction (for example, when a line image is formed at a pixel portion where the amount of exposure increases) may be corrected by rewriting the image data of the line with image data that is a thin line.

  Further, the above-described shading adjustment and exposure amount adjustment are not only performed for each DMD 36 of each exposure head 30, but also the light quantity distribution is relatively uniform in the DMDs 36 of all the exposure heads 30 mounted on the scanner 24. It is desirable to adjust so that.

  Further, in the exposure apparatus 10, the optical wavelength of the light beam corresponding to the spectral sensitivity characteristic of the photosensitive material 20 or emitted from the illumination device 38 serving as a light source is utilized using the optical filter 84 provided in the light amount measuring device 72. The exposure amount corresponding to the characteristics can be adjusted.

  Next, a procedure for correcting the connection between the images formed by the exposure beams emitted from the exposure heads 30 of the scanner 24 using the reference plate 170 and the light receiving element 172 of the measurement unit 70 will be described.

  As described above, in the exposure operation by the scanner 24 of the present embodiment, there is a portion that cannot be exposed between the exposure area 32A located on the leftmost side of the first row and the exposure area 32C located right next to the exposure area 32A. Since exposure is performed by the exposure area 32B located on the leftmost side of the second row (see FIG. 11), the exposure area connected to the exposure area 32A is the exposure area 32B. FIG. 14 shows the positional relationship between the exposure area 32A and the exposure area 32B.

  As shown in FIG. 14, the exposure area 32A and the exposure area 32B are connected to a connection pixel P1 that is a pixel of the exposure head 30A and a connection pixel P2 that is a pixel of the exposure head 30B. The procedure for selecting the connecting pixel P1 and the connecting pixel P2 and specifying the actual position is as follows. First, the controller 28 controls the movement of the stage 18 to place the slit 120 below the scanner 24, and the pixel of the exposure head 30A. Among them, the pixel to be overlapped with the pixel of the exposure head 30B is selected as the connecting pixel P1 and lit. At this time, the controller 28 drives and controls the ball screw 92 to move the moving base 74 and the light receiving element 172 to predetermined positions so that the light receiving element 172 is arranged corresponding to the slit 120 irradiated with the exposure beam. To stop.

  Subsequently, the stage 18 is moved slowly, and as shown in FIGS. 14 and 15, the slit 120 is moved along the Y-axis direction and arranged in the exposure area 32A. Let the intersection of the slit 120a and the slit 120b at this time be (X0, Y0). Here, as described above, the slit 120a forms an angle of 135 degrees with respect to the Y axis, and the slit 120b forms an angle of 45 degrees with respect to the Y axis.

  Next, as shown in FIG. 16, the stage 18 is moved, and the slit 120 is moved rightward in FIG. 16 along the Y axis. Then, as indicated by a two-dot chain line in FIG. 16, the stage 18 is stopped when the light from the connecting pixel P1 passes through the left slit 120a and is detected by the light receiving element 172. Let the intersection of the slit 120a and the slit 120b at this time be (X0, Y11).

  Subsequently, the stage 18 is moved in the reverse direction, and the slit 120 is moved to the left in FIG. 17 along the Y axis. Then, as indicated by a two-dot chain line in FIG. 17, the stage 18 is stopped when the light from the connecting pixel P <b> 2 passes through the right slit 120 b and is detected by the light receiving element 172. Let the intersection of the slit 120a and the slit 120b at this time be (X0, Y12).

  Here, if the coordinates of the connecting pixel P1 are (X1, Y1), X1 = X0 + (Y11−Y12) / 2 and Y1 = (Y11 + Y12) / 2.

  When the coordinates of the connection pixel P1 are obtained, the connection pixel P1 is turned off, and among the pixels of the exposure head 30B, the pixel that should be connected to the exposure area 32A and close to the connection pixel P1 is selected as the connection pixel P2. Light up.

  Then, the stage 18 is moved by Y to position the slit 120 in the exposure area 32B. At this time, the coordinates of the intersection of the slit 120a and the slit 120b are (X0, Y0 + Y).

  Then, as shown in FIG. 17, the stage 18 is moved, and the slit 120 is moved to the right in FIG. 17 along the Y axis. As indicated by a two-dot chain line in FIG. 17, the stage 18 is stopped when the light from the connecting pixel P2 passes through the left slit 120a and is detected by the light receiving element 172. Let the intersection of the slit 120a and the slit 120b at this time be (X0, Y21).

  Subsequently, the stage 18 is moved in the reverse direction, and the slit 120 is moved to the left in FIG. 17 along the Y axis. Then, as indicated by a two-dot chain line in FIG. 17, the stage 18 is stopped when the light from the connecting pixel P <b> 1 passes through the right slit 120 b and is detected by the light receiving element 172. Let the intersection of the slit 120a and the slit 120b at this time be (X0, Y22).

