JP4533785B2 - Alignment sensor position calibration method, reference pattern calibration method, exposure position correction method, calibration pattern, and alignment apparatus - Google Patents

Description

  The present invention relates to a position calibration method for an alignment sensor that detects a calibration pattern and calibrates the position of the alignment sensor, and an alignment sensor that is corrected in accordance with a reference scale on which the reference pattern is formed based on the calibration pattern. And a reference pattern calibration method for calibrating the reference scale, an exposure position correction method for correcting an exposure position using the reference pattern calibration method, and the alignment sensor position calibration method and the reference pattern calibration method described above. The present invention relates to an alignment apparatus using the calibration pattern and the principle of the alignment sensor position calibration method and the reference pattern calibration method described above.

  For example, an exposure apparatus has been developed that manufactures a filter or a printed circuit board such as a liquid crystal display or a plasma display by controlling a laser beam according to a desired image pattern and exposing and scanning a sheet-like photosensitive material. FIG. 24 shows a schematic configuration of such an exposure apparatus 300 (see Patent Document 1).

  The exposure apparatus 300 includes, for example, a rectangular platen 304 supported by six legs 302 and a movable stage 308 movable along two guide rails 306a and 306b disposed on the platen 304. A portal column 310 disposed on the surface plate 304; and a scanner 314 that irradiates the workpiece 312 fixed to the column 310 and positioned on the moving stage 308 with a laser beam.

  While the workpiece 312 is moved in the direction of the arrow together with the moving stage 308, a laser beam output from the scanner 314 is irradiated in a direction orthogonal to the direction of the arrow, thereby recording a two-dimensional image.

  Here, the scanner 314 is composed of a plurality of exposure heads that use a spatial light modulation element such as a digital micromirror device (DMD) as a pattern generator, and each exposure head produces a high-definition and high-speed two-dimensional image pattern. Is configured to record.

  The DMD is a mirror device in which a large number of micromirrors whose reflection surfaces change in response to a control signal are two-dimensionally arranged on a semiconductor substrate such as silicon. The laser beam output from a laser light source is collimated by a collimator lens. After the collimation, the two-dimensional image pattern is recorded by selectively reflecting with a DMD whose angle of the reflecting surface is controlled and condensing on the work 312 via the microlens array.

  In such an exposure apparatus 300, for example, in order to accurately align the exposure position of the workpiece 312 with, for example, the workpiece conveyance direction (Y direction) and the direction orthogonal thereto (X direction), the workpiece 312 is provided on the workpiece prior to exposure. An alignment mark is photographed with an alignment camera such as a CCD camera, and alignment is performed to match the exposure position to an appropriate position based on the mark measurement position (reference position data) obtained by this photographing.

  With respect to such an alignment function (exposure position alignment function), calibration of each part related to alignment measurement is performed at the time of manufacture, maintenance, or the like in order to guarantee the accuracy.

  For example, in the position calibration of the alignment scope, an apparatus that calibrates the position of the alignment scope that measures the printed circuit board prior to performing a predetermined process in the processing unit on the printed circuit board mounted on the mounting table. The reference scale on which the reference pattern is formed is provided on the mounting table, and after the alignment scope is moved to the reference pattern at a predetermined position, the alignment scope is moved based on the amount of misalignment between the intersection of the reference patterns and the center of the alignment scope. There is a technique in which the position calibration of the alignment scope is performed easily and with high accuracy with a simple configuration by performing position calibration (see, for example, Patent Document 2).

JP 2004-62155 A JP 2000-329523 A

  However, since the relative positional relationship between the workpiece conveyance direction and the reference pattern on the reference scale cannot be easily determined, if the reference scale itself is installed with a deviation, the deviation amount is also reflected in the position of the alignment camera. As a result, there is a problem that a desired image cannot be drawn / exposed on the workpiece.

  Therefore, it is necessary to calibrate the position of the alignment camera that reflects the deviation amount of the reference pattern, or to position and install the reference pattern of the reference scale with high accuracy in the workpiece transfer direction. Extremely difficult.

  The present invention has been made in consideration of such problems, and provides a position calibration method for an alignment sensor that can easily calibrate the position of an alignment camera (alignment sensor) even if the position of the alignment camera (alignment sensor) is shifted. The purpose is to do.

  Another object of the present invention is to provide a reference pattern calibration method capable of easily discriminating a deviation of a reference pattern even if the reference pattern of the reference scale is shifted and installed and calibrating the deviation of the reference pattern. Is to provide.

  Another object of the present invention is to calibrate the position easily even when the position of the alignment sensor is shifted due to the shift of the reference pattern of the reference scale when the workpiece is exposed. An object of the present invention is to provide an exposure position correction method capable of correcting an exposure position with high accuracy.

  Another object of the present invention is that even if the position of the alignment sensor is misaligned or the reference pattern of the reference scale is misaligned, the misalignment can be easily determined, and high accuracy An object of the present invention is to provide a calibration pattern and an alignment apparatus capable of realizing alignment measurement.

  A position calibration method for an alignment sensor according to the present invention includes a calibration pattern detection step for detecting a calibration pattern including at least one pattern whose relative positional relationship is known in advance by an alignment sensor, and the detected calibration calibration. A calibration value obtaining step for obtaining a calibration value of the alignment sensor based on a pattern, and a sensor calibration step for calibrating the position of the alignment sensor based on the calibration value.

  Thereby, even if the position of the alignment camera (alignment sensor) has shifted | deviated, the position can be calibrated easily.

  The method further includes a determination step of determining whether or not the acquired calibration value is within an allowable range, and performing the sensor calibration step when the calibration value is not within the allowable range. Also good.

  The method may further include a placing step of placing the member on which the one or more patterns whose relative positional relationship is known in advance is formed on the workpiece placing surface of the stage that conveys the workpiece. Also good.

  The calibration pattern includes the one or more patterns formed on the member, specifies two line segments having a predetermined angle relationship with each other, and the two line segments are the alignment lines. You may make it use in order to calibrate the position shift with respect to the direction orthogonal to the conveyance direction of the said workpiece | work at least in a sensor.

  The calibration pattern on the member is composed of the one or more patterns formed on the member and two line segments that are defined by predetermined portions on the stage and have a predetermined angle relationship with each other. The two line segments may be used to calibrate a positional deviation in at least the direction perpendicular to the conveyance direction of the workpiece in the alignment sensor.

  The predetermined angle may be a right angle.

  Further, in the method, a reference pattern on a reference scale installed on the workpiece placement surface is detected by at least one alignment sensor, and the position of the alignment sensor is converted to data based on imaging data of the reference pattern. A correction step for correcting may further be provided, and the calibration pattern detection step may detect the calibration pattern by the alignment sensor corrected in terms of data.

  In the sensor calibration step, the position of the alignment sensor corrected in terms of data may be further corrected in terms of data by the calibration value.

  Further, in the method, an angle formed between the workpiece conveyance direction and one of the two line segments in the detected calibration pattern is a first angle, and the workpiece conveyance direction is When the angle formed between the orthogonal direction and the other line segment of the two line segments in the detected calibration pattern is the second angle, the calibration value is the first angle. You may make it determine based on the relative angle of a 2nd angle.

  Next, in the reference pattern calibration method according to the present invention, at least one alignment sensor detects a reference pattern on a reference scale installed on a workpiece placement surface of a stage that conveys a workpiece, and image data of the reference pattern is detected. And a correction step for correcting the position of the alignment sensor in terms of data, and a calibration pattern including one or more patterns whose relative positional relationship is known in advance is detected by the corrected alignment sensor. A pattern detection step, a calibration value acquisition step for obtaining a calibration value of the reference pattern based on at least the detected calibration pattern, and a reference scale re-installation step for inclining and re-installing the reference scale by the calibration value It is characterized by having.

  Thereby, even if the reference pattern of the reference scale is shifted and installed, the shift can be easily determined, and the shift of the reference pattern can be calibrated.

