JP2006227345A - Method and apparatus for detecting pixel light beam defect - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately detect a defect in a pixel light beam in an apparatus for detecting a pixel light beam defect. <P>SOLUTION: Minute optical modulation elements M as a part in a large number of minute optical modulation elements M are successively selected by a selecting unit 210 from a spatial optical modulator 36 of an exposure apparatus 10; only the group Mg of selected minute optical modulation elements is wholly turned on by a modulation state controlling unit 220; the whole light quantity of the pixel light beams passing the group Mg of turned-on minute optical modulation elements is detected by a light quantity detecting unit 230; the light quantity is compared with a preliminarily obtained reference light quantity by a comparing unit; and if the detected light quantity is less than the reference light quantity, presence of a defect in the pixel light beams L passing the group Mg of minute optical modulation elements is judged by a judging unit. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  In the present invention, light emitted from a light source is subjected to spatial light modulation by a spatial light modulator formed by arranging a large number of minute light modulation elements to form an image on a photosensitive material, and an image pattern is exposed on the photosensitive material. The present invention relates to a pixel light beam defect detection method and apparatus applied to an exposure apparatus.

  Conventionally, a pixel light beam formed in accordance with the light modulation state of each of a large number of micro light modulation elements arranged in a spatial light modulator is imaged on a photosensitive material laminated on the surface of the substrate. An exposure apparatus that exposes an image pattern on a photosensitive material to create a printed wiring board or the like is known. In an exposure apparatus using such a spatial light modulator, an image pattern obtained by spatial light modulation of laser light can be directly formed (projected) on a photosensitive material, so that a light shielding mask or the like is not prepared. A printed circuit board can be created. As the spatial light modulator, a semiconductor manufacturing process is used to arrange a large number of micro mirrors that are the micro light modulation elements on a semiconductor substrate such as silicon, and each micro light modulator is arranged according to a control signal input from the outside. A DMD (digital micromirror device) in which the angle of the reflecting surface of the mirror is changed can be used.

  In the exposure apparatus as described above, each of the pixel light beams formed in accordance with the light modulation state of each minute light modulation element is imaged through the first imaging optical system. In the vicinity of the imaging position of each pixel light beam formed through the image optical system, each pixel light beam is individually passed through each of the arranged microlenses, and further, each of the microlenses is individually provided. A method of forming an image pattern on a photosensitive material by forming an image pattern on the photosensitive material through a second imaging optical system is known (see Patent Document 1). .

In the exposure apparatus, the light modulation states of all the micromirrors constituting the spatial light modulator are set so that the light amounts of the pixel light beams corresponding to the micromirrors are maximized, and the pixel light beams There is also known a method of measuring the total amount of light and inspecting whether or not the light amount is equal to or greater than a preset reference light amount, that is, whether or not the light amount used for exposure of the photosensitive material is sufficient. .
JP 2004-001244 A

  By the way, when dust adheres to the micromirror or microlens, the amount of light of the pixel light beam that passes through the micromirror or microlens to which dust has adhered is attenuated, and the light modulation state of the micromirror and the pixel that forms an image on the photosensitive material An error occurs in the correspondence relationship with the light amount of the light beam, and the light amount of each pixel light beam does not reach the desired light amount, so that the quality of the image pattern exposed to the photosensitive material is deteriorated. For this reason, there is a demand for detecting the presence of defects generated in the pixel light beam formed by the exposure apparatus.

  On the other hand, a method for inspecting whether or not the amount of light used for exposure of the photosensitive material is sufficient is applied, and a value obtained by measuring the entire amount of light of the pixel light beam is compared with a reference light amount. Thus, a method of detecting the presence of a defect in the pixel light beam can be considered. However, in such a method, the ratio of the light amount of the pixel light beam that attenuates due to dust adhering to one minute mirror with respect to the light amount of the entire pixel light beam, which is the reference light amount, becomes very small. There is a problem that the detection sensitivity of the defect becomes low.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a pixel light beam defect detection method and apparatus capable of more accurately detecting a defect of a pixel light beam.

  In the pixel light beam defect detection method of the present invention, light emitted from a light source is spatially light-modulated by a spatial light modulator formed by arranging a large number of minute light modulation elements to form an image on a photosensitive material. Further, the presence of defects in the pixel light beam formed by the exposure apparatus, which is applied to an exposure apparatus that exposes an image pattern by a pixel light beam formed according to the light modulation state of each micro light modulation element. A pixel light beam defect detecting method for detecting a plurality of minute light modulation elements in the plurality of minute light modulation elements sequentially from a spatial light modulator, and only the selected minute light modulation elements are selected. All are turned on, the total light quantity of the pixel light beam that has passed through the selected and turned on light-modulating element group is detected, the light quantity is compared with a reference light quantity acquired in advance, and the detected light quantity is No reference light intensity When it is, it is characterized in determining that the defect is present in the pixel light beam in passing through the micro-optical modulation element group.

The pixel light beam defect detection apparatus of the present invention forms an image on a photosensitive material by spatially modulating light emitted from a light source by a spatial light modulator formed by arranging a large number of minute light modulation elements. Further, the present invention is applied to an exposure apparatus that exposes an image pattern by a pixel light beam formed according to the light modulation state of each minute light modulation element, and detects the presence of a defect in the pixel light beam formed by the exposure apparatus. A pixel light beam defect detection device for selecting, from a spatial light modulator, a selection means for sequentially selecting a part of a plurality of minute light modulation elements, and only the selected minute light modulation element Detected by a light amount detection means, a light amount detection means for detecting the total light amount of the pixel light beam that has passed through the selected small light modulation element group, and a light amount detection means. A comparison means for comparing the amount with a reference light amount acquired in advance, and when the detected light amount is less than the reference light amount, it is determined that a defect exists in the pixel light beam that has passed through the minute light modulation element group, and the determination result And a judging means for outputting.

