JP2008046221A - Focus adjustment method and apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a focus adjustment method for acquiring waviness quantity of a processing object, controlling a focus adjustment mechanism provided at each optical system based on the waviness quantity thereby focusing on the processing object, by which each focus adjustment mechanism is more smoothly operated. <P>SOLUTION: The focus adjustment method is characterized in that the plurality of optical systems 162 each having the focus adjustment mechanism for focusing on the processing object 150, distance measurement means 184 for measuring the distance between the processing object 150 and themselves, and the processing object 150 are relatively moved, and the waviness quantity of the processing object 150 in the position of each optical system 162 is acquired based on the data measured along the moving direction by the distance measurement means 184 according to the above relative movement, and the acquired waviness quantity is interpolated regarding the moving direction to create the control data of the focus adjustment mechanism in each optical system 162. Thus, each focus adjustment mechanism is controlled based on the created control data. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a focus adjustment method and apparatus for acquiring a waviness amount of a processing target and controlling a focus adjustment mechanism provided in an optical system based on the waviness amount to focus on the processing target.

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

  For example, the DMD is a mirror device in which a large 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 using this DMD, , A light source that emits laser light, a lens system that collimates the laser light emitted from the light source, a DMD that is arranged at a substantially focal position of the lens system, and a lens system that forms an image of the laser light reflected by the DMD on the scanning surface , Each of the DMD micromirrors is controlled on and off by a control signal generated according to image data or the like, and the laser beam is modulated, and the modulated laser beam is set on the stage. Then, image exposure is performed on the photosensitive material moved along the scanning direction.

  As an exposure apparatus as described above, there has been proposed an exposure apparatus having an autofocus function for focusing the laser beam on the surface to be exposed following the waviness and thickness variation of the photosensitive material (for example, a patent) Reference 1).

  In the exposure apparatus as described above, an autofocus displacement sensor for measuring the distance from the exposed surface of the photosensitive material is disposed upstream of the exposure head in the moving direction of the photosensitive material. Before the exposure, the distance from the exposed surface of the photosensitive material is measured by a displacement sensor, and based on the obtained measurement information, a focus mechanism provided on the laser beam emission side of the exposure head is applied to the exposed surface by the laser beam. By controlling the exposure so that the focal points of the light beams coincide with each other, the accuracy of the focal position by the laser beam is improved.

Here, in an exposure apparatus having an autofocus function as described above, distance measurement is performed at predetermined intervals by a displacement sensor, and the distance measurement data is used for controlling the focus mechanism.
Japanese Patent Laying-Open No. 2005-266779

  However, if the distance measurement data for each predetermined interval is used as it is for the control of the focus mechanism as described above, there is an influence of measurement noise and the like, resulting in a high-frequency signal, and the focus mechanism cannot be moved smoothly. . Further, the error of the distance calculation result at the optical system position becomes large, and the focus cannot be accurately followed to the undulation of the measurement target. In addition, the amount of data is large, calculation processing becomes heavy, and there is a possibility of affecting tact.

  In view of the above circumstances, an object of the present invention is to provide a focus adjustment method and apparatus capable of moving a focus mechanism more smoothly and accurately.

  The focus adjustment method of the present invention relatively moves a plurality of distance measuring means for measuring a distance between a plurality of optical systems having a focus adjustment mechanism that focuses on the processing target and a processing target, and the processing target, Based on the measurement data measured along the moving direction by each distance measuring means by movement, the amount of waviness of the processing object at the position of each optical system is acquired, and the acquired amount of waviness is interpolated in the moving direction. To generate control data for the focus adjustment mechanism of each optical system, and control the focus adjustment mechanism based on the generated control data.

  In the focus adjustment method of the present invention, the swell amount can be acquired based on the thinned data obtained by thinning the measurement data measured along the moving direction by each distance measuring means.

  Further, the control data can be generated by the control data generating means provided for each optical system.