  Here, if the coordinates of the connection pixel P2 are (x2, y2), x2 = X0 + (Y21−Y22) / 2 and y2 = (Y21 + Y22) / 2.

  For the connection pixel P2 (x2, y2) obtained in this way, as shown in FIG. 18, an X coordinate difference ΔX = X2−X1 with the connection pixel P1 is obtained. Then, among the connecting pixels P2, the pixel having the smallest X coordinate difference ΔX is selected as the connecting pixel P2 (X2, Y2).

  Since the shift in the X direction is extremely small between the connecting pixel P1 and the connecting pixel P2, the exposure timing is corrected to remove the shift in the Y-axis direction, and the exposure head 30A and the exposure head 30B so that the images overlap in the X direction. By controlling the image data input to, it is possible to remove image shift and overlap between the connecting pixel P1 and the connecting pixel P2 as shown in FIG.

  Note that a plurality of connecting pixels P1 are designated in the exposure head 30A, the actual XY coordinates (X1, Y1) are specified for each of the plurality of connecting pixels P1 according to the above procedure, and the exposure head 30B is specified for each of the connecting pixels P1. By specifying the connecting pixel P2 from these pixels and specifying the actual XY coordinates (X2, Y2), it is possible to further reduce the image shift and overlap between the exposure head 30A and the exposure head 30B.

  As described above, in the exposure apparatus 10 of the present embodiment, the stage 18 is moved, and the light receiving element 172 detects the light amount of the exposure beam that passes through the slits 120a and 120b of the slit 120, whereby the exposure head 30A and the exposure head. The connection pixel P1 and the connection pixel P2 can be selected from the 30B pixels, and the actual position can be specified.

  Further, even when the relative positional relationship between the exposure head 30A and the exposure head 30B is deviated, the exposure head 30A and the exposure head 30B are input based on the positional information regarding the actual positions of the connection pixel P1 and the connection pixel P2. By controlling the image data to be performed, it is possible to accurately correct misalignment and overlap of images formed by the exposure heads 30A and 30B.

  Further, the above-described image stitch correction for the exposure heads 30A and 30B is performed for all the exposure heads 30 mounted on the scanner 24 of the exposure apparatus 10 in the same procedure. That is, connecting pixels between all the exposure heads 30 are specified, and corrections such as image data shift, image rotation, and magnification conversion are performed on the image data input to each exposure head 30 so that the images overlap at the connecting pixels. I do. Thereby, in the exposure operation by the exposure apparatus 10, an image with little shift at the joint can be formed over the entire exposure region.

  The above procedure corrects the stitching of the images formed by the exposure beams emitted from the exposure heads 30. In order to perform this correction, as described above, a plurality of images formed on the reference plate 170 are corrected. The exposure position by each exposure beam is detected using the slit 120. However, since each slit 120 is very small with a slit length (L1 in FIG. 9) of about 1 mm and a slit width of about 20 μm, the measurement unit 70 (reference plate 170) is staged in the manufacture of the exposure apparatus 10. In the detection of the exposure position that is performed for the first time after the 18 is mounted, each component can be obtained even if the stage 18 is moved to the target position (design value) and the slit 120 is disposed directly below the exposure head 30 (exposure beam irradiation position). In some cases, the slit 120 does not fit the exposure beam due to the accuracy error or assembly error, and the exposure position cannot be detected quickly.

  On the other hand, the I-shaped slit 80 formed on the slit plate 78 of the light quantity measuring device 72 has a slit length (L2 in FIG. 9) of about 30 mm and a slit width of about 3 mm. On the other hand, it is formed sufficiently large. Therefore, when the measurement of the light amount distribution and the exposure amount of the exposure beam described above is performed for the first time after the measurement unit 70 is attached to the stage 18, the stage 18 can be used even if the accuracy error or assembly error of each component is somewhat large. Is moved to the target position (design value) and the slit 80 is disposed just below the exposure head 30 (exposure beam irradiation position), the slit 80 is substantially aligned with the exposure beam, and the exposure position can be detected quickly. It becomes like this. Further, the relative positional relationship between the slit 80 and each slit 120 can be grasped in advance based on the design value of the measurement unit 70.

  Therefore, by measuring the exposure light amount distribution and exposure amount using the slit 80 first, the positional deviation between each slit 120 of the reference plate 170 and each exposure beam can be grasped via the slit 80. Thus, in the detection of the exposure position by the slit 120, the position can be quickly detected by aligning the slit 120 with the exposure beam in consideration of the positional deviation. Therefore, it is possible to shorten the adjustment time until the above-described connection correction is completed.

  Next, an exposure operation for the photosensitive material 20 by the exposure apparatus 10 configured as described above will be described.

  First, when image data corresponding to an exposure pattern is input to the controller 28, it is temporarily stored in a memory in the controller 28. This image data is data representing the density of each pixel constituting the image by binary values (whether or not dots are recorded).

