JPH0733232A - Device for positioning liquid crystal substrate - Google Patents

Abstract

PURPOSE:To correct the displacements at the time of carrying a substrate into the processing chamber inside a liquid crystal manufacturing processor automatically without adding external force by detecting the displacements of the center position of the substrate and the direction of rotation occurring inside a cassette, and driving a table, whereon the substrate is put, so as to connect the displacements. CONSTITUTION:This device is composed of a turn table 3, which sucks and rotates a substrate 2, a lifter 10, which floats the substrate 2 from the turn table, sensors 7a, 7b, 7c, 7d, and 7e, which detect the displacements of the direction rotation of the substrate 2 and the directions X and Y. The quantity of displacement in the direction of rotation of the substrate 2 is operated from the difference of the quantities of displacements before two pieces of sensors 7a and 7b driven in X direction detecting the edge position of the substrate 2. The displacement in the direction of rotation is corrected by rotating the turn table 3, and then the sensors 7a and 7b in X direction and the sensors 7d and 7e in Y direction detect and operate the quantity of displacement of the center position of the substrate 2, and a lifter 10 and the turn table 3 correct the center position of the substrate 2.

Description

Detailed Description of the Invention

[0001]

[Industrial field of application] When a liquid crystal substrate is transported into a liquid crystal manufacturing process apparatus, if it is transported with a deviation from the center position of the substrate and the direction of rotation, process defects and substrate destruction may occur. It will be. The present invention corrects these deviations to realize the transfer of the substrate to an appropriate position of the process apparatus, and contributes to the improvement of the process yield.

[0002]

2. Description of the Related Art Generally, a glass substrate for a liquid crystal screen has a rectangular shape, and its size tends to increase year by year. Currently, a size of 500 mm × 600 mm × 0.7 t is predominant. A liquid crystal substrate is a transistor formed on the front surface of the glass plate by depositing a thin film on the surface of this glass plate by various process equipment or by etching to form a required transistor. Since the structure is such that the transmittance is controlled so that it can be recognized by the human eye, it is necessary and endeavored to improve the transparency of the substrate as much as possible. The vapor deposition of these thin films and the etching process are called processes, and these are made into devices for each process. On the other hand, these boards are stored in a board storage case that is generally called a cassette.
It is accommodated in units of 0 and several sheets, and is conveyed to various process apparatuses in units of this cassette. The transferred substrate is taken out of the cassette by a transfer device such as a robot of various process devices, transferred to the inside of the device, and subjected to necessary processing. Further, after the processing is completed, it is returned to the cassette by the transport device and transported to the next device.

FIG. 1 is a conceptual diagram of a general manufacturing process apparatus for liquid crystal substrates, 1 is a cassette, 2 is a substrate,
Reference numeral 12 indicates a processing chamber for this substrate. The substrate stored in the cassette is transferred to the processing chamber 3 by the robot, and after the processing is completed, the substrate is collected again inside the cassette. There is a table having the same shape and size as the substrate in the processing chamber, and it is necessary to install the transported substrate with high accuracy so as not to stick out of this table. However, in the configuration of FIG.
Since the transfer robot only moves between the positions taught in advance, the substrate is set on the table in the processing chamber while containing the displacement of the substrate generated inside the cassette.

The apparatus has a cassette positioning mechanism, but the cassette is made slightly larger than the outer shape of the substrate in order to move the substrate in and out. It can be said that the cassette positioning mechanism alone is not sufficient because it may have a deviation in direction. In addition, the outer shape of the substrate itself includes some errors.

When the cassette is transferred to the apparatus, the internal substrate is not located at the center of the cassette and almost always hits either edge of the cassette and stops, so that the center of the cassette is not aligned with the center of the substrate. As long as the substrate inside is out of position, the substrate is taken out of the cassette by the carrier of the process equipment and transferred to the process chamber of the process equipment. In some cases, it will not be set.