  Further, it is possible to acquire a deviation amount of measurement data due to a difference in position between the optical system and each distance measuring unit in the moving direction, and correct the swell amount based on the obtained deviation amount.

  The focus adjustment apparatus of the present invention includes a plurality of optical systems having a focus adjustment mechanism for focusing on a processing target, a plurality of distance measuring means for measuring a distance from the processing target, the optical system, each distance measuring means, and processing Acquires the amount of waviness of the processing target at the position of each optical system based on the moving data for moving the target relative to each other and the measurement data measured along the moving direction by the distance measuring means by the movement of the moving means. An undulation amount acquiring means, a control data generating means for generating control data of the focus adjustment mechanism of each optical system by interpolating the undulation amount acquired by the undulation amount acquiring means with respect to the moving direction, and a control data generating means And a control means for controlling the focus adjustment mechanism based on the generated control data.

  In the focus adjustment apparatus of the present invention, the swell amount acquisition means acquires the swell amount based on the thinned data obtained by thinning the measurement data measured along the moving direction by each distance measuring means. be able to.

  Further, the control data generating means can be provided for each optical system.

  Further, it is provided with a correcting means for acquiring a deviation amount of measurement data due to a difference in position between the optical system and each distance measuring means in the moving direction and correcting the undulation amount based on the obtained deviation amount. Can do.

  Here, the “waviness amount” includes not only waviness to be processed but also a thickness dimension error.

  According to the focus adjustment method and apparatus of the present invention, a plurality of optical systems having a focus adjustment mechanism for focusing on a processing target and a plurality of distance measuring means for measuring the distance to the processing target are relatively connected to the processing target. Based on the measurement data measured along the moving direction by each distance measuring means by the movement, the waviness amount of the processing object at the position of each optical system is acquired, and the obtained waviness amount is obtained in the moving direction. Since the control data of the focus adjustment mechanism of each optical system is generated by interpolating and the focus adjustment mechanism is controlled based on the generated control data, smoothing is performed by performing interpolation as described above. Control data can be generated, and the focus adjustment mechanism can be moved more smoothly.

  Further, the focus can be made to follow the undulation of the measurement target with high accuracy.

  Further, in the focus adjustment method of the present invention, when the undulation amount is acquired based on the thinned data obtained by thinning out the measurement data measured along the moving direction by each distance measuring means, Since the amount of information can be reduced, the control data calculation process can be made lighter and performed at high speed.

  In addition, when the control data is generated by the control data generation means provided for each optical system, the control data calculation process can be distributed to each control data generation means, and the calculation can be performed at a higher speed. It can be carried out.

  Further, when the amount of measurement data deviation due to the difference in position in the movement direction between the optical system and each distance measuring means is acquired, and the amount of undulation is corrected based on the obtained amount of deviation, the above Thus, it is possible to perform the focus adjustment in consideration of the shift amount.

  Hereinafter, an exposure apparatus using an embodiment of a focus adjustment method and apparatus of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view showing a schematic configuration of an exposure apparatus using an embodiment of the present invention.

  FIG. 1 shows an exposure apparatus according to an embodiment of the present invention, and FIGS. 2 to 7 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 100 includes a rectangular thick plate-shaped installation base 156 supported by four legs 154. Two guides 158 extend along the longitudinal direction on the upper surface of the installation table 156, and a rectangular flat plate-like stage 152 is provided on the two guides 158. The stage 152 is arranged so that the longitudinal direction thereof faces the extending direction of the guide 158, is supported by the guide 158 so as to be reciprocally movable on the installation table 156, and is reciprocated along the guide 158 by being driven by a driving device (not shown). Moving. The photosensitive material 150 is sucked and held on the upper surface of the stage 152 in a state where the mounting position is determined by a positioning unit (not shown).

  Gates 160 and 161 are arranged at predetermined intervals on the upstream side and the downstream side in the moving direction of the stage 152 with respect to the center of the installation table 156. The gates 160 and 161 are formed in a U shape so as to straddle the moving path of the stage 152, and both end portions are fixed to both side surfaces of the installation table 156.

