JP4307062B2 - Exposure method and exposure apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an exposure method and an exposure apparatus.
[0002]
[Prior art]
As an apparatus for patterning a large substrate, a device that relatively moves a substrate and a photomask having a smaller area than the substrate and sequentially exposes a mask pattern to a plurality of exposure regions on the substrate is known (Patent Document). 1). This technique is used, for example, to form a pattern corresponding to one color filter in one exposure region and to take out a plurality of color filters from one substrate.
[0003]
[Patent Document 1]
JP 2000-347020 A
[Problems to be solved by the invention]
In the above-described technique, even if exposure is performed as designed, it may not be possible to perform exposure at an appropriate exposure position. For example, in recent years, a substrate from which a plurality of color filters are taken out and a substrate from which a plurality of TFT substrates are taken out are bonded together and then divided, and the bonded color filters and TFT substrates are taken out. . In this case, the position of the exposure region is set in the design stage so that the exposure region corresponding to the color filter and the exposure region corresponding to the TFT substrate are bonded to each other when the substrates are bonded to each other. However, due to various causes such as deformation of the substrate due to heat treatment after exposure and wrinkles of the aligner of the exposure apparatus, the exposure area of the substrate deviates from the originally planned position, and even if the substrates are bonded together, all the exposure areas It may not be possible to match the positions of each other.
[0005]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an exposure method capable of following another substrate with respect to the position of the exposure region on the substrate in an exposure method for sequentially exposing a plurality of exposure regions on the substrate.
[0006]
[Means for Solving the Problems]
The present invention will be described below. In order to facilitate understanding of the present invention, reference numerals in the accompanying drawings are appended in parentheses, but the present invention is not limited to the illustrated embodiment.
[0007]
In the exposure method of the present invention, the stage (2) of the exposure apparatus (1) and the photomask (4) are moved relative to each other in a plurality of exposure regions (100a ... 100a) of the exposure target substrate (100) on the stage. In the exposure method for performing sequential exposure, the same number of reference areas (101a... 101a) as the plurality of exposure areas to be copied as a reference with respect to the positions of the plurality of exposure areas on the exposure target substrate, and the periphery of the reference area An alignment mark (51, 51) arranged on the same surface is formed on the same surface, and a reference substrate (101) capable of transmitting light is mounted with the surface on which the reference region is formed on the stage of the exposure apparatus. location and, above upon combined sequentially positioning the photomask with respect to the respective reference region based on the transmission image of the alignment mark that has been transmitted through the upper side of the reference substrate follower Obtaining a relative positional relationship between the mask and the stage for each reference region; and a surface for exposing the exposure target substrate to the stage of the same exposure apparatus as the exposure apparatus on which the reference substrate is placed. Based on the relative positional relationship between the photomask and the stage acquired for each reference area, the position of each of the plurality of exposure areas on the exposure target substrate is specified. A step of exposing a pattern to each region, and each of the plurality of reference regions of the reference substrate and each of the plurality of exposure regions of the substrate to be exposed are bonded to each other, Solve the above-mentioned problems.
[0008]
If the photomask is sequentially aligned with respect to each reference area, the position of each position relative to the stage of the photomask when aligned is the same as the position of each reference area. According to the exposure method of the present invention, the relative positional relationship between the photomask and the stage when the photomask is sequentially aligned with respect to each reference area is obtained for each reference area. Is indirectly grasped as the arrangement of each position with respect to the stage of the photomask. Therefore, the position of each of the plurality of exposure areas on the exposure target substrate is specified based on the acquired relative positional relationship between the photomask and the stage, thereby following the arrangement of the reference areas of the reference substrate. An exposure area can be arranged on the exposure target substrate. Further, for example, when the position of the reference region is directly detected by scanning a laser on the reference substrate, and the photomask and the stage are moved relative to each other based on the detected position, the exposure of the photomask is performed. Due to a displacement (mis-attachment) of the mounting position with respect to the apparatus, a wrinkle of the drive device to be relatively moved, a displacement occurs between the detected position to be exposed and a position where the photomask is actually covered. However, according to the exposure method of the present invention, based on the relative positional relationship between the photomask and the stage when the photomask is actually aligned with the reference region, the photomask and the stage at the time of exposure are relatively Since it is moved, the error as described above is eliminated.
