JPH09230940A - Position correcting device for substrate for liquid crystal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correct deviations in the rotating direction and side end position of a substrate fully automatically without taking a long time when the substrate is carried to a process chamber in a liquid crystal manufacturing process device. SOLUTION: The substrate 3 for liquid crystal when carried out of a cassette 2 is temporarily pressed in from the front side of the cassette 2 with pins 16a and 16b provided to a robot hand part 15 to set the front-side direction of the substrate 3 to a specific direction, and at the position where a robot 1 carries the substrate 3 out of the cassette 2, the side end position of the substrate 3 is detected by a detector 17. Then the deviation quantity of the side end position of the substrate 2 from a reference position is calculated from the output of this detector 17 to obtain position correction data, thereby correcting subsequent conveyance position data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention corrects the deviation between the center position of a liquid crystal substrate and the direction of rotation when the liquid crystal substrate is carried into the liquid crystal manufacturing process device, thereby ensuring the proper position of the process device. It is necessary to prevent the occurrence of process defects and the destruction of the substrate by realizing the transfer of the substrate to the substrate and the safe storage in the cassette.

[0002]

2. Description of the Related Art A liquid crystal substrate is formed by depositing a thin film on a glass plate surface by various process equipment or by etching to form a required transistor, and controlling the liquid crystal by the transistor formed on the substrate surface. The structure is such that characters and figures are displayed by controlling the transmittance of light from the back surface of the substrate. The vapor deposition or etching process of these thin films is called a process, and each process is made into a device. These liquid crystal substrates generally have a rectangular shape, and the size thereof is increasing year by year, and is currently 500 mm × 600 mm × 0.
It is manufactured up to about 7t.

On the other hand, these substrates are accommodated in a substrate accommodating case, which is generally called a cassette, in units of ten or more, and are transferred in cassette units between various process apparatuses. The transferred substrate is taken out from 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 transferred to the next device.

[Prior Art 1] FIG. 9 is a conceptual diagram of a general liquid crystal substrate manufacturing process apparatus. 1 is a robot, 2 is a cassette, 3 is a substrate, and 12 is a processing chamber for the substrate. ing. The substrate stored in the cassette is the robot 1
Is transferred to the processing chamber 12 and is collected again by the robot 1 into the previous cassette 2 or another cassette (not shown) after the processing is completed. Here, the transferred substrate needs to be accurately set at a predetermined position in the processing chamber. However, in the configuration of FIG. 9, since the transfer robot only moves between the positions taught in advance, the transfer robot is transferred and loaded into the processing chamber or the cassette while including the positional deviation of each substrate generated inside the cassette. .

Since these devices have a positioning mechanism for the cassette itself, the position of the cassette is accurate. However, because the substrate enters and leaves the cassette, the inside width is made slightly larger than the width of the substrate. However, since the substrate in the cassette may be displaced from the cassette in the center position and the rotational direction, it can be said that the cassette positioning mechanism is not sufficient.

When the cassette is transferred to the apparatus, the internal substrate is not located at the center of the cassette, but is almost stopped by hitting either edge of the cassette, and the center of the cassette is not aligned with the center of the substrate. Usually, the position of the internal substrate is misaligned, and if the robot takes the substrate out of the cassette as it is and conveys it to the process chamber of the process equipment, the position of the substrate is misaligned and the substrate inside the process chamber does not work well. It may not be set, and in an extreme case, the substrate may come into contact with the device and be damaged.

Therefore, a position correcting mechanism shown in FIG. 10 is provided as a means for correcting this positional deviation.
In FIG. 10, reference numeral 2 is a cassette, 3 is a substrate, and 23 is a mechanism for sandwiching the left and right ends of the substrate 3 with a pusher to align the left and right sides of the substrate. For example, the left and right pushers are connected by a rack and pinion, and one is a cylinder. It is connected to a drive source such as. The left and right ends of the cassette are provided with windows necessary for the pusher to sandwich the substrate. 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 width of the board in the left-right direction, the position of all the boards in the cassette in the left-right direction is corrected.

[Prior Art 2] FIG. 11 is an external view showing another example of the prior art. A sensor detects the deviation between the center position of the substrate and the rotation direction generated in the cassette, and the detected value of the sensor is used. The shift amount is calculated, and the table on which the substrate is placed is driven according to the calculation result to correct the shift.

