JP5266964B2 - Substrate transfer system, semiconductor manufacturing apparatus, and substrate position calculation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the substrate conveyance accuracy of a substrate conveyance system, without failing to obtain a sensor signal of a substrate detecting sensor. <P>SOLUTION: The present invention relates to a substrate conveyance system 1, equipped with: a conveyance arm 31 for operating a fork 34; an arm-driving motor 32 for driving the conveyance arm 31; an electric motor encoder 33 for detecting the rotation angle of the arm-driving motor 32; a substrate detecting sensor 4 capable of detecting a substrate 5; a latch circuit 24, which receives a sensor signal 41 from the substrate detecting sensor 4 and maintains an encoder value from the electric motor encoder 33, at the same time the sensor signal 41 changes; storage means 25 for sequentially storing a change sequence of the sensor signal and the encoder value at that time, by respectively making a set; and an operation part for computing the position of the substrate, based on data stored in the storage means 25. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a semiconductor / liquid crystal manufacturing apparatus and a substrate inspection apparatus, and more particularly to a substrate transfer apparatus for positioning a substrate such as a wafer, liquid crystal glass, or reticle.

Conventionally, in a semiconductor or liquid crystal manufacturing apparatus or inspection apparatus (hereinafter collectively referred to as a semiconductor manufacturing apparatus), a transfer robot is used to transfer and position a substrate.
A configuration of a conventional substrate transfer system will be described with reference to FIG. In the figure, the substrate 5 is held on a fork 34 and is transported by a transport arm 31. The position of the fork 34 is controlled by the robot controller 2, and the position of the fork 34 is calculated and controlled from information on the motor arm 33 of the motor that drives the transfer arm 31 and the fork 34.
However, since the substrate 5 is not necessarily accurately held at the same position on the fork 34 every time it is transported, when the substrate 5 is held displaced from the fork 34, the fork 34 is positioned at a desired position. Even so, the substrate 5 is displaced from the desired position.
Therefore, conventionally, in order to accurately position the substrate 5 even in such a case, the relative position of the substrate 5 on the fork 34 is detected, and the position of the fork 34 is corrected by the relative position. Is transporting the substrate 5 (see, for example, Patent Document 1).
For this reason, in Patent Document 1, a substrate detection sensor 4 including a light emitting unit and a light receiving unit located on the front and back sides of the substrate 5 is disposed in the middle of the path along which the substrate is conveyed, 5, the sensor signal detected by the substrate detection sensor 4 is processed by the sensor processing circuit 21 of the robot controller 2, and the calculation unit 23 is connected to the fork 34 by the information of the sensor detection signal and the encoder processing circuit 22 at that time. The relative position of the substrate 5 was calculated.
Japanese Patent No. 3335444

However, when the encoder signal is processed after the substrate detection by the substrate detection sensor 4 is recognized in the software processing cycle, the sensor signal may be missed due to a timing error or processing delay within the software processing cycle. It was difficult to accurately grasp the substrate position.
For example, as shown in FIG. 4, when the substrate 5 is traversed by a transfer robot that holds the substrate 5 with the fork 34 with respect to one substrate detection sensor 4, the signal of the substrate detection sensor 4 is represented by the sensor signal 41 of FIG. It changes over time from left to right. However, in the edge portions A and B around the substrate 5, many change points may occur due to chattering of the substrate detection sensor 4 or the like.
On the other hand, the software processing cycle 43 of the figure shows the software processing cycle of the calculation unit 23 that acquires the sensor signal 41. The calculation unit 23 acquires the sensor signal 41 and the encoder signal 42 indicating the encoder signal at the timing indicated by the vertical line of the software processing cycle 43.
Here, there is no problem if the timing of the software processing cycle 43 can recognize all changes in the sensor signal 41 as in the case of acquiring the sensor signal 41 at the B position ([2] to [5] in the figure). However, as in the state at the A position, the change in the sensor signal 41 can be recognized only once at the timing of [1], and the sensor signal that can be acquired as a result by the calculation unit 23 is the calculation unit acquisition signal 45 Thus, there is a problem that the sensor signal is missed.
Further, when the software processing cycle 43 is long, there is a problem that the calculation unit 23 cannot accurately capture the encoder signal when the substrate 5 actually crosses the substrate detection sensor 4.
The present invention has been made in view of such problems, and it is an object of the present invention to prevent the sensor signal from being missed and to increase the accuracy of substrate conveyance of the substrate conveyance system.