  Next, the operator sets the photosensitive material 20 on the stage 18 stopped at the initial position shown in FIG. 1 and performs an input operation for starting exposure from the controller 28. The photosensitive material 20 for performing image exposure by the exposure apparatus 10 is a photosensitive epoxy resin or the like on the surface of a substrate or a glass plate as a material for forming a pattern (image exposure) such as a printed wiring board or a liquid crystal display element. In the case of a dry film, a laminate or the like is applied.

  When the exposure operation of the exposure apparatus 10 is started by the input operation described above, the drive device is controlled by the controller 28, and the stage 18 that has adsorbed the photosensitive material 20 to the upper surface moves along the guide 16 in the movement direction (arrow Y direction). The movement starts at a constant speed from the upstream side to the downstream side in the alignment measurement direction. Each CCD camera 26 is controlled and operated by the controller 28 in synchronization with the start of the movement of the stage or at a timing just before the leading edge of the photosensitive material 20 reaches just below each CCD camera 26.

  When the photosensitive material 20 passes below the CCD camera 26 as the stage 18 moves, alignment measurement by the CCD camera 26 is performed.

  In this alignment measurement, first, when the two alignment marks 21 provided near the corner on the downstream side (front end side) of the photosensitive material 20 in the moving direction reach directly below each CCD camera 26 (on the optical axis of the lens). Each CCD camera 26 captures the alignment mark 21 at a predetermined timing, and the captured image data, that is, the image data including the reference position data in which the reference of the exposure position is indicated by the alignment mark 21 is received by the controller 28. Output to the data processor. After photographing the alignment mark 21, the stage 18 resumes moving downstream.

  Further, when a plurality of alignment marks 21 are provided along the movement direction (scanning direction) as in the photosensitive material 20 of the present embodiment, the next alignment mark 21 (upstream side in the movement direction (rear end side) When the two alignment marks 21) provided in the vicinity of the corners of () reach directly below each CCD camera 26, each CCD camera 26 similarly takes an image of the alignment mark 21 at a predetermined timing and captures the image data. The data is output to the data processing unit of the controller 28.

  Similarly, when the photosensitive material is provided with three or more alignment marks along the moving direction, each time the alignment marks pass below the CCD camera 26, the CCD camera 26 uses a predetermined timing. The imaging of the alignment mark is repeatedly performed, and the captured image data is output to the data processing unit of the controller 28 for all the alignment marks.

  The data processing unit includes a mark position and an inter-mark pitch in the image determined from the input image data (reference position data) of each alignment mark 21, the position of the stage 18 when the alignment mark 21 is photographed, and the CCD. From the position of the camera 26, it is possible to grasp the deviation of the mounting position of the photosensitive material 20 on the stage 18, the deviation of the inclination of the photosensitive material 20 with respect to the moving direction, the dimensional accuracy error of the photosensitive material 20, etc. An appropriate exposure position for the exposed surface of the material 20 is calculated. Then, at the time of image exposure by the scanner 24, which will be described later, correction of exposure position deviation (alignment) in which the control signal generated based on the image data of the exposure pattern stored in the memory is aligned with the appropriate exposure position (alignment). Execute.

  When the photosensitive material 20 passes under the CCD camera 26, alignment measurement by the CCD camera 26 is completed, and then the stage 18 is driven in the reverse direction by the driving device and moves along the guide 16 in the scanning direction. As the stage 18 moves, the photosensitive material 20 moves below the scanner 24 to the downstream side in the scanning direction. When the image exposure area on the exposed surface reaches the exposure start position, each exposure head 30 of the scanner 24 is exposed to the exposure beam. And image exposure on the exposed surface of the photosensitive material 20 is started.

  Here, the image data stored in the memory of the controller 28 is sequentially read for each of a plurality of lines, and a control signal is generated for each exposure head 30 based on the image data read by the data processing unit. The control signal is subjected to the above-described shading adjustment for uniformizing the light amount distribution of the exposure beam, the adjustment of the exposure amount, and the correction of the exposure position deviation with respect to the photosensitive material 20 obtained by the alignment measurement. Then, the mirror drive control unit performs on / off control of each of the micromirrors 46 of the DMD 36 for each exposure head 30 based on the generated and corrected control signals.

  When the laser light emitted from the optical fiber 40 of the illumination device 38 is applied to the DMD 36, the laser light reflected when the micromirrors of the DMD 36 are in the on state passes through the corresponding microlenses 60 of the microlens array 54. An image is formed on the exposed surface of the photosensitive material 20 by a lens system including the same. In this manner, the laser light emitted from the illumination device 38 is turned on / off for each pixel, and the photosensitive material 20 is exposed in a pixel unit (exposure area) that is approximately the same number as the number of used pixels of the DMD 36.

