JP2009251290A - Exposure apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent misoperation of an exposure apparatus by improving exposure position precision of the exposure apparatus. <P>SOLUTION: The exposure apparatus includes: an imaging means 5 which has a plurality of photodetectors arranged linearly in a direction substantially orthogonal to the conveying direction of a color filter substrate 7 and which images an alignment mark 17 which is provided nearby an exposure start position on a surface of the color filter substrate 7 and outside an exposure area and comprises a plurality of thin lines orthogonal to one another; and a control means which processes image data imaged by the imaging means 5 and recognizes thin line substantially parallel to the arrangement direction of the plurality of photodetectors among the plurality of thin lines orthogonal to one another as a reference position in the conveying direction of the color filter substrate 7, and determines a position across a preset distance away from the recognized reference position as the exposure start position to control the timing of irradiation of the color filter substrate 7 with exposure light. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an exposure apparatus that irradiates a surface of an object to be exposed with exposure light and exposes a mask pattern through a photomask disposed on an optical path. Specifically, the exposure apparatus is provided on the surface of an object to be exposed. The present invention relates to an exposure apparatus that can set an exposure start position with high accuracy using a part of an alignment mark as a reference position.

In this type of conventional exposure apparatus, when transferring the image of the mask opening onto the object to be exposed, a reference position preset in a reference pattern formed on the object to be exposed being conveyed at a constant speed is used as a reference. The exposure operation is performed by controlling the setting of the exposure position and the irradiation timing of the exposure light. (For example, Patent Document 1)
JP2006-17895

  However, in such a conventional exposure apparatus, there is a possibility of erroneous detection when the exposure light irradiation position is specified for the first time in exposure on an object to be exposed using a mask, and the accuracy is high. There has been a problem that the exposure operation may not be possible.

  Accordingly, the present invention has been made in view of the above circumstances, and an object thereof is to provide an exposure apparatus capable of setting the exposure light irradiation position more accurately using a small mask.

  In order to achieve the above object, an exposure apparatus according to the present invention has a stage on which an exposure object having an exposure area set on the surface is placed on the upper surface, and the exposure object is conveyed in the setting direction of the exposure area; A mask stage that is disposed above the stage and holds a photomask in close proximity to the object to be exposed, and irradiates the object to be exposed through the photomask held on the mask stage. An exposure apparatus comprising: a light source that performs light irradiation; and a condensing lens that is disposed between the light source and the mask stage and that converts the exposure light applied to the photomask into parallel light, the transport direction of the object to be exposed A plurality of light receiving elements arranged in a straight line in a direction substantially perpendicular to the surface of the exposure object, provided near the exposure start position on the surface of the object to be exposed and outside the exposure area, and an alignment marker comprising a plurality of thin lines orthogonal to each other Image processing means for processing the image data picked up by the image pickup means, and fine lines that are substantially parallel to the direction in which the plurality of light receiving elements are arranged by the plurality of thin lines orthogonal to each other in the transport direction of the object to be exposed And a control means for controlling the irradiation timing of the exposure light to the object to be exposed, with a position that is recognized as a reference position and that is separated from the recognized reference position by a preset distance as an exposure start position.

  With such a configuration, the object to be exposed is placed on the upper surface of the stage, the object to be exposed is conveyed in the setting direction of a plurality of exposure areas, and the photomask is held in close proximity to the object to be exposed on the mask stage. The exposure object is irradiated with exposure light from a light source through a photomask. At that time, the exposure light applied to the photomask by the condenser lens is made parallel light. In addition, the image pickup means picks up an alignment mark provided near the exposure start position on the surface of the object to be exposed and outside the exposure area, further processes the image data picked up by the control means, and sets a part of the alignment mark as a reference position. Then, the exposure light irradiation timing to the object to be exposed is controlled with the position at a predetermined distance from the reference position as the exposure start position, and the object to be exposed is exposed.

  Further, the alignment mark composed of a plurality of thin lines orthogonal to each other is at least two thin lines substantially orthogonal to the arrangement direction of the plurality of light receiving elements and one thin line substantially parallel to the arrangement direction.

  The line width of at least two fine lines substantially perpendicular to the arrangement direction of the plurality of light receiving elements is 15 to 25 μm, and the line width of one thin line substantially parallel to the arrangement direction is 25 to 35 μm.

  The light source is a flash lamp that is turned on and off by the control means.