In FIG. 11, reference numeral 1 is a robot, 2 is a cassette, and 3 is a substrate. The robot 1 conveys the substrate 3 to a positioning device 14, and after positioning the substrate 3, the processing chamber 12 is positioned.
Transport to The positioning device 14 includes a turntable that attracts and swivels the substrate 2, a drive source that moves the turntable in the left-right and front-rear directions, and a sensor that detects each edge of the substrate 2 in the left-right and front-rear directions. With these sensors, the deviation from the reference position of the board is 3
The components ΔX, ΔY and the rotation angle Δθ are calculated, the rotation angle Δθ is first corrected by the turntable, and then the turntable drive source corrects ΔX, ΔY. (For example, JP-A-7-33232)

[0010]

The apparatus shown in FIGS. 9 and 10 only corrects the position in the left-right direction. Therefore, when the cassette is transferred to the liquid crystal manufacturing process apparatus for position correction in the front-back direction, the front-back direction is corrected. In order to align them, the operator had to manually tilt the cassette to align the positions of the end faces of the substrates and then install the cassette on the cassette base of the apparatus. Further, in this method, mechanical force is applied to both ends of the glass substrate, so that chipping (chipping) occurs at the edge of the substrate, causing cracking of the substrate, which not only deteriorates the yield but also requires repeated chipping processes. Grows every time. For this reason, if cracks occur in the final process,
All the processes up to that point are wasted and the loss is enormous. Further, since it is a contact type, dust is generated, and this dust makes a fatal defective product. In addition, the weight of the cassette is a dozen K
Since there is also a problem, even if it is difficult to carry, the operator is forced to perform a manual alignment operation, which poses a risk of mistakes in operation and forgetting to do so.

In the system of FIG. 11, the problems of the systems of FIGS. 9 and 10 can be solved, but a considerably long time is required to correct the positional deviation, and the transport efficiency is lowered. was there.

[0012]

SUMMARY OF THE INVENTION The present invention relates to a position correcting device in a liquid crystal substrate processing apparatus in which a robot for loading and unloading substrates for a plurality of liquid crystal substrates is arranged. When the substrate is unloaded, the robot hand is loaded from the front side of the cassette so that the front side of the substrate is aligned in a predetermined direction. The side edge position detector for detecting the side edge position of the board at a predetermined position of the board and the deviation amount of the side edge position of the board from the reference position are calculated by using the output of the side edge position detector as input A position correction device for a liquid crystal substrate, comprising a calculation means for obtaining correction data, and a robot control device for correcting subsequent transfer position data based on the position correction data of the calculation means. That.

[0013]

FIG. 1 is a perspective view showing an embodiment of the device of the present invention. In the figure, 1 is a substrate transport robot, 2 is a cassette, and 3 is a substrate stored in the cassette 2 in large numbers. A main body 12 is placed on a base 11 of the robot 1, and a swing shaft 13 that can move up and down in the Z direction in the figure and that can rotate in the horizontal direction, an arm portion 14 attached to the swing shaft 13, and a substrate 2 are mounted on the main body 12. It has a hand portion 15 for adsorbing and transporting. The arms 14 are rotatably connected to each other as shown in the figure, and cooperate with the swivel shaft 13 to move the hand 15 to each other.
Is moved on the XY plane (horizontal plane) in the figure. Positioning pins 16a and 16b are provided on the hand 15, and when the hand 15 is inserted into the cassette 2, the front end of the substrate 3 is pushed in and regulated so that the front end of the substrate 3 is parallel to the Y direction. A side edge position detector 17 is attached to the pivot shaft 13 of the robot 1 at a position where the side edge of the board 3 reaches when the board 3 is pulled out from the cassette 3 by the hand 15.
The side end position detector 17 is provided with a sensor 18 that detects a deviation from a reference position where the side end should be located when the substrate is pulled out.

