JP3588837B2 - Single-wafer coating method and apparatus - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a sheet-fed coating method and apparatus, and more particularly, to a method and apparatus for performing sheet-fed coating using a paint discharge apparatus represented by a die coater for precision coating. This method and apparatus are used not only for forming a coating film on a substrate to form a color filter for a liquid crystal display, but also for applying a liquid paint thinly and uniformly on a surface of a material to be coated supplied in a single-wafer method. It is suitable when coating is applied.
[0002]
[Prior art]
Conventionally, a spinner, a bar coater, and a roll coater have been used in a coating process for producing a color filter for a liquid crystal display. Since it has been strongly required to improve the physical properties of the film, the use of a die coater has recently been studied.
[0003]
Die coaters have been widely used for thick film coating and continuous application of high-viscosity paints, and gear pumps have been employed as fixed-rate pumps for feeding paints to the die coaters.
By adopting such a configuration, it is considered that a liquid can be sent without a pulsating flow by a gear pump, and a substantially uniform coating film can be formed on the surface of a long material to be coated.
[0004]
[Problems to be solved by the invention]
However, when a coating film is formed on a material to be coated using a die coater, the distance between the die coater and the material to be coated is set to a distance corresponding to the thickness of the coating film (a predetermined distance larger than the thickness of the coating film). ), It is possible to considerably reduce the variation in the distance (the ratio of the variation to the set thickness of the coating film) when performing thick film coating. When a thin film is applied for manufacturing, the variation in the interval becomes considerably large, and the variation in the film thickness between products actually obtained becomes large.
[0005]
This will be described in more detail.
Regardless of whether a thick film coating or a thin film coating is performed, there is a variation in the thickness of the material to be coated due to a material, a manufacturing process, and the like. However, this variation falls within an allowable error range in the manufacturing process of the material to be coated. However, since the material to be coated must also function as a mechanical strength holding member, the thickness is set to about 1 mm or more, and the set thickness is 1 mm, and if the tolerance is 1%, the material to be coated is not coated. The thickness of the work material becomes 1 mm ± 0.01 mm. Therefore, even if the distance between the stage for supporting and transporting the workpiece and the die coater is accurately set, the distance between the workpiece and the die coater has an error of ± 0.01 mm. Even if the distance between the coating material and the die coater has an error of ± 0.01 mm, if the coating film to be formed on the coating material is a thick film and its set thickness is 500 μm, The thickness variation ± 0.01 mm is only ± 2% of the set thickness. On the other hand, if the thickness of the coating film is 50 μm, ± 0.01 mm, which is the variation of the thickness, becomes ± 20% of the set thickness.
[0006]
Therefore, if the thickness of the coating film is set to be small, and if it is intended to achieve the same degree of variation as in the case of thick film coating, the tolerance of the thickness of the material to be coated must be significantly reduced. As a result, the yield of the material to be coated is deteriorated, and the cost of the material to be coated is significantly increased. On the other hand, if the tolerance of the thickness of the material to be coated is not reduced, the variation in the film thickness of the formed coating film becomes large, the yield of the coating film formed becomes poor, and the film formed This leads to significant cost increase.
[0007]
[Object of the invention]
The present invention has been made in view of the above problems, a single-wafer coating method that can significantly suppress the variation in the thickness of the coating film without reducing the tolerance of the thickness of the material to be coated and It is intended to provide such a device.
[0008]
[Means for Solving the Problems]
In the single-wafer coating method according to claim 1, the coating material is formed on the surface of the coating material by moving the coating material one by one while discharging the coating material from the coating material discharging device. Before starting the coating film forming operation on the workpiece, and before the workpiece is supported on the upper surface of the workpiece transport stage, the thickness of the workpiece is measured. Based on the thickness of the work material and the thickness of the coating film to be formed on the surface of the work material, the paint discharge device is set to the work material to set the distance between the paint discharge device and the work material. It is a method of contacting and separating.
[0009]
In the sheet-fed coating apparatus according to the second aspect, the coating material is moved one by one by a stage for transferring the coating material while applying the coating material from the coating device, thereby coating the surface of the coating material. In a single-wafer coating apparatus for forming a film, a coating material elevating means for supporting a coating material in a lifted state with respect to a coating material transfer stage, and a coating film forming operation for the coating material. A thickness measuring means for measuring a thickness of the workpiece before the workpiece is started and before the workpiece is supported on the upper surface of the stage for transporting the workpiece; Based on the thickness of the coating and the thickness of the coating film to be formed on the surface of the material to be coated, the paint discharging device is connected to the material to be coated so as to set the distance between the device and the material to be coated. And a driving means for driving the paint discharger to be released.