  According to the invention according to claim 1, a part of an alignment mark made of a plurality of mutually perpendicular thin lines provided near the exposure start position on the surface of the object to be exposed and outside the exposure area is recognized as a reference position, The exposure start position is controlled at a position separated from the reference position by a preset distance, so that the exposure start position can be set accurately without misdetecting the alignment mark. It becomes. Furthermore, it is possible to reduce the time of the exposure process.

  According to the second aspect of the present invention, by providing the mask stage with the displacement means, it is possible to align the mask pattern of the photomask and the exposure area of the object to be exposed, and the accurate exposure position can be set. It becomes.

  According to the invention of claim 3, the alignment mark composed of a plurality of fine lines orthogonal to each other is arranged with at least two thin lines substantially orthogonal to the arrangement direction of the plurality of light receiving elements and one line substantially parallel to the arrangement direction. By configuring with fine lines, the accuracy of the exposure start position and the exposure position can be further improved.

  According to the invention which concerns on Claim 4, the misrecognition at the time of recognizing a thin line is eliminated, and the precision of an exposure start position and an exposure position can further be improved.

  According to the invention which concerns on Claim 5, while being able to perform control of irradiation and stop of exposure light easily, the control can be performed at high speed.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a schematic diagram showing an embodiment of an exposure apparatus according to the present invention. This exposure apparatus irradiates the surface of an object to be exposed with predetermined timing through a photomask while exposing the object to be exposed in a predetermined direction, and exposes a predetermined exposure pattern. , The mask stage 2, the light source 3, the condenser lens 4, the imaging means 5, and the control means 6. In the following description, the case where the object to be exposed is a color filter substrate 7 coated with a color resist as a photosensitive resin will be described.

  The stage 1 has a color filter substrate 7 having an exposure area set on the surface and is placed on the upper surface, and conveys the color filter substrate 7 in the setting direction of the exposure area. It moves in the direction shown. Further, the stage 1 is provided with an opening (not shown) corresponding to the entire exposure region of the color filter substrate 7, and the color filter substrate 7 can be illuminated from below by the illumination means 9 disposed below the stage 1. It is like that.

  A mask stage 2 is disposed above the stage 1. The mask stage 2 holds the photomask 10 so as to be close to and opposed to the color filter substrate 7 with a predetermined gap, for example, 100 to 300 μm, and corresponds to a region where a plurality of mask patterns 11 of the photomask 10 are formed. Thus, an opening is provided and formed so as to hold the peripheral edge of the photomask 10. The mask stage 2 includes a mask stage position correction mechanism configured by a combination of a motor, a ball screw, a guide rail and the like (not shown) based on imaging data of an alignment mark 17 formed on a color filter substrate 7 to be described later. Used and corrected to a normal position in the relative positional relationship with the color filter substrate 7.

  The photomask 10 is for transferring the exposure light irradiated from the light source 3 to a color resist which is a photosensitive resin on the color filter substrate 7, and as shown in FIG. A light shielding film 12, a mask pattern 11, and an imaging window 14 are formed.

The transparent substrate 13 is a transparent glass substrate that transmits ultraviolet light and visible light with high efficiency, and is, for example, quartz glass.
Further, as shown in FIG. 2 (XX sectional view and YY sectional view), a light shielding film 12 is formed on one surface 13a of the transparent substrate 13. The light shielding film 12 shields exposure light and is an opaque thin film of, for example, chromium (Cr).

  A plurality of mask patterns 11 each having an opening having a predetermined shape that transmits exposure light are arranged in one direction on the light shielding film 12. This mask pattern 11 is for transferring the exposure light onto the black matrix pixels 18 formed on the color filter substrate 7 conveyed oppositely. For example, the pixel 18 has a rectangular shape that substantially matches the vertical and horizontal widths, and is formed at an interval that matches the pitch interval of the pixels 18. Although FIG. 2 shows a case where a plurality of mask patterns 11 are provided in a line, a plurality of mask patterns 11 may be provided.

  In the region corresponding to the formation region of the mask pattern 11 on the other surface 13b of the transparent substrate 13, an ultraviolet antireflection film 15 is formed as shown in FIG. 2 (XX sectional view). The transmission efficiency of ultraviolet components contained in exposure light can be improved.

