JP2008064833A - Exposure device, exposure method, and method for manufacturing panel substrate for display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent misalignment of an exposure position due to the change of a mask position while preventing decrease in the accuracy of gap control in exposure by a proximity XY-step system. <P>SOLUTION: A mask holder 20 is vertically moved and tilted to control a gap between a mask 2 and a substrate 1. A detection device 50 including a camera unit 59 is vertically moved by a moving mechanism 60 to adjust the focus of the camera unit 59 onto the surface of the mask 2 and to acquire an image of a position detection mark provided to the surface of the mask 2 by using the camera unit 59. An image signal output from the camera unit 59 is processed to detect the change in the position of the mask 2, and the position of the substrate 1 upon exposure is corrected according to the detection results about the change in the position of the mask 2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an exposure apparatus that performs exposure of a substrate, an exposure method, and a method of manufacturing a display panel substrate using the same in manufacturing a display panel substrate such as a liquid crystal display device.

  Manufacturing of TFT (Thin Film Transistor) substrates, color filter substrates, plasma display panel substrates, organic EL (Electroluminescence) display panel substrates, etc. for liquid crystal display devices used as display panels is performed using an exposure apparatus, and photolithography. This is performed by forming a pattern on the substrate by a technique. As an exposure apparatus, a projection method in which a mask pattern is projected onto a substrate using a lens or a mirror, and a minute gap (proximity gap) is provided between the mask and the substrate to transfer the mask pattern to the substrate. There is a proximity method. The proximity method is inferior in pattern resolution performance to the projection method, but the configuration of the irradiation optical system is simple, the processing capability is high, and it is suitable for mass production.

  The proximity exposure apparatus includes a chuck that holds the substrate by vacuum suction, and the chuck is mounted on a stage that moves and positions the substrate. Conventionally, the stage is composed of a three-axis stage of X, Y, and θ and a Z-tilt mechanism. The triaxial stage moves and positions the substrate by moving the chuck in the X and Y directions or rotating in the θ direction. The Z-tilt mechanism controls the gap between the mask and the substrate by supporting the chuck at three points, moving each point up and down, and moving and tilting the chuck in the Z direction.

On the other hand, Patent Document 1 discloses an exposure apparatus that controls the gap between a mask and a substrate by moving and tilting a mask holder that holds the mask up and down.
JP 2004-233398 A

  In recent years, in the manufacture of various substrates for display panels, a relatively large substrate is prepared in order to cope with an increase in size and a variety of sizes, and one or a plurality of substrates can be selected from one substrate depending on the size of the display panel. Manufactures display panel substrates. In this case, in the proximity method, when one surface of the substrate is to be exposed at once, a mask having the same size as the substrate is required, and the cost of the expensive mask is further increased. In view of this, the mainstream method is to divide and expose one surface of a substrate into a plurality of shots while using a mask that is relatively smaller than the substrate and moving the substrate stepwise in the XY direction by a stage. Hereinafter, this method is referred to as a proximity XY step method.

  In order to improve the exposure accuracy in the proximity exposure apparatus, it is necessary to accurately control the gap between the mask and the substrate. In the conventional proximity exposure apparatus, the gap control is performed by the Z-tilt mechanism of the stage, and the centers of the three points of the Z-tilt mechanism, which is the center position of the gap control, are aligned with the center of the substrate. For this reason, when one side of the substrate is exposed in a plurality of shots by the proximity XY step method, the center position of the gap control (the center of the substrate) is shifted from the center of the gap (the center of the mask), and the accuracy of the gap control is improved. There was a problem of lowering. In particular, as the substrate size increases and the difference from the mask size increases, the gap between the gap center (mask center) and the gap control center position (substrate center) increases, and the accuracy of the gap control decreases. It becomes remarkable.

  On the other hand, when gap control is performed by moving and tilting the mask holder up and down as in Patent Document 1, the center position of the gap control always coincides with the center of the gap (mask center). Therefore, the accuracy of the gap control does not deteriorate even when one surface of the substrate is exposed in a plurality of shots by the proximity XY step method.

  In the proximity method, the distance between the mask and the substrate is brought close to about 100 to 300 μm before exposure. After the exposure, the mask and the substrate are separated from each other in order to prevent the mask and the substrate from contacting each other during the movement and alignment of the substrate. At this time, a pressure change occurs due to the viscosity of the air between the mask and the substrate, and the mask is deformed. Then, when the deformed mask returns to its original position, the mask position changes slightly. For this reason, there has been a problem that the relative position between the mask and the substrate changes, and the printing position shifts.

  Conventionally, when gap control is performed by moving and tilting the chuck up and down, a position detection mark is provided on the surface of the mask, and an image of the position detection mark is acquired to detect a change in the position of the mask. It was possible to correct the position of the substrate during exposure. However, when gap control is performed by moving and tilting the mask holder up and down as described in Patent Document 1, when the mask moves up and down, the surface of the mask moves out of focus of the image acquisition device, and the position detection mark The image cannot be acquired. For this reason, it was not possible to correct the position of the substrate during exposure by detecting a change in the position of the mask.

  SUMMARY OF THE INVENTION An object of the present invention is to prevent a printing position shift due to a change in the position of a mask while preventing a gap control accuracy from being lowered in proximity XY step system exposure. Another object of the present invention is to quickly focus the image acquisition device that acquires the image of the position detection mark provided on the surface of the mask on the surface of the mask even when the mask moves up and down. Furthermore, an object of the present invention is to manufacture a high-quality display panel substrate.