  The method further includes a determination step of determining whether or not the acquired calibration value is within an allowable range, and performing the reference scale re-installation step when the calibration value is not within the allowable range. It may be.

  The method may further include a placing step of placing the member on which the one or more patterns whose relative positional relationship is known in advance is formed on the workpiece placing surface of the stage that conveys the workpiece. Also good.

  The calibration pattern includes the one or more patterns formed on the member, specifies two line segments having a predetermined angle relationship with each other, and the two line segments are the alignment lines. You may make it use in order to calibrate the position shift with respect to the direction orthogonal to the conveyance direction of the said workpiece | work at least in a sensor.

  The calibration pattern on the member is composed of the one or more patterns formed on the member and two line segments that are defined by predetermined portions on the stage and have a predetermined angle relationship with each other. The two line segments may be used to calibrate a positional deviation in at least the direction perpendicular to the conveyance direction of the workpiece in the alignment sensor.

  The predetermined angle may be a right angle.

  Further, in the method, a reference pattern on a reference scale installed on the workpiece placement surface is detected by at least one alignment sensor, and the position of the alignment sensor is converted to data based on imaging data of the reference pattern. A correction step for correcting may further be provided, and the calibration pattern detection step may detect the calibration pattern by the alignment sensor corrected in terms of data.

  Further, in the method, an angle formed between the workpiece conveyance direction and one of the two line segments in the detected calibration pattern is a first angle, and the workpiece conveyance direction is When the angle formed between the orthogonal direction and the other line segment of the two line segments in the detected calibration pattern is the second angle, the calibration value is the first angle. You may make it determine based on the relative angle of a 2nd angle.

  Next, the exposure position correction method according to the present invention is based on the relative positional relationship between the reference pattern on the reference scale installed on the workpiece placement surface of the stage that conveys the workpiece and the alignment mark formed on the workpiece. In an exposure position correction method for correcting an exposure position on a workpiece, the reference pattern is calibrated using the invention related to the reference pattern calibration method described above, and the calibrated reference pattern and the alignment mark formed on the workpiece The exposure position of the workpiece is corrected based on the relative positional relationship.

  This makes it easy to calibrate the position of the alignment sensor even if the position of the alignment sensor is shifted due to the shift of the reference pattern on the reference scale when exposing the workpiece, and corrects the exposure position with high accuracy. can do.

  Next, the calibration pattern according to the present invention includes at least one pattern formed on a member placed on the workpiece placement surface of the stage that transports the workpiece, and at least a calibration pattern for calibrating the position of the alignment sensor. The two or more line segments that are formed of the one or more patterns formed on the member and have a predetermined angle relationship with each other are specified, and the two line segments are defined in the alignment sensor. It is used for calibrating a positional deviation at least with respect to a direction orthogonal to the conveying direction of the workpiece.

  The calibration pattern according to the present invention includes at least one pattern formed on a member placed on the workpiece placement surface of the stage that conveys the workpiece, and is a calibration pattern that calibrates at least the position of the alignment sensor. The two or more line segments, which are configured by the one or more patterns formed on the member and specified parts on the stage and have a predetermined angle relationship with each other, are specified, and the 2 The two line segments are used to calibrate a positional shift in the alignment sensor with respect to at least a direction orthogonal to the conveyance direction of the workpiece.

  According to the invention relating to the calibration pattern, even if the position of the alignment sensor is shifted or the reference pattern of the reference scale is shifted and installed, the shift can be easily determined, and a high-precision alignment is achieved. Measurement can be realized.

  In the calibration pattern, the predetermined angle may be a right angle.

  Next, an alignment apparatus according to the present invention includes at least one pattern whose relative positional relationship is known in advance in an alignment apparatus for calibrating a displacement of an alignment sensor with respect to a work placement surface of a stage on which a work is conveyed. Calibration pattern detection means for detecting a calibration pattern by the alignment sensor; calibration value acquisition means for obtaining a calibration value of the alignment sensor based on the detected calibration pattern; and the alignment sensor as the calibration value. Sensor calibration means for calibrating based on the sensor.

  Thereby, even if the position of the alignment sensor is shifted or the reference pattern of the reference scale is shifted and installed, the shift can be easily determined, and high-precision alignment measurement can be realized. it can.

  And determining means for determining whether or not the acquired calibration value is in an allowable range in the configuration, and transferring control to processing in the sensor calibration means when the calibration value is not in the allowable range. You may make it have further.

  Moreover, in the said structure, you may make it further have the member by which the one or more pattern by which it mounted on the said workpiece | work mounting surface and the said relative positional relationship was known beforehand was formed.

  In this case, the calibration pattern is composed of the one or more patterns formed on the member, specifies two line segments having a predetermined angle relationship with each other, and the two line segments are The alignment sensor may be used to calibrate a positional deviation with respect to at least a direction orthogonal to the conveyance direction of the workpiece.

  Further, the calibration pattern in the member is composed of two or more patterns formed on the member and a specified portion on the stage, and having a predetermined angle relationship with each other. A line segment may be specified, and the two line segments may be used to calibrate a positional shift in the alignment sensor at least in a direction orthogonal to the conveyance direction of the workpiece.

  Further, in the above configuration, the reference pattern on the reference scale installed on the work placement surface is detected by at least one alignment sensor, and the position of the alignment sensor is converted into data based on the imaging data of the reference pattern. The correction pattern detecting unit may further include a correction unit that corrects the correction pattern, and the calibration pattern detection unit may detect the calibration pattern with the alignment sensor corrected in terms of data.

  The sensor calibration means may further correct the position of the alignment sensor corrected in terms of data by the calibration value.

  Further, in the above-described configuration, an angle formed between the workpiece conveyance direction and one of the two line segments in the detected calibration pattern is a first angle, and the workpiece conveyance direction is When the angle formed between the orthogonal direction and the other line segment of the two line segments in the detected calibration pattern is the second angle, the calibration value is the first angle. You may make it determine based on the relative angle of a 2nd angle.

  As described above, according to the alignment sensor position calibration method of the present invention, even if the position of the alignment camera (alignment sensor) is shifted, the position can be easily calibrated.

  Further, according to the reference pattern calibration method according to the present invention, even if the reference pattern of the reference scale is shifted and installed, the shift can be easily determined, and the shift of the reference pattern can be calibrated. .

  Further, according to the exposure position correction method according to the present invention, even when the position of the alignment sensor is shifted due to the shift of the reference pattern of the reference scale when the workpiece is exposed, the position is easily calibrated. And the exposure position can be corrected with high accuracy.

  Further, according to the calibration pattern and the alignment apparatus according to the present invention, even if the position of the alignment sensor is shifted or the reference pattern of the reference scale is shifted and installed, the shift can be easily determined. Therefore, highly accurate alignment measurement can be realized.

  Embodiments in which the alignment sensor position calibration method, reference pattern calibration method, exposure position correction method, calibration pattern, and alignment apparatus according to the present invention are applied to a digital exposure apparatus having, for example, a DMD are shown in FIGS. Will be described with reference to FIG.

  As shown in FIG. 1, the digital exposure apparatus 10 according to the present embodiment has an installation table 18 supported by six legs 16. Two guides 20 extend along the longitudinal direction on the upper surface of the installation base 18, and a stage 14 is slidably provided on the two guides 20. The stage 14 is disposed such that the longitudinal direction thereof is directed to the extending direction of the guide 20, and is supported by the guide 20 so as to be reciprocally movable on the installation table 18. The stage 14 is driven by a driving device (not shown) along the guide 20. Reciprocally move (arrow Y direction in FIG. 1).