  Further, when the photosensitive material 20 is moved at a constant speed together with the stage 18, the photosensitive material 20 is scanned in the direction opposite to the stage moving direction by the scanner 24, and a strip-shaped exposed region 34 (see FIG. 2).

  When the image exposure of the photosensitive material 20 by the scanner 24 is completed, the stage 18 is driven to the downstream side in the scanning direction as it is by the driving device and returns to the initial position on the most downstream side in the scanning direction. Thus, the exposure operation for the photosensitive material 20 by the exposure apparatus 10 is completed.

  Next, a calibration method for the alignment function (exposure alignment function) in the exposure apparatus 10 of the present embodiment will be described.

  In the exposure apparatus 10 of the present embodiment having the above-described alignment function, the posture change (rolling, pitching, and yawing) is caused when the CCD camera 26 moves, and the optical axis center of the photographing lens is arranged in the photographing position. May deviate from the normal position. Therefore, even if the exposure position is corrected using the alignment function and image exposure is performed, the exposure position may deviate from the proper position and exceed the allowable range.

  In order to calibrate the alignment function whose accuracy is affected by the cause of the optical axis deviation due to the change in the attitude of the CCD camera 26, a predetermined timing (for example, a predetermined number of photosensitivities) in manufacturing or maintenance of the exposure apparatus 10 or in an exposure operation. After the exposure operation on the material, the alignment function is calibrated by the calibration method described below.

  As a procedure of this calibration work, the CCD camera 26 is first calibrated, then the positional relationship between the exposure reference and the camera optical axis center is acquired, and the acquired information is reflected in the exposure position alignment by the exposure head 30. Although it is performed according to the procedure, this calibration operation can be performed in advance separately from the exposure procedure for the photosensitive material 20 or can be performed simultaneously with the exposure of the photosensitive material 20. Further, the calibration of the CCD camera 26 and the acquisition of the positional relationship between the exposure reference and the center of the optical axis of the camera can be performed continuously or individually. Here, the case where they are performed continuously will be described.

  Regarding the calibration of the CCD camera 26, first, the operator inputs the position data of the alignment mark 21 of the photosensitive material 20 to be exposed to the controller 28. By inputting this position data, the coordinates of the alignment mark 21 are acquired.

  Subsequently, when the operator performs a calibration start input operation from the controller 28, the calibration operation of the exposure apparatus 10 starts, and the controller 28 controls the drive source of each CCD camera 26 based on the input position data. Each CCD camera 26 is moved to a predetermined photographing position where the alignment mark 21 of the photosensitive material 20 is photographed. At this time, the position of each CCD camera 26 is controlled by the controller 28 by counting the pulses of each drive source (stepping motor), and is sent in the above-mentioned step of moving unit (U1).

  When each CCD camera 26 is arranged at the photographing position of the alignment mark 21, the stage 18 moves along the guide 16 from the upstream side to the downstream side in the alignment measurement direction, and the camera position detection unit 170B of the reference plate 170 is moved to each CCD. It moves to a position where it is located below the camera 26 (in the field of view).

  When the camera position detection unit 170B of the reference plate 170 is disposed in the field of view of each CCD camera 26, each CCD camera 26 is controlled by the controller 28 to shoot the camera position detection unit 170B. At this time, each CCD camera 26 photographs at least one of the plurality of detection marks 177A, 177B, and 177C arranged in the camera position detector 170B.

  Next, the controller 28 measures the amount of positional deviation from the center of the visual field (optical axis center) of the detected detection marks 177A, 177B, 177C by image processing or the like. Here, whether the photographed detection mark is the detection mark 177A, the detection mark 177B, or the detection mark 177C is switched using image processing such as pattern matching.

  Here, the detection marks 177A, 177B, and 177C that have been photographed are identified by the above-described pulses, and the detection marks 177A, 177B, and 177C are marked. The absolute position data is previously measured by another measuring means and stored in the controller 28. The difference between the absolute position data and the measurement result (measurement value) is calculated to calculate the reference plate 170 and each CCD. Position shift data with respect to the center of the optical axis of the camera 26 is acquired. From the measurement and calculation results, calibration data for correcting the deviation of the optical axis center of each CCD camera 26 at the position where the alignment mark 21 is photographed (alignment measurement position) is obtained. Stored in memory. Then, the calibration operation of the CCD camera 26 is finished, and then the operation proceeds to an operation for obtaining the positional relationship between the exposure reference and the center of the camera optical axis.

  When this operation is started, the drive device is controlled by the controller 28, and the stage 18 moves the beam position detection unit 170A of the reference plate 170 to the irradiation position (exposure position) of the laser beam by the exposure head 30. Next, a laser beam is irradiated from the exposure head 30 toward the beam position detection unit 170A of the reference plate 170, and the position of the exposure reference point is measured by the beam position detection operation described above.