[0009]
When the photomask and the stage are moved relative to each other, the relative movement between the photomask and the stage is made to match the relative position between the photomask and the stage acquired for each reference area. It is also possible to correct the relative positional relationship between the photomask and the stage acquired for each reference region in consideration of various circumstances, and the corrected positional relationship and the relative relationship between the photomask and the stage. Relative movement may be performed so as to match the correct positional relationship.
[0010]
Further , since the position of the exposure region is determined in accordance with the substrate to be bonded of the exposure target substrate, the position of the exposure region and the position of the reference region can be accurately matched when the two are bonded. Note that the reference substrate is preferably a substrate that has undergone all the steps that are performed before being bonded to the exposure target substrate. In this case, for example, a shift in the position of the reference region due to the deformation of the reference substrate that occurs in various processes such as a thermal process is reflected in the position of the exposure area on the exposure target substrate.
[0011]
In the exposure method of the present invention, the reference substrate may be an exposure target substrate exposed by an exposure apparatus different from the exposure apparatus. In this case, when the same type of exposure target substrate is exposed by a plurality of exposure apparatuses, the arrangement of the exposure areas can be unified with high accuracy. When a plurality of exposure apparatuses are of the same model, a method of transferring data on the relative positional relationship between the photomask and the stage for each reference area acquired in one exposure apparatus to another exposure apparatus is also conceivable. However, there is a difference in the wrinkles of driving devices for driving the stage between exposure apparatuses of the same model, and in the method of transferring data, the exposure area is shifted between the exposure apparatuses. Since the exposure method of the present invention can eliminate the influence of wrinkles of the driving device, the preferred embodiment of the present invention described above can arrange the exposure area even when the plurality of exposure devices are the same model. It is effective to unify with high accuracy.
[0012]
A first reflecting means (23) that moves following the movement of the photomask in a predetermined direction and reflects a laser, and a second reflecting means (22) that moves integrally with the stage and reflects the laser. ) And the laser reflected by the first reflecting means and the second reflecting means to measure the relative positional relationship between the first reflecting means and the second reflecting means In the step of arranging and obtaining an interferometer (20), the first reflecting means that measures the relative positional relationship between the photomask and the stage for each reference region with the laser interferometer; You may acquire based on a relative positional relationship with a 2nd reflection means. In the exposure method of the present invention, the exposure area can be more accurately aligned with the reference area as the relative positional relationship between the photomask and the stage is obtained more accurately. Therefore, by accurately measuring the relative positional relationship between the photomask and the stage using a laser interferometer, the exposure area can be accurately aligned with the reference area.
[0013]
The exposure apparatus of the present invention (1) is an exposure apparatus for implementing any of the above exposure method, and moved with movement of a predetermined direction of the photomask, a first reflection reflecting the laser Means (23), a second reflecting means (22) that moves integrally with the stage and reflects the laser, and receives the laser reflected by the first reflecting means and the second reflecting means. The above-described problem is solved by providing a laser interferometer (20) that measures the relative positional relationship between the first reflecting means and the second reflecting means. According to the exposure apparatus of the present invention, it is possible to realize a preferable aspect of the above-described exposure method of the present invention.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a side view showing a configuration of an exposure apparatus 1 of the present invention. The exposure apparatus 1 is configured as an apparatus that exposes a color filter CF substrate 100 (exposure target substrate) when patterning a color filter used in a liquid crystal display panel by photolithography.
[0015]
The CF substrate 100 is made of, for example, a glass substrate, and a resist is applied in a thin film shape on the surface. The CF substrate 100 is formed with a thickness of 1 mm and an area of 4 m ² , for example. From one CF substrate 100, six color filters are taken out. Therefore, as shown in FIG. 5B, the exposure apparatus 1 exposes the six exposure regions 100a... 100a on the CF substrate 100. The CF substrate 100 is bonded to a TFT substrate 101 (see FIG. 5A) having six exposure regions 101a... 101a corresponding to six TFT circuits after exposure by the exposure apparatus 1, and then divided. is there.