  The modulation state control means can continuously turn on the micro light modulation element groups sequentially selected by the selection means.

  The minute light modulation element group may be composed of a plurality of the minute light modulation elements or may be composed of one minute light modulation element.

  The spatial light modulator may be formed by arranging a large number of minute light modulation elements in a two-dimensional manner.

  Turning on the minute light modulation element is not limited to the case where the minute light modulation element is brought into a light modulation state that maximizes the amount of light of the pixel light beam that has passed through the minute light modulation element. Even when the light modulation state is set so as not to maximize the light amount of the beam, the light modulation state in which a pixel light beam having a light amount capable of detecting the presence of the defect is formed on the minute light modulation element. You can make it.

  According to the pixel light beam defect detection method and apparatus of the present invention, a part of minute light modulation elements among a number of minute light modulation elements are sequentially selected from the spatial light modulator, and the selected minute light modulation element is selected. All the light amounts of the pixel light beams that have passed through the micro light modulation element group selected and turned on are compared, and the total light amount is compared with a reference light amount acquired in advance. When the amount of light is less than the reference amount of light, it is determined that there is a defect in the pixel light beam that has passed through the group of minute light modulation elements. Compared to the case where all of them are turned on and the presence of a defect in the pixel light beam is determined, the reference light amount can be set smaller, and the light amount of the pixel light beam attenuated by the presence of the defect with respect to the reference light amount Larger proportion of It can be, that is, it is possible to increase the detection sensitivity of the defect, it is possible to detect the defective pixel light beam more accurately. Furthermore, the pixel light beam having the defect passes through any one of the minute light modulation elements in the minute light modulation element group that is turned on when it is determined that the defect exists. The optical path through which the light beam passes can be specified in a narrower range, and the position of the optical element having a defect can be narrowed down to a narrower range from the optical path of the pixel light beam specified in the narrow range.

  If the minute light modulation element group selected by the selection means is composed of one minute light modulation element, the ratio of the light amount of the pixel light beam attenuated by the presence of the defect to the reference light amount can be further increased. Therefore, the defect of the pixel light beam can be detected more accurately. Further, since the pixel light beam having the defect passes through one minute light modulation element that is turned on when it is determined that the defect exists, the position of the pixel light beam having the defect is specified. Furthermore, the position of the optical element having a defect can be narrowed down to a narrower range from the position of the specified pixel light beam.

  As described above, since the detection sensitivity of the presence of defects generated in the pixel light beam can be increased as the number of micro light modulation elements to be selected is reduced, the number of micro light modulation elements to be selected is as follows. , And can be determined according to the sensitivity required for detecting the presence of a defect generated in the pixel light beam.

  An embodiment relating to a pixel light beam defect detection apparatus of the present invention will be described. FIG. 1 is a diagram illustrating a schematic configuration of a pixel light beam defect detection apparatus and an exposure apparatus according to an embodiment of the present invention, and FIG. 2 is a perspective view illustrating a schematic configuration of the pixel light beam defect detection apparatus and the exposure apparatus as a whole. 3 is a perspective view showing how an exposure head accommodated in an exposure unit exposes a photosensitive material, FIG. 4 is an enlarged perspective view showing a configuration of a DMD, and FIG. 5 is a perspective view showing an operation of a micromirror. 6A is a plan view showing the trajectory of the pixel light beam when the DMD is not tilted, FIG. 6B is a plan view showing the trajectory of the pixel light beam when the DMD is tilted, and FIG. FIG. 8 is an enlarged cross-sectional view of the light receiving unit of the light amount detecting unit, and FIG. 9 is a diagram illustrating a state in which the pixel light beam emitted from the exposure head is detected.

[Configuration of pixel light beam defect detection device]
The pixel light beam defect detection device 200 according to the above embodiment detects the presence of a defect in the pixel light beam L formed by the exposure device 10.

  As shown in the figure, the exposure apparatus 10 is a spatial light modulator in which a large number of micromirrors M, which are micro light modulation elements, are arranged in a two-dimensional manner for light emitted from a light source 38 and emitted through an optical fiber 40. Spatial light modulation is performed by a certain DMD (digital micromirror device) 36, and a pixel light beam L corresponding to each micromirror M formed according to the light modulation state of each micromirror M is coupled onto the photosensitive material 12. An image pattern, for example, a wiring pattern is exposed on the photosensitive material 12. Details of the exposure apparatus 10 will be described later.

  The pixel light beam defect detection apparatus 200 sequentially selects, from the DMD 36, a selection unit 210 that selects some of the micromirrors M from among the micromirrors M, and a micromirror group that is the selected microlight modulation element group. Detected by the modulation state control unit 220 that turns on only Mg, the light amount detection unit 230 that detects the total light amount of the pixel light beam L that has passed through the minute mirror group Mg that is turned on, and the light amount detection unit 230 When the light quantity detected by the light quantity detection unit 230 is less than the reference light quantity in the selection of either the comparison unit 240 that compares the obtained light quantity with the reference light quantity acquired in advance or the micro mirror group Mg that is sequentially performed, It is determined that there is a defect in the pixel light beam L that has passed through the minute mirror group Mg, and a determination unit 250 that outputs the determination result and the synchronization and timing of the above-described units are controlled. And a detector controller 260 Recessed.