In order to solve the above problem, the present invention is configured as follows.
The present invention provides a substrate transfer system capable of detecting a substrate held on a fork and calculating a position of the substrate relative to the fork, a transfer arm that operates the fork, an arm drive motor that drives the transfer arm, A motor encoder that detects a rotation angle of the arm drive motor; a substrate detection sensor that is provided in a conveyance path of the substrate; and that can detect the substrate; receives a sensor signal from the substrate detection sensor; A latch circuit that holds an encoder value from the motor encoder at the same time as the change, a storage means for sequentially storing the change order of the sensor signal and the encoder value at that time as a set, and storing in the storage means And a calculation unit that calculates the position of the substrate based on the obtained data. It is an system.
Further, according to the present invention, the calculation unit calculates a difference in rotation position of the motor as a detection width from encoder values of the adjacent data in the order among the data, and the detection width is based on a preset threshold value. it is an board conveying systems that and calculates the position of the substrate with the even larger data.
Further, the present invention, the calculation unit is for the base plate conveyance systems that wherein the detection width destroys the data smaller than the threshold value.
Further, the present invention, the latch circuit, it is an board conveying system that is characterized in that it comprises a maskable mask circuit receiving the sensor signal.
The present invention also provides a semiconductor manufacturing apparatus comprising the above-described substrate transfer system.
Further, the present invention detects the substrate held by the substrate holding means, the calculation can be substrate transfer system the position of the substrate relative to the substrate holding means, a driving means for operating the front Stories substrate holding means, the drive A motor that drives the means; an encoder of the motor; a substrate detection sensor that is provided in a conveyance path of the substrate; and that detects the substrate; receives a sensor signal from the substrate detection sensor; and the sensor signal changes At the same time, holding means for holding the encoder value from the encoder, storage means for sequentially storing the change order of the sensor signal and the encoder value at that time as a set, and stored in the storage means And a calculating means for calculating the position of the substrate based on the data.
Further, according to the present invention, the calculation means calculates a difference in the motor position as a detection width from encoder values of the adjacent data in the order among the data, and the detection width is larger than a preset threshold value. it is an board conveying systems that and calculates the position of the substrate with a large data.
Further, the present invention, the retaining means is to the base plate conveyance systems that comprising: a maskable mask means the reception of said sensor signal.
The present invention also provides a semiconductor manufacturing apparatus comprising the above-described substrate transfer system.
Further, the present invention provides a method for detecting the substrate held by a substrate holding unit and calculating the position of the substrate with respect to the substrate holding unit in a substrate transfer system for transferring a substrate, the substrate holding unit comprising: The substrate in operation is detected by the substrate detection sensor, and the order when the sensor signal of the substrate detection sensor is changed and the position information of the substrate holding means at that time are sequentially stored as a set. The difference is calculated from the position information of the substrate holding means of the adjacent data in the order among the stored data, and the position of the substrate is calculated using data in which the difference is larger than a preset threshold value. A substrate position calculation method for a substrate transfer system is provided.

According to the present invention, since it is possible to prevent the sensor signal from being missed, the error in calculating the substrate position can be reduced, and the substrate can be transported more accurately.
In addition, according to the present invention, useless calculations can be reduced, so that the calculation of the calculation unit and the calculation means is accelerated, and high-speed substrate transfer can be performed.
In addition, according to the present invention, data that can be determined to be chattering is discarded, so that the capacity of a storage unit such as a memory can be reduced.
Further, according to the present invention, even when a plurality of substrate detection sensors are installed on the conveyance path, signals from the substrate detection sensors that are not related to the current substrate position calculation can be masked. The calculation of the unit and the calculation means is accelerated, and the capacity of the storage means such as a memory can be reduced.
Further, according to the present invention, a semiconductor manufacturing apparatus that can transport a substrate more accurately can be configured.

