JPH1152583A - Proximity aligner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform proximity exposure for a glass substrate whose size a larger than that of a photomask. SOLUTION: A mask holder is constituted of an upper surface mask holder having vacuum windows respectively vacuum-checking the upper surface sides of a set of opposite side parts at the outer peripheral shape of the photomask 3 and a lower surface mask holder 4DR having the vacuum windows respectively vacuum-chucking the lower surface sides of a set of the other opposite side parts at the outer peripheral shape of the photomask 3. A moving means moves an exposure chuck 2 and the glass substrate 1 along the opposed direction of the set of the opposite side parts vacuum-chucked and held by the vacuum window of the upper surface mask holder. An exposure shutter means shields light so as to prevent a part of the photomask 3 from being irradiated with a light beam at the proximity exposure. In the case of performing exposure for the glass substrate having an area larger than that of the photomask 3, the glass substrate 1 and the exposure chuck 2 are moved by the moving means after performing the first exposure, and the light shielding is executed at a part of the photomask 3 corresponding to a part exposed by the first time by the exposure shutter, so that second exposure is performed. Thus, a pattern made by the photomask 3 is formed on the full surface of the glass substrate 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a proximity exposure apparatus for forming a pattern on a glass substrate in a manufacturing process of a liquid crystal display, and more particularly to a proxy exposure apparatus capable of exposing a glass substrate larger than a photomask. The present invention relates to an exposure apparatus.

[0002]

2. Description of the Related Art A liquid crystal display (LCD: Liqui)
d Crystal Display) is a CRT (C
Since it can be made thinner and lighter than an Anode Ray Tube, a CTV (Color Tele Tube) can be used.
vision) and OA equipment, etc., and the screen size is increased to 10 inches or more.
Higher definition and color are also being promoted. Liquid crystal displays are made by drawing a fine pattern on the surface of a glass substrate by photolithography. The exposure apparatus draws this fine pattern on a glass substrate. As the exposure apparatus, there are a projection system in which a mask pattern is projected onto a glass substrate using a lens or a mirror, and a proximity system in which a mask pattern is transferred by providing a minute gap between a photomask and a glass substrate. is there. Although the proximity type exposure apparatus has poor pattern resolution performance compared to the projection type, the irradiation optical system is very simple, the throughput is high, and the cost performance is excellent in terms of the equipment cost. It is suitable for high-volume production equipment.

[0003]