  Here, the beam position detection unit 170A and the camera position detection unit 170B are provided on the same reference plate 170, and their positional relationship is measured in advance by another measurement means. As a result, the positional relationship between the exposure reference and the detection marks 177A, 177B, and 177C captured by the above-described camera calibration operation is determined. Therefore, by calculating the exposure reference data measured by this operation and the positional deviation data (calibration data) between the optical axis center of the CCD camera 26 acquired by the camera calibration operation, the exposure reference and the camera optical axis center are calculated. The exposure reference-camera optical axis center position data (correction data) indicating the positional relationship is obtained, and this data is stored in the memory of the controller 28. Then, the operation for obtaining the positional relationship between the exposure reference and the camera optical axis center is terminated, and the calibration operation is terminated.

  When the exposure apparatus 10 is calibrated by the calibration method of the alignment function described above, and the photosensitive material 20 is image-exposed with the calibrated exposure apparatus 10, the controller 28 reads the exposure reference-camera optical axis center position from the memory. Data is read out, and a control signal (exposure data) generated based on the image data of the exposure pattern is arithmetically processed using the exposure reference-camera optical axis center position data to reflect the calibration data in the exposure data. Further, as described above, correction control (alignment) for reflecting the correction data of the exposure position obtained by measuring the alignment of the photosensitive material 20 as described above is executed, and image exposure is performed by matching the control signal with the appropriate exposure position. .

  In the present embodiment, as shown in FIGS. 20A to 20D, each CCD camera 26 sent in the step of movement unit (U1) is always detected mark 177A regardless of the position. One of 177B and 177C is captured in the field of view. Thereby, even when the position of the alignment mark in the direction orthogonal to the scanning direction is changed according to the size (width dimension) of the photosensitive material, each CCD camera 26 is placed at a predetermined position corresponding to the position of the alignment mark. Calibration in the arranged state is possible, and highly accurate calibration corresponding to the photosensitive material to be exposed can be performed.

  In the exposure apparatus 10 of the present embodiment described above, the reference plate 170 of the beam position detection means provided in the measurement unit 70 adjusts (calibrates) functions very important for apparatus performance such as exposure accuracy and alignment accuracy. Therefore, it is positioned and attached to the stage 18 with high accuracy and is usually used until the life of the apparatus. When the exposure apparatus 10 is manufactured, each function of the apparatus is adjusted with high accuracy over several hours using the reference plate 170 as a reference.

  On the other hand, the light receiving element 172 of the beam position detecting means paired with the reference plate 170 (the beam position detecting unit 170A) may be replaced due to a failure, performance deterioration due to aging, or the like, and further removed by maintenance of the exposure apparatus 10. There is also. Therefore, when the reference plate 170 and the measurement unit 70 are removed from the stage 18 along with the replacement or removal of the light receiving element 172, it takes a lot of time to position them with high accuracy and attach them to the stage 18. The exposure function must be readjusted, and the work becomes extremely complicated.

  On the other hand, in the exposure apparatus 10 of the present embodiment, the light receiving element 172 attached to the moving base 74 via the attachment plate 190 can be attached and detached independently from the reference plate 170 without removing the reference plate 170. (Refer to FIG. 21 and FIG. 22). With the replacement or removal of the light receiving element 172, there is no need to reattach the reference plate 170 and readjustment of the exposure function, thereby reducing readjustment work associated with the attachment or detachment of the light receiving element 172 be able to. Moreover, since the tolerance of the mounting position accuracy of the light receiving element 172 is sufficiently larger than that of the reference plate 170, the position adjustment and mounting work when the light receiving element 172 is mounted again becomes easy.

  Furthermore, in the present embodiment, the light receiving device 86 attached to the moving base 74 via the attachment plate 180 is also connected to the reference plate 170 without removing the reference plate 170 in the same way for the light amount measurement means provided in the measurement unit 70. Since the light receiving element 86 can be attached and detached independently, the readjustment work accompanying the attachment and detachment of the light receiving element 86 is also reduced.

  In the present embodiment, the light receiving element 172 includes a moving base 74, guide shafts 90A and 90B, a ball screw 92, and a driving means (not shown). Are moved to the detection positions of the exposure beams corresponding to the plurality of slits 120 formed. Accordingly, for example, even if the same number of light receiving elements as the plurality of slits 120 are not provided, the beam detection at each slit 120 can be performed by one light receiving element 172 as in the present embodiment. Thus, since the number of light receiving elements can be smaller than that of the slits 120, the cost of the beam position detecting means can be reduced.