[0012]
[Action]
In the single-wafer coating method according to the first aspect, the coating material is formed on the surface of the coating material by moving the coating material one by one while discharging the coating material from the coating material discharging device. Before starting the coating film forming operation on the work material, the thickness of the work material was measured in a state before the work material was supported on the upper surface of the stage for transferring the work material, and the measured thickness was measured. Based on the thickness of the material to be coated and the thickness of the coating film to be formed on the surface of the material to be coated, the paint discharging device is set to set the distance between the paint discharging device and the material to be coated. The distance between the paint discharger and the material to be coated can be set accurately, even if the thickness of the material to be coated varies. A film can be formed. In addition, since the distance between the coating material discharge device and the material to be coated can be set accurately, it is possible to easily cope with thinning of the coating film.
[0013]
In the single-wafer coating apparatus according to claim 2, the surface of the material to be coated is moved one by one by a stage for transferring the material to be coated while applying the paint from the paint applying device. In forming the coating film, the coating material is lifted and supported by the coating material lifting / lowering means with respect to the coating material transporting stage, and the coating film for the coating material is Before the forming operation is started, and before the material to be coated is supported on the upper surface of the stage for transferring the material to be coated, the thickness of the material to be coated is measured. Based on the thickness of the material to be coated and the thickness of the coating film to be formed on the surface of the material to be coated, the paint discharging device is set to set a distance between the coating material discharging device and the material to be coated. Move away from the work material. Therefore, even if there is a thickness variation between the materials to be coated, the distance between the paint discharger and the material to be coated can be set accurately, and a high-quality coating film can be formed. In addition, since the distance between the coating material discharge device and the material to be coated can be set accurately, it is possible to easily cope with thinning of the coating film. Furthermore, since the lowering operation of the base can be started from the starting point of the lowering of the lift pins, the processing can be speeded up as a whole (shortening of the tact time), and the thickness of the material to be coated is measured in advance. In addition, the time required for coating can be reduced, and the productivity can be improved.
[0017]
【Example】
Hereinafter, the present invention will be described in detail with reference to the accompanying drawings showing embodiments.
FIG. 1 is a view schematically showing one embodiment of a sheet-fed coating apparatus according to the present invention.
This single-wafer coating apparatus includes a paint tank 1, a micro syringe pump 2, a paint discharge device 3 having a paint discharge slit 3a, a stage 4 reciprocated by a ball screw mechanism 4a, and a cover on the stage 4. A position sensor 5 such as an optical sensor for detecting the position of the coating material 8; an output signal from the position sensor 5; a state signal from an AC servomotor (not shown) for driving the ball screw mechanism 4a; And the sequencer 6 for controlling the paint discharge device 3 and the AC servomotor with the input of the status signal of the micro-syringe pump 2 and the status signal of the micro-syringe pump 2 as input. And a computer 7 for controlling the pump 2. The paint tank 1 and the micro syringe pump 2 communicate with each other by a paint suction pipe 1a, and the micro syringe pump 2 and the paint discharge device 3 communicate with each other by a paint discharge pipe 3b. The micro syringe pump 2 is selectively connected to a paint suction pipe 1a and a paint discharge pipe 3b by a switching valve 2a. The paint discharge device 3 is moved up and down between a position close to the upper surface of the color filter substrate 8 as a material to be coated supported on the stage 4 and a position sufficiently distant from the color filter substrate 8. It falls in response to the coating operation start command and rises in response to the coating operation end command. The computer 7 also controls the switching valve 2a. Although not particularly shown in FIG. 1, it is preferable to provide an on-off valve, a filter, and the like at predetermined positions of the paint suction pipe 1a. However, in place of the position sensor 5, it is preferable to adopt a configuration in which the position of the stage 4 is detected by counting output pulse signals from an encoder incorporated in an AC servomotor.
[0018]
The paint discharge device 3 has a base 3a having a slit 3b for discharging paint as a main component.
FIG. 2 is a schematic perspective view showing the relationship between the paint discharge device 3 and the stage 4.