  In the gate 160 arranged on the upstream side in the moving direction of the stage 152, three detection units 180 are moved in the moving direction of the stage 152 on the upper part of the front surface (above the moving path of the stage 152) facing the upstream side. Are fixedly arranged at predetermined intervals along a direction orthogonal to the direction. In the detection unit 180, a CCD camera 182 disposed on the upstream side and a displacement sensor 184 disposed on the downstream side are integrated into a substantially box shape. The lens unit 186 of the CCD camera 182 and the displacement sensor 184 Both sensor parts 188 are directed downward.

  In the gate 161 arranged on the downstream side in the moving direction of the stage 152, the scanner 162 is fixedly arranged on the upper part of the rear surface facing the downstream side (above the moving path of the stage 152).

  Further, the driving device of the stage 152, the scanner 162, and the detection unit 180 are connected to a controller 190 that controls them. By this controller 190, during the exposure operation of the exposure apparatus 100 described later, the stage 152 is controlled to move at a predetermined speed, the detection unit 180 is controlled to detect the photosensitive material 150 at a predetermined timing, and the exposure head 166 is controlled. The photosensitive material 150 is controlled to be exposed at a predetermined timing.

  As shown in FIGS. 2 and 3B, the scanner 162 includes a plurality of (for example, eight) exposure heads 166 arranged in an approximately matrix of m rows and n columns (for example, 2 rows and 4 columns). ing.

  As shown in FIG. 2, the exposure area 168 that is an area exposed by the exposure head 166 has a rectangular shape with a short side along the scanning direction, and is inclined at a predetermined inclination angle θ with respect to the scanning direction. . As the stage 152 moves, a strip-shaped exposed area 170 is formed for each exposure head 166 in the photosensitive material 150. As shown in FIGS. 1 and 2, the scanning direction is opposite to the stage moving direction.

  As shown in FIGS. 3A and 3B, the exposure heads 166 are arranged in a line, and each of the strip-shaped exposed areas 170 partially overlaps the adjacent exposed areas 170. Further, they are arranged at a predetermined interval (natural number times the long side of the exposure area, 1 time in the present embodiment) in the arrangement direction. Therefore, for example, the unexposed portion between the image region 168A located on the leftmost side of the first row and the image region 168C located on the right side of the image region 168A is the image located on the leftmost side of the second row. The area 168B is exposed. Similarly, a portion that cannot be exposed between the image area 168B and the image area 168D located on the right side of the image area 168B is exposed by the image area 168C.

  Each of the exposure heads 166A to 166H is a spatial light modulation element that modulates an incident light beam for each pixel in accordance with image data, as shown in FIG. 4 and FIGS. A digital micromirror device (DMD) 50 is provided. The DMD 50 is connected to the controller 190 having a scanner control unit including a data processing unit and a mirror drive control unit. The data processing unit of the controller 190 generates a control signal for driving and controlling each micromirror in the region to be controlled by the DMD 50 for each exposure head 166 based on the input image data.

  In addition, the mirror drive control unit controls the angle of the reflection surface of each micromirror of the DMD 50 for each exposure head 166 based on the control signal generated by the data processing unit. The control of the angle of the reflecting surface will be described later.

  On the light incident side of the DMD 50, a fiber array light source 66 including a laser emitting section in which emission ends (light emitting points) of an optical fiber are arranged in a line along a direction corresponding to the long side direction of the exposure area 168, a fiber A lens system 67 for correcting the laser light emitted from the array light source 66 and condensing it on the DMD, and a reflecting mirror 69 for reflecting the laser light transmitted through the lens system 67 toward the DMD 50 are arranged in this order.