  In the present embodiment, the CCD camera 26 that photographs the alignment mark 21 indicating the reference of the exposure position provided on the photosensitive material 20 in order to acquire the positional information of the photosensitive material 20 placed on the stage 18 is provided. In order to correspond to the photographing of the reference mark whose position is changed according to the size of the photosensitive material, it can be moved in the direction intersecting the scanning direction. In this case, as described above, since the CCD camera 26 arranged at the reference mark photographing position may deviate from the normal position due to the change in the attitude of the CCD camera 26 accompanying the movement, the measurement unit 70 mounted on the stage 18 may be displaced. In addition, a reference plate 170 provided with a camera position detection unit 170B is installed, and the camera position detection unit 170B of the reference plate 170 is disposed at a photographing position by the CCD camera 26 as the stage 18 moves, and in this state, the CCD The CCD camera 26 is calibrated by reading one of a plurality of detection marks 177A, 177B, and 177C arranged at predetermined intervals along the moving direction of the camera 26. As a result, it is possible to calibrate the alignment function whose accuracy is affected by the posture change factor accompanying the movement of the CCD camera 26, and the correction accuracy of the exposure position deviation with respect to the photosensitive material 20 can be improved.

  Here, a camera position detector 170B for calibrating the CCD camera 26 is integrally provided on the reference plate 170 including the slit 120 (beam position detector 170A) for detecting the exposure position by the exposure beam. As a result, the relative position between the slit 120 and the detection marks 177A, 177B, and 177C can be measured with high accuracy, and the slit 120 and the detection marks 177A, 177B, and 177C can be measured. Misalignment is less likely to occur between the two. Thus, the exposure position data of the exposure beam detected by the beam position detector 170A and the light receiving element 172 of the reference plate 170 and the calibration acquired using the camera position detector 170B provided integrally with the reference plate 170. If the correction data is obtained by calculating the operation data, the error is suppressed, and the alignment performed by reflecting the correction data can be performed with higher accuracy. In addition, the number of component parts can be reduced and attachment to the measurement unit 70 is facilitated as compared with the case where the beam position detection unit 170A and the camera position detection unit 170B are separated.

  Further, here, the measurement unit 70 is mounted on the stage 18 on which the photosensitive material 20 is placed, and the reference plate 170 provided with the camera position detection unit 170B is installed on the measurement unit 70. 18, the detection marks 177 </ b> A, 177 </ b> B, and 177 </ b> C can be photographed by the CCD camera 26 with the photosensitive material 20 placed thereon, so that even when the photosensitive material 20 is exposed by the exposure device 10. The alignment function can be calibrated, and the calibration work becomes easy.

  Further, in the exposure apparatus 10 of the present embodiment, the light receiving element 172 of the beam position detecting unit and the light receiving element 86 of the light amount measuring unit provided in the measurement unit 70 can be independently attached and detached independently of the reference plate 170. Accordingly, the reference plate 170 can be embedded in the stage and provided integrally.

  FIG. 23 and FIG. 24 show an example when the reference plate 170 is embedded in the stage. As shown in FIG. 23, the stage 200 in the modification example here has a front end portion 202 protruding forward, and a stepped portion 204 is recessed in the lower surface of the front end portion 202. A measurement subunit 210 having a configuration in which the upper plate portion 99 and the reference plate 170 in the measurement unit 70 described above are removed is attached.

  Further, a rectangular opening 206 is formed in the front end portion 202 of the stage 200 so that the longitudinal direction is parallel to the width direction of the stage 200 (arrow X direction). As shown in FIG. 24, the opening 206 is provided with a circumferential step 208 near the center in the depth direction, and the opening area below the step 208 is equal to the opening area above the upper. It is small around. The reference plate 170 is fitted into the opening 206 from above, and the peripheral edge of the lower surface is in contact with the step portion 208 and positioned in the depth direction, and is embedded in the front end portion 202 of the stage 200. Thus, the exposure beam LB irradiated from the exposure head 30 to the slit 120 of the reference plate 170 passes through the slit 120, passes through the opening 206, and is received by the light receiving element 172 disposed below the slit 120.

  In the modification described above, since the reference plate 170 is embedded in the front end portion 202 of the stage 200, the stability of the reference plate 170 is improved, and a decrease in beam position detection accuracy due to vibration or distortion can be suppressed. . Further, as in the exposure apparatus 10 of the present embodiment, even when a large number of exposure heads 30 are mounted to expose a large area and the reference plate 170 is enlarged, it can be stably installed on the stage 200. Thus, it is possible to easily cope with such an increase in the size of the reference plate.

  As mentioned above, although this invention was demonstrated in detail by the specific embodiment mentioned above, this invention is not limited to it, Various other forms can be implemented within the scope of the present invention.

  For example, in the above embodiment, the beam position detecting means, the light quantity measuring means, and the calibration member are integrally configured in the measurement unit 70 and arranged at the same end portion (downstream end portion in the moving direction) of the stage 18. However, only the beam position detecting means and the light quantity measuring means may be arranged at the same end of the stage 18. Further, the beam position detecting means and the light quantity measuring means arranged at the same end of the stage 18 may not be integrally formed, and the units may be arranged adjacent to each other as a separate body.