  An exposure apparatus according to the present invention is an exposure apparatus using a proximity method, in which a mask holder for holding a mask, a chuck for holding a substrate, a chuck is moved, and step movement and exposure of the substrate in the XY directions are performed. The position of the substrate is positioned, the mask holder is moved up and down and tilted to control the gap between the mask and the substrate, and the position detection mark image on the surface of the mask is acquired. An image acquisition device that outputs an image signal, a focus adjustment unit that moves the image acquisition device up and down to focus the image acquisition device on the surface of the mask, and processes the image signal output by the image acquisition device. And a processing means for detecting a change in the position of the mask and controlling the stage according to the detection result to correct the position of the substrate at the time of exposure.

  The exposure method of the present invention is an exposure method using a proximity method, wherein a position detection mark is provided on the surface of the mask, the mask is held by the mask holder, the substrate is held by the chuck, and the chuck is moved. Then, step movement of the substrate in the X and Y directions and positioning of the substrate during exposure are performed, and the mask holder is moved up and down and tilted to control the gap between the mask and the substrate, and the image acquisition device is moved up and down. The image acquisition device is focused on the mask surface, the image of the position detection mark is acquired using the image acquisition device, and the image signal output by the image acquisition device is processed to detect a change in the mask position. The position of the substrate at the time of exposure is corrected according to the detection result of the change in the position of the mask.

  Since the mask holder is moved up and down and tilted to control the gap between the mask and the substrate, the center position of the gap control always coincides with the center of the gap (mask center). Accordingly, even when one surface of the substrate is divided into a plurality of shots for exposure, the accuracy of gap control does not decrease. Then, the image acquisition device is moved up and down, the image acquisition device is focused on the mask surface, the image of the position detection mark is acquired using the image acquisition device, and the image signal output by the image acquisition device is processed. Then, a change in the position of the mask is detected, and the position of the substrate at the time of exposure is corrected in accordance with the detection result of the change in the position of the mask. Therefore, a deviation in the printing position due to a change in the position of the mask is prevented.

  Furthermore, in the exposure apparatus of the present invention, the focus adjustment means has an optical axis that is the same as the optical axis of the image acquisition apparatus, and detects the focus adjustment mark provided on the surface of the mask near the position detection mark. A detection means, a moving means for moving the image acquisition device and the optical detection means up and down, and a control means for controlling the movement means. The optical detection means focuses the light source and the light from the light source. The lens for irradiating the mark for position and the mark for position detection and collecting the reflected light, the first optical element for dividing the reflected light collected by the lens into two, and the first optical element A sensor for detecting a focus adjustment mark from one of the reflected light, the control means processes the detection signal of the sensor, and controls the moving means so that the focus of the image acquisition device is aligned with the surface of the mask, The image acquisition device is divided by the first optical element And acquires an image of the position detection marks from the other Shako.

  In the exposure method of the present invention, a focus adjustment mark is provided on the surface of the mask near the position detection mark, and an optical detection unit having the same optical axis as the optical axis of the image acquisition device is used. Light is applied to the focus adjustment mark and position detection mark, the reflected light is collected, the collected reflected light is divided into two, and the focus adjustment mark is detected from one of the divided reflected lights, and the focal point is focused. The detection signal of the adjustment mark is processed, the image acquisition device and the optical detection means are moved up and down so that the focus of the image acquisition device is on the surface of the mask, and the other of the reflected light divided by the optical detection means The image of the position detection mark is acquired using an image acquisition device.

  A focus adjustment mark is provided on the surface of the mask near the position detection mark, and reflection from the focus adjustment mark and the position detection mark is performed using an optical detection means having the same optical axis as the optical axis of the image acquisition device. The light is divided into two, the focus adjustment mark is detected from one of the divided reflected lights, and the image of the position detection mark is obtained from the other reflected light divided by the optical detection means using an image acquisition device. Therefore, a lens or the like for condensing the reflected light is shared, and the optical detection means necessary for adjusting the focus of the image acquisition device and the image acquisition device can be reduced as a whole. Accordingly, the exposure area of the mask can be widened.

  Furthermore, in the exposure apparatus of the present invention, the optical detection means has a second optical element that further divides one of the reflected lights divided by the first optical element into two, and the sensor is an image acquisition device. The first line sensor disposed at a position where one of the reflected lights divided by the second optical element forms an image when the focal point of the image is shifted by a predetermined distance from the surface of the mask, and the focal point of the image acquisition device And a second line sensor disposed at a position where the other of the reflected light divided by the second optical element forms an image when the first line is shifted downward by a predetermined distance from the surface of the mask. The sensor and the second line sensor detect a focus adjustment mark composed of a repetitive pattern, and the control means changes the intensity change rate of the detection signal of the first line sensor and the intensity change of the detection signal of the second line sensor. The proportion of To, and it controls the moving means.

  In the exposure method of the present invention, a focus adjustment mark composed of a repetitive pattern is provided on the surface of the mask near the position detection mark, and one of the divided reflected lights is further divided into two, and the first line sensor Is placed at a position where one of the divided reflected lights forms an image when the focus of the image acquisition device is shifted by a predetermined distance from the surface of the mask, and the second line sensor is placed at the focus of the image acquisition device. When shifted by a predetermined distance below the surface of the mask, the other part of the divided reflected light is placed at a position where an image is formed, the intensity change rate of the detection signal of the first line sensor and the detection of the second line sensor. The image acquisition device and the optical detection means are moved up and down so that the rate of signal intensity change is the same.

