JP2015005684A - Transfer robot and transfer method of disk-shaped transfer object - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent lowering in detection accuracy due to variation in scan timing of a sensor for detecting a wafer mounted on a hand, and accurately determine the difference between the position of the wafer mounted on the hand and a normal mounting position to securely transfer the wafer.SOLUTION: It is detected that three peripheral positions in a wafer 7 on a hand 23 which is in a stopped state and starts moving to a delivery position from a transfer start position have passed photoelectronic sensors 6L, 6C, 6R on the basis of changes in output signals of the respective photoelectronic sensors 6L, 6C, 6R. The center position of the wafer 7 is calculated on the basis of the movement amount of the wafer 7 on the orthogonal coordinate system which can be extracted from the detection information and position information of the respective photoelectronic sensors 6L, 6C, 6R. An operation instruction to specify an operation amount of a transfer driving mechanism 1 is generated on the basis of the difference between the center position of the wafer 7 and a reference center position, and operation of the transfer driving mechanism 1 is controlled on the basis of the operation instruction.

Description

  The present invention relates to a transport robot that transports a disk-shaped transport target such as a wafer, and a method for transporting a disk-shaped transport target using the transport robot.

  Conventionally, a disk on a hand is operated by operating a transport driving mechanism including the hand in a state where a disk-shaped transport object such as a wafer is placed and held on a transport hand (hereinafter abbreviated as “hand”). 2. Description of the Related Art A transfer robot configured to be able to transfer an object to be transferred to a predetermined transfer position (transfer target position) is known. For example, when the object to be transferred is a wafer, the wafer is manufactured in a precise disk shape (however, notches such as notches and orientation flats may be formed), so there is no error for each transferred wafer. It is considered a thing. In such a transport robot, if the disc-shaped transport object is placed at a regular placement position on the hand, the transport drive mechanism performs an appropriate operation so that the disc-shaped transport object on the hand is moved. It can be transported to a regular transfer position.

  However, if the disk-shaped transport object is placed at a position slightly displaced from the regular placement position on the hand, the disk-shaped transport object is moved to a position displaced from the regular transfer position according to the amount of displacement. The object will be transported.

  Therefore, the present applicant obtains the difference between the position of the disc-shaped conveyance object placed and held on the hand of the conveyance robot and the normal placement position, and appropriately controls the operation amount of the conveyance drive mechanism according to the difference. Therefore, as a transport robot capable of transporting a disk-shaped transport target object to a regular transport target position, the configuration shown in Patent Document 1 below has been invented and a patent application has already been filed.

  In the transport robot shown in Patent Document 1, the movement of the disc-shaped transport target placed on the hand is configured to be detected by a single sensor, and the passage sensed by the sensor when the disc-shaped transport target passes the sensor. Placed at the normal placement position on the hand and the passing distance in the first axis direction (Y-axis direction on the Cartesian coordinate system) with respect to the sensor of the disk-shaped conveyance object obtained based on the start point and the passage end point A Cartesian coordinate system of the placement position of the disc-shaped transport object on the hand and the normal placement position using the distance that the held disk-shaped transport object passes the sensor and the radius of the disk-shaped transport object. The above difference is obtained, calculated by converting the difference into a correction value in the robot movement polar coordinate system of the pivot axis and the arm, and outputting the correction value.

JP 2012-74469 A

  By the way, in the invention described in Patent Document 1, the disk-shaped conveyance object placed on the hand passes the sensor as the hand moves, and the passage start point and the passage end point of the disk-shaped conveyance object with respect to the sensor are detected. Thus, the above-described processing is performed based on the detected values. Therefore, there is a delay time from when the sensor detects the passage start point and the passage end point of the disc-shaped transport object until the data is taken in. Depending on the moving speed of the disc-shaped transport object, an error relative to the true value may occur. It may occur.

  When the hand is moved at a relatively slow constant speed, the above errors do not pose a major problem. However, the hand is moved at a high speed or the moving speed of the hand is accelerated while the object is being transported in a disk shape. Is transported to the transport target position, the transport speed at the time when the disc-shaped transport object placed on the hand finishes passing through the sensor is higher than the transport speed at the time when the disc-shaped transport object starts passing through the sensor. The possibility that the detection accuracy at the time of passing through the sensor is lower than the detection accuracy at the time of starting to pass through the sensor due to variations in the sensor scan timing cannot be excluded. In particular, as the moving speed of the hand is set faster to improve the transport efficiency of the disk-shaped transport object, the detected value (the disk shape detected by the sensor) with respect to the actual peripheral position (true value) of the disk-shaped transport object It is expected that the error in the peripheral position of the conveyance object will increase.