[Configuration of exposure apparatus]
Details of the exposure apparatus 10 according to the above embodiment will be described below.

  As shown in the figure, the exposure apparatus 10 is configured in a so-called flatbed type, and includes a flat stage 14 that holds a photosensitive material 12 that is an exposed member to be exposed by suction onto the surface. . Two guides 20 extending along the stage moving direction are installed on the upper surface of the thick plate-shaped installation base 18 supported by the four legs 16. The stage 14 is arranged so that the longitudinal direction thereof faces the stage moving direction, and is supported by the guide 20 so as to be reciprocally movable. The exposure apparatus 10 is provided with a drive device (not shown) for driving the stage 14 along the guide 20.

  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. Each of the end portions of the gate 22 is fixed to both side surfaces of the installation base 18. An exposure unit 24 is provided on one side of the gate 22 and a plurality of (for example, two) detection sensors 26 for detecting the front and rear ends of the photosensitive material 12 are provided on the other side. . The exposure unit 24 and the detection sensor 26 are respectively attached to the gate 22 and fixedly arranged above the moving path of the stage 14. The exposure unit 24 and the detection sensor 26 are connected to an exposure apparatus controller 28 that controls the synchronization and timing of each part of the exposure apparatus 10.

  In the exposure unit 24, as shown in FIG. 2, a plurality of (for example, eight) exposure heads 30A, 30B,... Arranged in a substantially matrix of i rows and j columns (for example, 2 rows and 4 columns). (Hereinafter, these are collectively referred to as exposure head 30) are installed.

  As shown in FIG. 3, exposure areas 32A, 32... By exposure heads 30A, 30B... (Hereinafter collectively referred to as exposure area 32) are, for example, the transport direction (the direction of arrow Y in the figure). ) In a rectangular shape having a long side. In this case, strip-shaped exposed areas 34A, 34B... (Hereinafter collectively referred to as exposed areas 34) are formed in the photosensitive material 12 for each exposure head 30 in accordance with the exposure operation. .

  Further, the exposure heads 30 in each row arranged so that the strip-shaped exposed regions 34 are arranged in the orthogonal direction (arrow X direction in the drawing) orthogonal to the transport direction without a gap are arranged at predetermined intervals in the column direction. The exposure area is shifted by a natural number times the long side). That is, for example, a portion that cannot be exposed between the exposure area 32A by the exposure head 30A and the exposure area 32B by the exposure head 30B can be the exposure area 32F by the exposure head 30F.

  As shown in FIG. 1, each exposure head 30 includes a digital micromirror device (DMD) as a spatial light modulator that spatially modulates a light beam emitted from a light source 38 and emitted through an optical fiber 40. 36. The DMD 36 is connected to the exposure apparatus controller 28 including an image data processing unit and a mirror drive control unit.

  The image data processing unit of the exposure apparatus controller 28 generates a control signal for driving and controlling the micromirrors to be controlled by the DMD 36 for each exposure head 30 based on the input image data. 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 image data processing unit.

  As shown in FIG. 2, bundle-shaped optical fibers 40 respectively drawn from the light sources 38 are disposed on the light incident side of the DMD 36 disposed in each exposure head 30. The light source 38 may be composed of an ultraviolet lamp (UV lamp), a xenon lamp or the like that can be used as a general light source.

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

  Further, as shown in FIG. 1, a mirror 42 that reflects the light emitted from the bundle optical fiber 40 toward the DMD 36 is disposed on the light incident side of the DMD 36 of each exposure head 30.

  As shown in FIG. 4, the DMD 36 has a rectangular shape in which a large number of micromirrors M arranged in a two-dimensional manner are supported and arranged on a SRAM cell (memory cell) 44 by columns not shown. The mirror device is configured by arranging a large number (for example, 600 × 800) of micromirrors M constituting a pixel (pixel) in a grid pattern. A micromirror M supported by a support column is provided at the top of each pixel, and a material having high reflectance such as aluminum is deposited on the surface of the micromirror M.

  Directly below the micromirror M, the above-described SRAM cell 44 of a silicon gate CMOS manufactured on a normal semiconductor memory manufacturing line is disposed via a post including a hinge and a yoke (not shown), and the whole is monolithic. (Integrated type).

  When a digital signal is written to the SRAM cell 44 of the DMD 36, the micromirror M supported by the support is tilted in a range of ± α degrees (for example, ± 10 degrees) with respect to the substrate side on which the DMD 36 is disposed with the diagonal line as the center. It is done. FIG. 5A shows a state where the micromirror M is tilted to + α degrees when the micromirror M is in the on state, and FIG. 5B shows a state where the micromirror M is tilted to −α degrees when the micromirror M is in the off state. Therefore, by controlling the inclination of the micromirror M in each pixel of the DMD 36 according to the image signal as described above, the light incident on the DMD 36 is reflected in a direction corresponding to the inclination of each micromirror M. It is done.

  FIG. 4 shows an example of a state in which a part of the DMD 36 is enlarged and the micromirror M is controlled to + α degrees or −α degrees. The on / off control of each micromirror M is performed by the exposure apparatus controller 28 connected to the DMD 36. For example, the light reflected by the micromirror M in the on state is the light emission side of the DMD 36. The photosensitive material 12 is exposed by being imaged through an imaging optical system 59 (see FIG. 1), which will be described later. The light reflected by the micro mirror M in the off state is incident on and absorbed by a light absorber (not shown) and does not expose the photosensitive material 12.