In the apparatus shown in the figure, the substrate 3 is placed in the cassette 2
The operation when taking out from the device will be described with reference to the flowchart of FIG. First, the turning shaft 13 of the robot 1 is moved in the Z direction, and the hand 15 is adjusted to the height at which the target substrate is taken out. Next, while keeping this height, the hand 15 is set to the cassette 2
Insert underneath the target board. At this time, hand 15
When the board is inserted into the cassette 2 to a predetermined position, the board is regulated between the positioning pins 16a and 16b provided on the hand 15 and the rear end surface of the cassette 2, and the direction of the front end of the board 3 (the front end surface) is shown. Are aligned in parallel in the Y direction. In this state, the hand 15 is slightly raised to scoop up the substrate 3, and then the substrate is sucked and fixed by a suction mechanism (not shown) and pulled out of the cassette 2. At this time, the pull-out direction is set to the X direction in the drawing along the outlet direction of the cassette 2 so that the side edge of the substrate faces the side edge position detector 17 when completely pulled out. The side edge position of the substrate is determined by the output state of the sensor 18 of the side edge position detector 17 with the hand 15 completely pulled out, the correction amount δ _n in the Y direction is determined, and the transfer data to the process device 4 is obtained. to correct.

FIG. 3 is a view showing a state in which the hand 15 sucking the substrate 3 is completely pulled out from the cassette 2,
FIG. 1A is a plan view, and FIG. 1B is a side view. In the figure, each reference numeral has the same function as in FIG.

FIG. 4 is a plan view showing an example of the side end position detector 17 of the apparatus shown in FIGS. 1 and 3. In the figure, the sensors a ₁ to a _n and the sensors b ₁ to b _n are symmetrically attached to the reference position C which should be located when the side edge of the substrate 3 is normal. Here, the sensors a ₁ and b ₁ have an allowable deviation amount Δ with respect to the reference position C.
Y _o apart, to a _n and b ₂ to the sensor a ₂ absence b
_{The n's} are mounted at positions separated by intervals ΔY ₁ to ΔY _n-1 as shown in the figure. Each sensor outputs an ON signal, that is, a 1 or high level signal when there is a substrate above it, and an OFF signal when there is no substrate, that is, a 0 or a low level signal (or a signal having the inverse relationship thereof). The one that outputs a binary logic signal is used.

In the side end position detector provided with the sensor as shown in FIG. 4, the distance Y _m from the reference position C to the m-th sensor is represented by Y _m = ΔY _o + ΔY ₁ + ... + ΔY _m-1 . be able to. Now, in FIG. 1, when the hand 15 of the robot 1 attracts the substrate 3 and pulls it out of the cassette 2 and reaches the position of FIG. 3, all the sensors on the left side of the m-th sensor b _m in FIG. If it is detected, the side edge position Y of the substrate 3 is to the right of the reference position C and is in the range of Y _m-1 ≤Y≤Y _m , that is, the side edge of the substrate is located at the sensor b _m-1 and the sensor b. _It can be determined that it is between _m and. Here, if the side edge of the substrate is located at the position closest to the sensor b _m , the position correction amount δ _m for moving the side edge of the substrate to the allowable range, that is, between the sensors a ₁ and b ₁ , is Y _m + ΔY _o ≧ δ _m ≧ Y _m −ΔY _o (1)

Further, when the side edge position of the substrate is located at the position closest to the sensor b _m-1 , the position correction amount δ _m is Y _m-1 + ΔY _o ≧ δ _m ≧ Y _m-1 −ΔY _o ...... (2 ) Must. Therefore, sensor b _m and sensor b _m-1
When there is a side edge position of the board between the and, the position correction amount δ _m for moving this to the allowable range is given by equation (1) and (2)
It can be determined in the range of Y _m-1 + ΔY _o ≧ δ _m ≧ Y _m −ΔY _o (3) where the formulas are satisfied.

Further, in order to satisfy the equation (3), it is necessary that Y _m-1 + ΔY _o ≧ Y _m −ΔY _o holds, and from this, 2 · ΔY _o ≧ Y _m −Y _m-1. ...... (4), the position correction amount δ _m and the sensor mounting pitch are set to appropriate values that satisfy the above equations (3) and (4), and the allowable error ΔY _o
Should be set for.