[0016]
An exposure apparatus 1 in FIG. 1 includes a stage 2 on which the CF substrate 100 is placed, a driving apparatus 3 that drives the stage 2 in the X-axis direction and the Y-axis direction (see FIG. 5B), and an upper side of the stage 2. A photomask 4 arranged, a driving device 5 that drives the photomask 4 in the X-axis direction, the Y-axis direction, and the θ-direction, and a measuring device 6 that measures the relative position between the stage 2 and the photomask 4; Cameras 7 and 7 for imaging the stage 2 from above the photomask 4, a light source 8 disposed above the photomask 4, and a control device 9 are provided.
[0017]
As shown in FIG. 5B, the photomask 4 has a size that covers one exposure region 100a. Further, the photomask 4 includes alignment marks 50 and 50 at positions outside the region corresponding to the exposure region 100a. The cameras 7 and 7 in FIG. 1 are provided at positions where the alignment marks 50 and 50 can be imaged, and output video signals based on the captured images to the control device 9. The driving device 3 and the driving device 5 are configured as, for example, electric motors and controlled by the control device 9.
[0018]
FIG. 2A is a plan view showing the configuration of the measuring device 6. The measuring apparatus 6 includes three types of measurements: a laser interferometer 20, an optical system 21, flat mirrors 22 and 22 (second reflecting means) extending over each of the two sides of the stage 2, and the periphery of the photomask 4. Retro reflectors 23 to 23 (first reflecting means) provided at points x1, x2, and y1.
[0019]
FIG. 2B is an enlarged side view showing the measuring device 6 at one measuring point. In the vicinity of the photomask 4, an attachment portion 24 for attaching the retro reflector 23 is provided. The mounting portion 24 includes a support member 25 that is fixed to the main body (not shown) of the exposure apparatus 1, a shaft portion 26 that is slidable to the left and right with respect to the support member 25, and the periphery of the shaft portion 26. And a coil spring 27 attached to the. The coil spring 27 is attached between the support member 25 and the flange portion 26 a of the shaft portion 26, and presses the end portion 26 b of the shaft portion 26 against the end portion of the photomask 4. A retroreflector 23 is attached to an end portion 26 c on the opposite side of the photomask 4 in the shaft portion 26.
[0020]
The flat mirror 22 has a planar reflecting surface and reflects the vertically incident laser beam L in the opposite direction. The retro-reflector 23 has a polygon mirror on the reflection surface, and reflects the laser light L incident on the reflection surface in the direction opposite to the incident direction. The optical system 21 includes, for example, a half mirror 28 provided between the laser interferometer 20 and the flat mirror 22, and a reflection mirror 29 provided between the half mirror 28 and the retroreflector 23. Yes. Therefore, the laser light L from the laser interferometer 20 is divided into two by the half mirror 28, one of which is incident on the flat mirror 22 and the other is incident on the retroreflector 23 via the reflecting mirror 29. Then, the laser light L reflected by the flat mirror 22 and the retroreflector 23 travels in the opposite direction on the same path and enters the laser interferometer 20.
[0021]
The laser interferometer 20 measures the relative distance between the flat mirror 22 and the retroreflector 23 based on the interference between the reflected light from the flat mirror 22 and the reflected light from the retroreflector 23. The laser interferometer 20 measures the distance to the flat mirror 22 based on the reflected light from the flat mirror 22, and measures the distance to the retro reflector 23 based on the reflected light from the retro reflector 23. The relative distance between them may be measured.
[0022]
As shown in FIG. 2A, the laser interferometer 20 measures the relative position between the stage 2 and the photomask 4 in the Y direction of the points x1 and x2 and the X direction of the point y1. Since the relative position in the Y direction is measured at two points x1 and x2, the relative position in the θ direction can also be specified from the difference between the relative positions of the two. In addition, you may measure by providing three laser interferometers 20 corresponding to three measurement points.
[0023]
A procedure of an exposure method using the exposure apparatus 1 having the above configuration will be described. FIG. 3 is a flowchart showing the procedure of the position measurement process executed by the control device 9. This process is executed, for example, when the user performs a predetermined input operation on the control device 9. This process is based on the premise that a TFT substrate 101 on which six TFT circuits are arranged is placed on the stage 2 as shown in FIG.