A guide rail 4b for slidably supporting the stage 4 and a ball screw mechanism 4a (not shown) are provided at a predetermined position on the base 9, and a cover for covering most of the space for accommodating the ball screw mechanism 4a and around the guide rail 4b. A member 4c is provided. The stage 4 is provided with a driving force transmitted by a ball screw mechanism 4a and guided by a guide rail 4b. Of the cover members 4c, the outermost cover member has an upper end portion bent substantially inward at a right angle, and is engaged with a groove 4d formed at a predetermined position on the outer surface of the stage 4. . Therefore, the degree to which dust generated from the ball screw mechanism 4a is scattered to the outside can be greatly reduced, and the inconvenience that paint or the like falling from above the stage 4 reaches the ball screw mechanism 4a and the guide rail 4b can be prevented. can do. In FIG. 2, among the cover members 4c, the cover member located at the center is shown as having no opening on the upper surface for simplicity, but is actually screwed with a ball screw. It has an opening (an opening parallel to the ball screw) necessary for connecting the member to be mounted and the stage 4. The stage 4 has a lift pin 10 as a coating material elevating means shown in FIG. 4, and the lift pin 10 is retracted so that the tip portion is located below the upper surface of the stage 4, so that the coating is performed. The material 8 is supported on the upper surface of the stage 4, and the material to be coated 8 can be sucked and held through a number of suction holes (not shown) formed on the upper surface of the stage 4. Conversely, by moving the lift pin 10 forward so that the tip is located above the upper surface of the stage 4, the workpiece 8 can be supported in a lifted state.
[0019]
A thickness sensor 4e for measuring the thickness of the material 8 to be coated is provided on the tip of a substantially inverted L-shaped support member 4d provided at a predetermined position above the base 9 (a predetermined position away from the cover member 4c). Is provided so as to be able to move up and down. FIG. 3 is a schematic diagram showing the relationship between the thickness sensor and the workpiece 8 on the stage 4. As is clear from this figure, the casing of the thickness sensor 4e has a lower end portion of the left half portion in FIG. 3 protruding in a chevron shape with reference to a virtual center line, and the right half portion in FIG. It is formed on a substantially flat surface having no portion. In addition to having a light source 4e1 for obliquely irradiating the workpiece 8 with measurement light such as a laser beam corresponding to the flat surface, the surface of the workpiece 8 caused by the measurement light has a light source 4e1. It has a light receiving unit 4e2 that receives the reflected light and the reflected light on the back surface. The light receiving section 4e2 is formed of, for example, an array type sensor, and the thickness of the workpiece 8 can be calculated by obtaining the interval between the light receiving positions of the two reflected lights and supplying it to a computer (not shown). . However, a laser displacement gauge, an electronic micro displacement gauge, an ultrasonic thickness gauge, or the like can be used as the thickness sensor 4e.
[0020]
Further, a paint discharge slit member of the paint discharge device 3 is provided at an end of a substantially inverted L-shaped support member 4f provided at a predetermined position above the base 9 (a predetermined position apart from the cover member 4c and the support member 4d). (For example, a slit die of a die coater) is provided. However, the base 3a is not provided directly on the support member 4f, but as shown in FIG. 5, a vertically movable shaft member 4g (for example, a ball screw mechanism 4g1 and a guide) provided at the tip of the support member 4f. The base 4h is provided at a predetermined position on the rail 4g2), and a base support frame 4j is provided at a predetermined position on the base 4h so as to be rotatable in a vertical plane via a rotating shaft 4i. The base 3a is provided so as to be held by the support frame 4j. The adjustment base 4k is connected to the base 4h so as to be located above the die supporting frame 4j, and at a predetermined position (the left and right ends in FIG. 4) of the adjustment base 4k. A pair of actuators 4l are provided, and by controlling the operation amounts of both actuators 4l, the base 3a is rotated around the rotation shaft 4i to adjust the parallelism between the base 3a and the workpiece 8. Can be.
[0021]
Further, a distance sensor 4m including a photoelectric sensor, an ultrasonic sensor, and the like is provided at each of a pair of corners on the upstream side of the stage 4 in the coating operation direction. The distance sensor 4m emits a measurement wave and detects a reflected wave from the base 3a, for example, and measures the time required from the emission of the measurement wave to the reception of the reflected wave by a computer (not shown) or the like. The distance between the upper surface of the stage 4 and the base 3a can be calculated based on the speed of the waves. However, it is preferable to use an electromagnetic induction sensor, an electronic micro displacement meter, or the like.
[0022]
Although not particularly shown, it has a loader for supplying the coating material 8 to the stage 4 and an unloader for removing the coating material 8 from the stage 4 after the coating is completed. As the loader and the unloader, for example, those having a cylindrical coordinate system industrial robot or the like as a main component can be adopted. The supply of the workpiece 8 is performed while the lift pins 10 are advanced, and the lift pins 10 are moved. It is preferable to take out the workpiece 8 in a state where it is advanced.