  An imaging window 14 is formed on the side of the mask pattern 11 in the arrangement direction as shown in FIG. The imaging window 14 is for imaging the alignment mark 17 and the pixel 18 formed on the color filter substrate 7 shown in FIG. 3 that is conveyed in the opposite direction. The imaging unit 5 described later uses the alignment mark 17 and the pixel. A reference position preset to 18 can be detected. The imaging window 14 is formed in a rectangular shape extending in a direction orthogonal to the conveyance direction of the color filter substrate 7.

  Further, as shown in FIG. 2 (YY cross-sectional view), visible light is transmitted and ultraviolet light is reflected in the region corresponding to the formation region of the imaging window 14 on the other surface 13b of the transparent substrate 13. A wavelength-selective film 16 is formed, and an ultraviolet component contained in the exposure light is irradiated to the color filter substrate 7 through the imaging window 14 formation region, so that it is possible to prevent the color resist applied to the color filter substrate 7 from being exposed. It has become.

  The alignment mark 17 formed on the color filter substrate 7 is composed of a plurality of fine lines orthogonal to each other as shown in FIG. It is composed of at least two perpendicular thin wires 17b and one fine wire 17a substantially parallel to the arrangement direction. The line width of each thin line is 15 to 25 μm for at least two thin lines 17 b that are substantially orthogonal to each other, and 25 to 35 μm for one thin line 17 a that is substantially parallel. The description of being substantially orthogonal or substantially parallel means that it is orthogonal or parallel within a predetermined allowable range, and so on.

  A light source 3 is disposed above the mask stage 2. The light source 3 emits ultraviolet exposure light that irradiates the color filter substrate 7 through the photomask 10, and is a flash lamp that is controlled by the control means 6 to be turned on and off.

  The exposure light emitted from the light source 3 is collimated by, for example, the condenser lens 4 and applied to the photomask 10.

  An imaging unit 5 is disposed above the stage 1. The imaging means 5 images the alignment marks 17 and the pixels 18 formed on the color filter substrate 7 through the half mirror 21 and receives light having a plurality of light receiving elements arranged in a straight line. A line CCD 22 as a surface, a condenser lens 23 that forms an image on the line CCD 22 with the alignment mark 17 and the pixel 18 disposed in front of the line CCD 22 and formed on the color filter substrate 7, and a light receiving element and a condenser lens. And an optical distance correction means 24 provided between the control unit 23 and the optical distance correction unit 23.

  The optical distance correcting means 24 substantially matches the optical distance between the light receiving element and the color filter substrate 7 and the optical distance between the light receiving element and the photomask 10 as shown in FIG. It is made of a transparent member having a predetermined refractive index larger than the refractive index, for example, a glass plate. As a result, the alignment mark 17 on the color filter substrate 7 that is shifted in the optical axis direction of the image pickup means 5 and the reference position set on the photomask 10 can be simultaneously focused and imaged.

  An illumination unit 9 is disposed below the stage 1 so as to face the mask stage 2. The illuminating means 9 radiates illumination light composed of visible light to illuminate the color filter substrate 7 from the back surface, and images the alignment marks 17 and pixels 18 of the color filter substrate 7 by the imaging means 5. For example, a halogen lamp or the like. An ultraviolet cut filter (not shown) is provided in front of the illumination unit 9 in the radiation direction of the illumination light, and a color resist applied to the color filter substrate 7 with ultraviolet rays included in visible light emitted from the illumination unit 9. Is prevented from being exposed.

  A control means 6 is arranged in connection with the stage 1, mask stage 2, light source 3 and imaging means 5. The control means 6 processes the images of the alignment marks 17 and the pixels 18 on the color filter substrate 7 imaged by the imaging means 5, and controls the irradiation timing of the exposure light emitted from the light source 3. 6, the stage drive controller 25, the image processing unit 26, the mask stage drive controller 27, the light source drive controller 28, the illumination means drive controller 29, the calculation unit 30, the memory 31, and the control unit 32. It has.

  The stage drive controller 25 moves the stage 1 at a predetermined speed in the direction of arrow A by the transport unit 8 and feeds back the output of the speed sensor provided in the transport unit 8 for speed control.

  The image processing unit 26 binarizes the image picked up by the image pickup means 5 and sequentially outputs image data for one line.

  The mask stage drive controller 27 is for displacing the mask stage 2 so that the alignment mark 17 formed on the color filter substrate 7 and the reference position set on the photomask 10 have a predetermined positional relationship. is there.