  When a focus adjustment mark composed of a repetitive pattern is detected by the line sensor, the detection signal of the line sensor repeatedly changes in intensity depending on the presence or absence of the repetitive pattern. The rate of change in the intensity of the detection signal, that is, the contrast of the reflected light changes depending on the focus of the optical detection means (the same as the focus of the image acquisition device). When the image acquisition device and the optical detection means are moved up and down, the rate of change in the intensity of the detection signal of the first line sensor becomes maximum when the focus of the image acquisition device is shifted a predetermined distance above the surface of the mask. The focus of the image acquisition device decreases as it approaches the surface of the mask. On the other hand, the intensity change rate of the detection signal of the second line sensor becomes maximum when the focus of the image acquisition device is shifted by a predetermined distance from the surface of the mask, and the focus of the image acquisition device approaches the surface of the mask. Get smaller. When the ratio of the intensity change of the detection signal of the first line sensor becomes the same as the ratio of the intensity change of the detection signal of the second line sensor, the focus of the image acquisition device is aligned with the surface of the mask. Since only the simple processing for obtaining the rate of change in the intensity of the detection signal of the line sensor is performed and there is no need to perform the processing of the image signal, the focus of the image acquisition device quickly matches the surface of the mask.

  The method for producing a display panel substrate of the present invention is to transfer the mask pattern onto the substrate using any one of the exposure apparatuses or exposure methods described above. By using the above-described exposure apparatus or exposure method, it is possible to prevent a shift in the printing position due to a change in the position of the mask while preventing a gap control accuracy from being lowered, and thus a high-quality display panel substrate is manufactured.

  According to the exposure apparatus and the exposure method of the present invention, the position detection mark is provided on the surface of the mask, the mask holder is moved up and down and tilted, the gap between the mask and the substrate is controlled, and the image acquisition device is moved up and down. Move, focus the image acquisition device on the mask surface, acquire the image of the position detection mark using the image acquisition device, process the image signal output by the image acquisition device to change the position of the mask By detecting and correcting the position of the substrate at the time of exposure according to the detection result of the change in the position of the mask, it is possible to prevent the printing position from being shifted due to the change in the position of the mask while preventing the gap control accuracy from being lowered. be able to.

  Further, according to the exposure apparatus and the exposure method of the present invention, the focus detection mark is provided on the surface of the mask near the position detection mark, and the optical detection means having the same optical axis as that of the image acquisition apparatus is used. Then, the reflected light from the focus adjustment mark and the position detection mark is divided into two, the focus adjustment mark is detected from one of the divided reflected lights, and from the other reflected light divided by the optical detection means, By acquiring the image of the position detection mark using the image acquisition device, the optical detection means necessary for focus adjustment of the image acquisition device and the image acquisition device can be reduced as a whole, so that the exposure area of the mask can be reduced. Can be taken widely.

  Furthermore, according to the exposure apparatus and the exposure method of the present invention, a focus adjustment mark comprising a repeated pattern is provided on the surface of the mask near the position detection mark, and one of the divided reflected lights is further divided into two, The first line sensor is arranged at a position where one of the divided reflected lights forms an image when the focus of the image acquisition device is shifted a predetermined distance above the surface of the mask, and the second line sensor is When the focus of the acquisition device deviates below the mask surface by a predetermined distance, it is easy to obtain the rate of change in the intensity of the detection signal of the line sensor by placing it at the position where the other of the divided reflected light forms an image. The image acquisition device can be quickly focused on the surface of the mask simply by performing processing.

  According to the manufacturing method of the display panel substrate of the present invention, it is possible to prevent the deviation of the printing position due to the change of the mask position while preventing the gap control accuracy from being lowered. Can be manufactured.

  FIG. 1 is a view showing the schematic arrangement of an exposure apparatus according to an embodiment of the present invention. The exposure apparatus includes a base 3, an X guide 4, an X stage 5, a Y guide 6, a Y stage 7, a θ stage 8, a chuck 10, a chuck support base 11, a mask holder 20, a load support mechanism 41, a Z-tilt mechanism 42, The detection device 50, the moving mechanism 60, the processing device 80, the stage drive circuit 90, the Z-tilt mechanism drive circuit 91, and the motor drive circuit 92 are configured. In addition to the above, the exposure apparatus includes an exposure light source, a supply unit that supplies the substrate 1 to the chuck 10, a recovery unit that recovers the substrate 1 from the chuck 10, a temperature control unit that manages the temperature in the apparatus, and the like. However, in this embodiment, portions not directly related to the invention are omitted.

  In FIG. 1, the chuck 10 is at an exposure position where the substrate 1 is exposed. The mask 2 is held by the mask holder 20 above the exposure position. The substrate 1 is mounted on the chuck 10 by a carry-in unit (not shown) at a delivery position away from the exposure position, and is recovered from the chuck 10 by a carry-out unit (not shown).

  The chuck 10 is mounted on the θ stage 8 via the chuck support 11, and a Y stage 7 and an X stage 5 are provided below the θ stage 8. The X stage 5 moves in the X direction (the horizontal direction in the drawing) along the X guide 4 provided on the base 3. As the X stage 5 moves in the X direction, the substrate 1 held by the chuck 10 moves between the delivery position and the exposure position. In addition, although a linear motor etc. are used as a drive means, illustration is abbreviate | omitted. The Y stage 7 moves in the Y direction (the drawing depth direction) along the Y guide 6 provided on the X stage 5, and the θ stage 8 rotates in the θ direction.

  At the exposure position, step movement of the substrate 1 in the XY direction is performed by movement of the X stage 5 in the X direction and movement of the Y stage 7 in the Y direction. The substrate 1 is positioned during exposure by moving the X stage 5 in the X direction, moving the Y stage 7 in the Y direction, and rotating the θ stage 8 in the θ direction. Further, the gap control between the mask 2 and the substrate 1 is performed by the movement and tilt of the Z-tilt mechanism 42 described later in the Z direction (vertical direction in the drawing).

  2A is a top view of the chuck support of the exposure apparatus according to the embodiment of the present invention, and FIG. 2B is a side view thereof. The chuck support base 11 includes a base plate 12, spokes 13, a rim 14, and ball pins 15.