  As shown in FIG. 5, the lens system 67 includes a pair of combination lenses 71 that collimate the laser light emitted from the fiber array light source 66 so that the light quantity distribution of the collimated laser light is uniform. A pair of combination lenses 73 to be corrected and a condensing lens 75 for condensing the laser light whose light quantity distribution has been corrected on the DMD. With respect to the arrangement direction of the laser emitting ends, the combination lens 73 spreads the light beam at a portion close to the optical axis of the lens and contracts the light beam at a portion away from the optical axis, and with respect to a direction orthogonal to the arrangement direction. Has a function of allowing light to pass through as it is, and corrects the laser light so that the light quantity distribution is uniform.

  As shown in FIG. 6, the DMD 50 is configured such that a micromirror 62 is supported on a SRAM cell (memory cell) 60 by a support column, and a large number of pixels (pixels) (for example, This is a mirror device formed by arranging micromirrors with a pitch of 13.68 μm, 1024 × 768) in a lattice pattern. Each pixel is provided with a micromirror 62 supported by a support column at the top, and a material having a high reflectance such as aluminum is deposited on the surface of the micromirror 62. The reflectance of the micromirror 62 is 90% or more.

  When a digital signal indicating the tilt state (modulation state) of the micromirror 60 is written in the SRAM cell 60 of the DMD 50 and further the digital signal is output from the SRAM cell 60 to the micromirror 62, the micromirror 62 supported by the support column. However, it is tilted in a range of ± α degrees (for example, ± 10 degrees) with respect to the substrate side on which the DMD 50 is disposed with the diagonal line as the center.

  FIG. 7 shows an example of a state in which a part of the DMD 50 is enlarged and the micromirror 62 is controlled to + α degrees or −α degrees, and FIG. 7A shows that the micromirror 62 is in an on state. FIG. 7B shows a state in which the micromirror 62 is tilted to −α degrees, which is an off state. As shown in FIGS. 7A and 7B, by controlling the inclination of the micromirror 62 in each pixel of the DMD 50 according to the image signal, the light beam incident on the DMD 50 is transmitted to each micromirror 62. Reflected in the tilt direction. Note that a light absorber (not shown) is arranged in the direction in which the light beam is reflected by the micromirror 62 in the off state. The on / off control of each micromirror 62 is performed by a scanner control unit including the above-described data processing unit and mirror drive control unit in response to a command from the controller 190.

  Further, on the light reflection side of the DMD 50, as shown in FIG. 5, lens systems 54 and 58 for forming an image of the laser light reflected by the DMD 50 on the scanning surface (exposed surface) 56 of the photosensitive material 150, and the lens system A focus mechanism 59 for adjusting the focal length of the laser light transmitted through 54 and 58 is arranged in this order.

  The lens systems 54 and 58 are arranged so that the DMD 50 and the exposed surface 56 are in a conjugate relationship. In this embodiment, the laser light emitted from the fiber array light source 66 is made uniform and incident on the DMD 50. Then, each pixel is enlarged by about 5 times by these lens systems 54 and 58 and is set to be condensed.

  The focus mechanism 59 includes a pair of glass members (pair wedge glass) 210 and 212 formed in a wedge shape (trapezoidal column shape) with a transparent glass material. In the present embodiment, the refractive index n of the glass members 210 and 212 is set to n = 1.53, and the pair of glass members 210 and 212 are arranged adjacent to each other along the optical axis of the laser beam in the direction reversed from each other. Has been.

  Specifically, the glass member 210 provided on the laser beam incident side (DMD 50 side) has a bottom surface directed to one side (above FIG. 5A) and a top surface parallel to the bottom surface on the other side. The plane that is directed to the lower side of FIG. 5A and perpendicular to the bottom surface and the top surface is disposed on the laser light incident side to form a light incident surface 210A. The tilted inclined surface is arranged on the laser beam emission side to form a light emission surface 210B, and the light incident surface 210A is substantially orthogonal to the optical axis of the laser beam emitted from the DMD 50 side. The surface 210B is arranged in an inclined direction.