In the proximity type exposure apparatus, positioning control of the glass substrate, that is, so-called proximity gap control is performed so that the distance between the photomask and the glass substrate becomes a minute gap (separation gap). However, increasing the speed of the proximity gap control is an important issue in improving the throughput of the exposure apparatus. However, as the size of the liquid crystal display has increased, the size of the glass substrate has also changed from 300 × 400 mm to 360 × 460 mm to 370 × 470 m, which can take four 10-inch class panels.
m, and the proximity method is now used for glass substrates of 550 x 650 mm or more, which can take 10.4 to 12.1 type panel panels or 6 15 or 15 type panel panels. It has been a proposition to apply the above exposure apparatus. When the size of the glass substrate is increased, there is a problem that it is difficult to speed up the proximity gap control. Hereinafter, this problem will be described with reference to FIG. As shown in FIG. 2, the glass substrate 1 is held by suction on an exposure chuck 2. The exposure chuck 2 is driven and controlled in the Z-axis direction by three tilt drive motors (not shown) to perform proximity gap control. The photomask 3 is suction-held from below by a suction-type mask holder 4 provided over the entire outer periphery thereof. That is, when the shape of the photomask 3 is a square, the mask holder 4 is arranged along the outer periphery of the square. The exposure chuck 2 inserts the glass substrate 1 along the inner wall surface of the mask holder 4. Gap detectors 5B-8
B denotes a gap window 5C to 8C formed of an LED and a CCD linear image sensor and formed in the photomask 3.
, The gap between the glass substrate 1 and the photomask 3 is measured. The tilt drive motor performs proximity gap control such that the detection gap is a gap of about several tens of μm at all four locations. In order to perform the proximity gap control, first, it is necessary to move the exposure chuck 2 in the Z-axis direction by the tilt drive motor to position the glass substrate 1 at the proximity gap control start position. Conventionally, the exposure chuck 2 is moved in the Z-axis direction by a tilt drive motor to position the glass substrate 1 at a proximity gap control start position. However, as the size of the photomask 3 has increased with the size of the glass substrate, air has accumulated in a space surrounded by the photomask 3, the mask holder 4, the glass substrate 1 and the exposure chuck 2, as shown in FIG. This air pocket caused the photomask 3 to bend in a convex shape as shown in the figure. As the exposure chuck 2 rises and stops at the proximity gap control start position, the amount of deflection of the photomask 3 increases, reaches the maximum amount of deflection, and then gradually decreases with the discharge of air accumulated in the space. It shows the property that the amount is also reduced. In the conventional exposure apparatus, the proximity gap control is started when a predetermined time elapses after the exposure chuck 2 stops at the proximity gap control start position. However, when the size of the photomask is increased, the amount of deflection of the photomask 3 does not reach the allowable amount of deflection within a predetermined time, so that a stable gap amount can be obtained even when the proximity gap control is performed after a predetermined time has elapsed. However, there is a problem that the fine condition of the product becomes unstable. In addition, since the gap changes between completion of the proximity gap control and completion of the exposure, the amount of exposure blur increases, and a high-definition product cannot be produced.
In the conventional proximity exposure apparatus, the glass substrate 1 and the exposure chuck 2 must be able to be inserted into the mask holder 4 of the photomask 3. However, a panel of 10.4 to 12.1 type class has 6 panels or 1 panel.
550 x 6 that can take 2 panels of 5 inch class
When performing exposure on a glass substrate 1 having a size of 50 mm or more using a conventional proximity exposure apparatus, the size of the photomask 3 must be sufficiently larger than the glass substrate 1. As the size of the photomask 3 increases, the amount of deflection of the photomask 3 due to its own weight also increases.
And the amount of deflection on the convex as described above also becomes large, and there is a problem that the time until the proximity gap control is greatly increased. When the photomask 3 becomes large,
Accompanying this, there has been a problem that the cost for creating a mask pattern has also increased, which is not preferable from the viewpoint of cost reduction. The present invention has been made in view of the above points, and an object of the present invention is to provide a proximity exposure apparatus capable of stably maintaining fine conditions of a product and producing a high-definition product. Another object of the present invention is to provide a proximity exposure apparatus capable of performing proximity exposure on a glass substrate having a size larger than that of a photomask.

[0004]

According to a first aspect of the present invention, there is provided a proximity exposure apparatus, wherein a gap formed between a photomask surface held by a mask holder and a glass substrate surface held by an exposure chuck is fixed. In a proximity exposure apparatus that performs proximity gap control so that the gap becomes a gap, an upper surface mask holder having an adsorption window for adsorbing the mask holder on the upper surface side of the photomask, and a lower surface side of the photomask And a lower surface mask holder having a suction window for adsorbing the photomask. The suction window of both the upper mask holder and the lower mask holder sucks and holds a portion along the outer peripheral shape of the photomask. . Conventionally, the photomask is held by a mask holder that sucks a portion along the outer peripheral shape only from the lower surface side. However, in the present invention, a lower mask holder that sucks the mask holder from the lower surface and an upper mask holder that sucks the mask holder from the upper surface This eliminates the deflection of the mask holder caused by inserting the glass substrate into the mask holder for exposure, and allows the proximity gap control to be performed faster than the conventional one. The conditions are stabilized, and a high-definition product can be created.

