JP2015004896A - Polarized light irradiation device for photo-alignment, and polarized light irradiation method for photo-alignment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a practical photo-alignment technique capable of more enhancing the in-plane uniformity of an exposure amount by devising a conveyance system.SOLUTION: An irradiation area R is irradiated with light from a light source 3 constituting a long light-emitting part through a polarization element unit 4 and a conveyance system 2 conveys a substrate S in a first direction, to reciprocate it, while allowing it to pass through the irradiation area R. The boundary 40 of each polarization element 41 is along the first direction and the conveyance system 2 conveys the substrate S in a second direction, after forward conveyance and before backward conveyance. Since the position of the boundary 40 is brought into a displaced state, when viewed from the substrate S, the exposure amount becomes uniform.

Description

  The invention of the present application relates to a polarized light irradiation technique performed when performing photo-alignment.

  In recent years, when obtaining an alignment film of a liquid crystal display element such as a liquid crystal panel or an alignment layer of a viewing angle compensation film, a technique called photo-alignment in which alignment is performed by light irradiation has been adopted. Hereinafter, films and layers in which alignment is caused by light irradiation are collectively referred to as a photo-alignment film. Note that “orientation” or “orientation treatment” is to give directionality to some property of an object.

  Photo-alignment is performed by irradiating polarized light to a film for a photo-alignment film (hereinafter referred to as a film material). The film material is made of resin such as polyimide, for example, and the film material is irradiated with polarized light polarized in a desired direction (direction to be oriented). By irradiation with polarized light having a predetermined wavelength, the molecular structure (for example, side chain) of the film material is aligned in the direction of the polarized light, and a photo-alignment film is obtained.

  The photo-alignment film has been enlarged with the enlargement of the liquid crystal panel in which it is used. For this reason, the width of the required irradiation region of polarized light is 1500 mm or more, which has been remarkably widened. As a polarized light irradiation apparatus that irradiates polarized light to such a wide irradiation region, there is an apparatus disclosed in Patent Document 1, for example. This apparatus includes a rod-shaped light source having a length corresponding to the width of the irradiation region and a wire grid polarizing element that polarizes light from the light source, and is transported in a direction perpendicular to the longitudinal direction of the light source. The material is irradiated with polarized light. Since it is necessary to irradiate polarized light having a wavelength in the visible to ultraviolet range for photo-alignment, an ultraviolet light source such as a high-pressure mercury lamp is often used as the rod-shaped light source.

JP 2006-126464 A Japanese Patent No. 4815995

  An important index for the quality of the photo-alignment treatment is the uniformity of the exposure amount. In the case of the uniformity of the exposure amount, it does not simply mean that the integrated exposure amount is uniform in the plane of the film material, but how much the polarized light is irradiated in a uniform amount. In other words, it is necessary to minimize the amount of unpolarized light (hereinafter referred to as non-polarized light) and to make the exposure amount uniform in a state where only polarized light is irradiated. When exposure is performed in a state that contains a large amount of non-polarized light locally, even if the exposure dose distribution as a whole is uniform, only that portion of the light is not sufficiently aligned. That is, the quality is lowered in terms of the uniformity of photo-alignment.

What becomes a problem from the viewpoint of uniform irradiation of polarized light is the finite nature of the polarizing element. The wire grid polarizing element is excellent as one capable of polarizing light in the visible to ultraviolet range, but it is difficult to manufacture a large size. For this reason, a plurality of wire grid polarizing elements arranged in a unit are used to cover the irradiation area.
When a plurality of wire grid polarization elements are arranged, non-polarized light is irradiated from the boundary portion (contact portion of the end face) of each polarization element, and photo-alignment processing can be performed at a position immediately below the boundary portion of each polarization element. Can not. When the photo-alignment process is performed in such a non-uniform illuminance distribution, the photo-alignment state is insufficient in the region of the surface of the workpiece (film material) that passes through the position immediately below the boundary of each polarizing element. In-plane uniformity of the photo-alignment treatment is reduced.

  In consideration of such a problem, in Patent Document 1, a light shielding plate is provided so as to block the boundary portion of each polarizing element so that light is not emitted from the boundary portion. By arranging the light shielding plate, the exposure amount is reduced in the region that has passed the position immediately below the light shielding plate, but it is better than being irradiated with a lot of non-polarized light and the optical orientation becomes locally insufficient. Is an idea. Decreasing the illuminance of polarized light at a position directly below the light shielding plate can increase the output of the light source to increase the illuminance as a whole, or lengthen the irradiation distance to mitigate the decrease in illuminance. In the following description, illuminance and exposure amount mean illuminance and exposure amount for polarized light.

Moreover, in order to eliminate the problem of illuminance reduction at a position immediately below the light shielding plate, Patent Document 2 discloses a structure in which two light irradiators each composed of a light source and a polarizing element unit are arranged in the workpiece conveyance direction. . In this structure, the boundary lines of the wire grid polarizing elements in the polarizing element unit are not aligned on the same straight line in the two light irradiators, and the arrangement is shifted in a direction perpendicular to the workpiece transport direction. ing. When a workpiece is added between two light irradiators and irradiated with polarized light, the surface of the work that has passed a position immediately below the boundary line (that is, a position immediately below the light shielding plate) in one light irradiator. Even in the area, the other light irradiator does not pass through the position immediately below the boundary line, so the exposure amount becomes uniform as a whole.
Although these techniques of Patent Document 1 and Patent Document 2 can irradiate polarized light with a certain degree of uniformity, they cannot sufficiently cope with a case where high productivity is required or higher uniformity is required. There is a face.