[0023]
Next, a single-wafer coating method will be described.
First, after returning to the origin of each part of the coating apparatus, the switching valve 2a is switched to the paint tank side, and the suction operation by the micro syringe pump 2 is performed. Then, the workpiece 8 is received from a loader (not shown) with the lift pins raised, and the lift pins are lowered to place the workpiece 8 at a predetermined position on the stage 4, and further, the workpiece 8 is vacuum-sucked. Thus, the workpiece 8 is fixed on the stage 4.
[0024]
Then, in this state, the thickness sensor 4e is lowered to a predetermined position, the reflected light of the light from the light source 4e1 by the coating material 8 is received by the light receiving unit 4e2, and the output signal from the light receiving unit 4e2 is sent to a computer (not shown). By supplying, the thickness of the coating material 8 is calculated. Of course, after the light receiving section 4e2 receives light, the thickness sensor 4e is raised.
[0025]
Then, after a predetermined amount of paint is sucked from the paint tank 1 into the micro syringe pump 2, the switching valve 2a is switched to the mouthpiece side, and the stage 4 is moved forward to move the workpiece 8 immediately below the mouthpiece 3a. And the forward running of the stage 4 is stopped. Next, the base 3a is lowered and a predetermined clearance (interval) is secured by controlling the lowering operation time. In this case, the clearance is uniquely determined by the thickness of the coating film to be formed on the workpiece 8, but the distance between the upper surface of the stage 4 and the base 3 a is limited by the thickness of the workpiece 8. It cannot be uniquely determined due to the variation. However, since the thickness of the workpiece 8 is measured using the thickness sensor 4e, the base 3a is lowered in consideration of this thickness, so that the upper surface of the workpiece 8 and the base 3a can be connected. The interval can be set accurately. Specifically, by lowering the base 3a while measuring the distance between the base 3a using the distance sensor 4m, the distance between the upper surface of the workpiece 8 and the base 3a is accurately set. Thereafter, the stage 4 is moved forward again to position the coating start position of the workpiece 8 immediately below the base 3a, and the stage 4 is stopped. By operating the micro syringe pump 2 substantially simultaneously with the stop operation of the stage 4, the paint is supplied to the base 3a to start the discharge of the paint, and after the start of the discharge of the paint, the stage 4 is stopped for a predetermined time. By maintaining the state, the paint bead 3e is formed between the base 3a and the workpiece 8 over the entire region in the predetermined cross direction. However, the paint may be continuously discharged from the base 3a without temporarily stopping the stage 4.
[0026]
After the paint bead 3e is formed as described above, the coating is started by moving the stage 4 forward at a predetermined speed. At the same time as the start of the coating, the pressure in the pressurizing chamber or the depressurizing chamber (not shown) is maintained at a predetermined pressure to increase or decrease the pressure, thereby stabilizing the paint bead 3e. Therefore, the paint consumed by the stabilization of the paint bead 3e and the paint discharged from the slit 3b of the base 3a equilibrates, and a short time after the start of coating, a stable paint film is formed. It will be in a steady coating state where formation can take place.
[0027]
When the material to be coated 8 reaches a position a predetermined distance before the coating end position, the supply of the paint by the micro syringe pump 2 is stopped, and at the same time, the pressurization and decompression of the base 3a are stopped. While consuming 3e, a coating film is formed by so-called squeegee coating. However, the supply of the paint may be stopped when the workpiece 8 reaches the coating end position. When the material to be coated 8 reaches the coating end position, the micro syringe pump 2 is operated in reverse to suction and collect a predetermined amount of the paint through the slit 3b of the mouthpiece 3a. However, in the case where the supply of the paint is stopped at the time when the material to be coated 8 reaches the coating end position, the suction and collection of the paint is performed when the material to be coated 8 passes the coating end position. Good. Thereafter, the coating is completed by raising the base 3 a and moving it away from the workpiece 8. Thereafter, the micro syringe pump 2 is operated to discharge the paint in order to eliminate a gap that may be formed in the slit 3b by the suction and collection of the paint. After that, the stage 4 continues to move forward, transports the workpiece 8 to a predetermined position for transferring the workpiece to the next step, stops, releases the vacuum suction, and raises the lift pin 10 to lift the workpiece. The material 8 is lifted, and the workpiece 8 is transferred to an unloader (not shown) at that position. At the same time, the paint is discharged by the micro syringe pump 2 and the base 3a is wiped to remove the paint remaining on the tip of the base 3a. Next, the stage 4 is caused to travel in the reverse direction to return to a predetermined position to receive the next workpiece 8, thereby completing a series of processes and preparing for the next workpiece 8 to be applied.