  The base plate 12 is mounted on the θ stage 8 indicated by a broken line in FIG. On the base plate 12, a plurality of spokes 13 are attached radially from the center of the base plate 12. A rim 14 is attached to the tip of each spoke 13, and adjacent rims 14 are connected to form a polygonal frame. A large number of ball pins 15 are provided on the upper surfaces of the spokes 13 and the rim 14.

  In the present embodiment, 21 ball pins 15 are provided, but the number and arrangement of the ball pins 15 are appropriately determined according to the size and shape of the chuck 10.

  A ball is rotatably attached to the upper end of each ball pin 15. A chuck 10 indicated by a broken line in FIG. 2B is mounted on the ball pin 15, and the chuck support 11 supports the chuck 10 at a number of points. The lower end of each ball pin 15 is screwed to the spoke 13 or the rim 14, and the ball pin 15 moves up and down by turning the screw, and the ball pin 15 has a height at each point where the ball 10 supports the chuck 10. Is adjusted.

  According to the present embodiment, since the chuck 10 is supported at a number of points, it is not necessary to give the chuck 10 greater rigidity than when the conventional chuck is supported at three points. Therefore, the thickness of the chuck 10 can be reduced and the chuck 10 can be reduced in weight. Further, the height of each point supporting the chuck 10 can be adjusted to correct the deflection of the chuck, and the flatness of the chuck 10 can be improved.

  In addition, according to the present embodiment, the chuck support base 11 is configured by the base plate 12, the spokes 13, and the rim 14, so that the chuck support base 11 can be lightened while ensuring the strength of the chuck support base 11. it can. However, the configuration of the chuck support base 11 is not limited to this.

  The chuck 10 includes a suction mechanism (not shown) for vacuum suction of the substrate, and is made of aluminum. In several places on the back surface of the chuck 10, V-shaped grooves that abut the balls of the ball pins 15 are provided. When the balls of the ball pins 15 fit into these grooves, the chuck mounted on the chuck support 11 is mounted. 10 positioning is performed.

  By using aluminum as the material of the chuck 10, it is possible to contribute to weight reduction of the chuck 10 and to obtain a sufficient heat dissipation effect during exposure. Furthermore, the reflectance can be lowered by covering the surface of the chuck 10 with an aluminum oxide film.

  FIG. 3 is a top view of the mask holder of the exposure apparatus according to the embodiment of the present invention. FIG. 4 is a side view of the mask holder of the exposure apparatus according to the embodiment of the present invention. 4 shows a state in which the mask holder support member 30b is removed as viewed in the direction of the arrow in FIG.

  As shown in FIG. 3, an opening for transmitting exposure light is provided at the center of the mask holder 20. As shown in FIG. 4, the mask 2 is attached to the lower surface of the mask holder 20 so as to cover the opening. The mask holder 20 holds the outer peripheral portion of the mask 2 by vacuum suction.

  As shown in FIG. 3, a plurality of support arms 21 are attached to the four sides of the mask holder 20. Around the four sides of the mask holder 20, mask holder support members 30a, 30b, 30c, and 30d are provided. Support plates 31 are attached to the mask holder support members 30a, 30b, 30c, and 30d at positions that overlap the support arms 21 when viewed from above, while changing the height of the support arms 21.

  As shown in FIG. 4, a load support mechanism 41 is provided between the support arm 21 and the support plate 31. The load support mechanism 41 is composed of an air cushion, for example, and supports the load of the mask holder 20 by air pressure.

  In the present embodiment, eight load support mechanisms 41 are provided, but the number and arrangement of the load support mechanisms 41 are appropriately determined according to the weight and shape of the mask holder 20.

  As shown in FIG. 3, tilt arms 22 are attached to three locations on the four sides of the mask holder 20. A Z-tilt mechanism 42 is attached to the mask holder support members 30a and 30b at a position overlapping the tilt arm 22 when viewed from above.

  As shown in FIG. 4, the Z-tilt mechanism 42 is connected to the tilt arm 22. Each Z-tilt mechanism 42 includes, for example, a motor and a ball screw driven by the motor, and moves and tilts the mask holder 20 up and down by moving each tilting arm 22 up and down with the ball screw. Gap control between the mask 2 and the substrate 1 is performed.

  According to the present embodiment, by moving and tilting the mask holder 20 up and down and performing gap control between the mask 2 and the substrate 1, the center position of the gap control is always the center of the gap (center of the mask 2). Matches. Accordingly, when the entire surface of the substrate 1 is exposed by being divided into a plurality of shots, it is possible to prevent the gap control accuracy from being lowered.

  Furthermore, according to the present embodiment, by supporting the load of the mask holder 20 with the load support mechanism 41 provided separately from the Z-tilt mechanism 42, the Z-tilt mechanism 42 moves the mask holder 20 up and down with a small force. It can be moved and tilted, and the accuracy of gap control can be improved.

  In FIG. 1, a focus adjustment mark and a position detection mark, which will be described later, are provided on the surface of the mask 2 held by the mask holder 20. A detection device 50 that detects a focus adjustment mark and an image of a position detection mark and a moving mechanism 60 that moves the detection device 50 up and down are arranged above the mask 2. Note that the focus adjustment mark and the position detection mark are provided in two places in the drawing depth direction, and the detection device 50 and the moving mechanism 60 are also arranged in two places in the drawing depth direction correspondingly.

  5 is a perspective view of the detection device and the movement mechanism, FIG. 6 is a top view of the detection device and the movement mechanism, and FIG. 7 is a front view of the movement mechanism. The detection device 50 includes a camera unit 59 that acquires an image of a position detection mark, and an optical detection unit that has the same optical axis as the optical axis of the camera unit 59 and detects a focus adjustment mark. 5 and 6, reference numeral 58 denotes a sensor unit of the optical detection unit.