On the other hand, in such a photo-alignment technique, the object (work) for irradiation with polarized light is a long object (hereinafter referred to as a long work) in which film materials are continuously connected. In some cases, the substrate already provided on the substrate and having a film material is a workpiece. When such a plate-shaped object is a workpiece, there are various variations in the conveyance system, and the degree of freedom is large. Therefore, it is considered that by devising the transport system, it is possible to compensate for non-uniform illuminance distribution due to the use of the light shielding plate and realize a highly uniform light alignment process.
The invention of the present application has been made in consideration of the above points, and the significance of providing a practical photo-alignment technique capable of increasing the in-plane uniformity of the exposure amount by devising the transport system. have.

In order to solve the above-mentioned problem, the invention described in claim 1 of the present application includes a light irradiator that irradiates a set irradiation region with polarized light, and a conveyance system that conveys the workpiece so as to pass through the irradiation region. A polarized light irradiation device for photo-alignment,
The light irradiator includes a light source that forms a long light-emitting portion, and a polarizing element unit disposed between the light source and the irradiation region,
The polarizing element unit is composed of a plurality of polarizing elements arranged along the longitudinal direction of the light emitting unit,
The workpieces are separated one by one, and the conveyance system conveys the workpiece by moving the workpiece holder that holds the workpiece,
The conveyance system conveys the workpiece so as to pass through the irradiation region by moving the workpiece holder in a first direction intersecting the longitudinal direction of the light emitting unit, and the boundary of each polarization element in the polarization element unit. The workpiece holder can be moved in a second direction that intersects the direction of the line,
The movement of the work holder in the second direction by the transport system has a configuration in which there is something that relatively displaces the position of the boundary line of each polarizing element viewed from the work in the second direction during light irradiation. .
In order to solve the above-mentioned problem, the invention according to claim 2 is the configuration according to claim 1, wherein the work holding body holding the work moves the irradiation area in the first direction by the transport system. The workpiece holding body is reciprocated so as to pass, and the transport system is configured to move in the second direction before the backward movement after the forward movement is completed. Have.
In order to solve the above-mentioned problem, the invention according to claim 3 is the configuration according to claim 1, wherein the transport system moves in the second direction while moving in the first direction. It is the structure which performs this movement.
Moreover, in order to solve the said subject, invention of Claim 4 is the structure of the said Claim 1, The said light irradiation device is a 1st 2nd several light irradiation device,
The boundary line of each polarizing element in the first light irradiator and the boundary line of each polarizing element in the second light irradiator are shifted from each other in the second direction.
In order to solve the above-mentioned problem, the invention according to claim 5 irradiates the irradiation area with light from the light source forming a long light emitting section through the polarizing element unit, and conveys the work so as to pass through the irradiation area. A polarized light irradiation method for photo-alignment that irradiates the work with polarized light for photo-alignment,
The polarizing element unit is composed of a plurality of polarizing elements arranged along the longitudinal direction of the light emitting unit,
The workpieces are separated one by one, and the workpiece is transferred by moving the workpiece holder that holds the workpiece.
The work holder is moved in a first direction that intersects the longitudinal direction of the light emitting unit to transport the work so as to pass through the irradiation region, and the second crossing the direction of the boundary line of each polarizing element in the polarizing element unit. A method of moving the work holder in two directions,
By conveying the work holder in the second direction, the position of the boundary line of each polarizing element viewed from the work is relatively displaced in the second direction during light irradiation.
In order to solve the above-mentioned problem, the invention according to claim 6 is the configuration according to claim 5, wherein the movement in the first direction is such that the work holding body holding the work passes through the irradiation region. The workpiece holding body is reciprocated, and has a configuration in which the second movement is performed before the backward movement after the forward movement is completed.
In order to solve the above problem, the invention according to claim 7 is that, in the configuration of claim 5, the movement in the second direction is performed while the movement in the first direction is being performed. It has a configuration.
Moreover, in order to solve the said subject, invention of Claim 8 is a structure of the said Claim 5, WHEREIN: The said light irradiation device is a 1st 2nd several light irradiation device,
The boundary line of each polarizing element in the first light irradiator and the boundary line of each polarizing element in the second light irradiator are shifted from each other in the second direction.

As described below, according to the invention of claim 1 or 5 of the present application, when the work is transported in the first direction and passed through the irradiation region, the work is transported in the second direction to remove the work from the work. Since the position of the boundary line of each polarizing element as seen is relatively displaced in the second direction, the exposure amount on the irradiated surface of the workpiece to be passed becomes uniform regardless of the presence of the boundary line.
According to the invention described in claim 2 or 6, in addition to the above effect, the work is reciprocated, which is suitable when a large amount of exposure is required. In addition, since the work is loaded and collected on one side of the irradiation region, the structure and operation are simplified.
Further, according to the invention of claim 3 or 7, in addition to the above effect, the transport in the second direction is performed during the transport in the first direction, so the tact time is shortened and the productivity is reduced. Will improve.
According to the invention described in claim 4 or 8, in addition to the above effect, since a plurality of light irradiators are provided, it is easy to increase the exposure amount, and in two polarizing element units, the polarizing element Since the boundary line is shifted, the exposure amount becomes uniform. And since the conveyance of the 2nd direction is introduce | transduced, an exposure amount can be made further uniform.