  The light source drive controller 28 controls the turning on and off of the light source 3.

  The illumination means drive controller 29 controls the lighting and extinction of the illumination means 9.

  The arithmetic unit 30 detects the center position in the transport direction of the pixels 18 formed on the color filter substrate 7 based on the image data from the image processing unit 26.

  The memory 31 includes control parameters input by operating means (not shown), such as the conveyance speed V of the color filter substrate 7, the irradiation time of the light source 3, the output value of the light source 3, and the alignment formed on the color filter substrate 7. The setting distance D from the reference position in the mark 17 to the first exposure light irradiation position, the result calculated by the calculation unit 29, and the like are temporarily stored.

  And the said control part 32 integrates and controls the whole apparatus so that each said component may drive appropriately.

  An operation method of the exposure apparatus configured as described above will be described. First, with the photomask 10 on the side where the light-shielding film 12 is formed, the imaging window 14 is positioned on the front side in the transport direction of the color filter substrate 7 (the direction of arrow A shown in FIG. 1), and Is held on the mask stage 2 so that the center axis X of the center is orthogonal to the transport direction.

  Next, the color filter substrate 7 coated with a predetermined color resist is placed at a predetermined position on the stage 1. When an exposure start switch (not shown) is turned on, the exposure apparatus is activated and the illumination unit 9 is turned on by the illumination unit drive controller 29 of the control unit 6. In addition, the stage drive controller 25 is activated and the stage 1 starts moving in the direction of arrow A at a predetermined speed V, and the color filter substrate 7 is transported in the same direction. At this time, position data of the color filter substrate 7 is always output from a position sensor (not shown) of the stage 1. Further, the imaging unit 5 is activated, and the alignment mark 17 formed on the color filter substrate 7 is detected through the imaging window 14 of the photomask 10. Specifically, the image picked up by the image pickup means 5 is binarized by the image processing section 26 of the control means 6, and a plurality of thin lines that are perpendicular to each other constituting the alignment mark 17 are present. Calculate points. Then, based on the calculated position information of the corners of the thin line and the reference position set in advance on the photomask 10 and confirmed by the imaging means 5, the mask stage 2 holding the photomask 10 is a motor (not shown), Using a mask stage position correction mechanism composed of a combination of a ball screw, a guide rail, and the like, position correction is performed in the direction orthogonal to the transport direction and in the rotation direction, and the normal position in the relative positional relationship with the color filter substrate 7 is corrected. Is done.

  Then, based on the data image-processed in the above process, the center line of one thin line that is substantially parallel to the arrangement direction of the plurality of light receiving elements arranged in the imaging means 5 is calculated. Then, the calculated center line of the thin line is set as a reference position, and the exposure light irradiation position is specified.

  A method for specifying the first exposure light irradiation position will be described. First, as shown in FIG. 4, a position that is separated from the calculated center line of the thin line by a distance D in the direction of arrow A is set as a first exposure light irradiation predicted position and stored in the memory 31.

  Next, based on the image data of the image picked up by the image pickup means 5, the leading edge 18a of the two edges 18a, 18b positioned ahead of the conveying direction of the pixel 18 of the color filter substrate 7 shown in FIG. Is detected. The detection of the leading edge 18a can be detected by capturing the moment when the image of the imaging means 5 changes from dark to bright. When the leading edge 18a is detected, the position data P1 is obtained from the output of the position sensor of the stage 1.

  Further, when the edge 18b on the rear side in the transport direction of the pixel 18 is detected by capturing the moment when the image of the imaging means 5 changes from light to dark, the position data P2 is acquired by the output of the position sensor of the stage 1. Is done.

  Therefore, the central position P0 between the two edge portions 18a and 18b of the pixel 18 is calculated by calculating (P1 + P2) / 2 by the calculation unit 30 using the two position data P1 and P2. The position where the center position P0 calculated by the calculation unit 30 and the predicted position of the first exposure light irradiation stored in the memory 31 coincide with each other as the first exposure light irradiation reference position in the memory 31 again. Remember me.

  Subsequently, the color filter substrate 7 is conveyed in the direction of arrow A shown in FIG. The position data of the color filter substrate 7 constantly output from a position sensor (not shown) of the stage 1 is compared with the first exposure light irradiation reference position data stored again in the memory 31. When the two data match, an operation signal for driving the light source 3 to be turned on is output from the light source drive controller 28 to the light source 3, and the light source 3 is turned on for a predetermined time. As a result, exposure light is emitted from the light source 3 for a predetermined time, and the mask pattern 11 of the photomask 10 is exposed onto the pixels 18 of the color filter substrate 7.