  In the above-described exposure apparatus 10, the number of light quantity measuring means (light quantity measuring devices 72) is set to one, but the number of light quantity measuring means is equal to or less than the number of exposure heads 30 provided in the scanner 24. It is good. In that case, since the light quantity measurement of the exposure beam with respect to the plurality of exposure heads 30 can be performed simultaneously by the plurality of light quantity measurement means, the light quantity measurement of all the exposure heads is performed with one light quantity as in the exposure apparatus 10 described above. The measurement time can be shortened as compared with the case where measurement is performed, and productivity can be further improved.

  In the above embodiment, the light amount measuring means (light amount measuring device 72) is used to perform shading adjustment and exposure amount adjustment to make the light amount distribution of each light beam emitted from the plurality of exposure heads 30 uniform. As described in the case of measuring the light amount distribution and the exposure amount of each light beam, the light amount measuring means is configured to perform either one of shading adjustment or exposure amount adjustment. It may be configured to measure.

  Further, the case where the detection marks (calibration reference marks) used for calibrating the CCD camera 26 are three types, ie, a circle, a cross, and a square, has been described. However, the shapes of the detection marks are other than those. The shape can be used, and four or more kinds of detection marks can be used. Even in such a case, as described above, by defining the visual field and movement unit of the CCD camera 26 and the arrangement pitch of the detection marks under predetermined conditions, an equivalent function can be realized.

  In the exposure operation of the exposure apparatus 10 in the above-described embodiment, the case where the photosensitive material 20 is scanned and exposed while the stage 18 is moved has been described. However, the exposure operation is not limited to such scanning exposure. In addition, the photosensitive material 20 moved to the first exposure position is temporarily stopped to expose only a predetermined exposure area, and after the exposure, the photosensitive material 20 is moved to the next exposure position and stopped again. It is also possible to repeat the movement of the photosensitive material 20 → stop at the exposure position → image exposure → movement...

  In the exposure apparatus 10 in the above embodiment, the exposure head provided with the DMD as the spatial modulation element has been described. In addition to such a reflective spatial light modulation element, a transmissive spatial light modulation element (LCD). Can also be used. For example, a liquid crystal shutter such as a MEMS (Micro Electro Mechanical Systems) type spatial light modulator (SLM), an optical element (PLZT element) that modulates transmitted light by an electro-optic effect, or a liquid crystal light shutter (FLC). It is also possible to use a spatial light modulation element other than the MEMS type, such as an array. Note that MEMS is a general term for a micro system that integrates micro-sized sensors, actuators, and control circuits based on a micro-machining technology based on an IC manufacturing process. A MEMS-type spatial light modulator is an electrostatic force. It means a spatial light modulator driven by electromechanical operation using Further, a plurality of grating light valves (GLVs) arranged in two dimensions can be used. In the configuration using these reflective spatial light modulator (GLV) and transmissive spatial light modulator (LCD), a lamp or the like can be used as a light source in addition to the laser described above.

  The light source in the above embodiment includes a fiber array light source including a plurality of combined laser light sources, and a single optical fiber that emits laser light incident from a single semiconductor laser having one light emitting point. A fiber array light source obtained by arraying fiber light sources provided with a light source (for example, an LD array, an organic EL array, etc.) in which a plurality of light emitting points are arranged in a two-dimensional manner can be applied.

  Further, the exposure apparatus 10 can use either a photon mode photosensitive material in which information is directly recorded by exposure or a heat mode photosensitive material in which information is recorded by heat generated by exposure. When using a photon mode photosensitive material, a GaN-based semiconductor laser, a wavelength conversion solid-state laser, or the like is used for the laser device. When using a heat mode photosensitive material, an AlGaAs-based semiconductor laser (infrared laser), A solid state laser is used.