1 is a schematic perspective view of a polarized light irradiation apparatus for photo-alignment according to an embodiment of the present invention. 2 is a schematic cross-sectional view of the light irradiator 1 shown in FIG. 1, (1) is a schematic cross-sectional view in the direction of the short side of the irradiation region R, and (2) is a schematic cross-sectional view in the direction of the long side of the irradiation region R. FIG. FIG. 2 is a schematic perspective view of a stage 5 shown in FIG. 1. 6 is a schematic plan view of stage moving mechanisms 61 and 62 provided in the transport system 2. FIG. 6 is a schematic front view of stage moving mechanisms 61 and 62 provided in the transport system 2. FIG. It is the plane schematic which showed operation | movement of the conveyance system 2 in the apparatus of embodiment. It is the plane schematic shown about the movement distance to the 2nd direction in the apparatus of embodiment. It is a perspective schematic diagram of the polarization light irradiation apparatus for photo-alignment concerning a second embodiment. It is the top view which showed roughly the arrangement position of each polarization element unit 4 in a second embodiment. It is the plane schematic which showed operation | movement of the conveyance system 2 in the apparatus of 2nd embodiment. It is the plane schematic shown about the movement distance to the 2nd direction in the apparatus of 2nd embodiment. It is the plane schematic shown about the polarized light irradiation apparatus and method for photo-alignment of 3rd embodiment. It is a figure which shows the result of the experiment which confirmed that integrated exposure amount became uniform by introduce | transducing conveyance of the board | substrate S to a 2nd direction.

Next, modes for carrying out the present invention (hereinafter referred to as embodiments) will be described.
FIG. 1 is a schematic perspective view of a polarized light irradiation apparatus for photo-alignment according to an embodiment of the present invention. The polarized light irradiation device shown in FIG. 1 is a device that performs photo-alignment processing on a plate-like workpiece (hereinafter referred to as a substrate) S such as a liquid crystal substrate with a film material.
Specifically, the apparatus of FIG. 1 includes a light irradiator 1 that irradiates polarized light to a set irradiation region R, and a transport system 2 that transports the substrate S so as to pass through the irradiation region R. Yes. As shown in FIG. 1, the irradiation region R is set as a rectangular horizontal region. The light irradiator 1 includes a light source 3 forming a long light emitting unit. The longitudinal direction of the light emitting part of the light source 3 coincides with the direction of the long side of the irradiation region R.

2 is a schematic cross-sectional view of the light irradiator 1 shown in FIG. 1, (1) is a schematic cross-sectional view in the direction of the short side of the irradiation region R, and (2) is the direction of the long side of the irradiation region R. FIG. As shown in FIG. 2, the light irradiator 1 includes a light source 3 that forms a long light-emitting portion, and a polarizing element unit 4 that is disposed between the light source 3 and the irradiation region R.
As the light source 3, a rod-shaped high-pressure mercury lamp is used. In addition, a metal halide lamp or LED may be used. The rod-shaped light source 3 is an example of the light source 3 that forms a long light-emitting portion. However, it can be said that the light sources 3 arranged in a line also form a long light-emitting portion.

  A mirror 31 is disposed behind the light source 3 (on the side opposite to the irradiation region R). The mirror 31 is a long one extending in the longitudinal direction of the light source 3, covers the back of the light source 3, reflects light to the irradiation region R side, and improves the light use efficiency. The mirror 31 forms an arc or a parabola in which the cross-sectional shape of the reflecting surface is an ellipse.

  The polarizing element unit 4 includes a plurality of polarizing elements 41 and a frame 42 that holds the plurality of polarizing elements 41. In this embodiment, each polarizing element 41 is a wire grid polarizing element 41. Each polarizing element 41 has a rectangular plate shape, and is arranged in the longitudinal direction of the light emitting portion of the light source 3. Therefore, the boundary line of each polarizing element 41 is perpendicular to the longitudinal direction of the light emitting portion.

The frame 42 holding the polarizing elements 41 has a rectangular frame shape that is long in the direction in which the polarizing elements 41 are arranged.
A light shielding plate 43 is provided so as to cover each boundary line 40. The light shielding plate 43 prevents unpolarized light from being emitted from the boundary 40.
Further, the light source 3 and the mirror 31 are accommodated in a lamp house 32. The polarizing element unit 4 is attached to the light irradiation opening of the lamp house 32.

The transport system 2 transports the substrate S by moving the work holder holding the substrate S. In this embodiment, the stage 5 is used as the work holder. FIG. 3 is a schematic perspective view of the stage 5 shown in FIG.
As shown in FIGS. 1 and 3, the stage 5 has a square shape, and holds the substrate S at substantially the center on the upper side. The stage 5 includes holding pins 51 so as to hold the substrate S at a position slightly lifted from the upper surface. The holding pins 51 are integrally held by the stage 5, and when the stage 5 moves, the held substrate S also moves together.
Four holding pins 51 are provided at square corner positions. In addition, depending on the size of the substrate S, it may be provided at the center position. Each holding pin 51 has a tubular shape and is connected to a vacuum exhaust system (not shown), and sucks the substrate S by vacuum suction from an opening at the upper end.

  The contact position of the holding pin 51 with respect to the substrate S is a position where there is no problem in the manufacturing process of the product using the substrate S. For example, when the substrate S is for manufacturing a liquid crystal display and a plurality of liquid crystal displays are manufactured from a single substrate, the holding pins 51 come into contact with each other at a location outside the area used for manufacturing each liquid crystal display. To.