  Hereinafter, specific examples of the method of the present invention will be described with reference to the drawings.

FIG. 2 is a block diagram showing the configuration of a substrate transfer system that implements the configuration and method of the present invention. FIG. 3 is a diagram showing a time chart when the substrate crosses the detection sensor in the substrate transfer system of FIG.
In FIG. 2, the substrate transport system 1 includes at least a transport robot 3 that transports a substrate 5, a robot controller 2 that controls the transport robot 3, and a substrate detection sensor 4 that can detect the substrate 5 transported by the transport robot 3. It is composed of
The transfer robot 3 generally includes a transfer arm 31, an arm drive motor 32, a motor encoder 33, and a fork 34. The fork 34 can hold the substrate 5 in a horizontal state. The fork 34 holds the substrate 5 by gripping a part of the periphery of the substrate 5 or sucking the back surface of the substrate 5. The transport arm 31 for driving the fork 34 has a horizontal articulated shape in which a plurality of horizontal arms are connected in this embodiment, but the form of the arm is not limited. At least an arm drive motor 32 (not shown) that drives each arm may be provided as long as it can cross the substrate 5 on the fork 34 with respect to the substrate detection sensor 4 described later. And what is necessary is just to have the motor encoder 33 of the arm drive motor 32 which is not shown in figure, the position of the fork 34 can be calculated from the rotation angle of a motor, and this can be controlled to a desired position.
The substrate detection sensor 4 is installed in the middle of the conveyance path of the substrate 5 held by the fork 34. In this embodiment, the substrate detection sensor 4 is a transmissive sensor including a light emitting unit and a light receiving unit positioned on the front and back sides of the substrate 5 so that the substrate 5 is sandwiched between the upper and lower sides, but the presence or absence of the substrate 5 can be detected. Any reflective sensor may be used. A plurality of substrate detection sensors 4 are installed as necessary.
The robot controller 2 includes an encoder processing circuit 22, a latch circuit 24, a FIFO memory 25, and a calculation unit 23 in addition to the drive circuit for the arm drive motor 32. The encoder processing circuit 22 receives an encoder signal 42 from the motor encoder 33 of the arm drive motor 32 and calculates an encoder value that is a rotation angle of the arm drive motor 32. The encoder signal is an A / B phase pulse signal or a serial communication signal, and the encoder value is a value obtained by processing and calculating the encoder signal, that is, a motor rotation angle. Since the transport arm 31 may be driven by a plurality of arm drive motors 32, the encoder processing circuit 22 is provided according to the number of motor encoders 33. The latch circuit 24 receives the encoder value from the encoder processing circuit 22 and the sensor signal 41 of the substrate detection sensor 4, generates latch data to be described later, and sends it to the FIFO memory 25. The calculation unit 23 reads the latch data stored in the FIFO memory 25 at a predetermined software processing cycle, calculates the position of the substrate 5 from the sensor signal 41 and the encoder value at that time, and calculates the position of the substrate 5 with respect to the fork 34. Calculate the relative position. Then, the robot controller 2 controls the arm drive motor 32 so as to correct the calculated displacement of the substrate 5 with respect to the fork 34, and positions the fork 34 with respect to a target transport position (not shown).

The present invention configured as described above is executed as follows.
First, the substrate 5 held on the fork 34 of the transfer robot 3 is transferred so as to pass through the substrate detection sensor 4. At this time, the substrate 5 passes between the light emitting portion and the light receiving portion of the substrate detection sensor 4 and shields the sensor light. As the substrate 5 passes between the light emitting portion and the light receiving portion of the substrate detection sensor 4, the sensor signal 41 of the substrate detection sensor 4 changes to ON / OFF or High / Low. In this embodiment, when the sensor light is shielded by the substrate 5, the sensor signal 41 changes from ON to OFF or from High to Low. The sensor signal 41 is input to the latch circuit 24.
The latch circuit 24 detects the change point of the sensor signal 41 from ON to OFF, the change point from OFF to ON, the change point from High to Low, or the change point from Low to High. The encoder value output from the processing circuit 22 is held for the required number of axes (for a plurality of motor encoders 33), and an order is generated for each change point of the sensor signal 41 and added to obtain latch data.
The held encoder value and the latch data of the order are set and input to and stored in the FIFO memory 25.
The encoder value and the sequential latch data stored in the FIFO memory are read into the calculation unit 23 in the software processing cycle of the calculation unit 23.