  In addition, when the center position of the disc-shaped transport object is calculated by using the diameter size of the disc-shaped transport object as a known value, an error in the diameter size in the disc-shaped transport object that is strictly manufactured is individual. Although the actual diameter size is different from the value used as a known value by, for example, expansion processing, the center position of the disc-shaped transport object calculated using the known diameter size is actually It will deviate from the center position (true value) of the disk-shaped transport object.

  When such a situation occurs, it is impossible to accurately calculate the center position of the disk-shaped transport object that is actually transported, and the correction value in the robot motion polar coordinate system obtained from the calculated value including the error is used. The amount of deviation from the reference placement position (reference grip position) of the disc-shaped transport target placed and held (gripped) on the hand by operating the transport drive mechanism based on the correction value is calculated. By correcting, the accuracy of transporting to a predetermined transport target position decreases.

  The present invention has been made paying attention to such problems, and its main purpose is to suppress the influence (influence of variations in scan timing) on the transfer speed and acceleration of the disk-like transfer object by the hand as much as possible. Without using the diameter size of the disc-shaped transport object as a known value, the difference between the position of the disc-shaped transport object placed and held on the hand and the normal center position is accurately obtained, and the disc-shaped transport object It is intended to provide a transport robot and a disk-shaped transport target transport method that can transport a target to a predetermined transport target position more accurately.

  That is, the present invention includes a transport drive mechanism capable of transporting a disk-shaped transport object on a hand to a predetermined transport target position by moving the hand from a transport start position to a delivery position along a linear movement path, and a transport The present invention relates to a transfer robot including a control unit that controls the operation of a drive mechanism.

  Here, the disk-shaped conveyance object may be a disk-shaped object, and examples thereof include a semiconductor wafer and a liquid crystal panel. Further, the control unit may be built in or attached to the transport driving mechanism, or may be provided outside the transport driving mechanism. As the transport drive mechanism, the hand is configured to be able to move back and forth linearly along two orthogonal axes, or the base end of the arm is configured to be pivotable around the pivot axis and provided at the distal end of the arm And a hand configured to be able to move forward and backward.

  The transfer robot according to the present invention is a disk-shaped transfer target on the hand if the hand is moved from the transfer start position to the delivery position in a state where the disk-shaped transfer target is mounted at a normal mounting position on the hand. An object can be accurately conveyed to a predetermined conveyance target position. This means that if the hand is moved from the transport start position to the delivery position in a state where the disc-shaped transport object is placed at a position shifted from the normal placement position on the hand, This means that the object to be transported is transported to a position moved according to the amount of displacement of the placement position with respect to a predetermined transport target position. In the transfer robot according to the present invention, even when the disk-shaped transfer object is placed at a position deviated from the normal placement position on the hand, the disk-like transfer object on the hand is set to a predetermined value. The structure described below is adopted so that it can be accurately transported to the transport target position.

  In other words, the transport robot according to the present invention includes, as the control unit, a peripheral position detection unit, a center position calculation unit, a displacement amount calculation unit, and an operation command generation unit, and an operation generated by the operation command generation unit. The present invention is characterized in that a configuration that controls the operation of the transport drive mechanism based on a command is applied.

  Specifically, the peripheral position detection means passes the disc-shaped transport object on the hand, which has started moving from the transport start position in the stopped state toward the delivery position, through three or more photoelectric sensors, and each of the photoelectric sensors By detecting a change in the output signal, it is detected that three or more different peripheral positions of the disc-shaped transport target have passed through the photoelectric sensors.

  Further, the center position calculation means, when the orthogonal coordinate system is defined by the first axis that is the normal movement path of the hand and the second axis that is orthogonal to the first axis in the horizontal plane including the first axis, Corresponding to the detection information at the start of passage of the peripheral position of the disc-shaped conveyance object with respect to each photoelectric sensor out of the detection information detected by the peripheral position detection means and the photoelectric sensor position information that is the installation position of each photoelectric sensor on the coordinate system The center position of the disc-shaped transport object is calculated using the amount of movement of the disc-shaped transport object that can be acquired in this way.