The transport system 2 includes stage moving mechanisms 61 and 62 that move the stage 5 for transporting the substrate S. 4 and 5 are schematic views of the stage moving mechanisms 61 and 62 provided in the transport system 2, FIG. 4 is a schematic plan view, and FIG. 5 is a schematic front view.
In this embodiment, the transport system 2 transports the substrate S in the first and second two different directions. The first direction is a horizontal direction perpendicular to the longitudinal direction of the light emitting part formed by the light source 3. The second direction is a direction that intersects the direction of the boundary line 40 of each polarizing element 41 in the polarizing element unit 4. In this embodiment, the second direction is a horizontal direction perpendicular to the direction of the boundary line 40 of each polarizing element 41. As described above, since the polarizing element unit 4 is arranged so that the direction of each boundary line 40 is in the horizontal direction perpendicular to the longitudinal direction of the light emitting portion, the first direction is equal to the direction of each boundary line 40. The second direction is a horizontal direction perpendicular to the direction of each boundary line 40.

The transport in the first direction is the main transport, and is a transport for transporting the substrate S from the mounting position of the substrate S to the irradiation region R and for allowing the substrate S to reach the collection position while passing through the irradiation region R. . The conveyance in the second direction is conveyance for making the exposure amount in the plane of the substrate S uniform.
As shown in FIG. 1, the transport system 2 includes a first stage moving mechanism 61 that moves the stage 5 in the first direction and a second stage moving mechanism 62 that moves the stage 5 in the second direction. I have. The stage 5 is mounted on the base plate 21, and the first stage moving mechanism 61 moves the stage 5 by moving the base plate 21. The second stage moving mechanism 62 is fixed to the base plate 21 and moves the stage 5 on the base plate 21.

  In this embodiment, a substrate mounting position is set on one side of the irradiation region R. The first stage moving mechanism 61 includes a first ball screw 611 extending from the substrate mounting position toward the irradiation region R, and a pair of first screws extending in parallel with the first ball screw 611 on both sides of the first ball screw 611. One linear guide 612 and a first drive source 613 for driving the first ball screw 611 are included.

As shown in FIG. 1, the first ball screw 611 and the pair of first linear guides 612 extend horizontally through the irradiation region R. A first drive source 613 is connected to one end of the first ball screw 611, and the other end is supported by a bearing. Both ends of the pair of first linear guides 612 are supported by bearings.
A first driven block 22 that is screwed into the first ball screw 611 (with which the screw is engaged) is fixed at substantially the center of the lower surface of the base plate 21. A pair of first guide blocks 23 is fixed to the lower surface of the base plate 21. The fixed position of the first guide block 23 corresponds to the positions of the first linear guides 612 on both sides. Bearings are provided in the first guide block 23, and linear guides on both sides penetrate the first guide block 23.

The first drive source 613 is a motor such as an AC servo motor. When the first drive source 613 rotates the ball screw, the base plate 21 and the stage 5 are guided by the pair of first linear guides 612. Move linearly together. Thereby, the substrate S held on the stage 5 is transported in the first direction.
The second stage moving mechanism 62 includes a second ball screw 621 fixed on the base plate 21, a pair of second linear guides 622 also fixed on the base, and a second ball screw 621. Is fixed from a second drive source 623 or the like for driving the motor.

The second ball screw 621 and the pair of second linear guides 622 are fixed so as to extend in the second direction. A second driven block 24 that is screwed into the second ball screw 621 is fixed at the center of the lower surface of the stage 5. A pair of second guide blocks 25 are fixed to the lower surface of the stage 5. The fixed position of the second guide block 25 corresponds to the positions of the second linear guides 622 on both sides. Bearings are provided in the second guide block 25, and linear guides on both sides penetrate the second guide block 25.
When the second drive source 623 rotates the ball screw, the stage 5 moves linearly on the base plate 21 while being guided by the pair of second linear guides 622. Thereby, the substrate S held on the stage 5 is transported in the second direction.

FIG. 6 is a schematic plan view showing the operation of the transport system 2 in the apparatus of the embodiment. As shown in FIG. 6A, in the initial state, the stage 5 is located at the substrate mounting position. When the substrate S is placed on the stage 5 and held by the holding pins 51, the transport system 2 drives the first drive source 613 to advance the base plate 21 and the stage 5 in the first direction. . When the stage 5 reaches the first advance limit position, the first drive source 613 is stopped. As shown in FIG. 6B, the first advance limit position is a position where the substrate S on the stage 5 completely passes through the irradiation region R. “Completely passing” means that the trailing edge of the substrate S passes through the irradiation region R.
The transport system 2 stops the base plate 21 and the stage 5 at the first advance limit position, and then operates the second drive source 623 to move the stage 5 on the base plate 21 in the second direction. The second drive source 623 stops when the stage 5 reaches the second advance limit position (FIG. 6 (3)).

  Next, the transport system 2 operates the first drive source 613 again to move the base plate 21 and the stage 5 in the first direction and in the opposite directions. That is, the first drive source 613 is operated so that the first ball screw 611 rotates in the reverse direction. The first drive source 613 stops when the stage 5 passes through the irradiation region R again and reaches the substrate recovery position (FIG. 6 (4)).

As shown in FIG. 4, the polarized light irradiation apparatus includes a control unit 7 that controls each unit of the apparatus. In addition, sensors (not shown) for monitoring the positions of the base plate 21 and the stage 5 are provided at various locations, and signals from the sensors are sent to the control unit 7. Furthermore, in the apparatus according to the embodiment, it is assumed that the robot mounts the substrate S on the stage 5 and collects the exposed substrate S from the stage 5. It is designed to exchange signals.
The control unit 7 is mounted with a sequence program for optimally controlling each unit including each drive source of the transport system 2. The sequence program sends a control signal to each part in accordance with a signal from the sensor, and operates the transport system 2 as shown in FIG.