In a proximity exposure apparatus according to a second aspect of the present invention, a gap formed between a photomask surface held by a mask holder and a glass substrate surface held by an exposure chuck becomes a predetermined gap. In a proximity exposure apparatus that performs exposure after performing proximity gap control, the mask holder has an upper surface mask holder having an adsorption window that adsorbs an upper surface of a pair of opposite sides in an outer peripheral shape of the photomask, A lower face mask holder having a suction window for sucking a lower surface of another pair of opposite sides in the outer peripheral shape of the photomask, and a pair of opposite sides held by the suction window of the upper mask holder; Moving means for moving the exposure chuck and the glass substrate along the facing direction of,
Exposure shutter means for blocking light so as not to irradiate a light beam at the time of proximity exposure to a part of the photomask is provided. That is, as in the second invention, a pair of opposing portions in the outer peripheral shape of the photomask are sucked by the suction window of the upper mask holder, so that the mask holder exists on the lower surface side of the photomask in the opposing direction. And the moving means can move the exposure chuck and the glass substrate along the facing direction. Therefore, when performing exposure on a glass substrate larger than the area of the photomask, after performing the first exposure, the glass substrate and the exposure chuck are moved by the moving unit, and the first exposed portion is exposed. The second exposure may be performed after a part of the corresponding photomask is shielded from light by the exposure shutter. This makes it possible to form a pattern using a photomask on the entire surface of the glass substrate.

[0006]

An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 2 is a diagram showing a schematic configuration of a proximity exposure apparatus according to the present invention. In the figure, the loader unit 5, the substrate transport unit 6, and the alignment stage unit 7 are shown, and other parts are omitted. The loader unit 5 sequentially supplies the glass substrates 1A, and employs an inline compatible roller conveyor system. Needless to say, a cassette type system may be used. The loader unit 5 is provided with a water-cooled loader cooling plate 51. The loader cooling plate 51 moves up and down in the loader unit 5 and comes into contact with the glass substrate 1A when ascending to adjust the temperature of the glass substrate 1A, that is, cool the glass substrate 1A.

The substrate transfer unit 6 is composed of three axes of X, θ and Z, and the glass substrate 1A on the loader unit 5
Is transported to the substrate loader centering unit 9 provided above the substrate transport unit 6, and the glass substrate 1 B centered and positioned on the substrate loader centering unit 9 is transported onto the exposure chuck 2. The X and θ axes of the substrate transfer unit 6 are driven by a linear motor, and the Z axis is driven by a servomotor. Here, the direction of the X axis from the loader unit 5 to the alignment stage unit 7 is the + X direction, and the opposite is the -X direction. The details of the substrate transport unit 6 will be described later. Above the substrate transport unit 6 and the substrate loader centering unit 9, a constant-temperature air blowing unit (HEPA unit) 8 is provided. The constant temperature blower unit 8 supplies air adjusted to a set temperature of ± 0.1 ° C. to 0.12 μm.
Are flowed down to the glass substrate 1B through a filter capable of collecting dust, and the temperature of the glass substrate 1B before being conveyed to the exposure chuck 2, that is, cooling is performed. A substrate centering unit 9 for centering the glass substrate 1B before being transferred to the alignment stage unit 7 is provided above the substrate transfer unit 6. The substrate loader centering unit 9 is compatible with various types of glass substrates, and is configured to automatically switch the glass width in the Y-axis direction and perform centering by a pulse motor driving method.

The alignment stage unit 7 includes the exposure chuck 2, a tilting Z stage 10, a glass substrate alignment stage 11, and the like. The exposure chuck 2 sucks and holds the glass substrate 1 transported by the substrate transport unit 6. Tilting Z stage 1
0 is a coarse movement stage that moves up and down the exposure chuck 2 in parallel,
It is composed of a three-point contact type tilt drive motor for tilting the glass substrate 1 and performing proximity gap control. The glass substrate alignment stage 11 has X
The glass substrate 1 is aligned with the photomask 3 by driving the Y and θ axes. In this embodiment,
Before the alignment, the edge of the glass substrate is detected in a non-contact manner using an edge detection sensor (not shown), and the glass substrate alignment stage 11 is detected based on the detected position.
Is driven to perform pre-alignment. Although not shown in FIG. 2, the substrate alignment stage 11 is provided with a step table for directly moving the exposure chuck 2 holding the glass substrate 1 in the X-axis direction. The step table is positioned by closed loop control using an optical linear scale.