  Further, the DMD 36 is arranged with a slight inclination so that the long side direction of the rectangular shape forms a predetermined angle θ (for example, 0.1 ° to 0.5 °) with the transport direction (the arrow Y direction in the drawing). It is preferable to do this. FIG. 6A shows a trajectory (hereinafter referred to as a transport trajectory) on the photosensitive material 12 by the above-described transport of the pixel light beam L formed by being reflected by each micromirror when the DMD 36 is not tilted. B) shows the transport locus of the pixel light beam L when the DMD 36 is tilted.

  As described above, by tilting the DMD 36, the pitch P2 of the transport line indicated by the transport trajectory of the pixel light beam L that has passed through each micromirror M (see FIG. 6B) is transported when the DMD 36 is not tilted. It can be made narrower than the line pitch Pl (see FIG. 6A), and the resolution of the image pattern exposed on the photosensitive material 12 can be greatly improved. On the other hand, since the tilt angle of the DMD 36 is very small, the transport width W2 when the DMD 36 is tilted and the transport radiation W1 when the DMD 36 is not tilted are substantially the same.

  Moreover, it can also arrange | position so that the substantially same position (dot) on the same conveyance line may be accumulated and exposed (multiple exposure) by a different micro mirror row | line | column. In such a case, the same region on the photosensitive material is subjected to multiple exposure, exposure can be controlled with higher resolution, and high-definition exposure can be realized. In addition, such high-resolution exposure can make the connection between the exposure heads inconspicuous.

  Next, the imaging optical system 59 provided on the light exit side of the DMD 36 of the exposure head 30 will be described. As shown in FIG. 1, the imaging optical system 59 sequentially forms a lens system 50 along an optical path from the DMD 36 side to the photosensitive material 12 side in order to form an image of a light source on the photosensitive material 12. , 52, a microlens array 54, and objective lens systems 56, 58 are arranged.

  Here, the lens systems 50 and 52 are configured as magnifying optical systems, and the area of the exposure area 32 on the photosensitive material 12 exposed by the pixel light beam reflected by the DMD 36 is enlarged to a required size. Yes.

  As shown in FIG. 1, the microlens array 54 is formed by integrally forming a plurality of microlenses 60 corresponding to the micromirrors M of the DMD 36 on a one-to-one basis. The pixel light beams 50 and 52 are arranged so as to pass therethrough.

  The entire microlens array 54 is formed in a rectangular flat plate shape, and apertures 62 (shown in FIG. 1) are integrally disposed in the portions where the microlenses 60 are formed. The aperture 62 forms an aperture stop that is disposed in one-to-one correspondence with each microlens 60.

  The objective lens systems 56 and 58 are configured as, for example, an equal magnification optical system. The photosensitive material 12 is disposed at a position where the pixel light beam L is imaged through the objective lens systems 56 and 58. The lens systems 50 and 52 and the objective lens systems 56 and 58 in the imaging optical system 59 are shown as one lens in FIG. 1, but a plurality of lenses (for example, a convex lens and a concave lens) are used. It may be a combination.

  With the exposure head 30 configured as described above, the light emitted from the light source 38 can be imaged on the surface of the photosensitive material 12 to form an image pattern.

[Configuration related to both exposure apparatus and pixel light beam defect detection apparatus]
As shown in FIG. 7, the light quantity detection unit 230 constituting the pixel light beam defect detection apparatus 200 is mounted on the stage 14 of the exposure apparatus 10. The light amount detection unit 230 includes a light receiving unit 72 and a feeding mechanism 74 that moves the light receiving unit 72 in an orthogonal direction (X direction in the drawing) orthogonal to the transport direction (Y direction in the drawing). By the conveyance in the conveyance direction of the stage 14 and the conveyance in the orthogonal direction by the feeding mechanism 74, the light amount detection unit 230 can be positioned in the conveyance direction and the orthogonal direction with respect to the exposure head 30, and the positioning is performed by a defect detection controller. This is performed by controlling the stage 14 and the feed mechanism 74 by 260. That is, the defect detection controller 260 controls the stage 14 via the exposure apparatus controller 28.

  As shown in FIGS. 8 and 9, the light receiving unit 72 includes a condensing lens 82 disposed in the optical path of the pixel light beam L incident through the opening 78 of the housing 76 of the light receiving unit 72, and the condensing lens 82. It has a light receiving element 86 that receives and photoelectrically converts the focused pixel light beam L.

  The feed mechanism 74 shown in FIG. 7 is arranged on the stage 14 so as to protrude from both ends in the orthogonal direction (X direction in the figure) at the end of the stage 14 where exposure is performed at the end. A pair of guide rails 88 and 90 and a feed shaft 92 are installed between the support plates 94 and 96 disposed.

  The feed shaft 92 can be constituted by, for example, a screw feed mechanism. When the screw shaft is rotationally controlled by a feed motor 98, the feed shaft 92 is moved along the screw shaft screwed into the screw shaft. The light receiving part 72 to which the screw component is fixed is configured to be fed by a required feed amount in the orthogonal direction. The feed shaft 92 may be composed of other generally used precision feed mechanisms.

  The feed shaft 92 operates under the control of the defect detection controller 260.

  Further, the pixel light beam defect detection apparatus 200 controls the DMD 36 by a signal from the mirror drive control unit of the exposure apparatus controller 28 in the exposure apparatus 10 and the modulation state control unit 220 of the pixel light beam defect detection apparatus 200. A changeover switch unit 270 that switches between when the DMD 36 is controlled by a signal is provided.