In the transport system 2, the moving distance of the second direction (indicated by in FIG. 7 d _m) is optimized in terms of the exposure amount uniform in the plane of the substrate S. Hereinafter, this point will be described with reference to FIG. FIG. 7 is a schematic plan view showing the movement distance in the second direction in the apparatus of the embodiment.
The reason why the stage 5 is moved in the second direction in addition to the first direction is to avoid the problem of non-uniform exposure amount due to the decrease in illuminance at the position immediately below the boundary line 40 described above. . As described above, in the apparatus of the embodiment, the transport system 2 reciprocates the stage 5 in the first direction. At this time, the stage 5 does not return through the same route, but is shifted slightly in the horizontal direction so as to return through a different route.

When the substrate S passes through the irradiation region R in the forward path and the return path, if the path is the same path, the location on the substrate S that has passed immediately below the boundary line 40 in the forward path is also immediately below the boundary line 40 in the return path. Will pass the position. In such transport of the substrate S, the uneven exposure amount due to local illuminance reduction is not eliminated.
On the other hand, when the substrate S returns through a different route, the portion on the substrate S that has passed the portion where the illuminance decreases on the forward path returns through the portion that is not the portion where the illuminance decreases on the return path. As a result, the exposure amount becomes uniform.

However, in this embodiment, there are a plurality of boundary lines 40 formed by a plurality of polarizing elements 41 (three or more polarizing elements 41). Therefore, the moving distance d _m in (integral multiples Distance or d _a) the distance of the boundary line 40 between the d _a will match, areas on the substrate S passing through the position of low intensity in the forward even backward illumination Therefore, the exposure dose is not uniformized. Accordingly, the moving distance d _m in the second direction, the distance of the polarizing element unit border 40 each polarization element 41 forms at 4 (hereinafter, the boundary line 40 between the distance) if it is outside the integral multiple of d _a Good (d _m ≠ n · d _a , n is an integer). In terms of tact time, the moving distance d _m is preferably short. Accordingly, the moving distance _{d m is} appropriately determined within a range of _d m <d _a.

Also, if the moving distance d _m may be Hazurere degree from a distance da between the boundary line 40, the situation illumination intensity in the region immediately below the respective boundaries 40 by what is is. 7 shows the moving distance d _m in the second _direction, with the distance d _a between the boundary lines 40, the illuminance distribution is shown schematically in the region immediately below the boundary line 40. The illuminance distribution shown here is the illuminance distribution on the straight line in the second direction passing through the position immediately below the boundary line 40 in the irradiation region R.
As shown in FIG. 7A, when the decrease in illuminance distribution is limited to a very narrow region at a position immediately below the boundary line 40, the moving distance dm exceeds the width w on one side of the region where the illuminance decrease occurs. A short distance is enough.

On the other hand, as shown in FIG. 7 (2), when the width w of the area illumination intensity has occurred to some extent wider, the moving distance d _m to exceed the width w but is set, width w, each boundary It does not exceed half of the line 40 between the distance _{d a.} Accordingly, the moving distance _{d m} would it is sufficient to 1/2 of each boundary line 40 between the distance _{d a.} That is, if d _m = d _a / 2, _a uniform exposure amount can be achieved regardless of the width w. However, in the case where the width w is small, d _m <d _a / 2 may be satisfied, and the tact time may be shortened by reducing the moving distance in the second direction.

The width w is also optimized from the relationship with the required exposure uniformity. For example, if the exposure dose uniformity is ± 5%, the width w is the width on one side of a region where the maximum illuminance is reduced by 10% or more.
In any case, the moving distance d _m is stored in the storage unit as a control value previously input to the control unit 7. Then, it is sent to the second drive source 623 as an operation amount.

The overall operation of the light distribution polarized light irradiation apparatus of the embodiment according to the above configuration will be described below. The following description is also a description of an embodiment of the invention of the polarized light irradiation method for light distribution.
The control unit 7 turns on the light source 3. Light from the light source 3 passes through each polarizing element 41 to become polarized light and is irradiated to the irradiation region R. The transport system 2 positions the base plate 21 and the stage 5 at a substrate mounting position that is a standby position.

  The substrate S to be photo-aligned is transported to the polarized light irradiation device by a lot transport mechanism such as AGV (Auto Guided Vehicle) or a single wafer transport mechanism such as an air conditioner bearer. Then, a single substrate S is mounted on the stage 5 by a robot (not shown). The substrate S is placed on each holding pin 51 and is vacuum-sucked on each holding pin 51.

  Upon receiving a substrate mounting completion signal from the robot, the control unit 7 sends a signal to the transport system 2 to perform the above-described series of transport operations. Thereby, the stage 5 reciprocates while passing through the irradiation region R, and the polarized light is irradiated onto the substrate S on the stage 5 during the passage. In the return path, the path shifted by the movement distance dm is moved, and each point in the surface of the substrate S is uniformly exposed.

When the base plate 21 reaches the substrate recovery position, the control unit 7 turns off vacuum suction and then sends a signal to the robot to recover the substrate S from the stage 5. In this embodiment, the backward moving distance is the same as the forward movement distance, thus the substrate recovery position is shifted from the amount corresponding substrate mounting position of the moving distance d _m in the second direction. The robot is taught in advance to collect the substrate S at this substrate collection position.