The function and effect of the present invention will be described with reference to FIG.
FIG. 3 shows a sensor signal 41 of the substrate detection sensor 4 when the substrate 5 passes through the substrate detection sensor 4 so as to shield the light, an encoder signal 42 from the motor encoder 33 at that time, and a latch. The time chart of the latch data 44 which the circuit 24 hold | maintains is shown.
At time A indicating when the substrate 5 starts to shield the substrate detection sensor 4, many change points are generated in the sensor signal 41 of the substrate detection sensor 4 due to chattering or the like. In addition, a large number of change points are also generated at time B indicating when the substrate 5 finishes passing through the substrate detection sensor 4.
At this change point, in the present invention, the change from high to low of the sensor signal 41 is detected by the latch circuit 24, and at the same time the change is detected, the encoder value from the encoder processing path 22 is held, 3 is added, and this is sequentially input to the FIFO memory 25 as latch data 44.
Then, with respect to the FIFO memory 25 in which a plurality of latch data 44 is stored, the calculation unit 23 reads out the latch data 44 in a predetermined software processing cycle according to the above order, thereby missing the change point of the sensor signal 41. And can be used for the calculation of the substrate position. The calculation unit acquisition signal 45 represents an image of the sensor signal that can be acquired by the calculation unit 23 as a result in the present invention.
Therefore, according to the present invention, the substrate position can be grasped more accurately and the error of the substrate positioning can be reduced without causing the sensor signal to be missed due to the timing error or the processing delay within the software processing period. Thus, the substrate transport accuracy can be increased.

  When a plurality of substrate detection sensors 4 are arranged in the substrate conveyance path, a number is determined in advance for each of the plurality of substrate detection sensors 4 arranged, and a sensor from the substrate position detection sensor 4 is assigned to the latch circuit 24. A mask circuit capable of masking reception of the signal 41 may be provided. This mask circuit masks the sensor signal 41 of the substrate detection sensor 4, which is not related to substrate detection in the current substrate transfer path, with respect to the latch circuit 24, and should not be detected originally, for example, the transfer arm 31. The generation of the latch data 44 due to the substrate position detection sensor 4 reacting and changing due to a part of the data can be prevented, unnecessary latch data can be eliminated, and the capacity of the FIFO memory 25 can be reduced. In addition, since unnecessary software processing of the calculation unit 23 is reduced, a high-performance calculation circuit is not required and the cost can be reduced.

Next, a procedure when the calculation unit 23 starts calculating the position of the substrate 5 using the latch data 44 stored in the FIFO memory 25 will be described.
FIG. 5 is a flowchart showing a procedure for detecting / excluding unnecessary latch data 44 executed by the arithmetic unit 23.
First, in step 1, the arithmetic unit 23 reads the latch data 44 stored in the FIFO memory 25 according to the above order, and acquires data.
Next, in step 2, the difference between the motor rotational positions is calculated as a detection width from the encoder values included in the latch data 44 at adjacent numbers.
Next, in step 3, the detection width is compared with a preset threshold value stored. If the threshold value is equal to or smaller than the threshold value, the adjacent latch data 44 equal to or smaller than the threshold value is determined to be chattering data. Proceeding to step 4, these latch data 44 are left or discarded.
Similarly, in step 3, this detection width is compared with a preset threshold value stored, and if it is equal to or greater than the threshold value, the latch data 44 adjacent to the threshold value is not a chattering data or the like. Proceeding to step 5 assuming that the data is the data 44, the motor rotation position of the encoder value included in the normal latch data 44 is stored in a memory (not shown).
In step 6, if reacquisition of the latch data 44 is necessary, the process returns to step 1, and if not necessary, the process is terminated, and although not shown in FIG. To start.
According to the above procedure, the chattering data mixed in the acquired latch data 44 without any omission can be detected and eliminated, unnecessary calculations in the calculation unit 23 can be eliminated, and the memory capacity can be reduced.