  On the upper surface (work placement surface) of the stage 14, the work 12 as an exposure object is placed in a form positioned at a predetermined placement position by a positioning unit (not shown). A plurality of grooves (not shown) are formed on the workpiece placement surface of the stage 14, and the workpiece 12 is placed on the workpiece placement surface of the stage 14 by making the inside of these grooves negative pressure by a negative pressure supply source. It is adsorbed and held. Further, a total of four alignment marks 13 indicating the reference of the exposure position are arranged on the work 12, one by one near the four corners of the work 12. Examples of the work 12 include a substrate, a photosensitive material, a printed circuit board, a display device substrate, a display device filter, and the like.

  A U-shaped gate 22 is provided at the center of the installation table 18 so as to straddle the movement path of the stage 14. Both ends of the gate 22 are fixed to both side surfaces of the installation base 18, and a scanner 24 for exposing the workpiece 12 is provided on one side across the gate 22, and provided on the workpiece 12 on the other side. An alignment unit 100 including a plurality (for example, two) of alignment cameras 26 (CCD cameras or the like) for photographing the alignment mark 13 is provided. In addition, when showing two alignment cameras separately, it describes with the 1st alignment camera 26A and the 2nd alignment camera 26B.

  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 provided on the camera mounting surface side of the unit base 102 along a direction (arrow X direction) orthogonal to the moving direction of the stage 14 (arrow Y direction: the conveying direction of the workpiece 12). Each alignment camera 26 is slidably guided by the pair of guide rails 104 and driven by a driving source such as a ball screw mechanism 106 prepared individually and a stepping motor (not shown) for driving the mechanism. Thus, the stage 14 moves independently in a direction orthogonal to the moving direction of the stage 14. The alignment camera 26 is arranged in such a manner 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. A strobe light source (LED strobe light source) 26c is attached.

  When the alignment mark 13 of the workpiece 12 is imaged, each alignment camera 26 is moved in the direction of the arrow X by the drive source and the ball screw mechanism 106 and arranged at a predetermined imaging position, that is, a lens. At the timing when the workpiece 12 moving with the movement of the stage 14 reaches the predetermined photographing position, the strobe light source 26c emits light, and the reflected light from the top surface of the workpiece 12 of the strobe light irradiated to the workpiece 12 is a lens. The alignment mark 13 is photographed by inputting to the camera body 26a via the unit 26b.

  Further, the drive device for the stage 14, the scanner 24, the alignment camera 26, and the drive source for moving the alignment camera 26 are connected to a controller 28 for controlling them. The controller 28 controls the stage 14 to move at a predetermined speed during an exposure operation of the exposure apparatus 10 described later, and the alignment camera 26 is placed at a predetermined position to mark the alignment mark 13 of the workpiece 12 at a predetermined timing. The scanner 24 is controlled to shoot, and the scanner 24 is controlled to expose the workpiece 12 at a predetermined timing.

  As shown in FIG. 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 arranged inside the scanner 24.

  The exposure area 32 by the exposure head 30 is calibrated to a rectangular shape with the scanning direction as a short side, for example. In this case, a strip-shaped exposed region 34 is formed on the work 12 for each exposure head 30 in accordance with the scanning exposure moving operation.

  In addition, as shown in FIG. 2, the exposure heads 30 in each row arranged in a line are arranged at a predetermined interval (in the arrangement direction) so that the strip-shaped exposed regions 34 are arranged without gaps in the direction orthogonal to the scanning direction. The exposure area 32 is shifted by a natural number times the long side). For this reason, for example, a portion that cannot be exposed between the exposure area 32 in the first row and the exposure area 32 in the second row can be exposed by the exposure area 32 in the second row.

  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 having a data processing unit and a mirror drive control unit.

  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 is provided with a plurality of multiplexing modules that synthesize laser beams emitted from a plurality of semiconductor laser chips and input them to an 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 makes the laser light emitted from the connection end of the optical fiber 40 uniform illumination light, and uniform A mirror 42 that reflects the laser light transmitted through the illumination 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 work 12 on the exposure surface on the light reflection side of the DMD 36. Optical members for exposure of the 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 (reflected by the DMD 36). By expanding the cross-sectional area of the beam bundle, the area of the exposure area 32 on the workpiece 12 by the laser beam reflected by the DMD 36 is expanded to a predetermined size. The workpiece 12 is disposed at the rear focal position of the objective lens system 56.

  As shown in FIG. 3, in the microlens array 54, a plurality of microlenses 60 corresponding one-to-one to each micromirror of the DMD 36 that reflects the laser light irradiated from the illumination device 38 through each optical fiber 40 are two-dimensional. The microlenses 60 are arranged on the optical axis of each laser beam (exposure beam) that has been transmitted through the lens system 50, respectively. Has been.

  In addition, as shown in FIG. 5, the DMD 36 is configured such that a micromirror (micromirror) 46 is supported by a support on an SRAM cell (memory cell) 44, and a large number of pixels (pixels) are formed. (For example, 600 × 800) of micromirrors 46 are arranged as a grid device. 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 semiconductor memory manufacturing line is disposed directly below the micromirror 46 via a pillar including a hinge and a yoke (not shown), and the whole is monolithic (integrated type). ).

  When a digital signal is written in the DMD SRAM cell 44, the micromirror 46 supported by the support is tilted in a range of ± a 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. 6A and 6B show an example of a state in which a part of the DMD 36 is enlarged and the micromirror 46 is controlled to + a degree or -a degree, and FIG. 6A shows that the micromirror 46 is in an on state. FIG. 6B illustrates a state in which the micromirror 46 is tilted to −a degrees, which is an off state. Therefore, by controlling the inclination of the micromirror 46 in each pixel of the DMD 36 as shown in FIGS. 6A and 6B in accordance with the image signal, the light incident on the DMD 36 moves in the inclination direction of each micromirror 46. Reflected.

  The 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 micromirror 46 in the on state is modulated into the exposure state, and on the light emitting side of the DMD 36. The light enters the provided projection optical system (see FIG. 3). Further, the light reflected by the micromirror 46 in the off state is modulated into a non-exposure state and enters a light absorber (not shown).

  Further, it is preferable that the DMD 36 is disposed with a slight inclination 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 46 when the DMD 36 is not tilted, and FIG. 4B shows the scanning trajectory of the exposure beam when the DMD 36 is tilted.

  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). 4B, by tilting the DMD 36, the pitch P2 of the scanning trajectory (scanning line) of the exposure beam by each micromirror 46 becomes narrower than the pitch P1 of the scanning line when the DMD 36 is not tilted, greatly increasing the resolution. Can be improved. On the other hand, since the tilt angle of the DMD 36 is very small, the scan width W2 when the DMD 36 is tilted and the scan width W1 when the DMD 36 is not tilted are substantially the same.

  Further, it is because 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 30 arranged in the scanning direction can be connected without a 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 with a predetermined interval in the direction orthogonal to the scanning direction instead of inclining the DMD 36.

  Next, a schematic configuration of an electric system for control in the controller 28 provided in the exposure apparatus 10 according to the present embodiment will be described with reference to the block diagram of FIG.

  In the electric system for control in the controller 28, the CPU 80 as the data processing unit described above is a main control unit that performs overall control of each part of the apparatus via the bus 78, and the operator inputs a command. Instruction input means 82 having switches mounted on the controller 28, a memory 84 for temporarily storing image data and the like, a memory 85 for storing calibration data described later, and each micro of each DMD 36 A DMD controller 86 as a mirror drive control unit for controlling the mirror 46, a camera movement controller 88 for driving and controlling a drive source (stepping motor or the like) for moving each alignment camera 26, and the workpiece 12 are mounted. A negative pressure supply source for generating a negative pressure in the groove on the upper surface of the stage 14, and the stage 14 For exposure processing control for controlling various devices such as a stage drive controller 90 for driving and controlling a driving device for moving in the inspection direction and the illumination device 38 required for exposure processing by the exposure device 10 The controller 92 is connected.