Therefore, a correction mechanism shown in FIG. 2 is provided as a means for correcting this positional deviation. In FIG. 2, 1 is a cassette, 2 is a substrate, and 13 is a pusher.
Is a mechanism for sandwiching the left and right ends of the board to position the board in the left-right direction. For example, the left and right pushers are connected by a rack and pinion, and one is connected to a drive source such as a cylinder. At the left and right ends of the cassette, a space necessary for the pusher to sandwich the substrate is secured. If the cylinder now works, the left and right pushers will move to the substrate side evenly and push the substrate. If the spacing when the pusher stops is set to be slightly larger than the outer diameter of the substrate, the horizontal positions of all the substrates in the cassette are corrected. However, even with this mechanism,
Since only the horizontal position correction is performed, when the cassette is loaded into the liquid crystal manufacturing process device for the front-back position correction, the operator manually tilts the cassette to align the front-back direction, and the positions of the end faces are aligned manually. Later it had to be installed on the cassette stand of the device.

[0007]

However, in this method,
Since mechanical force is applied to both ends of the glass substrate, chipping (chipping) occurs at the edge of the substrate, which causes cracking of the substrate, which not only deteriorates the yield but also chipping grows as the process is repeated. If this occurs in the final process, the loss will be enormous in proportion to the improvement in added value. Further, since it is a contact type, dust is generated, and this dust makes a fatal defective product. Further, the weight of the cassette is more than ten kilograms, and even if the cassette is carried, it is difficult to manually perform a positioning operation. Therefore, there is a risk of an operation error or a forgetting operation.

[0008]

In order to solve the above-mentioned problems of the prior art, the present invention detects the deviation of the center position and the rotation direction of the substrate inside the cassette with a sensor and deviates from the detection value of the sensor. The amount is calculated, and the table on which the substrate is placed is driven according to the calculation result to correct the deviation.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 3 shows an overall view of the present invention, in which 1 is a cassette, 2 is a substrate, and a substrate 2 is a processing chamber 1 by a robot.
Before being transferred to the processing chamber 2, the positioning device 14 of the present invention positions the film and then transfers it to the processing chamber 12.

FIG. 4 is a diagram showing details of the liquid crystal substrate positioning apparatus of the present invention. In the figure, 3 is a turntable for adsorbing and turning the substrate 2, 4 is its turning drive source, 5 is the turntable 3 and turning drive source 4 left and right (Y direction), and 6 is the front-back direction (X direction). A drive source that moves to, such as a motor can be used.
Reference numeral 10 is a lifter, a mechanism for floating the substrate 2 from the turntable 3, and 11 is a drive source for moving the lifter 10 in the vertical direction.

Reference numerals 7a, 7b, 7c, 7d and 7e denote sensors for detecting the edge of the substrate 2, and each sensor is moved in and out by drive sources 8a, 8b, 9a and 9b which drive the respective elements in the central direction. 7a and 7b are arranged on a straight line at positions corresponding to the same side of the substrate 2, and the displacement in the rotation direction of the substrate 2 is measured. 7a and 7c are in the X direction, 7d and 7
e is for measuring the amount of displacement of the substrate in the Y direction, and each driving source simultaneously moves the same amount toward the substrate. Although the drive sources are prepared for each of the figures, it is needless to say that the drive sources 8a, 8b or 9a, 9b can be respectively provided by using, for example, left and right reverse screw ball screws.

FIG. 5 is a diagram showing an example of the positional relationship when the substrate 2 is placed in this apparatus. “A” indicates the center position of the present apparatus, and “b” indicates the center position of the substrate 2, which are generally not aligned and have deviations in three directions of XY and θ. The three components of these deviations are ΔX, ΔY, and Δθ. here,
It is difficult to uniquely measure these three components, so first of all Δ
θ is measured and corrected, and then ΔXΔY is corrected.