  The displacement amount calculating means calculates the reference center position on the Cartesian coordinate system, which is the center position of the disk-shaped transport object when the disk-shaped transport object is placed at the normal placement position on the hand, and the center position calculation. The difference (displacement amount) from the center position of the disk-shaped conveyance object calculated by the means is calculated. Further, the operation command generating means operates the transport driving mechanism necessary for transporting the disc-shaped transport object on the hand to a predetermined transport target position based on the difference (displacement amount) calculated by the displacement amount calculating means. An operation command that defines the quantity is generated.

  As described above, in the transfer robot according to the present invention, the transfer is performed when the hand is in a stopped state as the timing at which three or more positions on the periphery of the disk-shaped transfer object on the hand pass through the corresponding three or more photoelectric sensors. The sensor is set to pass the disc-shaped transport object in the high-speed state because it is set at the time when it starts to move from the start position toward the delivery position, that is, when the hand is at the initial speed or close to the initial speed. Compared with the detection mode, the probability of being affected by variations in scan timing can be effectively approached to zero, and three or more positions on the periphery of the disc-shaped conveyance object on the hand are three or more photoelectric sensors. Can be detected accurately based on the change in the output signal of each photoelectric sensor, which increases the transport speed of disc-shaped transport objects. The accuracy of detecting a peripheral position of the disc-like object to be transported can be prevented or suppressed problems that can decrease I.

  Furthermore, in the transport robot according to the present invention, as information used when calculating the center position of the disc-shaped transport target actually placed on the hand, among the detection information detected by the peripheral position detection means, Since the movement amount of the disk-shaped conveyance object that can be acquired in association with the information that detected the event that the peripheral position of the disk-shaped conveyance object starts to pass with respect to the photoelectric sensor is used, conveyance of the hand in the stopped state is started. Even if it is configured to move while accelerating from the position toward the delivery position, it uses the detection information at the start time of the relatively slow passage, but it is relatively fast and affected by variations in scan timing. By not using detection information at the end point of easy passage, for example, by using detection information that includes an error with respect to the true value due to variations in scan timing, It is possible to avoid a situation that the calculated center position of the disc-like object to be transported.

  In particular, in the transfer robot according to the present embodiment, the amount of movement of the disc-shaped transfer object that can be acquired in association with the detection information at the start of passage of the peripheral position of the disc-shaped transfer object with respect to each photoelectric sensor described above, and each photoelectric sensor Based on the photoelectric sensor position information that is the sensor installation position, it is possible to define a plurality of peripheral positions and a plurality of photoelectric sensor position information on the disc-shaped conveyance object on a common orthogonal coordinate system. Thus, since the center position of the disc-shaped transport object on the orthogonal coordinate system is calculated, it is possible to improve the accuracy of calculating the center position of the disk-shaped transport object.

  In the transfer robot of the present invention, the center position of the disk-shaped transfer object on the orthogonal coordinate system is calculated without using the diameter size of the disk-shaped transfer object placed on the hand as a known value. Therefore, the center position of each disk-shaped transport object can be calculated with high accuracy even if it is a disk-shaped transport object having a different diameter size for each individual due to high-temperature processing or the like.

  Furthermore, since the photoelectric sensor is less expensive than, for example, a linear sensor, it is advantageous in terms of cost. Note that the photoelectric sensor may be either a transmission type or a reflection type.

  Thus, with the transfer robot according to the present invention, the center position of the disc-shaped transfer object actually placed on the hand can be calculated more accurately, and the actual placement on the hand is possible. The center position of the disc-shaped transport target object is orthogonal to the reference center position, which is the center position of the disc-shaped transport target object when the disc-shaped transport target object is placed on the regular placement position on the hand. An accurate difference on the coordinate system can be obtained, and an operation command in which the operation amount of the transport drive mechanism is corrected including this difference is generated, and based on this operation command (an operation command including the corrected operation amount) By operating the transport drive mechanism, correct the amount of discrepancy between the center position of the disk-shaped transport object actually placed on the hand and the reference center position, and place it on the hand. Move the object to be transported to the specified transport target position. It can be sent.