  When performing the exposure process with this control electric system, the operator operates the instruction input means 82 of the controller 28 to input an instruction such as image data to be subjected to the exposure process, for example. The CPU 80 to which the image data has been transmitted temporarily stores the image data in the memory 84, and in response to an instruction to start exposure processing, the CPU 80 causes the DMD controller 86 to perform image forming processing based on the image data read from the memory 84. In addition, the stage driving controller 90 and the exposure processing control controller 92 control the driving device, the illumination device 38, and the like to perform exposure processing.

  Then, in the exposure apparatus 10 according to the present embodiment, as shown in FIGS. 1 and 2, on the downstream side in the alignment measurement direction (upstream side in the exposure direction) in the moving direction of the stage 14 (arrow Y direction) Detection means for detecting the above-mentioned positional deviation by detecting the irradiated beam position and the amount of light is arranged, and this detection means is attached to the downstream edge of the stage 14 in the alignment measurement direction. A reference scale 70 and a photosensor 72 movably mounted on the back side of the reference scale 70 are provided.

  The reference scale 70 is formed of a rectangular glass plate, and a beam position detection unit 70A is provided on the downstream side of the stage 14 in the alignment measurement direction, and a camera position detection unit 70B is provided on the upstream side (see FIG. 8).

  The beam position detection unit 70A has a plurality of detection slits 74 formed in a transparent portion (translucent portion) with a “<” shape that opens in the X direction by patterning with a metal film such as chrome plating. They are arranged at predetermined intervals along the direction.

  As shown in FIG. 9A, the “<”-shaped detection slit has a linear first slit portion 74 a having a predetermined length located on the upstream side in the stage moving direction and a downstream side in the stage moving direction. A linear second slit portion 74b having a predetermined length and positioned is connected to each other at a right angle. That is, the first slit portion 74a and the second slit portion 74b are orthogonal to each other, and the first slit portion 74a has an angle of 135 degrees and the second slit portion 74b has an angle of 45 degrees with respect to the Y axis. .

  In addition, although the 1st slit part 74a and the 2nd slit part 74b in the slit 74 for a detection showed what formed the angle of 45 degree | times with respect to the moving direction of the stage 14, these 1st slit parts were illustrated. If the 74a and the second slit portion 74b can be inclined with respect to the pixel arrangement of the exposure head 30 and at the same time inclined with respect to the stage moving direction (a state in which they are not parallel to each other), the stage moving direction You may set the angle with respect to arbitrarily. Further, a diffraction grating may be used instead of the detection slit 74.

  Below the detection slit 74 in the beam position detector 70A, a photosensor 72 (CCD, CMOS, photodetector, etc.) for detecting light from the exposure head 30 and a moving device 76 for moving the photosensor 72 are provided. Has been placed. The moving device 76 moves the photosensor along the X direction by a conveying means such as a linear motor feeding mechanism, a screw feeding mechanism, or a conveying belt mechanism that is driven and controlled by a command from the controller 28, and stops it at each predetermined position. Here, based on a command from the controller 28, the photosensor 72 is moved to a predetermined position directly below each detection slit 74 in the beam position detection unit 70A and stopped.

  On the other hand, in the camera position detection unit 70B, as shown in FIG. 8, the detection mark 77A formed in a circular shape and the detection mark 77B formed in a cross shape are patterned in the X direction by patterning with a metal film such as chrome plating. Are arranged alternately at predetermined intervals. That is, the detection mark 77B functions as a reference pattern for detecting the position of the alignment camera 26.

  As shown in FIGS. 11A to 11D, the width dimension of the detection mark 77A: MA and the width dimension of the detection mark 77B: MB are equal (MA = MB), and the arrangement pitch of the detection marks 77A, 77B: P1 is set to a value obtained by subtracting ½ of the width dimension of the detection marks 77A and 77B from the length dimension L in the X direction of the field of view (imaging field of view) V of the alignment camera 26 (P1 = L -(MA / 2) = L- (MB / 2)). Here, the unit of movement U1 of the alignment camera 26 in the X direction is set to ½ of the width dimension of the detection marks 77A and 77B (U1 = MA / 2 = MB / 2).

  In the present embodiment, as shown in FIG. 12, the calibration member 200 is placed before placing the workpiece 12 on the workpiece placement surface 14 a of the stage 14. The calibration member 200 is formed with one or more patterns, and this pattern specifies two line segments having a predetermined angle relationship with each other. In the example of FIG. 12, it has a pattern (first to third marks 202A to 202C) in which three circular marks whose relative positional relationships are known are arranged, and the calibration member 200 is a workpiece placement surface. Assuming the case of ideal placement on 14a, circular marks 202A to 202C are formed at three corners of the four corners of the calibration member 200, and two of the marks (first and second marks) are formed. The first line segment 204A along the direction (X direction) orthogonal to the step movement direction is specified by the marks 202A and 202B), and the stage is moved by the two marks (first and third marks 202A and 202C). A second line segment 204B along the direction (Y direction) is specified. Accordingly, the angle formed by the two line segments 204A and 204B is a right angle in this example. The calibration member 200 can be formed of a rectangular glass plate in the same manner as the reference scale 70 described above.

  Here, before describing the calibration method according to the present embodiment, the adjustment method using the reference scale 70 described above will be described.

  First, an adjustment method in the beam position detection unit 70A formed on the reference scale 70 will be described with reference to FIGS. 9A, 9B, and 10. FIG.

  Here, a procedure for detecting a position of a beam irradiated from each exposure head of the scanner 24 and specifying an actual position when one specific pixel Z1 of the DMD 36 is turned on (when one specific pixel is turned on) is detected. explain. Note that this method, which is performed by specifying the actual position where the specific pixel Z1 is lit and detecting the amount of light of the lit specific pixel Z1, confirms the appropriate state of the specific pixel Z1, confirms the initial conditions, etc. Can also be used.

  First, when the operator operates the instruction input means 82 of the controller 28 to input an instruction for specifying an actual position where one specific pixel Z1 is lit, the CPU 80 that has received this instruction moves the stage 14. Then, a predetermined detection slit 74 for a predetermined exposure head 30 of the reference scale 70 is positioned below the scanner 24.

  Next, the CPU 80 outputs a control signal to the DMD controller 86 and the exposure processing control controller 92 to control only a specific pixel Z1 in a predetermined DMD 36 to be in a lighting state. Further, the CPU 80 outputs a control signal to the stage drive controller 90 to control the movement of the stage 14, and as shown by a solid line in FIG. 9A, the detection slit 74 should be a predetermined position on the exposure area 32 (for example, the origin). Position). At this time, the CPU 80 recognizes the intersection of the first slit portion 74 a and the second slit portion 74 b as (X0, Y0) and stores it in the memory 84. In FIG. 9A, the direction that rotates counterclockwise from the Y-axis is a positive angle.

  Next, as shown in FIG. 9A, the CPU 80 outputs a control signal to the stage drive controller 90 to control the movement of the stage 14, thereby moving the detection slit 74 to the right in FIG. 9A along the Y axis. Start moving. Then, the CPU 80 detects that the detection slit 74 is at the position indicated by the imaginary line to the right of the predetermined position, and as shown in FIG. 9B, the light from the lit specific pixel Z1 passes through the first slit portion 74a. When it is detected by the photosensor 72, a control signal is output to the stage drive controller 90 to stop the stage 14. The CPU 80 recognizes the intersection of the first slit portion 74a and the second slit portion 74b at this time as (X0, Y11) and stores it in the memory 84.

  Next, the CPU 80 outputs a control signal to the stage drive controller 90 to move the stage 14, and starts to move the detection slit 74 to the left in FIG. 9A along the Y axis. Then, the CPU 80 detects that the detection slit 74 is at the position indicated by the imaginary line on the left of the predetermined position, and the light from the specific pixel Z1 that is lit passes through the second slit portion 74b as shown in FIG. 9B. When it is detected by the photosensor 72, a control signal is output to the stage drive controller 90 to stop the stage 14. The CPU 80 recognizes the intersection of the first slit portion 74a and the second slit portion 74b at this time as (X0, Y12) and stores it in the memory 84.