Here, it is assumed that the sensors a ₁ to a _n and b are
Assuming that ₁ to b _n are installed at equal intervals ΔY, the equation (3) is expressed by {ΔY _o + (m−2) · ΔY} + ΔY _o ≧ δ _m and δ _m ≧ {ΔY _o + (m−1) · ΔY} −ΔY _{o, that} is, 2 · ΔY _o + (m−2) · ΔY ≧ δ _m ≧ (m−1) · ΔY (5)

The equation (4) can be simplified as 2 · ΔY _o ≧ ΔY (6)

Next, when the difference between the inner width of the cassette 2 and the width of the substrate 3 is L, the positional deviation of the substrate is maximum L on the left and right sides when the reference position is at the center in the width direction.
It will be within / 2. Now, as shown in FIG. 5, this maximum shift amount is set to L / 2 = Y _max from the reference position C to the left and right, and n (where n ≧ 1 natural number) sensors are provided between them, and the n-th sensor is provided. Maximum deviation from sensor Y _max
If the distance to the position is ΔY _max , then Y _max = Y _n + ΔY _max = (ΔY _o + ΔY ₁ + ... + ΔY _n-1 ) + ΔY _max .

Here, considering the condition to be satisfied when the side edge position of the substrate is outside the n-th sensor in the same manner as when the equation (4) is derived, m = n is set to 2. determine the value of the installation pitch [Delta] Y and [Delta] Y _max of the sensor as _{ΔY o ≧ Y max -Y n ......} (7) from 2 · ΔY _o ≧ ΔY _max ...... (8) equation (4) are satisfied, The position correction amount δ
_It is sufficient to determine _n according to equation (3).

Further, when the sensors a ₁ and b _{1 and} after are installed at equal intervals ΔY, Y _max = ΔY _o + (n−1) ΔY + ΔY _max (9) Applying equations (6) and (8) to ΔY and ΔY _max in equation (9), Y _max ≦ ΔY _o + (n−1) · 2 · ΔY _o + 2 · ΔY _o
Therefore, n ≧ (Y _max −ΔY _o ) / (2 · ΔY _o ) ... (10)

Therefore, when the sensors are installed at equal intervals ΔY, the number n of left and right sensors and the mounting pitches ΔY and ΔY are satisfied so as to satisfy the expressions (6) to (8) and (10).
defining a _max, becomes a position correction amount [delta] _m (5) that may be determined according to the formula accordingly.

As can be seen from the above description, if the number of sensors is increased, the allowable error ΔY _o can be set small, so that the accuracy of position correction can be improved.
Actually, the maximum amount of positional deviation is 4 mm to the left and right from the reference position (the difference between the inner width of the cassette and the width of the substrate is 8 mm
mm), even if two sensors are provided symmetrically with respect to the reference position, two position errors can be made within 1 mm.

That is, the allowable errors ΔY _o = 1 mm, Y _max =
If it is set to 4 mm, the mounting pitch ΔY of the sensor may be ΔY ≦ 2 mm 2 according to ΔY ≦ 2 · ΔY _{o in the} equation (6).

Further, the distance ΔY _max from the outermost sensor to the position where the side edge position of the substrate may come is 2 × 1 ≧ ΔY _max from the equation (8).

In equation (10), Y _max = 4 and ΔY _o =
When 1 is set, n ≧ (4-1) / 2 · 1, and it can be seen that n ≧ 1.5 is sufficient.

Therefore, when two sensors are installed symmetrically with respect to the reference position C by adopting n = 2, each sensor is (a) ΔY _o = 1 mm, ΔY = 2 mm, ΔY _max = 1
mm or (b) ΔY _o = 1 mm, ΔY = 1.5 mm, ΔY _max
= 1.5 mm.

FIG. 6 is a plan view showing an example of the side end position detector 17 in the above-mentioned manner, and a ₁ , a ₂ and b ₁ , b ₂ are symmetrical with respect to the reference position C. Two sensors are provided. In the figure, a _max and b _max indicate the side end position when the substrate is carried out with the maximum deviation, that is, the position of Y _max .

Next, a method of determining the correction amount δ _m in each of the cases (a) and (b) will be described.