  According to the polarized light irradiation apparatus or polarized light irradiation method of the embodiment related to the configuration and operation described above, the transport system 2 reciprocates the substrate S while passing through the irradiation region R, and the forward transport is completed. Thereafter, by moving in the second direction before carrying the return path, the return path is made different from the forward path, and the movement distance dm at that time is the distance da between the boundary lines 40 in each polarizing element 41. Therefore, a decrease in illuminance at a position immediately below the boundary line 40 of each polarizing element 41 is compensated, and the exposure amount in the plane of the substrate S becomes uniform.

Next, the apparatus and method of the second embodiment will be described.
FIG. 8 is a schematic perspective view of a polarized light irradiation apparatus for photo-alignment according to the second embodiment. The apparatus of the second embodiment shown in FIG. 8 includes two light irradiators 1. The structure of each light irradiator 1 is substantially the same as that of the apparatus of the first embodiment.
As shown in FIG. 8, in the two light irradiators 1, the longitudinal direction of the light emitting part of the light source 3 is a horizontal direction perpendicular to the first direction. In the two light irradiators 1, the arrangement of the polarizing elements 41 in the polarizing element unit 4 is shifted from each other. This point will be described with reference to FIG. FIG. 9 is a plan view schematically showing the arrangement position of each polarizing element unit 4 in the second embodiment.

As shown in FIG. 9, in the two light irradiators 1, the polarizing element unit 4 has basically the same structure, but the arrangement positions of the polarizing elements 41 are slightly different. That is, each polarizing element 41 of one polarizing element unit 4 is arranged so as to be shifted in the longitudinal direction of the light emitting portion of the light source (not shown in FIG. 9) with respect to each polarizing element 41 of the other polarizing element unit 4. . In this embodiment, the deviation amount is ½ of the width t of each polarizing element 41.
In order to obtain such a shifted position, the size and shape of the frame 42 and each polarizing element 41 and the number of each polarizing element 41 are the same in the two polarizing element units 4, and the mounting position with respect to the lamp house 32 is set. It may be set as a shifted position.

  FIG. 10 is a schematic plan view showing the operation of the transport system 2 in the apparatus of the second embodiment. Also in the second embodiment, the transport system 2 moves the stage 5 holding the substrate S in the first direction and the second direction, and the movement in the first direction is a reciprocating motion, and the forward path The substrate S passes through the irradiation region R in both the return path and the return path, and at this time, the substrate S is irradiated with polarized light. The movement in the second direction is performed between the forward movement and the forward movement, and the substrate S passes through the irradiation distance through different paths in the forward path and the return path. In addition, the two light irradiators 1 irradiate each irradiation region R with polarized light.

FIG. 11 is a schematic plan view showing the movement distance in the second direction in the apparatus of the second embodiment. Note that FIG. 11 also shows the case where the movement in the second direction is not performed for reference. 11 (1) does not move, (2) moves.
11 (1) (2), the illuminance distribution by the first light irradiation device 1 shown in I _1, showing the illuminance distribution by the second light irradiation device 1 in I _2. I ₁ and I ₂ are illuminance distributions on a straight line in the second direction passing through a position immediately below each boundary line 40, as in FIG. E indicates the distribution of the exposure amount in the surface of the substrate S after the end of the reciprocal conveyance.

  As can be seen from the above description, the substrate S sequentially passes through each irradiation region R in the forward path and the return path, and is irradiated with polarized light. Therefore, the exposure amount E is the sum of the exposure amounts when passing through each irradiation region R. In this case, even when the stage 5 does not move in the second direction (when the stage 5 reciprocates along the same path), the arrangement of the polarizing elements 41 is deviated, so as shown in FIG. It becomes uniform to some extent.

In the apparatus of the second embodiment, the movement distance dm in the second direction is optimally set in order to further uniform the exposure amount. As shown in FIG. 7 (1), in the distribution of the exposure amount E when the movement in the second direction is not performed, the location where the exposure amount takes the minimum value is any of the two polarizing element units 4. This is a location that passes directly below the boundary line 40 in the polarizing element unit 4. In the second embodiment, the two polarizing element units 4 are arranged so as to be shifted by a half (t / 2) of the width of the single polarizing element 41. Therefore, the interval between the positions where the minimum value is taken is also t / 2. Become. Since the place where the minimum value is taken is the place that passes directly below the boundary line 40 of any of the polarizing element units 4, it can be said that the distance between the boundary lines _da is t / 2.

Therefore, in order to make the exposure amount more uniform from the state shown in FIG. 7A, since the distance between boundary lines da = t / 2, the moving distance dm must be equal to t / 2 (or an integer multiple thereof). It would be good.
Then, the width w of the one side of the region where the exposure amount is decreased is essentially similar to the case shown in FIG. 7, it does not exceed 1/2 of the boundary line 40 between the distance d _a. Therefore, as in the case of the first embodiment, it is optimal to set the movement distance d _m = d _a / 2 = t / 4 (or a natural number multiple thereof).
In the case of the second embodiment, the width w of the side illumination intensity region is selected according to the degree of exposure uniformity required, if a narrow width w, the moving distance d _m is t / 4 It may be a shorter distance.

Next, the apparatus and method of the third embodiment will be described. FIG. 12 is a schematic plan view showing the polarized light irradiation apparatus and method for photo-alignment of the third embodiment.
The apparatus of the third embodiment is different from the first and second embodiments in conveyance by the conveyance system 2. In the first second embodiment, the transport of the substrate S in the first direction is a reciprocating motion, and the transport in the second direction is performed between the forward transport and the backward transport. In the embodiment, the conveyance in the first direction and the conveyance in the second direction are performed simultaneously. That is, the control unit 7 sends a signal to the first drive source 613 and the second drive source 623 to cause the first drive source 613 and the second drive source 623 to operate simultaneously. However, the operation of the second drive source 623 need not always be performed during the operation of the first drive source 613, and may be performed only while the substrate S is passing through the irradiation region R.