  Further, the glass member 212 provided on the laser beam emission side (exposed surface 56 side) has a bottom surface directed to the other side (downward in FIG. 5A) and a top surface parallel to the bottom surface on one side. And a plane perpendicular to the bottom surface and the top surface is disposed on the laser beam emission side to form a light emission surface 212B, and is directed to the light emission surface 212B. The inclined surface inclined in this manner is disposed on the laser light incident side to form a light incident surface 212A, and the light emitting surface 212B is substantially orthogonal to the optical axis of the laser light emitted from the DMD 50 side. The incident surface 212A is arranged in an inclined direction.

  Then, as shown in FIGS. 5A and 5B, the pair of glass members 210 and 212 has a slight gap between the light emitting surface 210B of the glass member 210 and the light incident surface 212A of the glass member 212. In a non-contact state, the light incident surface 210A of the glass member 210 and the light emitting surface 212B of the glass member 212 are made parallel to each other and substantially orthogonal to the optical axis of the laser light as described above. In the present embodiment, the distance between the light exit surface 210B of the glass member 210 and the light incident surface 212A of the glass member 212 is set to 0.1 mm.

  The focus mechanism 59 is configured as described above. When the focal length of the laser beam is adjusted by the focus mechanism 59, the glass member 210 is moved by the focus mechanism control unit of the controller 190 as shown in FIG. It moves from the reference position indicated by the two-dot chain line in the direction of the arrow SA shown in FIG. 8A or the direction of the arrow SB shown in FIG.

  Here, when the glass member 210 is at the reference position, the distance between the light incident surface 210A of the glass member 210 and the light emitting surface 212B of the glass member 212, that is, the glass member 210 including a slight gap provided therebetween. , 212, when the total thickness dimension is t, the thickness dimension t decreases by Δt (−Δt) when the glass member 210 moves from the reference position in the direction of the arrow SA by a predetermined distance (−Δt). Increases by Δt (+ Δt) when it has moved from the reference position in the direction of arrow SB by a predetermined distance.

  Thus, when the thickness dimension t of the glass members 210 and 212 changes (± Δt), the transmission distance through which the laser light passes through the glass members 210 and 212 changes, and the focal length FD of the laser light changes ( ± ΔFD). Note that PS shown in FIG. 8 represents an imaging plane.

  Further, assuming that the refractive index n of the glass members 210 and 212 (n = 1.53 in the present embodiment), the change in the focal length FD of the laser light according to the amount of change in the thickness dimension t of the glass members 210 and 212. The amount is determined by the following formula.

+ ΔFD = + Δt − (+ Δt) / n
−ΔFD = −Δt − (− Δt) / n
Next, an exposure operation for the photosensitive material 150 by the exposure apparatus 100 configured as described above and data processing contents in the exposure operation will be described.

  First, when image data corresponding to an exposure pattern is input to the controller 190, it is temporarily stored in a frame memory in the controller. This image data is data representing the density of each pixel constituting the image by binary values (whether or not dots are recorded).

  Next, the photosensitive material 150 is set on the stage 152, and the operator performs an exposure start input operation from the operation unit of the controller 190. The photosensitive material 150 for performing image exposure by the exposure apparatus 100 includes 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 device. In the case of a dry film, a laminate or the like is applied.

  When the exposure operation of the exposure apparatus 100 is started by the above input operation, the controller 190 controls the driving device, and the stage 152 starts moving at a constant speed from the origin position shown in FIG. . Each detection unit 180 is controlled and operated by the controller 190 in synchronization with the start of the movement of the stage or at a timing just before the leading edge of the photosensitive material 150 reaches just below the CCD camera 182 of the detection unit 180.

  When the photosensitive material 150 passes below the detection unit 180 as the stage 152 moves (moves from 150A to 150B in FIG. 9), alignment measurement by the CCD camera 182 and focus measurement by the displacement sensor 184 are simultaneously performed. Done.

  First, when the photosensitive material 150 passes below the three CCD cameras 182, as shown in FIG. 10A, each CCD camera 182 images the photosensitive material 150, and the captured image data (imaging image). Data) is output to the data processing unit of the controller 190.

