JP2012027271A - Exposure device, exposure method and method for manufacturing color filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exposure device in which a mask can be initially arranged so as not to be inclined to a substrate transfer direction, in a continuous exposure system for small masks that exposes using small masks arranged in a direction perpendicular to the substrate transfer direction while continuously transferring substrates.SOLUTION: On a transfer stage 2, an alignment mark 8 is provided as a reference in adjusting an initial position of a photomask 4. A driving mechanism 6 that holds the photomask 4 within an exposure head 3 not only moves the photomask 4 in parallel but also rotates the photomask 4 to adjust its inclination to a transfer direction (y axis). In adjusting the initial position of the photomask 4, a positional relationship between the alignment mark 8 and a pattern on the photomask 4 is determined from an image captured by an imaging device 7, and an inclination of the photomask 4 is adjusted by the driving mechanism 6 so that each line in an image forming pattern on the photomask 4 is aligned in a direction perpendicular to the transfer direction based on a position of the alignment mark 8.

Description

  The present invention relates to an exposure apparatus and an exposure method used for forming a colored layer of a color filter. The present invention also relates to a method for manufacturing a color filter.

  In order to reduce manufacturing costs, a plurality of color filters used for liquid crystal display devices and touch panels are generally formed side by side on a single large glass substrate (mother glass). With the spread of large-sized liquid crystal display devices and the like, the size of the glass substrate is also increasing. However, if a photomask having a size that can be exposed on the front surface of the glass substrate is manufactured, the manufacturing cost is significantly increased. . Therefore, in order to reduce the cost of the photomask used in the exposure process of the colored layer, various exposure methods using a plurality of photomasks smaller than the glass substrate (hereinafter referred to as “small mask exposure method”) have been studied.

  In the small mask exposure method, multiple small photomasks are arranged in a direction orthogonal to the substrate transport direction, and the pattern on the photomask is repeated by irradiating the substrate with light from a light source while continuously transporting the substrate. Transcript. As the light source, either a continuously lit light source or a flashing light source can be used. When a flashing light source is used, the substrate is transported by a predetermined pitch each time the light source is turned on, so that multiple shot exposures are performed while sequentially moving the photomask in one direction.

  During exposure, the light shielding layer (black matrix or wiring layer) on the substrate is imaged with a camera, and the exposure target area is detected from the captured image to align the photomask. Specifically, the positional relationship between the photomask and the substrate in the direction orthogonal to the transport direction is obtained based on the image pattern of the substrate photographed through the pattern observation opening provided in the photomask, and the photomask is appropriate. Make adjustments so that they are positioned. In addition, when a flashing light source is used, the position of the photomask opening and the exposure target portion (pixel) on the substrate in the transport direction need to be aligned at the time of lighting. The conveyance speed is adjusted.

  Note that when the photomask is inclined with respect to the transport direction of the substrate, the colored layer is shifted from the grid-shaped light-shielding layer provided on the substrate. Therefore, when the photomask is set on the exposure head, it is important that the openings on the photomask are accurately aligned in a direction perpendicular to the transport direction.

  Here, a conventional method for adjusting the initial position of the photomask will be described.

  FIG. 5 is a schematic diagram for explaining a small mask exposure method.

  Above the transfer stage 81, a plurality of photomasks 82 are arranged in two rows. The photomask 82 is aligned in a direction (x-axis direction) perpendicular to the substrate transport direction (y-axis positive direction) at predetermined intervals in each column, and is arranged to be complementary in different columns. ing. The photomask 82 is formed with slits (not shown) for exposing a colored layer of the same color of the color filter. Each of the photomasks 82 is attached to an exposure head having a light source.

  On the substrate 83 to be exposed, a plurality of exposure regions 84 are formed in a matrix at predetermined intervals, and a plurality of alignment marks 85 are formed. Each exposure area 84 corresponds to one color filter. The exposure region 84 is a region partitioned by a light shielding layer such as a black matrix, and openings corresponding to a plurality of pixels are formed by the light shielding layer patterned in a grid shape. The alignment mark 85 is used to adjust the initial position of the photomask 82, and details thereof will be described later.