  Next, the CPU 80 reads the coordinates (X0, Y11) and (X0, Y12) stored in the memory 84 to obtain the coordinates of the specific pixel Z1, and specifies the actual position. Here, if the coordinates of the specific pixel Z1 are (X1, Y1), X1 = X0 + (Y11−Y12) / 2 and Y1 = (Y11 + Y12) / 2.

  As described above, when the detection sensor 74 having the second slit part 74b intersecting with the first slit part 74a and the photosensor 72 are used in combination, the photosensor 72 has the first slit part 74a. Or only the light of the predetermined range which passes the 2nd slit part 74b is detected. Therefore, the photo sensor 72 can use a commercially available inexpensive one without having a fine and special configuration for detecting the light amount in a narrow range corresponding to the first slit portion 74a or the second slit portion 74b.

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

  In exposure apparatus 10 according to the present embodiment having the alignment function described above, as described above, alignment camera 26 undergoes posture change (rolling, pitching, and yawing) as it moves and is photographed in a state where it is disposed at the photographing position. Since the center of the optical axis of the lens may deviate from the normal position, even if the exposure position is corrected using the alignment function and image exposure is performed, the exposure position deviates from the proper position and exceeds the allowable range. May end up.

  In order to calibrate the alignment function that is affected by the optical axis deviation caused by the change in the orientation of the alignment camera 26, the alignment function is calibrated by the calibration method described below at the time of manufacturing or maintenance of the exposure apparatus 10. To implement.

  As a procedure for this calibration work, the alignment 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 workpiece 12 or can be performed at the same time when the workpiece 12 is exposed. Further, the calibration of the alignment camera 26 and the acquisition of the positional relationship between the exposure reference and the camera optical axis center can be performed continuously or individually. Here, the case where they are performed continuously will be described.

  Regarding the calibration of the alignment camera, first, the operator inputs the position data of the alignment mark 13 of the workpiece 12 to the controller 28 in step S1 shown in FIG. By inputting this position data, the coordinates of the alignment mark 13 are acquired.

  Subsequently, when the operator performs an input operation for starting calibration from the instruction input means 82 of the controller 28, the calibration operation of the exposure apparatus 10 is started. In step S2, the camera movement controller 88 of the controller 28 is input as described above. The drive source of the alignment camera 26 is controlled based on the position data, and each alignment camera 26 is moved to a predetermined photographing position where the alignment mark 13 of the work 12 is photographed. At this time, the position of each alignment 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 alignment camera 26 is placed at the photographing position of the alignment mark 13, the stage 14 moves from the upstream side to the downstream side in the alignment measurement direction along the guide 20 in step S 3, and the camera position detection unit of the reference scale 70. 70B is moved to a position where it is arranged below each alignment camera 26 (within the visual field).

  When the camera position detection unit 70B of the reference scale 70 is disposed within the field of view of each alignment camera 26, each alignment camera 26 is controlled by the controller 28 to photograph the camera position detection unit 70B. At this time, each alignment camera 26 photographs at least one of the plurality of detection marks 77A and 77B arranged in the camera position detection unit 70B.

  Next, on the stage S4, the controller 28 measures the amount of displacement of the detected detection marks 77A and 77B from the center of the visual field (optical axis center) by image processing or the like. Here, whether the captured detection mark is the detection mark 77A or 77B is switched using image processing such as pattern matching.

  Here, which of the plurality of detection marks 77A and 77B that have been photographed is specified by the above pulse, the absolute position data of each of the detection marks 77A and 77B is as follows. It is measured in advance 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, and the reference scale 70 and the optical axis of each alignment camera 26 are calculated. Acquires positional deviation data from the center. From the measurement and calculation results, calibration data for correcting the deviation of the optical axis center of each alignment camera 26 at the position where the alignment mark 13 is photographed (alignment measurement position) is obtained. (See FIG. 7). Then, the calibration operation of the alignment camera 26 is finished, and then the operation proceeds to an operation for obtaining the positional relationship between the exposure reference and the camera optical axis center.

  When this operation is started, the driving device is controlled by the controller 28 in step S101 shown in FIG. 13, and the stage 14 causes the beam position detector 70A of the reference scale 70 to be irradiated with the laser beam irradiation position (exposure). To position). Next, in step S102, a laser beam is irradiated from the exposure head 30 toward the beam position detection unit 70A of the reference scale 70, and the position of the exposure reference point is measured by the beam position detection operation described above (step S103).

  Here, the beam position detector 70A and the camera position detector 70B are provided on the same reference scale 70, and their positional relationship is measured in advance by another measuring means. Thereby, the positional relationship between the exposure reference and the detection marks 77A and 77B photographed 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 alignment camera 26 acquired by the camera configuration operation, the exposure reference and the camera optical axis center are calculated. Exposure reference-camera optical axis center position data (correction data) indicating the positional relationship is obtained, and this data is stored in the memory 85 of the controller (step S104). 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.

  Next, a calibration method according to the present embodiment, particularly, an alignment camera position method (first calibration method) using the calibration member 200 will be described with reference to FIGS. 12 and 15 to 19.

  First, in step S201 in FIG. 15, the calibration member 200 is placed on the workpiece placement surface 14a of the stage 14 (see FIG. 12). At this time, ideally, as shown in FIG. 12, the first and second marks 202A and 202B are along the step movement direction, and the first and third marks 202A and 202C are perpendicular to the step movement direction. The calibration member 200 is placed along the line.

  Thereafter, in step S202, the operator operates the instruction input means 82 of the controller 28 to input a command for moving the stage 14 in one direction, so that the CPU 80 moves the stage 14 in one direction. In moving the stage 14, the reference pattern (camera position detection unit 70B) of the reference scale 70 first enters the field of view of the alignment camera 26, and then the pattern of the calibration member 200 enters. Yes. Accordingly, in the next step 203, the above-described exposure alignment process (see steps S1 to S5 in FIG. 13) is performed. The calibration data acquired by the exposure alignment process is the one in which the alignment unit 100 is ideally attached and the arrangement direction of the first and second alignment cameras 26A and 26B is perpendicular to the stage moving direction. It is assumed that you are doing. However, the alignment unit 100 or the like may slightly shift with respect to the direction orthogonal to the stage moving direction due to changes with time or ambient temperature. Therefore, the following processing is performed.

  That is, in step S204, when the first mark 202A enters the field of view of the first alignment camera 26A, the CPU 80 obtains the coordinates (first coordinates m1) of the first marks 202A and performs the second alignment. When the second mark 202B enters the field of view of the camera 26B, the CPU 80 obtains the coordinates (second coordinates m2) of the second mark 202B. For example, as shown in FIG. 16, when the alignment unit 100 is displaced with time and the position of the first alignment camera 26A is closer to the calibration member 200 than the second alignment camera 26B, the first to first The coordinates m1 to m3 of the third marks 202A to 202C are recognized as being shifted corresponding to the positional shifts of the first and second alignment cameras 26A and 26B. In FIG. 16, the first and second alignment cameras 26 </ b> A and 26 </ b> B are illustrated with emphasis so that the positional deviation can be seen. That is, one line segment (first line segment 204A) specified by the first coordinate m1 and the second coordinate m2 does not coincide with the direction (X direction) orthogonal to the stage moving direction, and a certain angle is set. It has a positional relationship. This angle is equal to an angle formed by a line segment (reference line segment 206) connecting the camera optical axes of the first and second alignment cameras 26A and 26B and the X direction.

  These first and second coordinates m1 and m2 are a pattern matching process for the image data of the first and second marks 202A and 202B formed on the calibration member 200, and an alignment camera corresponding to each of the marks 202A and 202B. It can be calculated based on the moving distance of the stage 14 when entering the visual field of 26A and 26B and the distance between the first mark 202A and the second mark 202B. These first and second coordinates m1 and m2 are stored in the memory 85.