  The moving mechanism 60 includes a fixed base 61, a base plate 62, a guide 63, a taper block 64, a roller 65, a ball screw 66, a coupling 67, a motor 68, a roller support member 69, an arm 70, a spring 71, an upper plate 72, and a connection. A plate 73, a lifting block 74, a mounting position adjuster 75, a guide 76, and a support block 77 are configured. The fixed base 61 and the support block 77 are attached to any of the mask holder support members 30a, 30b, 30c, and 30d described above by an attachment member (not shown).

  5 to 7, a base plate 62 is attached to the fixed base 61, and a guide 63 is provided on the base plate 62. A taper block 64 having an inclined surface that contacts the roller 65 is mounted on the guide 63. A moving portion of a ball screw 66 is attached to the taper block 64, and the screw portion of the ball screw 66 is connected to a shaft of a motor 68 by a coupling 67.

  In FIG. 7, the roller support member 69 has a side surface with the letter “L” reversed, and supports the roller 65 in a rotatable manner. A groove is formed on the upper surface of the roller support member 69, and the arm 70 extends to both sides of the roller support member 69 through the groove on the upper surface of the roller support member 69. An upper plate 72 is attached to the upper surface of the roller support member 69, and a connecting plate 73 is bolted to the upper plate 72.

  Spring 71 is attached to both ends of the arm 70, and the roller 65 is pressed against the inclined surface of the taper block 64 by the spring 71. When the motor 68 rotates the threaded portion of the ball screw 66, the taper block 64 moves left and right along the guide 63, the roller 65 pressed against the inclined surface of the taper block 64 moves up and down, and the connecting plate 73 is moved. Move up and down.

  5 and 6, a lifting block 74 is attached to the connecting plate 73, and the detection device 50 is attached to the lifting block 74 via an attachment position adjuster 75. When the connecting plate 73 moves up and down, the elevating block 74 is guided by a guide 76 provided between the support plate 77 and moved up and down, and the detection device 50 moves up and down. As the detection device 50 moves up and down, the focus of the camera unit 59 of the detection device 50 moves up and down.

  According to the present embodiment, by making the angle of the inclined surface of the taper block 64 less than 45 degrees, the vertical movement amount of the detection device 50 can be made smaller than the horizontal movement amount of the taper block 64. it can. Therefore, the focus of the camera unit 59 of the detection device 50 can be adjusted with high accuracy.

  In FIG. 1, the processing device 80 includes an MPU 81, a memory 82, interfaces 83, 84, 85, 86, 87, and a bus 88. The memory 82 has an up / down movement program 82a for moving the detection device 50 up and down by the moving mechanism 60, an autofocus for processing the detection signal of the sensor unit 58 and focusing the camera unit 59 on the surface of the mask 2. A processing program 82b, an image processing program 82c for processing an image signal of the camera unit 59, and a mask position calculation program 82d for detecting a change in the position of the mask 2 are stored. The memory 82 also stores focus position data 82e used by the vertical movement program 82a and image recognition template data 82f used by the image processing program 82c.

  The MPU 81 controls the stage drive circuit 90 via the bus 88 and the interface 83. The stage drive circuit 90 drives the X stage 5, the Y stage 7, and the θ stage 8 under the control of the MPU 81 to perform step movement of the substrate 1 in the XY direction and positioning of the substrate 1 during exposure. Next, the MPU 81 controls the Z-tilt mechanism drive circuit 91 via the bus 88 and the interface 84. The Z-tilt mechanism drive circuit 91 controls the gap between the mask 2 and the substrate 1 by driving the Z-tilt mechanism 42 under the control of the MPU 81. During these periods, the MPU 81 executes the vertical movement program 82a and the autofocus processing program 82b stored in the memory 82 in parallel.

  In the up / down movement program 82 a, the MPU 81 controls the motor drive circuit 92 via the bus 88 and the interface 85. The motor driving circuit 92 drives the motor 68 of the moving mechanism 60 under the control of the MPU 81 and moves the detection device 50 up and down by the moving mechanism 60. At this time, the MPU 81 uses the focus position data 82e indicating the approximate height of the surface of the mask 2 before and during the gap control, and the focus of the camera unit 59 of the detection device 50 moves up and down across the surface of the mask 2. The motor drive circuit 92 is controlled so as to move to

  FIG. 8 is a diagram illustrating a schematic configuration of the detection apparatus. The optical detection unit of the detection device 50 includes a light source 51, half mirrors 52, 55, and 56, a lens 53, a rhomboid prism 54, a mirror 57, and a sensor unit 58. The light source 51 is made of a light emitting diode, for example, and the light from the light source 51 is reflected by the half mirror 52 and enters the lens 53. The lens 53 irradiates the focus adjustment mark and the position detection mark provided on the surface of the mask 2 with the light from the light source 51 via the rhomboid prism 54, and emits the light from the focus adjustment mark and the position detection mark. Collect the reflected light. The mask 2 is held by the mask holder 20 with the surface on which the focus adjustment mark and the position detection mark are provided facing down.

  The reflected light collected by the lens 53 passes through the half mirror 52 and enters the half mirror 55. The half mirror 55 divides the reflected light collected by the lens 53 into two. Instead of the half mirror 55, the reflected light may be divided into two using other optical elements such as a prism. About half of the reflected light incident on the half mirror 55 is reflected by the half mirror 55 and enters the half mirror 56. The remaining half of the reflected light incident on the half mirror 55 passes through the half mirror 55 and enters the camera unit 59. The sensor unit 58 detects the focus adjustment mark from one of the reflected lights divided by the half mirror 55, and the camera unit 59 acquires the image of the position detection mark from the other reflected light divided by the half mirror 55. To do.