  FIG. 6 is a diagram for explaining a conventional method for adjusting the initial position of a photomask.

  After the photomask 82 is attached to the exposure head, first, the substrate 83 with the alignment mark 85 is moved from the position indicated by the two-dot chain line in FIG. 6A to the position indicated by the solid line. Using the imaging device 86 disposed below the transfer stage 81, the alignment mark 85 of the substrate 83 is photographed, and the position of the alignment mark recognized in the photographed image is registered as the reference position.

  Next, as illustrated in FIG. 6B, the substrate 83 is pulled out from below the photomask 82, and then the alignment mark on the photomask 82 is photographed by the imaging device 86. While photographing the alignment mark on the photomask 82, the photomask 82 is moved by a driving mechanism (not shown), and the position and inclination of the photomask 82 are adjusted based on the registered reference position. The initial position adjustment of the photomask is performed only once before the production of the product is started, and is not performed after the production is started. This is because the processing tact is not reduced.

JP 2006-292955 A

  FIG. 7 is a diagram for explaining the inclination of the photomask, and FIG. 8 is a diagram for explaining a defect of the color filter due to the inclination of the photomask. In FIG. 7, a two-dot chain line represents an initial position where the photomask should be originally arranged.

  In recent years, since a glass substrate has become larger, exposure processing for forming a light-shielding layer such as a black matrix is not performed on the entire substrate at once, but a photomask smaller than the substrate is arranged in the x-axis direction and the y-axis. It is common to divide into multiple shots while moving in the direction (so-called step exposure). Moreover, since the positional relationship with the light shielding layer needs to be fixed, the alignment mark mentioned above is simultaneously exposed using the same photomask as the light shielding layer.

  However, when stepwise exposing the light shielding layer, there may be variations in the arrangement of the light shielding layer due to the positional deviation of the photomask for light shielding layer exposure or the difference in exposure conditions for each shot. In this case, the position of the alignment mark exposed together with the light shielding layer also varies for each exposure region.

  If the position of the alignment mark provided on the substrate is deviated, the adjustment reference position itself is deviated when the initial position of the colored layer forming photomask is adjusted in the step of FIG. 5 described above. The positional deviation in the x-axis direction or the y-axis direction of the initial position of the photomask can be corrected during the exposure process of the colored layer. For example, the pattern on the light-shielding layer is read by the imaging device, and the position of the light-shielding layer is detected. Correction is made by finely adjusting the position of the photomask 82 so as to follow the change. However, since the inclination of the photomask 82 with respect to the substrate transport direction (y-axis direction) is not corrected during the exposure process, the initial position of the photomask 82 is only an angle θ with respect to the y-axis, as shown in FIG. When tilted, the color layer is significantly displaced depending on the exposure position in the x-axis direction.

  Specifically, when the photomask 82 is inclined at a certain angle with respect to the y-axis, the inclination of the colored layer 88 with respect to the light shielding layer 89 is constant regardless of which part of the photomask 82 is exposed. The positional deviation of the colored layer in the y-axis direction is relatively large at the left side portion and the right side portion of the photomask 82. As a result, as shown in FIG. 8, in the region on the substrate exposed in the left and right portions of the photomask 82, a gap is formed between the colored layer 88 and the light shielding layer 89 (so-called white spots), Defective product will occur.

  Therefore, the present invention relates to a small mask continuous exposure method in which exposure is performed using a small mask arranged in a direction orthogonal to the substrate transport direction while continuously transporting the substrate, and the mask is not inclined with respect to the substrate transport direction. It is an object to provide an exposure apparatus and an exposure method that can be initially arranged. The present invention also relates to a method of manufacturing a color filter that can manufacture a color filter without causing white spots between a light shielding layer and a colored layer on a substrate.

  The present invention relates to an exposure apparatus that performs an exposure process while continuously transporting a substrate in a certain direction. An exposure apparatus according to the present invention includes a transport stage, each of which includes a light source, a photomask, and a drive mechanism that holds the photomask rotatably and parallelly movable in a transport direction and a direction orthogonal thereto. A plurality of exposure heads arranged side by side in a direction perpendicular to the transport direction above the stage, a plurality of alignment marks provided on the transport stage corresponding to each of the exposure heads, an alignment mark, and a pattern on the photomask And an imaging device for photographing When the initial position of the photomask is adjusted, the drive mechanism is configured so that the pixel formation pattern on the photomask is aligned in a direction orthogonal to the transport direction based on the image captured by the imaging device. Correct the tilt.