  In the present invention, as the “movement amount of the disk-shaped conveyance object” used in the calculation process in the center position calculation means, for example, a detection value by a detection device (sensor or camera) that can directly detect the movement of the disk-shaped conveyance object itself It is also possible to apply. On the other hand, if the transfer robot has a hand movement amount detection unit capable of detecting the movement amount of at least the first axis of the hand, the peripheral position detection of the passage start of the peripheral position of the disc-shaped transfer object with respect to each photoelectric sensor is performed. The “movement amount of the disc-shaped conveyance object” can be obtained based on the detection value of the hand movement amount detection unit at the time point detected by the means. Usually, the transfer robot is configured to transfer a disk-shaped transfer object on the hand to a predetermined transfer target position while controlling the movement of the hand. Therefore, the amount of movement of the hand is under the control of the transfer robot. Focusing on the fact that it can be acquired very easily or relatively easily, it is efficient to acquire the movement amount of the disc-shaped conveyance object on the hand based on the movement amount of the hand.

  In the transport robot according to the present invention, the center position calculation means of the control unit uses the photoelectric sensor position information that is the installation position of each photoelectric sensor on the orthogonal coordinate system. Even if it is installed, it is inevitable that a slight error will occur. Therefore, in the transfer robot according to the present invention, with reference to one placement position of the disc-like transfer object on the hand, the transfer robot starts to move from the transfer start position to the delivery position in a state where the transfer position is placed at the reference placement position. The reference movement amount, which is the amount moved along the first axis until the time when three or more peripheral positions of the disc-shaped conveyance object on the hand start to pass through each photoelectric sensor, and the reference movement amount are extracted. On the hand that has started to move from the transfer start position to the delivery position in a state where the disk-shaped transfer object used for the transfer is placed on the calibration placement position displaced from the reference placement position on the hand The amount of movement along the first axis up to the point when three or more peripheral positions of the disc-shaped conveyance object start to pass through each photoelectric sensor, and the same number of movements as the photoelectric sensors The position coordinate of each photoelectric sensor is estimated using a plurality of sets of calibration movement amounts, each of which is a set, and the relative position coordinates of each calibration placement position with respect to the reference placement position. The photoelectric sensor position information based on the photoelectric sensor position coordinates can be configured to be used by the center position calculation means. By adopting such a configuration, it is possible to accurately calculate the center position of the disc-shaped conveyance object placed and held on the hand without being affected by the installation error of each photoelectric sensor. Here, there are multiple sets of “calibration movement amounts” used to accurately calculate the center position of the disk-shaped conveyance object. The number of calibration movement amounts in each group (not the movement amount value itself) When the movement amount itself is regarded as data, the number of the data) is the same as the photoelectric sensor. In other words, the number of calibration movement amounts acquired by the process of extracting one set of calibration movement amounts is the same as the number of photoelectric sensors. In addition, only one set is sufficient as the “reference movement amount” used when accurately calculating the center position of the disk-shaped transport object in the above-described manner, and the number of reference movement amounts in one set is the reference placement position. In the state of being placed on the first axis by the time when three or more peripheral positions of the disc-shaped transport object on the hand that has started to move from the transport start position to the delivery position begin to pass through the photoelectric sensors, respectively. Since it is each moving amount moved along, it is the same number as the photoelectric sensor.