[Operation of pixel light beam defect detector]
Next, the operation of the pixel light beam defect detection apparatus 200 that detects the presence of defects in the pixel light beam L formed by the exposure apparatus 10 will be described.

  First, the case where the minute mirror group Mg constituting the minute light modulation element group is composed of one minute mirror will be described with reference to FIG. 10 showing the minute mirror group composed of one minute mirror.

<When a group of micromirrors consists of one micromirror>
Under the control of the defect detection controller 260, the stage 14 of the exposure apparatus 10 is moved in the transport direction (Y direction in the figure), the light receiving part 72 is sent in the orthogonal direction (X direction in the figure), and the light receiving part 72 is exposed. The pixel light beam L emitted from the head 30A is positioned at a location where it can be detected.

  Here, the defect detection controller 260 controls the changeover switch unit 270, and the pixel light beam defect detection apparatus 200 from the state in which the DMD 36 is controlled by the mirror drive control unit of the exposure apparatus controller 28 by the changeover switch unit 270. The modulation state control unit 220 switches to a state in which the DMD 36 is controlled. The operation of each unit described below is executed under the control of the defect detection controller 260.

  Next, the selection unit 210 sequentially selects some of the micromirrors M from the DMD 36 of the exposure head 30A. Here, as shown in FIG. 10, one micromirror M is selected sequentially. That is, the selection unit 210 sequentially selects a micro mirror group Mg (1), a micro mirror group Mg (2),..., A micro mirror group Mg (e) each consisting of one micro mirror.

  When the selection unit 210 selects the micro mirror group Mg (1), the information is input to the modulation state control unit 220, and the modulation state control unit 220 turns on only the micro mirror group Mg (1).

  The light amount detection unit 230 detects the total light amount of the pixel light beam L (1) that is reflected by the micro mirror group Mg (1) that is turned on and passes through the imaging optical system 59. That is, the pixel light beam L (1) emitted from the micromirror group Mg (1) turned on in the DMD 36 is condensed by the condenser lens 82 and received by the light receiving element 86, and the amount of light is detected.

  The comparison unit 240 compares the light amount detected by the light amount detection unit 230 with a reference light amount acquired in advance by performing an experiment or the like. The comparison unit 240 stores the reference light amount in advance.

  The determination unit 250 determines that there is a defect in the pixel light beam L (1) that has passed through the minute mirror group Mg (1) when the light amount detected by the light amount detection unit 230 is less than a reference light amount. The determination result is output.

  The determination result may not only indicate the presence of a defect, but may also indicate the position of the micromirror group Mg or the position of the pixel light beam L where a defect corresponding to the micromirror group Mg exists.

  Pixel light beams L (1) and L (2) that pass through the micro mirror groups Mg (1), Mg (2), Mg (3),... Mg (e) sequentially selected by the selector 210. , L (3),... L (e) When it is not determined that a defect exists, no signal is output from the determination unit 250, and the pixel light beam of the exposure head 30A is output. The operation of detecting the presence of a defect related to L is terminated.

  When it is determined that there is a defect in the pixel light beam L that has passed through one of the micromirror groups Mg, the pixel light beam defect detection device 200 detects the presence of a defect in the pixel light beam L thereafter. The operation may be terminated. On the other hand, for all the micromirror groups Mg, by determining whether or not there is a defect in the pixel light beam L that has passed through these micromirror groups Mg, The operation of the pixel light beam defect detection apparatus 200 may be continued so as to specify all positions.

  Next, the defect detection controller 260 can detect the pixel light beam L emitted from the exposure head 30B by controlling the movement of the stage 14 and the feed mechanism 74 in the same manner as described above. Locate in place. Then, similarly to the above, an operation for detecting the presence of a defect in the pixel light beam L emitted from the exposure head 30B is executed.

  As described above, the pixel light beam defect detection apparatus 200 moves the light receiving unit 72 to a position where the pixel light beam L emitted from each of the exposure heads 30A, 30B. The same operation as described above for detecting the presence of a defect in the pixel light beam L is performed for each of 30B.

  When the operation for detecting the presence of the defect of the pixel light beam L is completed for all the exposure heads 30, the defect detection controller 260 controls the changeover switch unit 270, and the changeover switch unit 270 detects the pixel light beam defect. The state where the DMD 36 is controlled by the modulation state control unit 220 of the apparatus 200 is switched to the state where the DMD 36 is controlled by the mirror drive control unit of the exposure apparatus controller 28.

  Next, the case where the minute mirror group Mg, which is the minute light modulation element group, is composed of a plurality of minute mirrors will be described with reference to FIG. 11 showing the minute mirror group composed of a plurality of minute mirrors.

<When a group of micromirrors is composed of a plurality of micromirrors>
Similarly to the above, the defect detection controller 260 positions the light receiving unit 72 at a position where the pixel light beam L emitted from the exposure head 30A can be detected, and the changeover switch unit 270 controls the modulation state control unit 220. To switch to a state in which the DMD 36 is controlled.

  Next, the selection unit 210 sequentially selects some of the micromirrors M from the DMD 36 of the exposure head 30A. Here, as shown in FIG. 11, the selection unit 210 sequentially, a micromirror group Mg (1, 1) composed of a plurality of (for example, nine rows and three columns) micromirrors M, micromirrors. Group Mg (1,2) Micromirror group Mg (2,1)... Micromirror group Mg (n, m) is selected.