  FIG. 9 is a diagram illustrating an example of a focus adjustment mark and a position detection mark. The focus adjustment mark is formed by repeating a plurality of elongated patterns 2a. The position detection mark of this example is configured by attaching a portion 2b protruding to both sides to a central elongated pattern 2a. The lens 53 of the optical detection unit condenses the reflected light from the region including the entire position detection mark. On the other hand, the camera unit 59 acquires an image of a region indicated by a broken line in the drawing.

  FIG. 10 is a diagram illustrating another example of the focus adjustment mark and the position detection mark. The position detection mark of this example is configured by a cross-shaped pattern 2c. The camera unit 59 acquires an image of an area indicated by a broken line in the drawing.

  FIG. 11 is a diagram showing still another example of the focus adjustment mark and the position detection mark. The position detection mark 2d of this example is configured by attaching a portion 2d that obliquely intersects the central elongated pattern 2a. The camera unit 59 acquires an image of an area indicated by a broken line in the drawing.

  The focus adjustment mark and the position detection mark are not limited to the examples shown in FIGS. 9 to 11, and the position detection mark may have a shape that can easily process the image signal of the image acquired by the camera unit 59. That's fine. In addition, the focus adjustment mark may be provided on the surface of the mask 2 near the position detection mark and may be a repetitive pattern.

  FIG. 12 is a diagram for explaining the operation of the optical detection unit. In FIG. 12, the light source 51, the half mirror 52, the rhomboid prism 54, and the mirror 57 in FIG. 8 are omitted. The half mirror 56 further divides one of the reflected lights divided by the half mirror 55 into two. Instead of the half mirror 56, the reflected light may be divided into two using other optical elements such as a prism. The sensor unit 58 includes two CCD line sensors 58a and 58b. About half of the reflected light incident on the half mirror 56 is reflected by the half mirror 56, then reflected by a mirror 57 (not shown), and enters the CCD line sensor 58a. The remaining half of the reflected light incident on the half mirror 56 passes through the half mirror 56 and enters the CCD line sensor 58b.

  The CCD line sensor 58a is disposed at a position where one of the reflected lights divided by the half mirror 56 forms an image when the focus of the camera unit 59 is shifted by a predetermined distance from the surface of the mask 2. On the other hand, the CCD line sensor 58 b is arranged at a position where the other of the reflected light divided by the half mirror 56 forms an image when the focus of the camera unit 59 is shifted downward by a predetermined distance from the surface of the mask 2.

  FIG. 13A is a diagram showing the detection signal of the line sensor, FIG. 13B is a diagram showing the relationship between the contrast of the reflected light and the focus, and FIG. 13C is the difference between the contrast of the reflected light and the focus. It is a figure which shows a relationship. The detection signals of the CCD line sensors 58a and 58b repeatedly change in intensity depending on the presence or absence of the elongated pattern 2a of the focus adjustment mark, as shown in FIG. The magnitude of the detection signal where there is no elongated pattern 2a is Id, and the magnitude of the detection signal where there is an elongated pattern 2a is Ib.

  In FIG. 1, the MPU 81 inputs a detection signal from the sensor unit 58 of the optical detection unit of the detection apparatus 50 via the interface 86 and the bus 88. Then, the MPU 81 executes the autofocus processing program 82b, and for each of the detection signals of the CCD line sensors 58a and 58b, the ratio of the intensity change of the detection signal is set to the reflected light contrast M = (Ib−Id) / (Ib + Id). ).

  As shown in FIG. 13B, the contrast M of the reflected light varies depending on the focal point of the optical detection unit (the same as the focal point of the camera unit 59). The horizontal axis of FIG. 13B indicates the distance Z from the surface of the mask 2 to the focal point of the camera unit 59. When the vertical movement program 82a is executed to move the camera unit 59 and the optical detection unit up and down, the CCD The rate of change in the intensity of the detection signal of the line sensor 58a (the contrast Ma of the reflected light) is maximized when the focus of the camera unit 59 is shifted by a predetermined distance Zd from the surface of the mask 2, and the focus of the camera unit 59 is It becomes smaller as it approaches the surface of the mask 2. On the other hand, the intensity change rate (contrast Mb of reflected light) of the detection signal of the CCD line sensor 58b becomes maximum when the focus of the camera unit 59 is shifted by a predetermined distance Zd from the surface of the mask 2, and the camera unit 59 Decreases as the focal point approaches the surface of the mask 2. Then, as shown in FIG. 13C, when the difference Ma−Mb between the two becomes zero, the focus of the camera unit 59 is aligned with the surface of the mask 2.

  In FIG. 1, the MPU 81 drives the motor via the bus 88 and the interface 85 so that the intensity change rate of the detection signal of the CCD line sensor 58a and the intensity change rate of the detection signal of the CCD line sensor 58b become the same. The circuit 92 is controlled. The camera unit 59 is quickly focused on the surface of the mask 2 because only the simple process of obtaining the intensity change ratio of the detection signals of the CCD line sensors 58a and 58b is required and the image signal need not be processed.

  The camera unit 59 acquires an image of the position detection mark in a state where the focus is on the surface of the mask 2 and outputs an image signal. The MPU 81 inputs an image signal from the camera unit 59 via the interface 87 and the bus 88. Then, the MPU 81 executes the image processing program 82c and the mask position calculation program 82d stored in the memory 82.

  In the image processing program 82c, the MPU 81 temporarily stores the image signal input from the camera unit 59 in a storage device (not shown) and compares it with the image recognition template data 82f stored in the memory 82. In the mask position calculation program 82d, the MPU 81 calculates the position of the mask 2 based on the comparison result of the image processing program 82c, and detects a change in the position of the mask 2. Then, the MPU 81 corrects the position of the substrate 1 at the time of exposure by controlling the stage drive circuit 90 according to the detection result of the change in the position of the mask 2.