The periphery of the photomask 3 is suction-held by an upper mask holder 4U and lower mask holders 4DF and 4DR. FIG. 3 shows the upper mask holder 4U and the lower mask holders 4DF and 4DF.
It is a figure which shows the detail of DR. The upper surface mask holder 4U holds the upper surface portions near the left and right sides along the Y-axis direction of the photomask 3 by vacuum suction with the suction windows 42 and 43. The top mask holder 4U has a rectangular shape when viewed from the top as shown in the figure. The suction windows 42 and 43 are provided at a portion in contact with the photomask 3. The lower mask holder 4DF holds the lower surface of the photomask 3 near the front surface along the X-axis direction by vacuum suction using a suction window. The lower surface mask holder 4DR vacuum-adsorbs and holds the lower surface portion near the rear surface side of the photomask 3 along the X-axis direction by an adsorption window. In this manner, the photomask 3 is held by vacuum suction on the four sides near the four sides by the upper mask holder 4U and the lower mask holders 4DF and 4DR in the same manner as the conventional mask holder. The deflection of the mask 3 under its own weight can be minimized.

Note that rectangular gap windows 5C to 8C are provided at the four corners of the photomask 3 as in the prior art.
On the upper surface side of the photomask 3, gap windows 5C and 6C
, And an alignment detector for performing alignment (high-precision alignment) between the photomask 3 and the glass substrate 1 based on reflected light from an alignment pattern provided on the glass substrate 1. However, since it is not directly related to the description of the present invention, it is omitted here. Also, in this embodiment, before the photomask 3 is vacuum-adsorbed and held by the upper mask holder 4U and the lower mask holders 4DF and 4DR, three reference pins 31 to 31 are provided.
Positioning by pin alignment is performed by 33 and three pusher pins 34 to 36. That is, since the reference pins are fixed, these reference pins 31 to 33
By pressing the three pusher pins 34 to 36 against the, positioning by pin alignment is performed. When the pin alignment is completed, the photomask 3 is held by the upper mask holder 4U and the lower mask holders 4DF and 4DR by vacuum suction, respectively, and the glass substrate 1
The proximity gap between the photomask 3 and the photomask 3 is controlled using a gap detector, and thereafter, high-precision alignment is performed using an alignment detector. In the high-precision alignment, the amount of movement of a microscope (not shown) and the amount of displacement of the alignment mark from the center of the alignment detector are obtained based on the photomask 3 and are fed back to the glass substrate alignment stage 11 to obtain the photomask 3. And the glass substrate are aligned. The alignment stage unit 7 has an optical system for irradiating the photomask 3 on the glass substrate 1C with ultraviolet rays from an exposure unit (not shown). Note that an exposure shutter (not shown in FIG. 2) is provided to control the ultraviolet light from the exposure unit so as not to irradiate the glass substrate in the already exposed area.

FIG. 4 is a diagram showing a detailed configuration of the exposure shutter. The exposure shutter 71 emits ultraviolet light from the exposure unit, and is attached to the shutter arm 72. The shutter arm 72 is a slide guide 73
, And slide along the shutter direction, that is, the X-axis direction. The slide guide 74 has driving means for reciprocatingly driving the shutter arm 72, that is, the exposure shutter 71 in the X-axis direction. This driving means is a motor 7
5 and pulleys 76 and 77 and a belt 78. The motor 75 and the pulley 76 are directly connected. The belt 78 and the shutter arm 72 are also directly connected. Motor 7
The rotational driving force of No. 5 is converted into linear driving force of the shutter arm 72 by the pulleys 76 and 77 and the belt 78.
Therefore, by controlling the rotation direction and rotation speed of the rotation of the motor 75, the reciprocating movement speed and position of the shutter arm 72, that is, the exposure shutter 71 in the X-axis direction are controlled. The protruding portions 7A of the belt 78 are detected by the photo sensors 70 and 79 provided near the pulleys 76 and 77, the origin is returned accordingly, and the runaway of the motor is prevented. This photo sensor is for returning to the origin (photo sensor 70).
Or just Further, the photo sensors 70 and 79 may detect a coupling member between the shutter arm 72 and the belt 78.