  The present invention also relates to an exposure method for performing an exposure process while continuously transporting a substrate in a certain direction. In the exposure method of the present invention, a plurality of photomasks are arranged side by side in a direction perpendicular to the substrate transport direction above the transport stage. A plurality of alignment marks provided on the transfer stage corresponding to each photomask and a pattern on the photomask are photographed using an imaging device. When adjusting the initial position of the photomask, the inclination of the photomask relative to the transport direction is corrected so that the pixel formation pattern on the photomask is aligned in a direction perpendicular to the transport direction based on the image captured by the imaging device To do. After correcting the inclination of the photomask, the resist is irradiated with light emitted from the light source through the pixel formation pattern on the photomask while continuously transporting the substrate coated with the resist in the transport direction.

  The present invention also relates to a color filter manufacturing method for manufacturing a color filter in which a light shielding layer and a plurality of colored layers are formed on a substrate. In the color filter manufacturing method according to the present invention, a light shielding layer for partitioning a plurality of pixel formation regions arranged in a matrix is formed on a substrate. A plurality of photomasks are arranged above the transfer stage in a direction orthogonal to the substrate transfer direction. A plurality of alignment marks provided on the transfer stage corresponding to each photomask and a pattern on the photomask are photographed using an imaging device. When adjusting the initial position of the photomask, the inclination of the photomask relative to the transport direction is corrected so that the pixel formation pattern on the photomask is aligned in a direction perpendicular to the transport direction based on the image captured by the imaging device To do. After correction of the photomask tilt, the resist-coated substrate was transported continuously in the transport direction, and the light emitted from the light source was irradiated to the resist through the pixel formation pattern on the photomask, and was partitioned by the light shielding layer. A colored layer covering the pixel formation region is formed.

  According to the present invention, since the alignment mark provided on the transfer stage is used as a reference, the inclination of the photomask at the initial placement can always be made constant.

The top view which shows typically the exposure apparatus of this invention Side view of the exposure apparatus shown in FIG. The figure for demonstrating the initial position adjustment method of the photomask which the exposure apparatus of this invention performs The top view which shows a part of color filter exposed by the exposure apparatus of this invention Schematic diagram for explaining the small mask exposure system The figure for demonstrating the initial position adjustment method of the conventional photomask Diagram for explaining the tilt of the photomask The figure for explaining the trouble of the color filter due to the inclination of the photomask

  FIG. 1 is a plan view schematically showing the exposure apparatus of the present invention, and FIG. 2 is a side view of the exposure apparatus shown in FIG.

  The exposure apparatus 1 includes a transfer stage 2, a plurality of exposure heads 3, and an imaging device 7.

  The transfer stage 2 is a stage serving as a transfer path for the substrate 10. For example, the substrate can be floated by blowing air to the lower surface of the substrate. The transport stage 2 is provided with a plurality of alignment marks 8 at positions corresponding to the lower portions of the exposure heads 3. The alignment mark 8 is used as a reference when adjusting the initial position of the photomask 4 attached to the exposure head 3. It is preferable that the part where the alignment mark 8 is provided is transparent so that the alignment mark 8 can be observed from below the transfer stage 2. The entire transfer stage 2 may be transparent.

  The exposure heads 3 are arranged in two rows above the transport stage 2 in a direction perpendicular to the substrate transport direction (y-axis positive direction). Each of the exposure heads 3 includes a light source 5, a photomask 4, and a drive mechanism 6 that holds the photomask 4 movably. The drive mechanism 6 can not only translate the photomask 4 in the x-axis direction and the y-axis direction but also rotate the photomask 4 to adjust the inclination with respect to the y-axis.