In the case of (a), (i) when the sensors a ₁ and a ₂ detect the substrate and the sensors b ₁ and b ₂ do not detect, the side edge positions of the substrate are the sensors a ₁ and b. _Since it is between ₁ and within the allowable error, the correction amount δ _m = δ ₁ = 0. (ii) When only the sensor a ₂ detects the substrate, or when the sensors a ₁ , a ₂ and b ₁ detect and only the sensor b ₂ does not detect, the side end position of the substrate is the sensor a ₁
And a ₂ or between sensors b ₁ and b ₂ . In the formula (3), m = 2, ΔY _o = 1 and Y _m-1
= ΔY _o = 1 and Y _m = ΔY _o + ΔY = 1 + 2 = 3, the correction amount δ ₂ is substituted into the formula (3), and 1 + 1 ≧ δ ₂ ≧ 3-1, and the correction amount δ ₂ = It can be seen that it may be 2 mm. Further, the correction direction is in the Y2 direction in the figure when only the sensor a1 detects the substrate, and the sensors a1, a
When 2 and b1 are detecting the substrate, the direction is Y1 in the figure. (iii) All of the sensors a ₁ , a ₂ , b ₁ , b ₂ are not detecting the substrate, or when all are detecting, the side edge position of the substrate is outside the sensor a ₂ or b _2. . Therefore, in equation (3), m = 3, ΔY _o = 1 and Y _m-1 =
Since 3, Y _m = Y _max = 4, substituting them into the equation (3) results in 3 + 1 ≧ δ ₃ ≧ 4-1, and if the correction amount δ ₃ is set to an appropriate value within the range of ₃ to 4 mm. I know it's good. Also, the correction direction is to the Y1 direction in the figure when all the sensors detect the board,
If all the sensors do not detect the board, Y in the figure
It should be 2 directions.

In the case of (b), (i) when the sensors a ₁ and a ₂ detect the substrate and the sensors b ₁ and b ₂ do not detect, the side end positions of the substrate are the sensors a ₁ and b. _Since it is between ₁ and within the allowable error, the correction amount δ _m = δ ₁ = 0. (ii) When only the sensor a ₂ is detecting the substrate, or when the sensors a ₁ , a ₂ and b ₁ are detecting and only the sensor b ₂ is not detecting, the side end position of the substrate is the sensor a ₁
And a ₂ or between sensors b ₁ and b ₂ . In the formula (3), m = 2, ΔY _o = 1 and Y _m-1
= ΔY _o = 1 and Y _m = ΔY _o + ΔY = 1 + 1.5 = 2.5 Therefore, the correction amount δ ₂ is 1 + 1 ≧ δ ₂ ≧ 2.5-1 by substituting them into the equation (3), It can be seen that it may be set to an appropriate value within the range of 2 ≧ δ ₂ ≧ 1.5. The correction direction may be determined according to the output state of each sensor as in the case of (a) above. (iii) All of the sensors a ₁ , a ₂ , b ₁ , b ₂ are not detecting the substrate, or when all are detecting, the side edge position of the substrate is outside the sensor a ₂ or b _2. . In the equation (3), m = 3, ΔY _o = 1 and Y _m-1 = 3, Y _m = Y
_{Since max} = 4, substituting them into the equation (3) gives 2.5 + 1 ≧ δ ₃ ≧ 4-1, and the correction amount δ ₃ should be set to an appropriate value within the range of ₃ to 3.5 mm. Recognize. The correction direction may be determined according to the output state of each sensor as in the case of (a) above.

The above is summarized as shown in FIGS. 7 and 8.

Therefore, according to the mounting state of the sensor, as shown in FIG.
Alternatively, the data of FIG. 8 is determined and stored in advance, and when the substrate is pulled out by the hand 15 of the robot 1, the side edge position is detected depending on the state in which each sensor of the side edge position detector 15 detects the substrate. It is possible to immediately obtain the correction amount and the correction direction in the Y direction by determining the above and reading the previously stored data. From this result, when the substrate is transported to the next process device, if the correction amount is taken into account and the substrate is moved, the substrate will be installed correctly.

In the above embodiment, a plurality of sensors are arranged symmetrically with respect to the reference position, and the presence or absence of the side edge position of the substrate is determined by a binary logic signal indicating whether or not each sensor detects the substrate. Although the range is determined, the side edge position detector is not limited to this type, and the deviation amount of the side edge of the substrate from the reference position may be quantitatively detected. In this case, if a side sensor is used as the side edge position detector, which is called a line sensor whose output changes linearly in response to a change in the position of the substrate, or a CCD sensor, the correction amount can be calculated by comparing these outputs with a reference value. Since the difference can be directly obtained, the positioning can be performed with higher accuracy.