  According to the embodiment described above, the position detection mark is provided on the surface of the mask 2, the mask holder 20 is moved up and down and tilted to control the gap between the mask 2 and the substrate 1, and the camera unit 59 is Moving up and down, the camera unit 59 is focused on the surface of the mask 2, a position detection mark image is acquired using the camera unit 59, and the image signal output from the camera unit 59 is processed to process the mask 2. By detecting the change in the position and correcting the position of the substrate 1 at the time of exposure according to the detection result of the change in the position of the mask 2, it is possible to prevent the gap control from being deteriorated and to prevent the gap 2 from being changed Deviation of the printing position can be prevented.

  Further, according to the embodiment described above, the focus adjustment mark is provided on the surface of the mask 2 near the position detection mark, and the optical detection unit having the same optical axis as the optical axis of the camera unit 59 is used. The reflected light from the focus adjustment mark and the position detection mark is divided into two, the focus adjustment mark is detected from one of the divided reflected lights, and the other of the reflected light divided by the optical detection unit is used as a camera. By acquiring the image of the position detection mark using the unit 59, the optical detection unit necessary for the focus adjustment of the camera unit 59 and the camera unit 59 can be reduced as a whole, so that the exposure area of the mask 2 can be reduced. Can be taken widely.

  Further, the rhomboid prism 54 is disposed between the lens 53 and the mask 2, and the optical axes of the camera unit 59 and the optical detection unit are shifted from above the focus adjustment mark and the position detection mark, thereby allowing the mask 2. The exposure area can be made wider.

  Furthermore, according to the embodiment described above, a focus adjustment mark made of a repetitive pattern is provided on the surface of the mask 2 near the position detection mark, and one of the divided reflected lights is further divided into two, and the CCD When the focal point of the camera unit 59 is shifted by a predetermined distance from the surface of the mask 2, the line sensor 58 a is disposed at a position where one of the divided reflected lights forms an image, and the CCD line sensor 58 b is disposed at the camera unit 59. Is placed at a position where the other of the divided reflected light forms an image when the focal point of the mask 2 is deviated by a predetermined distance from the surface of the mask 2, the intensity change rate of the detection signals of the CCD line sensors 58 a and 58 b can be set. The camera unit 59 can be quickly focused on the surface of the mask 2 simply by performing a simple process.

  By transferring the mask pattern to the substrate using the exposure apparatus or exposure method of the present invention, it is possible to prevent the printing position from being shifted due to the change in the mask position while preventing the gap control accuracy from being lowered. A high-quality display panel substrate can be manufactured.

  For example, FIG. 14 is a flowchart showing an example of the manufacturing process of the TFT substrate of the liquid crystal display device. In the thin film formation step (step 101), a thin film such as a conductor film or an insulator film, which becomes a transparent electrode for driving liquid crystal, is formed on a glass substrate by sputtering, plasma chemical vapor deposition (CVD), or the like. In the resist coating process (step 102), a photosensitive resin material (photoresist) is applied by a roll coating method or the like to form a photoresist film on the thin film formed in the thin film forming process (step 101). In the exposure step (step 103), the mask pattern is transferred to the photoresist film using a proximity exposure apparatus, a projection exposure apparatus, or the like. In the development step (step 104), a developer is supplied onto the photoresist film by a shower development method or the like to remove unnecessary portions of the photoresist film. In the etching process (step 105), a portion of the thin film formed in the thin film formation process (step 101) that is not masked by the photoresist film is removed by wet etching. In the stripping step (step 106), the photoresist film that has finished the role of the mask in the etching step (step 105) is stripped with a stripping solution. Before or after each of these steps, a substrate cleaning / drying step is performed as necessary. These steps are repeated several times to form a TFT array on the glass substrate.

  FIG. 15 is a flowchart showing an example of the manufacturing process of the color filter substrate of the liquid crystal display device. In the black matrix forming step (step 201), a black matrix is formed on the glass substrate by processes such as resist coating, exposure, development, etching, and peeling. In the colored pattern forming step (step 202), a colored pattern is formed on the glass substrate by a dyeing method, a pigment dispersion method, a printing method, an electrodeposition method, or the like. This process is repeated for the R, G, and B coloring patterns. In the protective film forming step (step 203), a protective film is formed on the colored pattern, and in the transparent electrode film forming step (step 204), a transparent electrode film is formed on the protective film. Before, during or after each of these steps, a substrate cleaning / drying step is performed as necessary.

  In the TFT substrate manufacturing process shown in FIG. 14, in the exposure process (step 103), in the color filter substrate manufacturing process shown in FIG. 15, in the black matrix forming process (step 201) and the colored pattern forming process (step 202). In this exposure process, the exposure apparatus or the exposure method of the present invention can be applied.