  The imaging device 7 photographs the alignment mark 8 provided on the transport stage 2 and the pattern on the photomask 4. As an example, the imaging device 7 is disposed below the transfer stage 2 as shown in FIG. However, the imaging device 7 may be disposed at a place other than the lower side of the transport stage 2 by bending the optical path of light incident on the imaging device 7 using a mirror or a prism. The pattern to be imaged by the imaging device 7 may be a pixel formation pattern formed on the photomask 4 or an alignment mark provided for positioning. The imaging device 7 may photograph the alignment mark 8 and the pattern on the photomask 4 at the same time, or may photograph in any order. In the latter case, since there is a difference between the z-coordinate of the alignment mark 8 and the z-coordinate of the pattern on the photomask 4, in order to obtain a clear image, the focusing lens provided in the optical system of the imaging device 7 is used in the z-axis direction. Move to to focus. Alternatively, the focus may be adjusted by moving the entire imaging device 7 in the z-axis direction.

  When adjusting the initial position of the photomask 4, the drive mechanism 6 determines the inclination of the photomask 4 and the positions of the photomask 4 in the x-axis direction and the y-axis direction based on the image taken by the imaging device 7. adjust. Hereinafter, this point will be described in detail.

  On the substrate 10, exposure regions partitioned by a light shielding layer such as a black matrix are provided in a matrix at predetermined intervals. In the exposure process of the colored layer, the substrate 10 is held by a transport mechanism (not shown) and continuously transported on the transport stage in the positive y-axis direction. By irradiating the substrate with light from the light source intermittently (when using a flashing light source) or continuously (when using a continuous lighting light source) while transporting the substrate, the resist on the exposure region is patterned.

  FIG. 3 is a view for explaining an initial mask position adjusting method performed by the exposure apparatus of the present invention.

  In FIG. 3, the position where the photomask 4 should be originally arranged is indicated by a two-dot chain line. In addition, the alignment mark 8 serving as a reference for determining the initial position of the photomask 4 is represented by a black circle. The pixel forming pattern 9 provided in a matrix on the photomask 4 is for patterning a colored layer at each pixel position on the substrate, and is typically an opening. A mask may be used.

  The alignment mark 8 on the transfer stage 2 and the pattern on the photomask 4 are detected from the image captured by the imaging device 7 (FIG. 2), and the arrangement of the photomask 4 with respect to the alignment mark 8 is obtained. The positional relationship between the alignment mark 8 and the photomask 4 is obtained by executing predetermined image processing using a control device of the exposure apparatus.

  Here, as shown in FIG. 3A, the photomask 4 is shifted in the x-axis direction and the y-axis direction with respect to the position of the two-dot chain line where the photomask 4 is supposed to be disposed, and the clock with respect to the y-axis. Assume a case where the robot is tilted around the angle θ.

  First, the drive mechanism rotates the photomask 4 in the direction indicated by the arrow in FIG. 3A to correct the inclination of the photomask 4 with respect to the y-axis as shown in FIG. More specifically, the photomask 4 is rotated so that the alignment direction (broken line in FIG. 3B) of each column of the pixel forming pattern 9 provided on the photomask 4 is orthogonal to the transport direction (y-axis). Control the amount.

  Next, the positions of the photomask in the x-axis direction and the y-axis direction with respect to the alignment mark 8 are obtained from the image of the photomask 4 and the alignment mark 8 taken after correcting the rotation angle of the photomask 4. The drive mechanism moves the photomask 4 in the x-axis direction and the y-axis direction so that the photomask 4 is arranged at a predetermined initial position with reference to the alignment mark 8 as shown in FIG. Adjust the position to.

  FIG. 4 is a plan view showing a part of the color filter exposed by the exposure apparatus of the present invention.

  When the photomask is inclined with respect to the y-axis, a location where the positional deviation between the light-shielding layer and the colored layer in the y-axis direction becomes relatively large occurs on the substrate (see FIG. 8).