FIG. 12 shows a preferable transport of the substrate S in the third embodiment, in which the in-plane uniformity of the light amount becomes higher. As shown in FIG. 12A, when the substrate S is transported in the first direction and the leading edge reaches the edge of the irradiation region R, the transport in the second direction starts. It is preferable that the conveyance in the second direction is completed when the irradiation region R is completely passed. 12 (1), a chain line shows the locus of a point P ₁ with the front edge of the substrate S, the two-dot chain line shows the locus of a point P ₂ with a trailing edge.

In addition to the case shown in FIG. 12 (1), as shown in FIG. 12 (2), the movement in the second direction is performed across time zones including the time zone passing through the irradiation region R. But it ’s okay. Furthermore, as shown in FIG. 12 (3), the movement in the second direction is not linear but may be zigzag.
In all cases shown in FIG. 12 also, the moving distance d _m in the second direction is the same as the embodiment described above. Note that in either embodiment, the moving distance d _m is, it is required that does not match an integer multiple of the boundary line between the distance a, this addition, the movement in the second direction even substrate S part It must be ensured that the irradiation region R is not deviated.

In the third embodiment, the substrate S can be transported only in the forward path. In this case, the substrate S is mounted on the stage 5 on one side of the irradiation region R, and the substrate S is recovered from the stage 5 on the other side. If only the forward transport is performed, the tact time is shortened, which is preferable in terms of productivity.
However, also in the third embodiment, the substrate S may be irradiated with polarized light by performing reciprocal conveyance. In this case, it is preferable to carry out the conveyance in the second direction at the same time while passing through the irradiation area R of the forward path and the backward path.

  If the substrate S is irradiated with polarized light by reciprocal conveyance, the exposure amount is doubled compared to the case of only the forward path (when the conveyance speed is not changed). Therefore, it is suitable for a photo-alignment process that requires a large amount of exposure. When the substrate S is reciprocated, the substrate S can be mounted and collected on one side of the irradiation region R, so that the structure of the apparatus and its surroundings is simplified. Although the tact time is increased by the amount of the return path, the tact time can be shortened by increasing the conveyance speed.

  In each of the embodiments described above, the movement of the work holder in the second direction by the transport system 2 causes the position of the boundary line 40 of each polarizing element 41 viewed from the substrate S to be in the second direction during light irradiation. It can be said that they are relatively displaced. Since the position of the boundary line 40 is relatively displaced during light irradiation, the area where the illuminance decreases due to the influence of the boundary line 40 is displaced in the plane of the substrate S, thereby achieving uniform exposure. To do.

  In each embodiment, the transport of the substrate S in the first direction is a direction perpendicular to the longitudinal direction of the light emitting portion of the light source 3, but is not limited thereto. The conveyance in the first direction is for the substrate S to pass through the irradiation region R, and it is sufficient that the substrate S intersects the longitudinal direction of the light emitting part of the light source 3. Even if the polarized light is irradiated while transporting the substrate S in a direction oblique to the longitudinal direction of the light emitting portion of the light source 3, the uneven exposure amount due to the presence of the boundary line 40 of each polarizing element 41 is compensated. And uniform exposure can be performed. Also in this case, the amount of exposure becomes more uniform when the movement in the second direction is introduced.

The second direction is a direction perpendicular to the direction of the boundary line 40 of each polarizing element 41 in each of the above embodiments and examples, but is not limited to this. Even if the substrate S is transported along the direction of the boundary line 40, the effect of uniforming the amount of exposure cannot be obtained. However, if the direction intersects the direction of the boundary line 40, the effect can be obtained.
In each embodiment and example, the stage 5 is employed as an example of a member that holds the substrate S during conveyance, and members other than the stage 5 may be employed.

Further, as the transport system 2, in addition to the above-described ball screw rotated by a driving source, a transport mechanism (linear motor stage) using magnetism as disclosed in, for example, Japanese Patent No. 4581641 may be adopted. is there. In this mechanism, a stage 5 provided with a magnetic pole is disposed on a platen having magnetic poles arranged in a grid pattern on the upper surface, and the stage 5 is slightly floated from the platen by air injection or the like, This is a mechanism for moving the stage 5 by controlling the polarity of. Even when this mechanism is employed, it is preferable to provide linear guides on both sides for guiding the movement of the stage 5 in order to maintain accuracy in the transport direction of the substrate S.
A transport mechanism using magnetism and a transport mechanism using a ball screw and a drive source as described above may be used in combination. For example, it is conceivable to use a transfer mechanism (linear motor stage) using magnetism for transfer in the first direction, and to use a transfer mechanism using a ball screw and a drive source for transfer in the second direction. .

In the first and second embodiments, the substrate recovery position is a position shifted by the movement distance dm in the second direction with respect to the substrate mounting position, but the substrate S is recovered at the same position as the substrate mounting position. You may do it. In this case, after the base plate 21 and the stage 5 are moved on the return path by the same distance as the forward path, an operation for moving the base plate 21 and the stage 5 in the second direction in the opposite direction is added. Although the tact time is somewhat longer, the robot always loads and collects the substrate S at the same position, which is simplified in this respect.
Note that the workpieces do not have to be plate-shaped as long as they are separated one by one and held by the workpiece holder. The term “separated” is intended to exclude strips that are connected in a roll and roll-to-roll.
In addition, the present invention can be applied to a structure in which a light shielding plate is not provided at a boundary portion between a plurality of polarizing elements of a polarizing element unit in the sense of compensating for a decrease in illuminance of polarized light.