  The data processing unit detects an alignment mark or a reference hole provided in the photosensitive material 150 as an alignment reference portion or an edge portion or a corner portion of the photosensitive material 150 as an alignment reference portion from the input photographing data. A proper exposure position with respect to the position and the exposed surface 56 is grasped. Then, at the time of image exposure by the scanner 162, which will be described later, correction control (alignment) is performed in which a control signal generated based on the image data of the exposure pattern stored in the frame memory is adjusted to the appropriate exposure position to perform image exposure. .

  Further, when the photosensitive material 150 passes below the three displacement sensors 184, each displacement sensor 184 is a distance between the front surface and the exposed surface 56 including detection of the rear end (edge detection processing) of the photosensitive material 150. Measurement is performed (see FIG. 10A), and the measured measurement data (focus measurement data) is output to the scanner control unit of the controller 190.

  The scanner control unit recognizes the leading end and the trailing end of the photosensitive material 150 based on the input focus measurement data, and executes arithmetic processing for grasping the waviness and thickness dimension error of the photosensitive material 150. Further, based on this processing result, control data for driving and controlling the focus mechanism 59 of each exposure head 166 is generated and output to the scanner 162, and the focal position of the light beam irradiated from each exposure head 166 is set to the photosensitive material 150. The focus control is performed so as to coincide with the exposed surface 56.

  Here, the contents of the above arithmetic processing and focus control will be described.

  Assuming that the moving direction of the photosensitive material 150 is the Y direction and the direction orthogonal to the moving direction (the width direction of the photosensitive material 150) is the X direction, the arithmetic processing in the Y direction is performed first by moving the photosensitive material 150 by the displacement sensor 184. Accordingly, a plurality of average values of the measurement data acquired at a predetermined movement interval are obtained. In the present embodiment, as shown in FIG. 11, measurement data is acquired at intervals of 1 mm as the photosensitive material 150 moves, the moving average of the measurement data of 8 mm before and after is calculated, and the moving average of the measurement data at intervals of 1 mm is obtained. get. At this time, for the measurement data from the front end of the photosensitive material 150 to 8 mm, the moving average value α at the position of 8 mm from the front end is used as shown in FIG. For the measurement data from the rear end to 8 mm, the moving average value β at the position 8 mm from the rear end is used as shown in FIG.

  As described above, measurement data obtained by moving average at intervals of 1 mm from the front end to the rear end of the photosensitive material 150 is acquired.

  Next, the controller 190 performs a thinning process on the measurement data at 1 mm intervals obtained as described above, and obtains measurement data at 10 mm intervals. By using the thinning data at intervals of 10 mm as described above, the subsequent arithmetic processing can be lightened and the speed can be increased.

  Then, in the controller 190, as shown in FIG. 13, the measurement data Z1 to Z6 at intervals of 10 mm are subtracted from the displacement sensor reference position Z0 to calculate the substrate undulation amounts Z1 'to Z6'. The displacement sensor reference position Z0 is a distance between the photosensitive material 150 and the displacement sensor 184 when the photosensitive material 150 is flat.

  Then, the substrate undulation amounts Z1 'to Z6' are acquired for each displacement sensor 184.

  Next, the substrate waviness amounts Z1 ′ to Z6 ′ obtained for each displacement sensor 184 as described above (white circles in FIG. 14) are linearly interpolated in the X direction as shown in FIG. Substrate waviness amounts Z1 ″ to Z6 ″ of the photosensitive material 150 at the position of the exposure head 166 (X marks in FIG. 14) are calculated. In the present embodiment, linear interpolation is performed in the X direction, but other interpolation methods may be used.

  Then, a peeling error in the Y direction of the exposure head 166 is added to the substrate waviness amounts Z1 ″ to Z6 ″ for each exposure head 166 acquired as described above.

  Here, the peeling error in the Y direction of the exposure head 166 is a deviation amount of the substrate waviness due to a difference in position between the exposure head 166 and the displacement sensor in the Y direction. For example, as shown in FIG. 15, when there is undulation of the rail of the guide 158, the peeling error in the Y direction is D.