  As described above, in the configuration in which the photoelectric sensor position coordinates are estimated using the relative position coordinates of each calibration placement position with respect to the reference placement position, the accurate placement of each calibration placement position with respect to the reference placement position is determined. As a configuration for efficiently acquiring position coordinates, in the present invention, the disc-shaped transport object is extracted after the reference movement amount extraction process or after the n-th set (n is an integer of 1 or more) calibration movement amount extraction process. The hand is displaced from the delivery position by an arbitrary amount of displacement by the calibration position correction operation of the first group or m-th group (m is n + 1) to which an arbitrary amount of displacement is added while being placed on the hand. The disk-shaped transfer object is moved to the position, transferred to a predetermined transfer destination, the hand returned to the transfer start position is moved to the delivery position without position correction operation, and transferred to the transfer destination. The first set or the mth set (m is n + 1) for calibration movement at the timing when the object is placed on the hand, returned to the transfer start position, and moved toward the delivery position without the position correction operation. The control unit controls the operation of the transport drive mechanism so as to perform the quantity extraction process, and extracts the relative position coordinates of each calibration placement position with respect to the reference placement position and each set of calibration peripheral positions. It is possible to employ a configuration that is acquired on the basis of the amount of displacement during the calibration position correction operation performed in the above. If it is the said structure, the process which extracts the movement amount for 1st calibration after the process which extracted the reference | standard movement amount, and the movement amount for calibration of the nth group (n is an integer greater than or equal to 1, for example, 4) After the process of extracting the calibration movement amount of the m-th set (m is n + 1, for example, 5 if n is 4), the movement amount for calibration of each set is extracted through both processes. The amount of displacement during the calibration position correction operation to be performed can be grasped (acquired), and the position of each calibration placement position relative to the reference placement position can be determined based on the amount of displacement during the calibration position correction operation. Accurate relative position coordinates can be acquired.

  In addition, the method for transporting a disc-shaped transport object according to the present invention includes moving a hand from a transport start position to a delivery position along a linear movement path so that the disc-shaped transport object on the hand has a predetermined transport purpose. The present invention relates to a transport method used when transporting a disk-shaped transport object to a transport target position using a transport robot having a transport drive mechanism capable of transport to a position, a peripheral position detection step, a center position calculation step, The operation of the transport drive mechanism is controlled based on the motion command generated in the motion command generation step through the displacement amount calculation step and the motion command generation step.

  Specifically, in the peripheral position detection step, the disc-shaped transport object on the hand that has started moving from the transport start position in the stopped state to the delivery position is passed through three or more photoelectric sensors, and each of the photoelectric sensors This is a processing step of detecting that three or more different peripheral positions of the disc-shaped transport object have passed through the photoelectric sensors by detecting a change in the output signal. The center position calculating step is performed when the orthogonal coordinate system is defined by a first axis that is a normal movement path of the hand and a second axis that is orthogonal to the first axis in a horizontal plane including the first axis. The detection information at the start of passage of the peripheral position of the disc-shaped conveyance object with respect to each photoelectric sensor among the photoelectric sensor position information that is the installation position of each photoelectric sensor on the Cartesian coordinate system and the detection information detected in the peripheral position detection step. This is a processing step of calculating the center position of the disk-shaped transfer object on the orthogonal coordinate system based on the movement amount of the wafer that can be acquired in association.

  In addition, the displacement amount calculating step includes a reference center position and a center position on an orthogonal coordinate system that is a center position of the disk-shaped transport object when the disk-shaped transport object is placed at a normal placement position on the hand. It is a processing step of calculating a difference (displacement amount) from the center position of the disk-shaped conveyance object calculated in the calculation step, and the operation command generation step is based on the difference (displacement amount) calculated in the displacement amount calculation step. This is a processing step for generating an operation command that defines the operation amount of the transport drive mechanism necessary for transporting the disc-shaped transport target on the hand to a predetermined transport target position. And if it is a disc-shaped conveyance object conveyance method that controls the operation of the conveyance drive mechanism based on the operation command generated in the operation command generation step, it obtains the operation effect according to the operation effect exhibited by the above-described transfer robot. Can do.

  According to the present invention, the disc-shaped transport object on the hand that has started moving from the transport start position in the stopped state toward the delivery position is different from each other at the periphery of the disk-shaped transport object by three or more photoelectric sensors. Detects the time at which three or more points have passed through the photoelectric sensor, and uses detection information at the start of passage of the peripheral position of the disc-shaped conveyance object with respect to each photoelectric sensor and the position information of the photoelectric sensor among the detected information And calculate the center of the disc-shaped transport object placed on the hand, and accurately calculate the difference between the calculated value and the center of the disc-shaped transport object placed on the regular placement position on the hand. By operating the transport drive mechanism based on the operation command generated based on this difference, the disk-shaped transport object is precisely moved to a predetermined transport target position (regular transfer position). In it it is possible to convey. If the present invention adopts such a configuration or a transport method, it is difficult to be affected by the transport speed and acceleration of the disk-shaped transport object, and the diameter size of the disk-shaped transport object is used as a known value. Therefore, the difference between the position of the disc-shaped transport object placed and held on the hand and the normal center position can be accurately obtained, and the disc-shaped transport object can be accurately transported to a predetermined transport target position. It becomes possible.