1 is a perspective view showing an exposure apparatus according to an embodiment of the present invention. FIG. 2 is a perspective view illustrating a configuration of a scanner according to an embodiment of the present invention and a positional relationship between a stage and a measurement unit. It is a schematic block diagram which shows the optical system of the exposure head which concerns on one Embodiment of this invention. (A) is a principal part top view which shows the scanning locus | trajectory of the exposure beam by each micromirror in the exposure apparatus which concerns on the 1st Embodiment of this invention when DMD (digital micromirror device) is not inclined, (B) is. It is a principal part top view which shows the scanning trace of the exposure beam at the time of inclining DMD. FIG. 5 is a partially enlarged view showing a configuration of a DMD provided in an exposure apparatus according to an embodiment of the present invention. (A) And (B) is explanatory drawing for demonstrating operation | movement of DMD of FIG. It is a perspective view which shows the structure of the alignment unit which concerns on one Embodiment of this invention. It is a perspective view which shows the structure of the measurement unit which concerns on one Embodiment of this invention. It is a top view which shows typically the measurement unit which concerns on one Embodiment of this invention. It is explanatory drawing which shows the state which detects the light quantity of the pixel currently lighted using the slit in the light quantity measuring device which concerns on one Embodiment of this invention. It is explanatory drawing which shows the state which detects the light quantity distribution and exposure amount of an exposure beam with the light quantity measuring device which concerns on one Embodiment of this invention. It is a graph which illustrates the light quantity distribution measured with the light quantity measuring device which concerns on one Embodiment of this invention. It is a graph which illustrates the characteristic of the exposure beam in the exposure apparatus which concerns on one Embodiment of this invention. In an exposure apparatus according to an embodiment of the present invention, a specific exposure area exposed by a specific exposure head and another exposure area exposed by another exposure head and connected to the specific exposure area It is a top view which shows a positional relationship. It is a top view which shows the positional relationship of the specific exposure area and other exposure area in FIG. 14, and the slit provided in the reference | standard plate of the measurement unit. It is explanatory drawing which shows the procedure which specifies the position of the specific connection pixel which is a connection pixel of a specific exposure head with a slit. It is explanatory drawing which shows the procedure which pinpoints the position of the pixel which is going to connect with a specific exposure area among the pixels of another exposure head with a slit. It is explanatory drawing which shows the procedure which selects an actual connection pixel from the pixel by which the position was specified by the procedure of FIG. 17 among the pixels of another exposure head. It is a top view which shows the state with which the specific exposure area and the other exposure area 32 were connected by the specific connection pixel and the other connection pixel. (A)-(D) is explanatory drawing which shows the relationship between the mark for a detection at the time of image | photographing the camera position detection part which concerns on one Embodiment of this invention with a CCD camera, and an imaging | photography visual field. It is an expansion perspective view which expands and shows the structure of the movement base vicinity in the measurement unit of FIG. It is a disassembled perspective view which shows the state from which the light receiving element was removed from the movement base shown in FIG. It is a perspective view which shows the state by which the reference board was embed | buried under the stage which concerns on the modification of this invention. FIG. 24 is a side sectional view showing the stage and the reference plate shown in FIG. 23 in a partial section.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Exposure apparatus 18 Stage 20 Photosensitive material 24 Scanner (exposure means)
28 Controller (Connecting correction means)
30 exposure head (exposure means)
32 Exposure area (exposure area)
48 Exposure beam 74 Moving base (moving means)
90A Guide shaft (moving means)
90B Guide shaft (moving means)
92 Ball screw (moving means)
170 Reference plate (beam position detection means / reference plate)
170A Beam position detector (beam position detector)
172 Light receiving element (beam position detecting means / light detector)
180 Mounting plate (detachment means)
184 screw (detachment means)
200 Stage 202 Front end (one end)
206 Aperture LB Exposure beam

Claims (5)

A plurality of exposure heads that scan and expose a photosensitive material by irradiating a light beam modulated according to image information;
A stage that moves relative to the plurality of exposure heads and conveys a photosensitive material along a scanning direction;
A beam position detecting means provided at one end in the moving direction of the stage and detecting an exposure position on an exposure surface of each light beam irradiated from the plurality of exposure heads;
With
The beam position detecting means includes
A reference plate in which a plurality of slit-like light-transmitting portions that transmit a light beam are formed corresponding to the plurality of exposure heads;
A light detector that detects a light beam transmitted through the light transmitting portion and is detachable independently of the reference plate;
An exposure apparatus comprising: A plurality of exposure heads that scan and expose a photosensitive material by irradiating a light beam modulated according to image information;
A stage that moves relative to the plurality of exposure heads and conveys a photosensitive material along a scanning direction;
A beam position detecting means provided at one end in the moving direction of the stage and detecting an exposure position on an exposure surface of each light beam irradiated from the plurality of exposure heads;
With
The beam position detecting means includes
A reference plate in which a plurality of slit-like light-transmitting portions that transmit a light beam are formed corresponding to the plurality of exposure heads;
A photodetector for detecting a light beam transmitted through the light transmitting portion;
Attaching / detaching means for detachably attaching the photodetector independently of the reference plate;
An exposure apparatus comprising: The exposure apparatus according to claim 1, wherein the reference plate is embedded in the one end portion of the stage.   The said beam position detection means further has a moving means to which the said photodetector is moved to the detection position of each light beam corresponding to these translucent parts, The Claim 1 characterized by the above-mentioned. 2. The exposure apparatus according to item 1.   Based on the beam position information on the exposure surface of each light beam acquired by the beam position detecting means, the connection correction for correcting the connection of the exposure areas exposed by the light beams emitted from the plurality of exposure heads. 5. The exposure apparatus according to claim 1, further comprising means.

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