Block diagram showing a conventional substrate transfer system The block diagram which shows the board | substrate conveyance system of this invention Time chart of substrate transfer system of the present invention Time chart of conventional substrate transfer system The flowchart which shows the process sequence in this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Board | substrate conveyance system 2 Robot controller 21 Sensor processing circuit 22 Encoder processing circuit 23 Calculation part (CPU)
24 latch circuit 25 FIFO memory 3 transfer robot 31 transfer arm 32 arm drive motor 33 motor encoder 34 fork 4 substrate detection sensor 5 substrate 41 sensor signal 42 encoder signal 43 software processing cycle 44 latch data

Claims (8)

In the substrate transfer system capable of detecting the substrate held on the fork and calculating the position of the substrate relative to the fork,
A transfer arm for operating the fork;
An arm drive motor for driving the transfer arm;
A motor encoder for detecting a rotation angle of the arm drive motor;
A substrate detection sensor provided in a conveyance path of the substrate and capable of detecting the substrate;
A latch circuit that receives a sensor signal from the substrate detection sensor and holds an encoder value from the motor encoder at the same time as the sensor signal changes;
Storage means for sequentially storing data in which the order of change of the sensor signal and the encoder value at that time are set as a set;
A difference in rotational position of the motor is calculated as a detection width from the encoder values in the data in the order adjacent to each other among the data, and the data having the detection width larger than a preset threshold is selected and selected. A calculation unit for calculating the position of the substrate based on the encoder value in the data ,
A substrate transfer system comprising: The arithmetic unit, the substrate transport system of claim 1, wherein the detection range is equal to or discarding the data smaller than the threshold value. 3. The substrate transfer system according to claim 1, wherein the latch circuit includes a mask circuit capable of masking reception of the sensor signal. The semiconductor manufacturing apparatus comprising: a substrate transfer system according to any one of claims 1 to 3. In the substrate transfer system capable of detecting the substrate held by the substrate holding means and calculating the position of the substrate with respect to the substrate holding means,
Driving means for operating the substrate holding means;
A motor for driving the driving means;
An encoder of the motor;
A substrate detection sensor provided in a conveyance path of the substrate and capable of detecting the substrate;
Holding means for receiving a sensor signal from the substrate detection sensor and holding an encoder value from the encoder at the same time as the sensor signal changes;
Storage means for sequentially storing data in which the order of change of the sensor signal and the encoder value at that time are set as a set;
A difference in rotational position of the motor is calculated as a detection width from the encoder values in the data in the order adjacent to each other among the data, and the data having the detection width larger than a preset threshold is selected and selected. Calculating means for calculating the position of the substrate based on the encoder value in the data ,
A substrate transfer system comprising: 6. The substrate transfer system according to claim 5 , wherein the holding unit includes a mask unit capable of masking reception of the sensor signal. The semiconductor manufacturing apparatus comprising: a substrate transfer system according to claim 5 or 6. In a substrate transfer system for transferring a substrate, a method of detecting the substrate held by a substrate holding unit and calculating a position of the substrate with respect to the substrate holding unit,
Operating the substrate holding means by a motor ;
The substrate in operation is detected by a substrate detection sensor,
Sequentially, the data when the order when the sensor signal of the substrate detection sensor is changed and the encoder value of the motor encoder that detects the rotation angle of the motor, which is information on the position of the substrate holding means at that time , is set. Remember ,
Calculates the difference between the rotational position of the motor as a detection width from the encoder value each other in the data of the order in which adjacent one of the previous SL data,
Selecting the data for which the detection width is greater than a preset threshold;
A substrate position calculation method for a substrate transfer system, wherein the substrate position is calculated based on the encoder value in the selected data.

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