Next, the exposure operation of the proximity exposure apparatus of the present invention will be described with reference to FIG. FIG. 1 is a view of a part of the alignment stage unit 7 of FIG. 2 as viewed from the back side (−Y direction) of the drawing. That is, the glass substrate 1 is transported from the right side to the exposure chuck 2 by the substrate transport unit 6, and then transported to the unloader unit side by another substrate transport unit (not shown). FIG. 1A shows a state after the photomask 3 is suction-held by the upper mask holder 4U and the lower mask holders 4DF and 4DR, and the glass substrate 1 is transferred onto the exposure chuck 2 by the substrate transfer unit 6. . This state is called the origin position for convenience. A control unit that controls the operation of the proximity exposure apparatus from the state of the origin position includes:
The process proceeds as follows. First, the Z-axis of the substrate alignment stage 11 is driven to raise the glass substrate 1, the exposure chuck 2, and the step table 41 to position them at a predetermined step start position. Step table 41
To move the glass substrate and the exposure chuck 2 stepwise toward the unloader unit (+ X direction). Here, the unloader unit is located on the opposite side of the loader unit 5 and is not shown in the drawing. The three-point contact type tilt drive motor is driven to raise the glass substrate 1 to the proximity control position. Then, after a predetermined time has elapsed, proximity gap control is performed using a gap detector, and high-precision alignment is performed using an alignment detector. The first exposure is performed by retracting the respective detection systems, that is, the gap detector and the alignment detector. The Z-axis of the substrate alignment stage 11 is driven to lower the glass substrate 1, the exposure chuck 2, and the step table 41 to the above-described step position, and then the step table 41 is step-moved toward the loader unit 5 (-X direction). Let it. Similarly, the proximity gap control, high-precision alignment, and retraction of the detection system are performed, and the exposure shutter 71 is advanced from the loader unit 5 side to the upper portion of the glass substrate 1 and the photomask 3, and the exposure is already performed in the first exposure. The second exposure is performed while shielding the exposed portion from light so as not to be exposed. That is, in this embodiment, exposure for four patterns is performed in the first exposure, and exposure for two patterns is performed in the second exposure. In addition,
It goes without saying that two exposures may be performed in the first exposure and four exposures may be performed in the second exposure.

FIGS. 5 and 6 are views showing details of the substrate transfer unit 6. FIG. FIGS. 5A and 5B are diagrams showing a state in which the glass substrate 1 is transported from the loader unit 5 to the substrate centering unit 9, and FIG. 5A is a top view thereof, and FIG. ) Shows the side view. FIG.
(A) and the transfer arm 6 indicated by a dotted line in FIG.
Reference numeral 1 denotes a state where the X-axis linear motor 62 has moved to the loader unit 5 side along the guide groove 63 by driving. In this case, the U-shaped tip of the transfer arm 61 lifts the glass substrate 1 from the loader unit 5 and
5A and FIG. 5 by driving the shaft linear motor 62.
It moves to the substrate centering unit 9 side as shown in FIG. Glass substrate 1 by substrate centering unit 9
Is completed, the substrate transport unit 6 transports the glass substrate 1 to the alignment stage unit 7. FIG. 5C is a top view showing a state where the θ-axis linear motor 65 of the substrate transfer unit 6 is rotated counterclockwise by 90 degrees. FIG. 6A shows FIG.
From the state of (C), it is further rotated 90 degrees counterclockwise, and X
FIG. 6 is a top view showing a state in which the glass substrate 1 is transported to the exposure chuck 2 side by driving the shaft linear motor 62.
(B) is a side view thereof. The transfer arm 61 enters an escape groove provided in the exposure chuck 2. The exposure chuck 2 has a clearance groove so that the U-shaped tip of the transfer arm 61 does not interfere. Therefore, as shown in the side view of FIG. 6B, the lower part of the U-shaped arm tip of the transfer arm 61 is as if it has entered the exposure chuck 2. In this state, the Z-axis servo motor 6
The glass substrate 1 is sucked and held on the exposure chuck 2 as shown in FIG. After a series of processes as described above, the glass substrate 1 is moved onto the exposure chuck 2 from above the loader unit 5.