  Thereafter, in step S205, when the stage 14 is further moved in one direction so that the third mark 202C enters the field of view of the first alignment camera 26A, the CPU 80 determines the coordinates of the third mark ( A third coordinate m3) is obtained. As in the above, the third coordinate m3 is the pattern matching for the imaging data of the third mark 202C formed on the calibration member 200, and the third mark 202C is within the field of view of the first alignment camera 26A. It can be calculated based on the moving distance of the stage 14 at the stage of entering and the separation distance between the first mark 202A and the third mark 202C. The third coordinate m3 is stored in the memory 85.

  Thereafter, in step S206, the apparent misalignment between the two alignment cameras 26A and 26B is calculated. This calculation is obtained by an angle (first angle θ1) formed by the first line segment 204A specified by the first coordinate m1 and the second coordinate m2 and the direction orthogonal to the stage moving direction. it can. Here, as shown in FIG. 17, when the direction perpendicular to the stage moving direction is the x-axis direction of the xy coordinate system and only a real number region of 0 or more is considered, the first line segment 204A is in the first quadrant. In this case, + θ1 is set, and in the fourth quadrant, −θ1 is set. If the calibration member 200 is ideally placed, the first angle θ1 is obtained as the actual positional deviation between the two alignment cameras 26A and 26B. However, every time calibration is performed, the calibration member 200 is ideally placed (the angle formed by the second line segment 204B specified by the first coordinate m1 and the third coordinate m2 and the stage moving direction is 0). It is difficult to set the angle (°), and it is placed with a certain degree of inclination.

  Therefore, in the next step S207, the displacement of the calibration member 200 is calculated. This calculation can be obtained from an angle (second angle θ2) formed by the second line segment 204B specified by the first coordinate m1 and the third coordinate m2 and the stage moving direction. Here, as shown in FIG. 18, when the stage moving direction is the y-axis direction of the xy coordinate system and only the real number region of 0 or less is considered, if the second line segment 204B is in the fourth quadrant, + θ2 is set. When in the third quadrant, −θ2.

Thereafter, in step S208, the actual positional deviation (adjustment angle φ) of the alignment cameras 26A and 26B is calculated. This positional deviation (adjustment angle φ) is, as described above, a line segment (reference line segment 206) connecting the camera optical axes of the first and second alignment cameras 26A and 26B and a direction orthogonal to the stage moving direction. In this case, it is also a positional shift of the alignment unit 100. This operation is
Position shift (adjustment angle φ) = (first angle ± θ1) − (second angle ± θ2)
Can be obtained.

  As shown in FIG. 19, when the direction orthogonal to the stage moving direction is the x-axis direction of the xy coordinate system and only a real number region of 0 or more is considered, the adjustment angle + φ is the first and second reference lines The minute is shifted by φ toward the first quadrant, and the adjustment angle −φ indicates that the reference line segment is shifted by φ toward the fourth quadrant.

  Thereafter, in step S209, it is determined whether or not the adjustment angle φ has deviated from the allowable range. Examples of the allowable range include ± 2 (seconds). If the adjustment angle φ deviates from the allowable range, the process proceeds to the next step S210, and the calibration data acquired by the above-described exposure alignment process (see step S1 to step S5 in FIG. 13) is added to the calibration data. The adjustment angle φ obtained in step S208 is reflected.

  That is, by reflecting the calibration data and the adjustment angle φ, the alignment cameras 26A and 26B are pseudo-installed at correct positions (positions where the reference line segment 206 in FIG. 16 coincides with the direction perpendicular to the stage moving direction). Thus, the workpiece 12 can be exposed with high accuracy in the subsequent exposure processing described below.

  When it is determined in step S209 that the adjustment angle φ is within the allowable range, or when the processing in step S210 is completed, the first calibration method ends.

  Next, another calibration method according to the present embodiment, in particular, a calibration method (second calibration method) of the reference scale 70 using the calibration member 200 will be described with reference to FIG.

  First, the processing from step S301 to step S309 in FIG. 20 is the same as the processing from step S201 to step S209 of the first calibration method shown in FIG.

  In the next step S309, if it is determined that the adjustment angle φ is out of the allowable range, the process proceeds to the next step S310, and the operator adjusts the reference scale by the adjustment angle φ obtained in step S308. Calibrate 70 slope. That is, the reference scale 70 is tilted in a direction that cancels the adjustment angle φ and is installed again. Thereafter, in step S311, the operator operates the instruction input means 82 of the controller 28 to input a command for returning the stage 14 to the original position, so that the CPU 80 moves and returns the stage 14 to the original position. Then, it returns to step S302 and repeats the process after this step S302.

  In step S309, when it is determined that the adjustment angle φ is within the allowable range, the second calibration method ends.

  In the above-described example, the example in which the alignment cameras 26 </ b> A and 26 </ b> B are moved along the pair of guide rails 104 of the alignment unit 100 has been shown. However, the alignment cameras 26 </ b> A and 26 </ b> B are along the pair of guide rails 104. For example, the present invention can be easily applied to the case of moving in a direction orthogonal to the extending direction of the guide rail 104 or in other directions.

  Next, the exposure process with respect to the workpiece | work 12 by the exposure apparatus 10 comprised as mentioned above is demonstrated.

  First, when image data corresponding to the exposure pattern is input to the controller 28, it is temporarily stored in the memory 84 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 workpiece 12 is set on the workpiece placement surface 14 a of the stage 14, and the operator performs an exposure start input operation from the instruction input means 82 of the controller 28.

  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 14 that sucks the workpiece 12 on the upper surface is along the guide 20 and upstream in the alignment measurement direction. Starts moving at a constant speed from the downstream to the downstream. Each alignment camera 26 is controlled and operated by the controller 28 in synchronization with the start of the movement of the stage 14 or at a timing just before the tip of the workpiece 12 reaches just below each alignment camera 26.

  When the workpiece 12 passes under the alignment camera 26 as the stage 14 moves, alignment measurement by the alignment camera 26 is performed.

  In this alignment measurement, first, when the two alignment marks 13 provided near the corner on the downstream side (front end side) in the movement direction of the workpiece 12 reach directly below each alignment camera 26 (on the optical axis of the lens), Each alignment camera 26 captures the alignment mark 13 at a predetermined timing, and the captured image data, that is, image data including the reference position data in which the reference of the exposure position is indicated by the alignment mark 13 is the data of the controller 28. It outputs to CPU80 which is a processing part. After the alignment mark 13 is photographed, the stage 14 resumes moving downstream.

  Further, when a plurality of alignment marks 13 are provided along the movement direction (scanning direction) as in the workpiece 12 of the present embodiment, the next alignment mark 13 (upstream side in the movement direction (rear end side) When the two alignment marks 13) provided near the corners of () reach just below each alignment camera 26, each alignment camera 26 similarly shoots the alignment mark 13 at a predetermined timing and takes the image data. The data is output to the CPU 80 of the controller 28.

  Similarly, when the workpiece 12 is provided with three or more alignment marks 13 along the moving direction, each time the alignment marks 13 pass below the alignment camera 26, the alignment camera 26 is detected at a predetermined timing. The alignment mark 13 is repeatedly photographed, and the photographed image data is output to the CPU 80 of the controller 28 for all the alignment marks 13.

  The CPU 80 determines the mark position and inter-mark pitch in the image determined from the input image data (reference position data) of each alignment mark 13, the position of the stage 14 when the alignment mark 13 is photographed, and the alignment camera 26. From this position, the displacement of the mounting position of the work 12 on the stage 14, the deviation of the inclination of the work 12 with respect to the moving direction, the dimensional accuracy error of the work 12, etc. are ascertained from the position of An appropriate exposure position is calculated. Then, at the time of image exposure by the scanner 24 described later, correction control (alignment) is performed in which a control signal created based on the image data of the exposure pattern stored in the memory 84 is adjusted to the appropriate exposure position to perform image exposure. To do.