When the selection unit 210 selects the micro mirror group Mg (1, 1), the information is input to the modulation state control unit 220, and the modulation state control unit 220 turns on only the micro mirror group Mg (1, 1). Let me.

  The light amount detection unit 230 detects the total light amount of the pixel light beam L (1, 1) reflected by the micro mirror group Mg (1, 1) that has been turned on and passed through the imaging optical system 59.

The comparison unit 240 compares the light amount detected by the light amount detection unit 230 with a reference light amount.

  When the light amount detected by the light amount detection unit 230 is less than the reference light amount, the determination unit 250 has a defect in the pixel light beam L (1, 1) that has passed through the minute mirror group Mg (1, 1). It is determined that it exists, and the determination result is output.

  The determination result may not only indicate the presence of a defect, but may also indicate the position of the micromirror group Mg or the position of the pixel light beam L where a defect corresponding to the micromirror group Mg exists.

  Pixel light beams L () that pass through each of the micromirror groups Mg (1,1), Mg (1,2), Mg (2,1)... Mg (n, m) sequentially selected by the selector 210. 1, 1), L (1,2), L (2,1)... L (n, m), it is determined that there is no defect. The operation of detecting the presence of a defect in the pixel light beam L of the exposure head 30A by the pixel light beam defect detection apparatus 200 is terminated.

  As described above, the pixel light beam defect detection apparatus 200 moves the light receiving unit 72 to a position where the pixel light beam L emitted from each of the exposure heads 30A, 30B. The same operation as described above for detecting the presence of a defect in the pixel light beam L is performed for each of 30B.

  When the operation of detecting the presence of a defect in the pixel light beam L is completed for all the exposure heads 30, the defect detection controller 260 controls the changeover switch unit 270, and the changeover switch unit 270 detects the pixel light beam defect. The state where the DMD 36 is controlled by the modulation state control unit 220 of the apparatus 200 is switched to the state where the DMD 36 is controlled by the mirror drive control unit of the exposure apparatus controller 28.

  The modulation state control unit 220 is reflected by the minute mirror group Mg and is reflected by the minute mirror group Mg and the state where the light amount of the pixel light beam L passing through the imaging optical system 59 is maximized (the above-described on state). The present invention is not limited to the case of taking a binary value in a state where the pixel light beam L is not formed without passing through the imaging optical system 59 (off state). The on state of the micro mirror group Mg is the same as described above even when it takes an intermediate value between the state where the light amount of the pixel light beam L is maximum and the state where the pixel light beam L is not formed. In addition, the defect of the pixel light beam L can be detected.

[Various Modes of Operation for Detecting Defect in Pixel Light Beam]
The micro mirror groups sequentially selected by the selection unit 210 are not limited to being intermittently turned on, but may be continuously turned on. Hereinafter, a case where the modulation state control unit 220 intermittently turns on the micromirror group sequentially selected by the selection unit 210 and a case where the micromirror group is continuously turned on are compared.

12 (a-1) and 12 (a-2) show a case where the micromirror group is intermittently turned on. FIGS. 12 (b-1) and 12 (b-2) show that the micromirror group is continuously on. 12 (a-1) and 12 (b-1) are diagrams illustrating a case where the micromirror groups Mg (1), Mg (2), Mg (3), and Mg (4) are turned on. 12 (a-2) and (b-2) are the timing charts shown in FIGS. 12 (a-2) and 12 (b-2). The mirror groups Mg (1) to Mg (1) to Mg sequentially detected by the light quantity detection unit 230 on the coordinates where the vertical axis represents the light quantity E and the horizontal axis represents time t. It is a figure which shows the light quantity of the pixel light beam L which passed through (4).

  As shown in FIGS. 12A-1 and 12A-2, when the micromirror group is intermittently turned on, the light quantity of the pixel light beam L detected by the light quantity detection unit 230 is determined by each micromirror. The increment and decrement are repeated each time the group is turned on. Here, since the light quantity of the pixel light beam L (3) that has passed through the minute mirror group Mg (3) is less than the reference light quantity Ke, it is determined that there is a defect in the pixel light beam L (3).

  On the other hand, when the micromirror group is continuously turned on and the detection time is shortened by the time δ, as shown in FIGS. The amount of light of the pixel light beam L detected at 230 becomes substantially constant without repeatedly increasing and decreasing each time each micromirror group is turned on. Further, it is possible to detect that the light amount of the pixel light beam L (3) that has passed through the minute mirror group Mg (3) is less than the reference light amount Ke, and to determine that there is a defect in the pixel light beam L (3). Can do. In this way, the time required to detect the presence of a defect in the pixel light beam L that has passed through one minute mirror group Mg can be shortened, and the entire operation for detecting the defect in the pixel light beam L can be performed. Can be shortened.

  Further, every time the exposure apparatus 10 carries the table 14 once in one direction and performs exposure, one or a plurality of micro mirror groups Mg in the DMD 30 are related to defects in the pixel light beam L passing through the micro mirror groups Mg. The presence may be inspected, and the operation of detecting the defect of the pixel light beam L may be executed little by little.

  Furthermore, the micromirror group Mg may be a combination of the micromirror M located at the center of the DMD 30 and the micromirror M located at the periphery. In this way, the difference in the amount of light (shading effect) between the central portion and the peripheral portion can be canceled out, and the total light amount of the pixel light beam L passing through the minute mirror group Mg can be reduced to any minute mirror group Mg. Even in the case of selection, it can be set to a constant value accurately.