[0024]
The TFT substrate 101 is placed with the surface (film surface) to be bonded to the CF substrate 100 facing down. The TFT substrate 101 has already been patterned by an exposure apparatus different from the exposure apparatus 1. Similar to the CF substrate 100, the TFT substrate 101 sequentially exposes the exposure regions 101a to 101a by moving the photomask smaller than the TFT substrate 101 and the TFT substrate 101 relative to each other. The TFT substrate 101 has a plurality of sets of alignment marks 51 and 51 around the exposure regions 101a. The alignment marks 51 and 51 indicate the positions of the exposure regions 101a... 101a. For example, when the exposure region 101a is exposed, the alignment marks 51 are also simultaneously patterned by a photomask. The TFT substrate 101 may be mounted on the stage 2 manually by the user, or may be performed by a transfer device (not shown) of the exposure apparatus 1 for mounting the substrate 100 on the stage 2. Good.
[0025]
In step S1, the control device 9 operates the drive device 3 so that the photomask 4 is positioned above any one of the exposure regions 101a... 101a (for example, (1) in FIG. 5A). The stage 2 is moved under control. This control is performed based on the design position of the exposure areas 101a... 101a recorded in advance in the control device 9, for example.
[0026]
Next, based on the video signal from the camera 7, the control device 9 drives the driving device 3 so that the alignment marks 50, 50 of the photomask 4 and the alignment marks 51, 51 of the exposure area 101 a of (1) are aligned. And operation | movement of the drive device 5 is controlled (step S2).
[0027]
When the alignment is completed, the control device 9 measures the relative position between the stage 2 and the photomask 4 based on the signal from the measurement device 6 (step S3), and records the measured value in its own storage area. (Step S4).
[0028]
In step S5, it is determined whether or not the measurement has been completed for all the exposure regions 101a to 101a. If it is determined that the measurement has not been completed, steps S1 to S4 are repeated, and (2) to (6) The position is sequentially measured up to the exposure area 101a.
[0029]
FIG. 4 is a flowchart showing a procedure of exposure processing executed by the control device 9. This process is executed when the CF substrate 100 is placed on the stage 2. First, the control device 9 selects any one exposure area 101a (for example, FIG. 5) from the relative positions of the photomask 4 and the stage 2 measured for each exposure area 101a... 101a in the position measurement process (FIG. 3). The relative position for (a) (1)) is acquired (step S11). Next, the operations of the driving device 3 and the driving device 5 are controlled to match the relative position with the actual relative position between the photomask 4 and the stage 2 (step S12). Then, the light source 8 is driven to perform exposure (step S13). In step S14, it is determined whether or not the exposure corresponding to all the exposure regions 101a... 101a has been completed. If it is determined that the exposure has not been completed, steps S1 to S3 are repeated, and (2) to (6). ) Exposure regions 101a... 101a are sequentially performed.
[0030]
As described above, in the exposure apparatus 1, the relative position between the photomask 4 and the stage 2 is measured by sequentially aligning the photomask 4 with the exposure regions 101a... 101a in the position measurement process of FIG. As shown in FIGS. 5A and 5B, the relative position between the photomask 4 and the stage 2 when performing exposure of the exposure regions 100a... 100a is matched with the measured relative position. In addition, the exposure regions 100a... 100a can be formed following the positional relationship between the exposure regions 101a.
[0031]
The present invention is not limited to the above embodiment, and may be implemented in various forms as long as it is substantially the same as the technical idea of the present invention.
[0032]
As the reference substrate, any substrate can be used as long as the same number of reference regions as the plurality of exposure regions on the exposure target substrate are formed.
[0033]
For example, the CF substrate 100 exposed by an exposure apparatus different from the exposure apparatus 1 may be used. In this case, alignment marks for alignment with the photomask 4 may be provided in the exposure regions 100a... 100a of the CF substrate 100 serving as the reference substrate, as in the exposure regions 101a. The CF substrate 100 serving as a reference substrate may be one that has been exposed by the exposure method of the present invention using the TFT substrate 101 as a reference substrate.
[0034]
The reference substrate may be another substrate that is bonded to the CF substrate 100 or the TFT substrate 101 and used for a liquid crystal display panel. As the reference substrate, a special substrate for causing the exposure apparatus 1 to follow the position of the exposure region 100a... 100a may be prepared. A pattern may not be formed in the reference region of the reference substrate. For example, only the alignment mark may be patterned around the reference region.