  Then, the substrate waviness amounts Z1 ″ to Z6 ″ for each exposure head 166 to which the Y direction peeling error is added are subjected to cubic spline interpolation in the Y direction, as shown in FIG. Based on the result of the cubic spline interpolation, control data of the focus mechanism 59 at 1 mm intervals is acquired.

  Here, the cubic spline interpolation is performed by the controller 190, and is calculated by a CPU provided for each exposure head 166. As described above, by performing the cubic spline interpolation by the CPU provided for each exposure head 166, the calculation processing speed can be increased. In this embodiment, cubic spline interpolation is performed, but other interpolation methods may be used.

  Then, the control data of the focus mechanism 59 for each exposure head 166 acquired as described above is input to the focus mechanism control unit of the controller 190, and the focus mechanism 59 is controlled. The above is the contents of arithmetic processing and focus control.

  When the photosensitive material 150 passes through the detection unit 180 (position 150B in FIG. 9), alignment measurement and focus measurement (simultaneous measurement) by the detection unit 180 are completed. Further, the photosensitive material 150 that has passed through the detection unit 180 moves toward the scanner 162 as the stage 152 moves. When the exposure material reaches the exposure start position, each exposure head 166 of the scanner 162 irradiates a light beam to irradiate the photosensitive material 150. Image exposure on the surface to be exposed 56 is started.

  Here, the image data stored in the frame memory in the controller is sequentially read for each of a plurality of lines, and the data processing unit generates a control signal for each exposure head 166 based on the read image data. This control signal is subjected to correction of the exposure position deviation with respect to the photosensitive material 150 measured by the alignment by the correction control (alignment) described above. Then, the mirror drive control unit performs on / off control of each micromirror of the DMD 50 for each exposure head 166 based on the generated and corrected control signals.

  When laser light is emitted from the fiber array light source 66 to the DMD 50, the laser light reflected when the micromirrors of the DMD 50 are on is imaged on the exposed surface 56 of the photosensitive material 150 by the lens systems 54 and 58. Is done. Here, the focus of the laser beam is adjusted on the exposed surface 56 according to the distance between the exposed surface and the exposure head (lens system) at the exposure position by focus control performed using the focus mechanism 59 described above. .

  In this manner, the laser light emitted from the fiber array light source 66 is turned on / off for each pixel, and the exposed surface 56 of the photosensitive material 150 is exposed in a pixel unit (exposure area 168) that is substantially the same as the number of pixels used in the DMD 50. Is done. Further, when the photosensitive material 150 moves downstream together with the stage 152, the exposed surface 56 is scanned and exposed in the direction opposite to the stage moving direction by the laser beam. The exposed surface 56 is formed with a strip-shaped exposed region 170 that is scanned and exposed by the laser beam of each exposure head 166. In this scanning exposure, the focus of the laser beam is adjusted on the exposed surface 56 so as to follow the shape of the exposed surface 56 and follow the shape of the exposed surface 56 in synchronization with the scanning by focus control.

  When the photosensitive material 150 passes through the scanner 162 (150C position in FIG. 9) and image exposure of the photosensitive material 150 by the scanner 162 is completed, the stage 152 is driven in the reverse direction by the driving device, and the most upstream side along the guide 158 Return to the origin at. Thus, the exposure operation for the photosensitive material 150 by the exposure apparatus 100 is completed.

  In the above-described embodiment, the exposure head including the DMD as the spatial modulation element has been described. As the spatial modulation element, for example, a micro electro mechanical systems (SMEM) type spatial modulation element (SLM; Spatial Light) in addition to the DMD. Modulator), an optical element (PLZT element) that modulates transmitted light by an electro-optic effect, a liquid crystal light shutter (FLC), and the like can also be used.

  The present invention is not limited to the exposure apparatus as described above, and can be applied to an apparatus that irradiates a focused beam, such as a laser annealing apparatus.