FIG. 6 is a diagram showing a method of correcting Δθ.
In FIG. 6 (a), the sensors 7a and 7b are arranged at an equal distance of (1/2) × L in the Y direction from the center in the Y direction. If this sensor turns on at the same time, Δθ
It is installed parallel to the Y-axis so that = 0, and is installed on a single table having a drive axis in the X-axis direction. First, the sensors 7a and 7b move forward to search for one side edge of the substrate. The moving amount after the sensor 7a is turned on until the sensor 7b is turned on is H. Sensor 7a and sensor 7b
Since they are arranged apart from each other by L, Δθ is obtained by tan (Δθ) = H / L, and the rotation direction is determined by the turn-on order of the two sensors 7a and 7b.

The turntable is swung in the opposite direction by 1/2 of Δθ obtained above to correct the deviation of the rotation direction of the substrate 2, and the substrate 2 is moved in the XY directions as shown in FIG. 6 (b). Position in parallel.

Next, the deviation between ΔX and ΔY is corrected. Figure 6
The sensors 7a and 7c, and 7d and 7e shown in (c) and (d) are located at the positions indicated by the solid squares at the beginning, and are arranged at equal intervals around the turntable. The distance between them is M and N.
Further, the sensors 7a and 7c are operated in opposite directions by the driving source so that the sensors 7a and 7c simultaneously approach and separate from each other by the same amount. Further, the sensors 7d and 7e have the same mechanism.

Now, the sensors 7a and 7c are moved in the direction of the edge of the substrate, and the sensor 7c is further turned on at a position indicated by a solid line square as shown in FIG. It is assumed that the sensor 7a is turned on at the position. From this result, the shift amount ΔX in the X-axis direction is obtained from ΔX = 1/2 × ΔM, and the shift direction is determined by the turn-on order of the sensors 7a and 7c.

Next, as shown in FIG. 6 (d), the sensors 7d and 7
By driving e in the direction of the substrate 2, the sensor 7d is turned on at the position of the solid line square and then moved by ΔN until the sensor 7e is turned on at the position of the dotted line square, and the deviation amount ΔY in the Y direction is It is determined from ΔY = 1/2 × ΔN, and the direction is determined in the order of turning on the sensors 7d and 7e.

After that, after the turntable is moved by -.DELTA.X and -.DELTA.Y, the substrate 2 is once lifted from the turntable 3 by the lifter 10, the turntable 3 is returned to the original position, and then the lifter 10 is lowered. The center position of 2 matches the center position of this unit, and the centering is completed. The above operation is shown in a flowchart of FIG.

The above description uses a two-dimensional drive source in the X and Y directions, but the correction of ΔX and ΔY is performed on either the X axis or the Y axis and the existing two rotation axes. It is also possible. FIG. 8 is a diagram for explaining this method, in which the correction in the turning direction and the deviation amounts ΔX and Δ in the X and Y directions are performed.
The method until obtaining Y is the same as the method shown in FIG. From ΔX and ΔY obtained by the method of FIG. 6, as shown in FIG. 8A, the deviation angle Δα from the center position is obtained from tan (Δα) = ΔX / ΔY. Next, in order to distribute the vector (ΔX, ΔY) in the correction axis X direction,
As in (b), the substrate 2 is rotated by Δα. Next, the turntable 3 is moved in the X-axis direction by − | (ΔX, ΔY) | by the absolute value of the vector as shown in FIG. 8C, and then the substrate 2 is floated by the lifter 10. After returning the turntable 3 to the original position, the lifter 1
0 is lowered and the substrate is placed on the turntable 3. Finally, if the substrate is rotated by -Δα, the substrate is corrected to the expected center position as shown in Fig. 8D. The above control is shown in a flow chart of FIG.