[0038]

According to the present invention, when the substrate is transferred to the processing chamber in the liquid crystal manufacturing process apparatus, the displacement of the substrate generated in the cassette is fully automatic and no time is required for position detection. Since it can be corrected, chipping and dust, which have been the cause of substrate cracking, which has been a problem in the past, can be minimized, and manual alignment is not required, improving the efficiency of liquid crystal substrate production. In addition, a remarkable effect can be obtained in improving yield and reliability.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the device of the present invention.

FIG. 2 is a flowchart for explaining the operation of the present invention.

3 is a diagram showing a state in which the hand 15 sucking the substrate 3 is completely pulled out from the cassette 2 in the embodiment of FIG.

FIG. 4 is a plan view showing an example of a side edge position detector of a substrate used in the apparatus of the present invention.

FIG. 5 is a plan view showing the positional relationship between the maximum displacement amount Y _max of the side edge position of the substrate used in the apparatus of the present invention and the sensor.

FIG. 6 is a plan view showing an example of a specific sensor arrangement in the side edge position detector of the substrate used in the apparatus of the present invention.

FIG. 7 is a diagram showing an example of a combination of output states of respective sensors and a correction amount and a correction direction at the time of detecting a side edge position of a substrate in the apparatus of the present invention.

FIG. 8 is a diagram showing another example of the combination of the output states of the sensors and the correction amount and the correction direction when the side edge position of the substrate is detected in the device of the present invention.

FIG. 9 is a perspective view showing an example of a conventional device.

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

FIG. 11 is a perspective view showing an example of another conventional device.

[Explanation of symbols]

 1 Robot 2 Cassette 3 Liquid Crystal Substrate 4 Process Device 5 Liquid Crystal Positioning Device 11 Base 12 Robot Main Body 13 Swivel Axis 14 Arm 15 Hands 16a, 16b Positioning Pins 17 Substrate Side Position Detector 18 Sensor

Claims (3)

[Claims] 1. A position correction device in a liquid crystal substrate processing apparatus in which a robot for loading and unloading a plurality of liquid crystal substrates is arranged in a cassette capable of storing a plurality of liquid crystal substrates. A front direction regulating means for pushing the substrate from the front side of the cassette once to align the front side of the substrate in a predetermined direction is provided in the hand part of the robot, and the robot carries out the substrate from the cassette. The side edge position detector for detecting the side edge position of the substrate at a predetermined position in the state where the side edge position of the substrate is deviated from the reference position by using the output of the side edge position detector as an input. A liquid comprising a calculation means for calculating the amount to obtain the position correction data, and a robot controller for correcting the subsequent transfer position data by the position correction data of the calculation means. Position correction device for crystal substrates. 2. The side edge position detector has a sensor that outputs a binary signal depending on the presence or absence of the substrate at a position symmetrical to the reference position of the side edge when the substrate is pulled out from the cassette. A predetermined number of pairs of sensors are provided, and the first group of the sensors is located at a position of ± ΔY _o from the reference position, and the second and subsequent groups have a predetermined ΔY of 2 · ΔY _o ≧ ΔY.
N sets for each separation, where n ≧ (Y _max −ΔY _o ) / (2 · ΔY _o ), Y _max = 1/2 of the difference between the inner width of the substrate housing portion of the cassette and the substrate width, ΔY _o = allowable deviation amount of the end position on the substrate side, the calculating means is arranged to detect the m-th sensor and the (m-th) sensor.
-1) When it is detected that there is a side edge of the substrate between the pair of sensors, 2 · ΔY _o + (m−2) · ΔY ≧ δ _m ≧ (m−1) · Δ
The liquid crystal substrate position correcting device according to claim 1, wherein a predetermined value δ _m that satisfies Y 1 is output as the side edge position correction data. 3. The position correcting device for a liquid crystal substrate according to claim 1, wherein the side edge position detector is a sensor for quantitatively detecting the amount of deviation of the side edge position of the substrate from the reference position. .