The perspective view of the exposure apparatus using one Embodiment of the focus adjustment apparatus of this invention Perspective view showing the configuration of the scanner (A) Plan view showing exposed areas formed on the photosensitive material, (B) Drawing showing the arrangement of exposure areas by each exposure head A perspective view showing a schematic configuration of an exposure head (A) Cross-sectional view in the sub-scanning direction along the optical axis showing the configuration of the exposure head shown in FIG. 4, (B) Side view of (A). Partial enlarged view showing the configuration of a digital micromirror device (DMD) Explanatory diagram for explaining the operation of DMD Explanatory diagram for explaining the structure of the focus mechanism and the operation of the focus mechanism (A) Plan view showing the exposure operation by the exposure apparatus of FIG. 1, (B) is a side view of (A). (A) A side view showing a state of focus measurement by the exposure apparatus of FIG. 1, (B) a side view showing a state of focus control of laser light irradiated from the exposure head. The figure for demonstrating the method of acquiring measurement data with a displacement sensor The figure for demonstrating the method of acquiring measurement data with a displacement sensor Diagram for explaining how to calculate the amount of swell The figure for demonstrating the method to calculate the board | substrate waviness amount of the photosensitive material 150 in each exposure head position from the board | substrate waviness amount acquired for every displacement sensor. The figure for demonstrating the peeling error of the Y direction of an exposure head The figure for demonstrating the method of calculating the control data of a focus mechanism

Explanation of symbols

56 Surface to be exposed 59 Focus mechanism (focus adjustment mechanism)
100 exposure apparatus 150 photosensitive material (object to be processed)
152 stage (moving means)
162 Scanner 166 Exposure head (optical system)
180 Detection unit 182 CCD camera 184 Displacement sensor (distance measuring means)
190 controller (waviness acquisition means, control data generation means, control means, correction means)

Claims (8)

A plurality of optical systems having a focus adjustment mechanism for focusing on a processing target and a plurality of distance measuring means for measuring a distance from the processing target and the processing target are relatively moved;
Based on the measurement data measured along the moving direction by the distance measuring means by the movement, the amount of waviness of the processing object at the position of each optical system is acquired,
Interpolating the acquired amount of waviness in the direction of movement to generate control data for the focus adjustment mechanism of each optical system;
A focus adjustment method, wherein the focus adjustment mechanism is controlled based on the generated control data.   2. The focus adjustment method according to claim 1, wherein the swell amount is acquired based on thinned data obtained by thinning measurement data measured along the moving direction by the distance measuring means.   3. The focus adjustment method according to claim 1, wherein the control data is generated by a control data generation unit provided for each of the optical systems.   The amount of deviation of the measurement data due to a difference in position in the movement direction between the optical system and each distance measuring means is acquired, and the amount of undulation is corrected based on the acquired amount of deviation. Item 4. The focus adjustment method according to any one of Items 1 to 3. A plurality of optical systems having a focus adjustment mechanism for focusing on a workpiece;
A plurality of distance measuring means for measuring the distance to the workpiece;
Moving means for relatively moving the optical system and the distance measuring means and the processing object;
Based on the measurement data measured along the moving direction by the distance measuring means by the movement by the moving means, a waviness amount acquiring means for acquiring the waviness amount of the processing target at the position of each optical system;
Control data generating means for generating control data of the focus adjusting mechanism of each optical system by interpolating the waviness amount acquired by the waviness amount acquiring means with respect to the moving direction;
And a control means for controlling the focus adjustment mechanism based on the control data generated by the control data generation means.   6. The swell amount acquisition unit acquires the swell amount based on thinned data obtained by thinning out measurement data measured along the moving direction by the distance measuring units. Focus adjustment device.   The focus adjustment apparatus according to claim 5 or 6, wherein the control data generation means is provided for each of the optical systems.   Compensating means for obtaining a deviation amount of the measurement data due to a difference in position in the movement direction between the optical system and each distance measuring means, and correcting the waviness amount based on the obtained deviation amount. The focus adjusting apparatus according to claim 5, wherein:

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