[0028]
Therefore, even if there is considerable variation in the thickness of the coating material 8, the thickness of the coating material 8 is measured, and the die 3a is lowered in consideration of this thickness. The distance between the upper surface of the work material 8 and the base 3a can be set accurately, and as a result, the thickness of the obtained coating film can be made to match the set thickness with high accuracy.
Further, since the distance between the material to be coated and the base 3a can be set with high precision, it is possible to easily cope with a thin coating film.
[0029]
In the above-described embodiment, the thickness of the workpiece 8 is measured while the workpiece 8 is suction-held on the stage 4. However, as shown in FIG. It is possible to measure the thickness of the workpiece 8 in a state where it is supported by the lift pins 10 which have been raised in this case, and in this case, the thickness calculation process can be started from the time when the lift pins 10 start lowering. Since the timing at which the lowering operation of the base 3a can be started can be advanced, the processing can be speeded up as a whole.
[0030]
In addition, the thickness of the material to be coated is measured in a process before the material 8 to be coated is supplied to the stage 4 by the loader (for example, a process of drying the material to be washed stored in a rack and the like). In this case, the tact time of the coating process can be reduced.
[0031]
【The invention's effect】
According to the first aspect of the present invention, even if there is a thickness variation between the materials to be coated, the distance between the paint discharger and the material to be coated can be set accurately, and a high quality coating film can be formed. In addition, since the distance between the paint discharge device and the material to be coated can be accurately set, a unique effect that the film can be easily made thinner can be obtained.
[0032]
According to the second aspect of the present invention, even if there is a variation in the thickness between the materials to be coated, the distance between the paint discharging device and the material to be coated can be accurately set, and a high quality coating film can be formed. In addition, since the distance between the paint discharge device and the material to be coated can be set accurately, it is possible to easily cope with thinning of the coating film, Since the distance from the material can be set accurately, it is easy to cope with thinning of the coating film, and since the lowering operation of the base can be started from the start of the lowering of the lift pin, the overall processing speed is increased (Shortening of tact time), and furthermore, the thickness of the material to be coated is measured in advance, so that the time required for coating can be shortened, and the unique effect of improving productivity can be achieved. Play.
[Brief description of the drawings]
FIG. 1 is a view schematically showing an embodiment of a sheet-fed coating apparatus according to the present invention.
FIG. 2 is a schematic perspective view showing a relationship between a paint discharge device and a stage.
FIG. 3 is a schematic diagram showing a relationship between a thickness sensor and a material to be coated.
FIG. 4 is a schematic diagram showing a relationship between a thickness sensor and a material to be coated.
FIG. 5 is a schematic view showing a base supporting mechanism and a stage.
[Explanation of symbols]
Reference Signs List 3 paint discharger 4 stage 4e thickness sensor 4g vertical moving shaft member 8 coating material 10 lift pin

Claims (2)

In the single-wafer coating method, a coating material is formed on the surface of the coating material (8) by moving the coating material (8) one by one while discharging the coating material from the coating material discharging device (3). A coating material raising / lowering means (10) for supporting the coating material (8) in a lifted state with respect to the coating material transfer stage (4), and a coating film forming operation on the coating material (8). Before starting, the thickness of the workpiece (8) is measured and measured before the workpiece (8) is supported on the upper surface of the workpiece transport stage (4). Of the coating material discharge device (3) and the coating material (8) based on the thickness of the coating material (8) and the thickness of the coating film to be formed on the surface of the coating material (8). A single-wafer coating method, comprising: bringing a paint discharge device (3) into and out of contact with a workpiece (8) to set a distance. In a single-wafer coating apparatus for forming a coating film on the surface of the coating material (8) by moving the coating material (8) one by one while discharging the coating material from the coating material discharging device (3), A coating material raising / lowering means (10) for supporting the coating material (8) in a lifted state with respect to the coating material transfer stage (4), and a coating film forming operation on the coating material (8). A thickness measuring means (4e) for measuring the thickness of the workpiece in a state before the start and before the workpiece (8) is supported on the upper surface of the workpiece transport stage (4 ); And the paint discharge device (3) and the coating material (3) based on the measured thickness of the coating material (8) and the thickness of the coating film to be formed on the surface of the coating material (8). 8) a paint discharge device driving means (4g) for bringing the paint discharge device (3) into and out of contact with the workpiece (8) so as to set the distance to the paint discharge device (8). DOO sheet coating apparatus according to claim.

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