  Different micromirror groups Mg may include the same micromirror M as a part thereof, that is, the micromirror group Mg may overlap with other micromirror groups Mg. . That is, the operation of detecting the defect of the pixel light beam L may be performed while shifting the phase at which the micromirror is turned on.

  Further, the defect detection method in the case where the micromirror group is composed of a plurality of micromirrors and the defect detection method in the case where the micromirror group is composed of one micromirror may be combined. . That is, after grasping the approximate position of the pixel light beam having a defect by detecting the micro mirror group composed of a plurality of micro mirrors, each micro mirror in the micro mirror group when the pixel light beam having the defect is detected is detected. On the other hand, detection may be performed on a group of micromirrors including a single micromirror so that the exact position of a defective pixel light beam may be grasped.

[Operation of exposure apparatus]
Next, the operation of exposing the image pattern onto the photosensitive material 12 by the exposure apparatus 10 will be described.

  Although not shown, the light source 38 collimates a laser beam such as ultraviolet light emitted from each of the laser light emitting elements in a divergent light state with a collimator lens and condenses it with a condenser lens. The light is incident on the incident end face, multiplexed in the optical fiber, and incident on the optical fiber 40 coupled to the output end of the optical fiber.

  In the exposure apparatus 10, image data corresponding to the image pattern is input to an exposure apparatus controller 28 connected to the DMD 36 and temporarily stored in a memory in the exposure apparatus controller 28. This image data is data representing the density of each pixel constituting the image pattern in binary (whether or not dots are recorded).

  The stage 14 having the photosensitive material 12 adsorbed on the surface thereof is moved at a constant speed along the guide 20 from the upstream side to the downstream side in the transport direction by a driving device (not shown). When the leading edge of the photosensitive material 12 is detected by the detection sensor 26 attached to the gate 22 as the stage 14 passes under the gate 22, the image data stored in the memory is sequentially read out for a plurality of lines. Based on the image data read by the image data processing unit, a control signal for controlling the minute mirror M is generated for each exposure head 30.

  Then, each mirror of the DMD 36 is controlled to be turned on / off for each exposure head 30 based on a control signal in which the shading adjustment for uniformizing the light amount distribution and the adjustment of the exposure amount are performed by the mirror drive control unit of the exposure apparatus controller 28. The

  When the light beam emitted from the optical fiber 40 and reflected by the mirror 42 is irradiated to the DMD 36, the laser light reflected when the micromirror of the DMD 36 is in the on state is reflected by the corresponding microlens 60 of the microlens array 54. An image is formed on the exposure surface of the photosensitive material 12 through a lens system including In this way, the pixel light beam L emitted from the DMD 36 is turned on / off for each micromirror, and the photosensitive material 12 is exposed in pixel units (exposure areas) that are approximately the same number of pixels as the DMD 36.

  In addition, by moving the photosensitive material 12 together with the stage 14 at a constant speed, the photosensitive material 12 is relatively moved in the direction opposite to the stage moving direction by the exposure unit 24, and a strip-shaped exposure has been completed for each exposure head 30. A region 34 is formed, and an image pattern is exposed on the photosensitive material 12.

  That is, the image pattern is formed on the photosensitive material 12 by irradiating the photosensitive material 12 with the pixel light beam L generated by performing modulation corresponding to the image pattern to be exposed and formed by the DMD 36.

  When exposure of the photosensitive material 12 by the exposure unit 24 is completed and the rear end of the photosensitive material 12 is detected by the detection sensor 26, the stage 14 is moved to the most upstream side in the transport direction along the guide 20 by a driving device (not shown). It is returned to a certain origin, and again moved along the guide 20 from the upstream side in the transport direction to the downstream side at a constant speed.

  In the exposure apparatus 10 according to the present embodiment, a DMD is used as a spatial light modulator used in the exposure head 30. For example, a spatial light modulator (SLM) (SLM) is used. Reflective diffraction grating type grating light valve element (GLV element, manufactured by Silicon Light Machine Co., Ltd., for details of the GLV element, see US Pat. No. 5,311,360). Spaces other than MEMS types, such as optical elements (PLZT elements) that modulate transmitted light by the electro-optic effect, or transmissive spatial light modulators such as liquid crystal light shutters (FLC), etc. An optical modulator can be used in place of the DMD.

  Note that MEMS is a general term for a micro system that integrates micro-sized sensors, actuators, and control circuits based on a micro-machining technology based on an IC manufacturing process. A MEMS-type spatial light modulator is an electrostatic force. It means a spatial light modulator driven by electromechanical operation using

  Next, another embodiment of the light quantity detection unit will be described with reference to FIGS. FIG. 13 is a perspective view showing an essential part of the light quantity detection unit. FIG. 14 is a block diagram showing another configuration of the light quantity detection unit.

  As shown in FIG. 14, the light amount detection unit 100 is installed in the vicinity of the imaging position of the pixel light beam L that faces the exit end from which the pixel light beam L is emitted from the exposure head 30 provided in the exposure unit 24.

  The exposure unit 24 is provided with a plurality of exposure heads 30 arranged in parallel in an orthogonal direction (X direction in the drawing) orthogonal to the transport direction (Y direction in the drawing), that is, in the width direction of the stage 14. Since the extending pixel light beam L is emitted, the light amount detection unit 100 is provided extending in the width direction corresponding to the extending direction of the pixel light beam L.