Next, the result of an experiment that confirms that the exposure amount becomes uniform by introducing the transport of the substrate S in the second direction as described above will be described as an example. FIG. 13 is a diagram illustrating a result of an experiment for confirming that the integrated exposure amount becomes uniform by introducing the transport of the substrate S in the second direction.
In this experiment, the width of the irradiation region R viewed in the second direction was 1500 mm, the light source 3 was a high-pressure mercury lamp, and the average illuminance in the irradiation region R was about 130 mW / cm ² .

  The width t of each polarizing element 41 is 150 mm, and therefore the distance between the boundary lines is 150 mm. FIG. 13 (1) shows the exposure amount distribution when the substrate S is transported and irradiated with polarized light on the same path in the forward path and the return path without moving in the second direction, and (2 ) Shows an exposure amount distribution in which the exposure amount distribution is more uniform when the return path is transported after moving about 75 mm in the second direction after the forward path. The exposure amount distribution is a distribution in the second direction as in FIGS.

As shown in FIG. 13 (1), when the movement in the second direction is not performed, a portion where the exposure dose is greatly reduced periodically is observed. The location where the exposure value is a minimum value is a location that has passed a position immediately below the boundary line 40 of each polarizing element 41. In this example, the minimum value was about 70.4% with respect to the maximum value (uniformity of ± 14.8%).
On the other hand, in the example in which the movement in the second direction of about 80 mm was introduced, the uniformity was greatly improved as shown in FIG. In this example, the minimum value was about 85% with respect to the maximum value (± 7.5% uniformity). As described above, it was found that the uniformity of the exposure amount is greatly improved by appropriately introducing the movement in the second direction.

DESCRIPTION OF SYMBOLS 1 Light irradiator 2 Conveyance system 21 Base plate 3 Light source 4 Polarizing element unit 40 Boundary line 41 Polarizing element 43 Light-shielding plate 5 Stage 61 First stage moving mechanism 611 First ball screw 612 First linear guide 613 First Drive source 62 Second stage moving mechanism 611 Second ball screw 612 Second linear guide 613 Second drive source 7 Control unit S Substrate R Irradiation region

Claims (8)

A polarized light irradiation device for photo-alignment comprising a light irradiator that irradiates polarized light to a set irradiation region, and a transport system that transports a workpiece so as to pass through the irradiation region,
The light irradiator includes a light source that forms a long light-emitting portion, and a polarizing element unit disposed between the light source and the irradiation region,
The polarizing element unit is composed of a plurality of polarizing elements arranged along the longitudinal direction of the light emitting unit,
The workpieces are separated one by one, and the conveyance system conveys the workpiece by moving the workpiece holder that holds the workpiece,
The conveyance system conveys the workpiece so as to pass through the irradiation region by moving the workpiece holder in a first direction intersecting the longitudinal direction of the light emitting unit, and the boundary of each polarization element in the polarization element unit. The workpiece holder can be moved in a second direction that intersects the direction of the line,
The movement of the work holder in the second direction by the transport system is to relatively displace the position of the boundary line of each polarizing element viewed from the work in the second direction during light irradiation. A polarized light irradiation device for photo-alignment.   The movement in the first direction by the transfer system is to reciprocate the workpiece holder so that the workpiece holder holding the workpiece passes through an irradiation area, and the transfer system is configured to move in the forward direction. The polarized light irradiation apparatus for light distribution according to claim 1, wherein the movement in the second direction is performed before the return path movement after completion.   2. The polarized light irradiation apparatus for light distribution according to claim 1, wherein the transport system moves in the second direction when moving in the first direction. . The light irradiator is a first and second plurality of light irradiators,
The boundary line of each polarizing element in the first light irradiator and the boundary line of each polarizing element in the second light irradiator are shifted from each other in the second direction. A polarized light irradiation apparatus for photo-alignment as described in 1. For light alignment, which irradiates the irradiation area with light from the light source that forms a long light-emitting section, and irradiates the workpiece with polarized light for photo-alignment by transporting the workpiece through the irradiation area. A polarized light irradiation method,
The polarizing element unit is composed of a plurality of polarizing elements arranged along the longitudinal direction of the light emitting unit,
The workpieces are separated one by one, and the workpiece is transferred by moving the workpiece holder that holds the workpiece.
The work holder is moved in a first direction that intersects the longitudinal direction of the light emitting unit to transport the work so as to pass through the irradiation region, and the second crossing the direction of the boundary line of each polarizing element in the polarizing element unit. A method of moving the work holder in two directions,
Polarizing light for photo-alignment characterized in that the position of the boundary line of each polarizing element viewed from the work is relatively displaced in the second direction during light irradiation by transporting the work holder in the second direction Light irradiation method.   The movement in the first direction is to reciprocate the work holding body so that the work holding body holding the work passes through the irradiation region, and before the backward movement after the forward movement is completed. 6. The method for irradiating polarized light for light distribution according to claim 5, wherein the movement in the second direction is performed.   The polarized light irradiation method for light distribution according to claim 5, wherein the movement in the second direction is performed while the movement in the first direction is being performed. The light irradiator is a first and second plurality of light irradiators,
The boundary line of each polarization element in the first light irradiator and the boundary line of each polarization element in the second light irradiator are shifted from each other in the second direction. The polarized light irradiation method for photo-alignment according to claim 5.

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