  Thereafter, each time the center P0 of each pixel 18 arranged in the transport direction of the color filter substrate 7 is detected, it is stored in the memory 31 as the second and subsequent exposure light irradiation reference positions, and the color filter substrate 7 is transported. Thus, every time the second and subsequent exposure light irradiation positions are reached, an operation signal for lighting the light source 3 is output from the light source drive controller 28 to the light source 3, and the light source 3 is turned on for a predetermined time. Thereby, the mask pattern 11 of the photomask 10 is exposed on each pixel 18 of the color filter substrate 7. Further, by repeating the same operation, the mask pattern 11 of the photomask 10 is exposed on the pixels 18 on the entire surface of the color filter substrate 7.

  In the present embodiment, the case where exposure light irradiation and stop control is performed by controlling the turning on and off of the light source has been described, but the present invention is not limited to this, and exposure light irradiation and You may control a stop.

  Furthermore, in the present embodiment, the case where the illumination means 9 is provided below the stage 1 to provide the back illumination has been described, but the present invention is not limited to this, and the illumination means 9 may be provided above the stage 1 to provide epi-illumination. .

  In the above description, the case where the object to be exposed is the color filter substrate 7 has been described. However, the present invention is not limited to this, and the object to be exposed is provided with a predetermined reference pattern in a matrix. Anything may be used.

It is a conceptual diagram which shows embodiment of the exposure apparatus by this invention. It is the top view and sectional drawing of a photomask used in the said exposure apparatus. It is a top view of the color filter board | substrate used in the said exposure apparatus. It is detail drawing of the alignment mark formed in the said color filter substrate. It is explanatory drawing which shows optical distance correction | amendment of the imaging means with which the said exposure apparatus was equipped. It is a block diagram which shows schematic structure of the control means of the said exposure apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Stage 2 Mask stage 3 Light source 4 Condensing lens 5 Imaging means 6 Control means 7 Color filter substrate 10 Photomask 11 Mask pattern 14 Imaging window 17 Alignment marks 17a and 17b Fine line pattern

Claims (5)

A stage for placing an exposure object having an exposure area set on the surface thereof on the upper surface, and transporting the exposure object in a setting direction of the exposure area;
A mask stage disposed above the stage and holding a photomask in close proximity to the object to be exposed;
A light source that irradiates exposure light to the object to be exposed through a photomask held on the mask stage;
An exposure apparatus including a condensing lens disposed between the light source and a mask stage and configured to convert exposure light applied to the photomask into parallel light;
A plurality of light receiving elements arranged in a straight line in a direction substantially orthogonal to the conveying direction of the object to be exposed, provided near the exposure start position on the surface of the object to be exposed and outside the exposure area, and orthogonal to each other; An imaging means for imaging an alignment mark composed of a plurality of thin lines;
The image data picked up by the image pickup means is processed, and the thin lines that are substantially parallel to the arrangement direction of the plurality of light receiving elements are recognized as a reference position in the transport direction of the exposed body by the plurality of thin lines orthogonal to each other. An exposure apparatus comprising: control means for controlling exposure light irradiation timing to the object to be exposed with a position separated from the reference position set in advance as an exposure start position. The mask stage includes a plurality of fine lines perpendicular to each other provided on the surface of the object to be imaged captured by the imaging unit, and fine line image data substantially orthogonal to the arrangement direction of the plurality of light receiving elements, 2. The exposure apparatus according to claim 1, further comprising a displacement unit that measures a shift amount from set data and corrects the position of the photomask so that the photomask can be displaced. The alignment mark composed of a plurality of thin lines orthogonal to each other is at least two thin lines substantially orthogonal to the arrangement direction of the plurality of light receiving elements and one thin line substantially parallel to the arrangement direction. The exposure apparatus according to claim 1 or 2.   The line width of at least two fine lines substantially orthogonal to the arrangement direction of the plurality of light receiving elements is 15 to 25 μm, and the line width of one thin line substantially parallel to the arrangement direction is 25 to 35 μm. The exposure apparatus according to claim 3. The exposure apparatus according to claim 1, wherein the light source is a flash lamp that is turned on and off by the control unit.