[0035]
Any substrate can be used as long as the substrate and the photomask are moved relative to each other to sequentially expose a plurality of exposure regions. For example, the TFT substrate 101 may be an exposure target substrate.
[0036]
The alignment between the photomask and the reference substrate is not limited to aligning the alignment marks on the photomask and the reference substrate. For example, the edge of the exposure region 101a and the edge of the mask pattern of the photomask may be matched.
[0037]
【The invention's effect】
If the photomask is sequentially aligned with respect to each reference area, the position of each position relative to the stage of the photomask when aligned is the same as the position of each reference area. According to the exposure method of the present invention, the relative positional relationship between the photomask and the stage when the photomask is sequentially aligned with respect to each reference area is obtained for each reference area. Is indirectly grasped as the arrangement of each position with respect to the stage of the photomask. Therefore, based on the acquired relative positional relationship between the photomask and the stage, the position of the plurality of exposure areas on the exposure target substrate is specified, and the pattern is exposed to each area, whereby the reference of the reference substrate The exposure area can be arranged on the exposure target substrate following the arrangement of the area.
[Brief description of the drawings]
FIG. 1 is a side view showing the arrangement of an exposure apparatus according to the present invention.
FIG. 2 is a view showing a measuring apparatus of the exposure apparatus in FIG. 1;
FIG. 3 is a flowchart showing a procedure of position measurement processing executed by the control device of the exposure apparatus of FIG. 1;
4 is a flowchart showing a procedure of exposure processing executed by a control device of the exposure apparatus in FIG. 1;
5 is a plan view showing a state on the stage of the exposure apparatus in FIG. 1. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Exposure apparatus 2 Stage 4 Photomask 20 Laser interferometer 22 Flat mirror 23 Retro reflector 100 CF substrate 100a Exposure area 101 TFT substrate 101a Exposure area

Claims (4)

In an exposure method of sequentially exposing a plurality of exposure areas of an exposure target substrate on the stage by relatively moving the stage of the exposure apparatus and a photomask,
The same number of reference regions as the plurality of exposure regions to be copied as a reference with respect to the positions of the plurality of exposure regions on the exposure target substrate, and alignment marks arranged around the reference region are formed on the same surface , A reference substrate capable of transmitting light is placed on the stage of the exposure apparatus with a surface on which a reference region is formed facing down, and the photomask is based on a transmission image of the alignment mark transmitted above the reference substrate. Obtaining a relative positional relationship between the photomask and the stage for each of the reference regions when sequentially aligning with respect to each of the reference regions;
Place the exposure target substrate on the surface of the same exposure apparatus as the exposure apparatus on which the reference substrate is placed, and place the photomask and the stage acquired for each reference region. A step of identifying each position of the plurality of exposure areas on the exposure target substrate based on a relative positional relationship and exposing a pattern to each area, and
An exposure method characterized in that each of the plurality of reference regions of the reference substrate and each of the plurality of exposure regions of the exposure target substrate are bonded to each other.   The exposure method according to claim 1, wherein the reference substrate is an exposure target substrate exposed by an exposure apparatus different from the exposure apparatus. The first reflecting means that moves following the movement of the photomask in a predetermined direction and reflects the laser, the second reflecting means that moves integrally with the stage and reflects the laser, and the first And a laser interferometer that receives the laser reflected by the reflecting means and the second reflecting means and measures the relative positional relationship between the first reflecting means and the second reflecting means. ,
In the obtaining step, a relative positional relationship between the photomask and the stage for each reference region is measured by the laser interferometer, and the relative relationship between the first reflecting means and the second reflecting means. The exposure method according to claim 1, wherein the exposure method is acquired based on a positional relationship. An exposure apparatus for realizing the exposure method according to any one of claims 1 to 3,
A first reflecting means that moves following the movement of the photomask in a predetermined direction and reflects the laser;
Second reflecting means that moves integrally with the stage and reflects the laser;
A laser interferometer that receives the laser reflected by the first reflecting means and the second reflecting means and measures a relative positional relationship between the first reflecting means and the second reflecting means; An exposure apparatus comprising:

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