In the above embodiment, the case where the exposure shutter 71 moves in the X-axis direction has been described.
It goes without saying that it may be movable in the Y-axis direction. Also, the case where the step table moves in the X-axis direction has been described, but this may also be such that the step table moves in the Y-axis direction. Further, in the above embodiment,
Although the upper mask holder 4U has a rectangular shape, it may have a shape like the lower mask holders 4DF and 4DR.

[0015]

According to the proximity exposure apparatus of the first aspect of the present invention, there is an effect that a high-definition product can be produced while stabilizing the fine conditions of the product. According to the proximity exposure apparatus of the second aspect of the present invention, there is an effect that proximity exposure can be performed on a glass substrate having a size larger than that of a photomask.

[Brief description of the drawings]

FIG. 1 is a diagram of a part of the alignment stage unit of FIG. 2 as viewed from the back side (−Y direction) of the drawing, and is a diagram illustrating an operation state at the time of proximity exposure.

FIG. 2 is a diagram showing a schematic configuration of a proximity exposure apparatus according to the present invention.

FIG. 3 is a diagram showing details of an upper mask holder and a lower mask holder of FIG. 2;

FIG. 4 is a diagram showing a detailed configuration of an exposure shutter.

FIG. 5 is a diagram illustrating a detailed configuration of a substrate transport unit.

FIG. 6 is another diagram showing a detailed configuration of the substrate transport unit.

FIG. 7 is a diagram for explaining a problem of a conventional proximity exposure apparatus.

[Explanation of symbols]

1, 1A, 1B, 1C: glass substrate, 2: exposure chuck, 3: mask, 4: mask holder, 4DF, 4DR ...
Lower mask holder, 4U ... Upper mask holder, 5B-8
B: Gap detector, 5C to 8C: Gap window, 5: Loader unit, 6: Substrate transfer unit, 7: Alignment stage unit, 8: Constant temperature blowing unit (HEPA)
Unit 9) substrate centering unit 10 tilting Z stage 11 glass substrate alignment stage 31-33 reference pin 34-36 pusher pin 41 step table 51 loader cooling plate 61 Transfer arm, 62: X-axis linear motor, 63: guide groove, 64: Z-axis servo motor, 6
5 θ-axis linear motor, 71 exposure shutter, 72 shutter arm, 73, 74 slide guide, 75 motor, 76, 77 pulley, 78 belt, 79, 7
0 ... Photo sensor

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Shigehiro Takami 3-16-3 Higashi, Shibuya-ku, Tokyo Inside Hitachi Electronics Engineering Co., Ltd. (72) Inventor Kazuma Seki 3-163-3 Higashi, Shibuya-ku, Tokyo No. Hitachi Electronics Engineering Co., Ltd. (72) Inventor Manabu Minegishi 3-16-3 Higashi, Shibuya-ku, Tokyo Inside Hitachi Electronics Engineering Co., Ltd.

Claims (2)

[Claims] An exposure is performed after performing a proximity gap control so that a gap formed between a photomask surface held by a mask holder and a glass substrate surface held by an exposure chuck is a predetermined gap. In the proximity exposure apparatus, the mask holder includes: an upper mask holder having an attraction window that adsorbs on the upper surface side of the photomask; and a lower mask holder having an attraction window that adsorbs at the lower surface side of the photomask. A proximity exposure apparatus, wherein a portion along the outer peripheral shape of the photomask is suction-held by both suction windows of the upper mask holder and the lower mask holder. 2. Exposure is performed after proximity gap control is performed so that a gap formed between a photomask surface held by a mask holder and a glass substrate surface held by an exposure chuck is a predetermined gap. In the proximity exposure apparatus, the mask holder is provided with an upper surface mask holder having an adsorption window for adsorbing an upper surface side of a pair of opposite sides in the outer shape of the photomask, and another one in the outer shape of the photomask. A lower surface mask holder having a suction window for sucking a lower surface side of the opposite side portion of the set, and the exposure chuck and the exposure chuck along a facing direction of the set opposite side portion sucked and held by the suction window of the upper surface mask holder. Moving means for moving the glass substrate, and a light beam at the time of proximity exposure irradiates a part of the photomask An exposure shutter means for blocking light so as not to block the light.