It is conceivable that the sensor used for position detection may cause a considerable amount of error in the detection result due to its mounting error and sensitivity error of the sensor itself. Therefore, in the third aspect of the present invention, such a mechanical error is detected by using the liquid crystal substrate installed in the center position in advance as a model and detecting the position of the model substrate with each sensor. The stored position data is stored as an error inherent to the sensor, and when the actual position of the board is detected,
This peculiar error is subtracted from the data as an offset amount to automatically correct the sensor mounting position error and sensitivity error. As a result, the mounting accuracy and detection sensitivity of the sensor do not have to be specified so strictly, and the work becomes extremely easy even when these are removed and inspected or replaced with a new one at the time of maintenance or failure of the device.

[0021]

According to the present invention, when the substrate is transferred to the processing chamber in the liquid crystal manufacturing process apparatus, the deviation between the center position and the rotation direction of the substrate generated in the cassette is fully automatic and an external force is applied to the substrate. Since it can be corrected without adding, it can minimize chipping and dust generation, which are the causes of cracking of the substrate, which was a problem in the past, and it also eliminates the need for manual alignment, thus producing liquid crystal substrates. It is possible to obtain a remarkable effect in improving efficiency, yield, and reliability.

[Brief description of drawings]

FIG. 1 is an overall view showing an example of a conventional device.

FIG. 2 is a diagram showing an example of a conventional positioning device used in the device of FIG.

FIG. 3 is an overall view showing an embodiment of a positioning device of the present invention.

FIG. 4 is a diagram for explaining the structure of the embodiment of FIG.

FIG. 5 is a diagram showing a positional relationship when a substrate is installed in this apparatus.

FIG. 6 is a diagram for explaining a method of correcting the displacement of the substrate.

FIG. 7 is a flowchart showing a procedure for correcting a displacement of a board.

FIG. 8 is a diagram for explaining another example of the method for correcting the displacement of the substrate.

FIG. 9 is a flowchart showing the procedure of another example of the method of correcting the displacement of the substrate.

[Explanation of symbols]

 1 cassette 2 liquid crystal substrate 3 turntable 4 drive source 5 drive source 6 drive source 7a, 7b, 7c, 7d, 7e sensor 8a, 8b drive source 9a, 9b drive source 10 lifter 11 drive source 12 processing chamber 13 pusher 14 liquid crystal positioning Device a Center of positioning device b Center of substrate

Claims (3)

[Claims] 1. A turntable rotating and moving on an XY plane, a suction mechanism for fixing a liquid crystal substrate on the turntable, a lifter for floating the liquid crystal substrate from the turntable, LCD substrate 4
First and second X-direction sensors arranged in the Y direction on the same drive mechanism for detecting the position of one of the sides, and for moving the first and second sensors in the X direction A first drive source, a detector for measuring the amount of movement of the drive mechanism that mounts the two sensors, and a Y for detecting the position of the edge of the other side of the liquid crystal substrate.
A direction sensor, a second drive source for moving the Y direction sensor in the Y direction, and a movement amount from a reference position of the Y direction sensor to a detection position of an edge of another side of the liquid crystal substrate. And a movement amount from one of the two X-direction sensors detecting the position of the edge of the liquid crystal substrate to the other X-direction sensor detecting the edge. Calculating means for calculating a correction amount in the turning direction of the liquid crystal substrate, and after turning the turntable by the output of the calculating means, the X direction sensor and the Y direction sensor are used to measure the X direction and the Y direction of the liquid crystal substrate. Each edge position is detected, the deviation amount of the central position of the liquid crystal substrate is calculated from the detection result, and the lifter and the turntable are driven according to the central position deviation amount calculation result. Positioning device of a liquid crystal substrate and a control circuit for moving the serial LCD substrate to the center position. 2. The liquid crystal substrate positioning apparatus according to claim 1, wherein the turntable is moved in either the X direction or the Y direction. 3. An error obtained by previously detecting a position of a liquid crystal substrate having no deviation in the turning direction and the XY direction is used as an offset for a position detection error of each sensor due to mounting or variation of parts. The liquid crystal substrate positioning apparatus according to claim 1, wherein the error is automatically corrected by performing the above operation.