  On the other hand, in the present invention, instead of using the alignment mark provided on the substrate as in the prior art, the initial alignment of the photomask is performed using the stationary alignment mark provided on the transfer stage. Thereby, since the inclination of the photomask with respect to the conveyance direction can be surely corrected, misalignment between the light shielding layer 13 and the colored layer 12 due to the inclination of the photomask is prevented. Accordingly, during exposure processing of the colored layer, the position of the photomask is finely adjusted in the x-axis direction or the y-axis direction following the pattern of the light-shielding layer, thereby opening the light-shielding layer 13 as shown in FIG. The colored layer 12 can be formed without gaps in the portions. In addition, since the alignment mark provided on the transfer stage is used as a position reference, the initial position of the photomask can be adjusted in the same way even if the size of the substrate, the exposure area partitioned on it, and the type of photomask change. Can do.

  In this embodiment, both the rotation angle of the photomask and the positions in the x-axis and y-axis directions are corrected. However, the alignment in the x-axis direction and the y-axis direction is also performed during the exposure process. Therefore, at the initial positioning stage, only the rotation angle of the photomask may be corrected, and adjustment in the x-axis and y-axis directions may be omitted.

  The number of imaging devices is not particularly limited, and may be one or the same as the number of exposure heads. When the number of imaging devices is smaller than the number of exposure heads, the imaging device can be moved in the x-axis direction and shared by a plurality of exposure heads, and the initial position of the photomask is adjusted while appropriately moving the imaging devices in the x-axis direction. It can be performed.

  The present invention can be used in an exposure apparatus that performs an exposure process when manufacturing a color filter or the like.

DESCRIPTION OF SYMBOLS 1 Exposure apparatus 2 Conveyance stage 3 Exposure head 4 Photomask 5 Light source 6 Drive mechanism 7 Imaging apparatus 8 Alignment mark 9 Pixel formation pattern

Claims (4)

An exposure apparatus that performs exposure processing while continuously transporting a substrate in a certain direction,
A transfer stage;
Each has a light source, a photomask, and a drive mechanism that holds the photomask in a freely rotatable manner and in a direction parallel to the transport direction, and orthogonal to the transport direction above the transport stage. A plurality of exposure heads arranged side by side in a direction to
A plurality of alignment marks provided on the transfer stage corresponding to each of the exposure heads;
An imaging device that photographs the alignment mark and a pattern on the photomask;
The drive mechanism is configured such that when the initial position of the photomask is adjusted, the pixel formation pattern on the photomask is aligned in a direction orthogonal to the transport direction based on an image taken by an imaging device. An exposure apparatus that corrects an inclination of the photomask with respect to a transport direction.   2. The exposure apparatus according to claim 1, wherein at the time of adjusting the initial position of the photomask, the drive mechanism further adjusts the transport direction of the photomask and a position in a direction perpendicular thereto. An exposure method for performing an exposure process while continuously transporting a substrate in a certain direction,
Above the transfer stage, a plurality of photomasks are arranged in a direction perpendicular to the transfer direction of the substrate,
Photographing a plurality of alignment marks provided on the transfer stage corresponding to each of the photomasks and a pattern on the photomask using an imaging device,
When adjusting the initial position of the photomask, based on the image photographed by the imaging device, the pixel formation pattern on the photomask is aligned in a direction orthogonal to the transport direction, and Correct the tilt of the photomask,
Irradiating the resist with light emitted from a light source through the pixel formation pattern on the photomask while continuously transporting the substrate coated with a resist in the transport direction after correcting the inclination of the photomask; Exposure method. A color filter manufacturing method for manufacturing a color filter in which a light shielding layer and a colored layer of a plurality of colors are formed on a substrate,
Forming a light shielding layer on the substrate for partitioning a plurality of pixel formation regions arranged in a matrix;
Above the transfer stage, a plurality of photomasks are arranged in a direction perpendicular to the transfer direction of the substrate,
Photographing a plurality of alignment marks provided on the transfer stage corresponding to each of the photomasks and a pattern on the photomask using an imaging device,
When adjusting the initial position of the photomask, based on the image photographed by the imaging device, the pixel formation pattern on the photomask is aligned in a direction orthogonal to the transport direction, and Correct the tilt of the photomask,
After the photomask tilt correction, while continuously transporting the substrate coated with a resist in the transport direction, the resist is irradiated with light emitted from a light source through the pixel formation pattern on the photomask, A method for producing a color filter, comprising forming a colored layer covering a pixel formation region partitioned by the light shielding layer.

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