  When the workpiece 12 passes under the alignment camera 26, the alignment measurement by the alignment camera 26 is completed, and then the stage 14 is driven in the reverse direction by the driving device and moves along the guide 20 in the exposure direction. Then, the workpiece 12 moves below the scanner 24 to the downstream side in the exposure direction as the stage 14 moves, and when the image exposure area on the exposed surface reaches the exposure start position, each exposure head 30 of the scanner 24 emits light. Irradiation of the beam starts image exposure on the exposed surface of the workpiece 12.

  Here, the image data stored in the memory 84 of the controller 28 is sequentially read out for each of a plurality of lines, and a control signal is generated for each exposure head 30 based on the image data read out by the CPU 80 as a data processing unit. Is done. This control signal is subjected to correction of the exposure position deviation with respect to the workpiece 12 subjected to the alignment measurement by the above-described correction control (alignment). Then, the DMD controller 86 as a mirror drive control unit controls each of the DMD micromirrors 46 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 micromirror 46 of the DMD 36 is in the on state is reflected by the corresponding microlens 60 of the microlens array 54. Is formed on the exposure surface of the workpiece 12 by a lens system including In this manner, the laser light emitted from the illumination device 38 is turned on / off for each pixel, and the work 12 is exposed in a pixel unit (exposure area 32) that is approximately the same number as the number of used pixels of the DMD 36.

  Further, when the work 12 is moved at a constant speed together with the stage 14, the work 12 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) for each exposure head 30. ) Is formed.

  When the image exposure of the workpiece 12 by the scanner 24 is completed, the stage 14 is directly driven to the downstream side in the exposure direction by the driving device and returns to the origin on the most downstream side in the exposure direction (the most upstream side in the alignment measurement direction). To do. Thus, the exposure operation for the workpiece 12 by the exposure apparatus 10 is completed.

  As described above, in the first and second calibration methods according to the present embodiment, even if the position of the alignment camera 26 (the position of the alignment unit 100 or the like) is shifted, the position can be easily calibrated. it can. Further, even if the reference pattern of the reference scale 70 is shifted and installed, the shift can be easily determined, and the shift of the reference pattern 70 can be calibrated. That is, highly accurate alignment measurement can be realized.

  In the above-described calibration member 200, an example in which three circular marks 202A to 202C are formed has been shown. In addition, as shown in FIG. Two marks 202A to 202D) may be formed. In this case, as described above, the calibration process may be performed using the first to third marks 202A to 202C, but the following process may be performed.

  That is, as shown in FIG. 22, for example, the coordinate of the first mark 202A (first coordinate m1) and the coordinate of the second mark 202B (second coordinate m2) are along the direction orthogonal to the stage moving direction. A line segment (first line segment 204A) is specified. A line segment (third line segment 204C) along the direction orthogonal to the stage moving direction by the coordinates of the third mark 202C (third coordinate m3) and the coordinate of the fourth mark 202D (fourth coordinate m4). Is identified. Then, the fourth line segment 204D is specified by the midpoint coordinate n1 of the first line segment 204A and the midpoint coordinate n2 of the third line segment 204C, and further, for example, the first line segment 204A and the fourth line segment The angle formed by the minute 204D is defined as a third angle θ3. Since the third angle θ3 has a relationship of (90 ° + first angle θ1), the third angle θ3 can be easily applied to the first calibration method and the second calibration method described above. Note that the second angle θ2 (not shown) is the second specified by the first coordinate m1 and the third coordinate m3, as in the processing described in the first and second calibration methods. It can be obtained from the angle formed by the line segment 204B and the stage moving direction.

  In the above example, the first and second line segments 204A and 204B and the first line segment 204A to the fourth line segment 204D are formed only by the marks 202A to 202C and 202A to 202D formed on the calibration member 200. In addition, as shown in FIG. 23, a part 210 of the work placement surface 14a of the stage 14 provided on the part where the calibration member 200 is not placed or the stage 14 is provided. A portion 212 of the formed member may be used as one mark. In FIG. 23, the first and second marks 202A and 202B formed on the calibration member 200 and the part 210 of the member existing on the workpiece mounting surface 14a or the part 212 of the member existing on the stage 14 are described above. A case where one pattern used in the second calibration method is formed is shown.

  Moreover, although the example using two alignment cameras 26A and 26B was shown in the above-described example, one alignment camera (for example, 26A) in the alignment unit 100 is made longer by extending the movement range in the X direction. For example, the same position calibration can be performed in 26A).

  In the above-described embodiment, an example in which the present invention is applied to the digital exposure apparatus 10 has been described. However, the present invention can also be applied to an analog exposure apparatus, an inkjet apparatus, and various alignment apparatuses.

  That is, the alignment sensor position calibration method, reference pattern calibration method, exposure position correction method, calibration pattern, and alignment apparatus according to the present invention are not limited to the above-described embodiments, and do not depart from the gist of the present invention. Of course, various configurations can be adopted.

It is a perspective view which shows schematic structure of the exposure apparatus which concerns on this Embodiment. It is a perspective view which shows schematic structure of the scanner in the exposure apparatus which concerns on this Embodiment. It is a schematic block diagram which shows the optical system of the exposure head in the exposure apparatus which concerns on this Embodiment. FIG. 4A is a main part plan view showing a scanning trajectory of the exposure beam by each micromirror when the DMD is not tilted in the exposure apparatus according to the present embodiment, and FIG. 4B is a scan of the exposure beam when the DMD is tilted. It is a principal part top view which shows a locus | trajectory. It is the elements on larger scale which show the structure of DMD provided in the exposure apparatus which concerns on this Embodiment. 6A and 6B are explanatory diagrams for explaining the operation of the DMD of FIG. It is a perspective view which shows the structure of the alignment unit in the exposure apparatus which concerns on this Embodiment. It is a top view which shows the reference | standard scale installed in the exposure apparatus which concerns on this Embodiment. FIG. 9A is an explanatory diagram illustrating a state in which a specific pixel that is lit using a detection slit and a light wraparound pixel are detected in the exposure apparatus according to the present embodiment, and FIG. 9B is a specific pixel that is lit. It is explanatory drawing which shows a signal when a photo sensor detects. It is a block diagram which shows schematic structure of the electric system for control in the controller provided in the exposure apparatus which concerns on this Embodiment. FIGS. 11A to 11D are explanatory views showing the relationship between the detection mark and the field of view when the camera position detection unit in the exposure apparatus according to the present embodiment is imaged by the alignment camera. It is explanatory drawing which shows the relationship between the reference scale mounted on the workpiece | work mounting surface of the exposure apparatus which concerns on this Embodiment, the member for calibration, and an alignment camera. It is a flowchart which shows the flow of control of the camera calibration operation | movement performed with the exposure apparatus which concerns on this Embodiment. It is a flowchart which shows the flow of control of acquisition operation | movement of the positional relationship of the exposure reference | standard and camera optical axis center which are performed with the exposure apparatus which concerns on this Embodiment. It is a flowchart which shows the 1st calibration method (position calibration method of an alignment camera) which concerns on this Embodiment. It is explanatory drawing which shows the principle which calibrates the position of an alignment camera. It is explanatory drawing which shows the relationship of the 1st angle calculated | required based on the 1st line segment specified by the 1st and 2nd mark. It is explanatory drawing which shows the relationship of the 2nd angle calculated | required based on the 2nd line segment specified by the 1st and 3rd mark. It is explanatory drawing which shows the relationship of the adjustment angle calculated | required from the 1st and 2nd angle. It is a flowchart which shows the 2nd calibration method (reference pattern calibration method) which concerns on this Embodiment. It is a top view which shows the other example of arrangement | positioning of the mark formed in the member for calibration. It is explanatory drawing which shows the principle which calibrates the position of an alignment camera with the example of arrangement | positioning of FIG. It is a top view which shows the other example of the pattern for comprising the position of an alignment camera. It is a perspective view which shows schematic structure of the digital exposure apparatus which concerns on a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Exposure apparatus 12 ... Work 14 ... Stage 24 ... Scanner 26, 26A, 26B ... Alignment camera 28 ... Controller 30 ... Exposure head 70 ... Reference scale 70A ... Beam position detection part 70B ... Camera position detection part 74 ... Detection slit 84 85 ... Memory 100 ... Alignment unit 200 ... Calibration member 202A-202D ... Mark 204A-204D ... Line segment 210, 212 ... Part of member