1 is a diagram showing a schematic configuration of an exposure apparatus according to an embodiment of the present invention. 2A is a top view of the chuck support of the exposure apparatus according to the embodiment of the present invention, and FIG. 2B is a side view thereof. It is a top view of the mask holder of the exposure apparatus by one Embodiment of this invention. It is a side view of the mask holder of the exposure apparatus by one Embodiment of this invention. It is a perspective view of a detection apparatus and a moving mechanism. It is a top view of a detection apparatus and a moving mechanism. It is a front view of a moving mechanism. It is a figure which shows schematic structure of a detection apparatus. It is a figure which shows an example of the mark for focus adjustment, and the mark for position detection. It is a figure which shows the other example of the mark for focus adjustment, and the mark for position detection. It is a figure which shows the further another example of the mark for focus adjustment, and the mark for position detection. It is a figure explaining operation | movement of an optical detection part. FIG. 13A is a diagram showing the detection signal of the line sensor, FIG. 13B is a diagram showing the relationship between the contrast of the reflected light and the focus, and FIG. 13C is the difference between the contrast of the reflected light and the focus. It is a figure which shows a relationship. It is a flowchart which shows an example of the manufacturing process of the TFT substrate of a liquid crystal display device. It is a flowchart which shows an example of the manufacturing process of the color filter board | substrate of a liquid crystal display device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate 2 Mask 3 Base 4 X guide 5 X stage 6 Y guide 7 Y stage 8 θ stage 10 Chuck 11 Chuck support base 12 Base plate 13 Spoke 14 Rim 15 Ball pin 20 Mask holder 21 Support arm 22 Tilt arm 30a, 30b, 30c, 30d Mask holder support member 31 Support plate 41 Load support mechanism 42 Z-tilt mechanism 50 Detection device 51 Light source 52, 55, 56 Half mirror 53 Lens 54 Romboid prism 57 Mirror 58 Sensor unit 58a, 58b CCD line sensor 59 Camera unit 60 Moving mechanism 61 Fixed base 62 Base plate 63 Guide 64 Tapered block 65 Roller 66 Ball screw 67 Coupling 68 Motor 69 Roller support member 70 Arm 71 Spring 72 Upper plate 73 Connecting plate 74 Lifting block 75 Mounting position Fushigu 76 guide 77 support block 80 processor 81 MPU
82 Memory 83, 84, 85, 86, 87 Interface 88 Bus 90 Stage drive circuit 91 Z-tilt mechanism drive circuit 92 Motor drive circuit

Claims (8)

An exposure apparatus using a proximity method,
A mask holder for holding the mask;
A chuck for holding a substrate;
A stage for moving the chuck and performing step movement of the substrate in the XY directions and positioning of the substrate during exposure;
Gap control means for moving and tilting the mask holder up and down to control the gap between the mask and the substrate;
An image acquisition device for acquiring an image of a position detection mark provided on the surface of the mask and outputting an image signal;
Focus adjustment means for moving the image acquisition device up and down to focus the image acquisition device on the surface of the mask;
Processing means for detecting a change in the position of the mask by processing the image signal output from the image acquisition device, controlling the stage according to the detection result, and correcting the position of the substrate at the time of exposure; An exposure apparatus characterized by the above. The focusing means is
An optical detection means for detecting a focus adjustment mark provided on the surface of the mask near the position detection mark, having the same optical axis as the optical axis of the image acquisition device;
Moving means for moving the image acquisition device and the optical detection means up and down;
Control means for controlling the moving means,
The optical detection means includes
A light source;
A lens for irradiating the focus adjustment mark and the position detection mark with light from the light source and collecting the reflected light;
A first optical element that divides the reflected light collected by the lens into two;
A sensor for detecting a focus adjustment mark from one of the reflected lights divided by the first optical element,
The control means processes the detection signal of the sensor, and controls the moving means so that the focus of the image acquisition device is aligned with the surface of the mask,
The exposure apparatus according to claim 1, wherein the image acquisition apparatus acquires an image of a position detection mark from the other reflected light divided by the first optical element. The optical detection means includes a second optical element that further divides one of the reflected lights divided by the first optical element into two,
The sensor is
A first line sensor disposed at a position where one of the reflected lights divided by the second optical element forms an image when the focus of the image acquisition device is shifted by a predetermined distance from the surface of the mask;
A second line sensor disposed at a position where the other of the reflected light divided by the second optical element forms an image when the focal point of the image acquisition device is shifted by a predetermined distance from the surface of the mask; Have
The first line sensor and the second line sensor detect a focus adjustment mark composed of a repetitive pattern,
The control means controls the moving means so that the ratio of the intensity change of the detection signal of the first line sensor is the same as the ratio of the intensity change of the detection signal of the second line sensor. The exposure apparatus according to claim 2. An exposure method using a proximity method,
A mark for position detection is provided on the surface of the mask,
Hold the mask with the mask holder,
Hold the substrate with the chuck,
Move the chuck, perform step movement of the substrate in the XY direction and position the substrate during exposure,
Move and tilt the mask holder up and down to control the gap between the mask and the substrate,
Move the image acquisition device up and down to focus the image acquisition device on the surface of the mask,
Obtain an image of the position detection mark using an image acquisition device,
Process the image signal output by the image acquisition device to detect changes in the mask position,
An exposure method comprising correcting a position of a substrate at the time of exposure according to a detection result of a change in a mask position. A focus adjustment mark is provided on the mask surface near the position detection mark.
Using optical detection means having the same optical axis as the optical axis of the image acquisition device, the light from the light source is irradiated onto the focus adjustment mark and the position detection mark, the reflected light is condensed, and the collected reflected light is collected. , And the focus adjustment mark is detected from one of the divided reflected lights.
Processing the detection signal of the focus adjustment mark, moving the image acquisition device and the optical detection means up and down so that the focus of the image acquisition device matches the surface of the mask,
5. The exposure method according to claim 4, wherein an image of the position detection mark is acquired from the other reflected light divided by the optical detection means using an image acquisition device. A focus adjustment mark consisting of a repeating pattern is provided on the surface of the mask near the position detection mark.
One of the divided reflected lights is further divided into two,
The first line sensor is disposed at a position where one of the divided reflected lights forms an image when the focus of the image acquisition device is shifted by a predetermined distance from the surface of the mask,
The second line sensor is arranged at a position where the other of the divided reflected lights forms an image when the focus of the image acquisition device is shifted by a predetermined distance from the surface of the mask,
The image acquisition device and the optical detection means are moved up and down so that the rate of change in the intensity of the detection signal of the first line sensor is the same as the rate of change in the intensity of the detection signal of the second line sensor. The exposure method according to claim 5.   A method for manufacturing a display panel substrate, comprising: transferring a mask pattern onto the substrate using the exposure apparatus according to claim 1.   A method for manufacturing a display panel substrate, wherein a mask pattern is transferred to a substrate using the exposure method according to claim 4.

Images