  The light quantity detection unit 100 has a beam incident surface 102 facing the emission end of the pixel light beam L in the exposure head 30 and extending in the extending direction of the pixel light beam L, and a beam incident surface on which the pixel light beam L is incident. A light guide sheet member 106 having a beam emitting surface 104 for emitting a pixel light beam L in which the shape of the beam 102 is deformed from the middle and the width of the extending direction of the beam incident surface 102 is formed narrow is provided.

  The conductive sheet member 106 is a member that causes the pixel light beam L emitted from the exposure head to enter from the beam incident surface 102 and emits the pixel light beam L from the beam emission surface 104. The light guide sheet member 106 divides the portion following the linear beam incident surface 102 into three portions from the middle and overlaps to form the beam emission surface 104, and receives the width on the beam emission surface 104 side. This is configured to match the shape of the light receiving surface of the portion 110.

  Further, the light quantity detection unit 100 is provided with a condensing optical system 108 so as to face the beam emitting surface 104, and the light receiving surface of the light receiving unit 110 is positioned at the condensing position of the condensing optical system 108. The unit 110 is disposed. The light receiving unit 110 is formed of a known light detection sensor that detects the amount of light received by the light receiving surface, such as a PD (photodiode) or a photomulti-flyer.

  The light amount detection unit 100 is provided with an amplifier 112 that amplifies a signal indicating the light amount of the pixel light beam L detected by the light receiving unit 110, and a signal output from the amplifier 112 is input to the comparison unit 240. .

  As described above, the light amount detection unit 100 detects the light amount of the pixel light beam L emitted from each exposure head 30 without including the feed mechanism 74 included in the light amount detection unit 230 described above. Can do. Other operations in the light amount detection unit 100 are the same as those of the light amount detection unit 230.

  The pixel light beam defect detection apparatus and the exposure apparatus of the present invention are not limited to the above-described embodiments, and it is needless to say that various other configurations can be employed without departing from the gist of the present invention. is there.

The figure which shows schematic structure of the optical system of the pixel light beam defect detection apparatus and exposure apparatus which concern on embodiment of this invention The perspective view which shows schematic structure of the pixel light beam defect detection apparatus and the exposure apparatus whole The perspective view which shows a mode that the exposure head accommodated in the exposure unit exposes a photosensitive material The perspective view which expands and shows the structure of DMD Perspective view showing operation of micromirror (A) is a plan view showing the transport locus of the pixel light beam when the DMD is not tilted, and (B) is a plan view showing the transport locus of the pixel light beam when the DMD is tilted. Perspective view of light intensity detector Enlarged sectional view of the fluorescent part of the light quantity detection part The figure which shows the insulator which detects the pixel light beam inject | emitted from the exposure head The figure which shows the micromirror group which consists of one micromirror The figure which shows the micro mirror group which consists of plural micro mirrors The figure which shows the difference between the case where the minute mirror group is turned on intermittently and the case where it is turned on continuously A perspective view showing the main part of the light amount detection unit taken out. Block diagram showing another configuration of the light amount detection unit

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Exposure apparatus 12 Photosensitive material 36 DMD
38 light source 40 optical fiber 200 pixel light beam defect detection device 210 selection unit 220 modulation state control unit 230 light amount detection unit 240 comparison unit 250 determination unit 260 defect detection controller L pixel light beam M micro mirror Mg micro mirror group

Claims (5)

Light emitted from the light source is subjected to spatial light modulation by a spatial light modulator formed by arranging a large number of minute light modulation elements and imaged on a photosensitive material, and the light of each of the minute light modulation elements is formed on the photosensitive material. A pixel light beam defect detection method for detecting the presence of defects in the pixel light beam formed by the exposure apparatus, which is applied to an exposure apparatus that exposes an image pattern by a pixel light beam formed according to a modulation state. ,
From the spatial light modulator, sequentially select a part of the small light modulation elements among the large number of small light modulation elements,
Only the selected minute light modulation element is turned on,
Detecting the total light amount of the pixel light beam that has passed through the group of micro light modulation elements selected and turned on;
Compare the light quantity with a reference light quantity acquired in advance,
A pixel light beam defect detection method, comprising: determining that a defect exists in the pixel light beam that has passed through the minute light modulation element group when the detected light amount is less than the reference light amount. Light emitted from the light source is subjected to spatial light modulation by a spatial light modulator formed by arranging a large number of minute light modulation elements and imaged on a photosensitive material, and the light of each of the minute light modulation elements is formed on the photosensitive material. A pixel light beam defect detection apparatus for detecting the presence of defects in the pixel light beam formed by the exposure apparatus, which is applied to an exposure apparatus that exposes an image pattern by a pixel light beam formed according to a modulation state. ,
Selecting means for selecting, from the spatial light modulator, a part of the minute light modulation elements in the number of minute light modulation elements in order;
Modulation state control means for turning on only all of the selected minute light modulation elements;
A light amount detecting means for detecting the total light amount of the pixel light beam that has passed through the micro light modulation element group selected and turned on;
Comparison means for comparing the light quantity detected by the light quantity detection means with a reference light quantity acquired in advance;
And determining means for determining that a defect exists in the pixel light beam that has passed through the minute light modulation element group and outputting the determination result when the detected light amount is less than the reference light amount. A pixel light beam defect detection device. The pixel light beam defect detection apparatus, wherein the modulation state control means continuously turns on the minute light modulation element groups sequentially selected by the selection means. The pixel light beam defect detection apparatus, wherein the minute light modulation element group is composed of a plurality of the minute light modulation elements. The pixel light beam defect detection apparatus, wherein the minute light modulation element group is composed of one minute light modulation element.

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