Claims (20)

A calibration pattern detecting step for detecting a calibration pattern including one or more patterns whose relative positional relationship is known in advance by an alignment sensor;
A calibration value obtaining step for obtaining a calibration value of the alignment sensor based on the detected calibration pattern;
A position calibration method luer line placement sensor having a sensor calibration step of calibrating based on the position of the alignment sensor to the calibration value,
Further comprising a placing step of placing a member on which one or more patterns whose relative positional relationships are known in advance are formed on a workpiece placing surface of a stage that conveys the workpiece;
The calibration pattern on the member is composed of the one or more patterns formed on the member and two line segments that are defined by predetermined portions on the stage and have a predetermined angle relationship with each other. Identify
The alignment sensor position calibration method, wherein the two line segments are used to calibrate a positional shift in the alignment sensor with respect to at least a direction orthogonal to the workpiece conveyance direction . In the alignment sensor position calibration method according to claim 1,
The alignment sensor position further comprising a determination step of determining whether or not the acquired calibration value is within an allowable range, and performing the sensor calibration step when the calibration value is not within the allowable range. Calibration method. In the alignment sensor position calibration method according to claim 1 ,
The alignment sensor position calibration method, wherein the predetermined angle is a right angle. In the alignment sensor position calibration method according to any one of claims 1 to 3 ,
A correction step of detecting a reference pattern on a reference scale placed on the workpiece placement surface with at least one alignment sensor and correcting the position of the alignment sensor in terms of data based on imaging data of the reference pattern; Have
In the calibration pattern detecting step, the calibration pattern is detected by the alignment sensor corrected in terms of data. In the alignment sensor position calibration method according to claim 4 ,
In the sensor calibration step, the position of the alignment sensor corrected in terms of data is further corrected in terms of data by the calibration value. In the alignment sensor position calibration method according to any one of claims 1 to 5 ,
The angle formed by the conveyance direction of the workpiece and one of the two line segments in the detected calibration pattern is a first angle,
When the angle formed between the direction perpendicular to the conveyance direction of the workpiece and the other line segment of the two line segments in the detected calibration pattern is the second angle,
The alignment sensor position calibration method, wherein the calibration value is determined based on a relative angle between the first angle and the second angle. At least one alignment sensor detects a reference pattern on a reference scale placed on the workpiece placement surface of the stage that conveys the workpiece, and the position of the alignment sensor is corrected in terms of data based on imaging data of the reference pattern. A correction step to
A calibration pattern detection step of detecting a calibration pattern including one or more patterns whose relative positional relationship is known in advance by the corrected alignment sensor;
A calibration value obtaining step for obtaining a calibration value of the reference pattern based on at least the detected calibration pattern;
And a reference scale re-installation step for re-installing the reference scale by inclining the calibration value by the calibration value. The reference pattern calibration method according to claim 7 , wherein
The reference pattern further comprising: a determination step of determining whether or not the acquired calibration value is within an allowable range, and performing the reference scale resetting step when the calibration value is not within the allowable range. Calibration method. The reference pattern calibration method according to claim 7 or 8 ,
A reference pattern calibrating method, further comprising a placing step of placing the member on which one or more patterns whose relative positional relations are known in advance are placed on a workpiece placing surface of a stage that conveys the workpiece. . The reference pattern calibration method according to claim 9 , wherein
The calibration pattern is composed of the one or more patterns formed on the member, and specifies two line segments having a predetermined angle relationship with each other,
2. The reference pattern calibration method according to claim 2, wherein the two line segments are used to calibrate a positional shift in the alignment sensor at least in a direction orthogonal to a conveyance direction of the workpiece. The reference pattern calibration method according to claim 9 , wherein
The calibration pattern on the member is composed of the one or more patterns formed on the member and two line segments that are defined by predetermined portions on the stage and have a predetermined angle relationship with each other. Identify
2. The reference pattern calibration method according to claim 2, wherein the two line segments are used to calibrate a positional shift in the alignment sensor at least in a direction orthogonal to a conveyance direction of the workpiece. The reference pattern calibration method according to claim 10 or 11 ,
The reference pattern calibration method, wherein the predetermined angle is a right angle. In the reference pattern calibration method according to any one of claims 9 to 12 ,
A correction step of detecting a reference pattern on a reference scale placed on the workpiece placement surface with at least one alignment sensor and correcting the position of the alignment sensor in terms of data based on imaging data of the reference pattern; Have
In the calibration pattern detection step, the calibration pattern is detected by the alignment sensor corrected in terms of data. In the reference pattern calibration method according to any one of claims 10 to 13 ,
The angle formed by the conveyance direction of the workpiece and one of the two line segments in the detected calibration pattern is a first angle,
When the angle formed between the direction perpendicular to the conveyance direction of the workpiece and the other line segment of the two line segments in the detected calibration pattern is the second angle,
The reference pattern calibration method, wherein the calibration value is determined based on a relative angle between the first angle and the second angle. In an exposure position correction method for correcting an exposure position on a workpiece based on a relative positional relationship between a reference pattern on a reference scale installed on a workpiece placement surface of a stage that conveys the workpiece and an alignment mark formed on the workpiece. ,
Calibrating the reference pattern using the reference pattern calibration method according to any one of claims 7 to 14 ,
An exposure position correction method, comprising: correcting an exposure position on the workpiece based on a relative positional relationship between the calibrated reference pattern and the alignment mark formed on the workpiece. In the alignment apparatus for calibrating the displacement of the alignment sensor with respect to the work placement surface of the stage on which the work is conveyed,
Calibration pattern detection means for detecting a calibration pattern including one or more patterns whose relative positional relationship is known in advance by the alignment sensor;
Calibration value acquisition means for obtaining a calibration value of the alignment sensor based on the detected calibration pattern;
Sensor calibration means for calibrating the alignment sensor based on the calibration value ;
And a member on which the one or more patterns on which the relative positional relationship is known have been formed are placed on the workpiece placement surface,
The calibration pattern on the member is composed of the one or more patterns formed on the member and two line segments that are defined by predetermined portions on the stage and have a predetermined angle relationship with each other. Identify
The two line segments, the alignment device according to claim is used Rukoto to calibrate the positional deviation with respect to a direction perpendicular to the conveying direction of at least the work of the alignment sensor. The alignment apparatus according to claim 16 , wherein
It further comprises: a determination unit that determines whether or not the acquired calibration value is within an allowable range, and when the calibration value is not within the allowable range, shifts control to processing in the sensor calibration unit. Alignment device. The alignment apparatus according to claim 16 or 17 ,
Correction means for detecting a reference pattern on a reference scale placed on the workpiece placement surface by at least one alignment sensor and correcting the position of the alignment sensor in terms of data based on imaging data of the reference pattern; Have
The alignment apparatus according to claim 1, wherein the calibration pattern detection means detects the calibration pattern with the alignment sensor corrected in terms of data. The alignment apparatus according to claim 18 , wherein
The alignment apparatus characterized in that the sensor calibration means further corrects the position of the alignment sensor corrected in terms of data by the calibration value. In the alignment apparatus of any one of Claims 16-19 ,
The angle formed by the conveyance direction of the workpiece and one of the two line segments in the detected calibration pattern is a first angle,
When the angle formed between the direction perpendicular to the conveyance direction of the workpiece and the other line segment of the two line segments in the detected calibration pattern is the second angle,
The alignment apparatus, wherein the calibration value is determined based on a relative angle between the first angle and the second angle.

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