1 is an overall schematic diagram of a transfer robot according to an embodiment of the present invention. FIG. 2 is a diagram corresponding to FIG. 1 of the transfer robot in which the hand is in a delivery position in the embodiment. The figure which shows the relative position of the wafer and photoelectric sensor in the same embodiment on an orthogonal coordinate system. FIG. 3 is a view corresponding to FIG. 2 in a state in which the hand is moved to the delivery position in a state where the wafer is placed at a position not matching the regular placement position on the hand. The functional block diagram of the control part in the embodiment. The figure which shows the position fluctuation amount (position correction amount) of the wafer at the time of the calibration process of the embodiment. The flowchart of the wafer conveyance method which concerns on the same embodiment. FIG. 4 is a diagram corresponding to FIG. 4 of a transfer robot according to a modification of the present embodiment.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  The transfer robot T according to the present embodiment moves the hand 23 from the transfer start position (S) shown in FIG. 1 to the delivery position (E) shown in FIG. A transport drive mechanism 1 capable of transporting the upper disc-shaped transport object 7 to a predetermined transport target position, and a control unit 4 that controls the operation of the transport drive mechanism 1 are provided.

  In this embodiment, the wafer 7 is applied as a disk-shaped conveyance object. The wafer 7 is formed with high accuracy in order to eliminate the occurrence of dimensional errors for each individual. Below, the case where the wafer 7 having a diameter of, for example, 300 mm (radius is 150 mm) is transferred to a predetermined transfer target position (regular transfer position) by the transfer robot T will be described.

  As shown in FIGS. 1 and 2, the transfer robot T of the present embodiment is disposed in the wafer transfer chamber A, and the wafer 7 is placed in the processing chamber adjacent to the wafer transfer chamber A or the port B1 in the load lock chamber B. The wafer 7 can be delivered or delivered into a FOUP on a load port (not shown) adjacent to the wafer transfer chamber A. Hereinafter, a case where the wafer 7 is transferred to a predetermined transfer target position (regular transfer position) set in the processing chamber or the load lock chamber B will be described.

  The transport driving mechanism 1 according to the present embodiment has an arm 2 that can move a hand 23 provided at a tip portion along a linear movement path between a transport start position (S) and a delivery position (E). And a main body 3 that rotatably supports the proximal end portion of the arm 2 by the pivot shaft 31. That is, the transport drive mechanism 1 in this embodiment is capable of linear motion and turning motion.

  In the present embodiment, as shown in FIG. 1, the wafer 7 on the hand 23 passes when the hand 23 starts to move from the transfer start position (S) toward the delivery position (E) ( A plurality of photoelectric sensors (typically fiber sensors and the like) 6L, 6C, and 6R are arranged at the crossing position. Specifically, the photoelectric sensors 6L, 6C, and 6R are arranged so that three different positions on the periphery of the wafer 7 can be detected by the three photoelectric sensors 6L, 6C, and 6R. In this specification, for convenience, the left photoelectric sensor, the central photoelectric sensor, and the right photoelectric sensor in FIG. 1 and FIG. 2 are referred to as the “left photoelectric sensor 6L” and the “central photoelectric sensor 6C”, respectively. And “right photoelectric sensor 6R”.

  The left photoelectric sensor 6L, the central photoelectric sensor 6C, and the right photoelectric sensor 6R include, for example, a light projecting unit and a light receiving unit (sensor head) that receives light, and light projected from the light projecting unit toward the light receiving unit ( When the sensor optical axis is blocked or reflected by the object to be detected (wafer 7 in this embodiment), the amount of light reaching the light receiving portion changes, and the change is detected by the light receiving portion and converted into an electrical signal. , To output. In the present embodiment, any of a reflective photoelectric sensor and a transmissive photoelectric sensor can be preferably used. Even if the wafer 7 is made of a transparent material, the light intensity level changes due to the difference in refractive index at the periphery of the wafer 7, and the change is detected by the light receiving unit and converted into an electrical signal. And can be output. In the present embodiment, a photoelectric sensor capable of outputting a binarized signal is applied in which an electrical signal output when the amount of light reaching the sensor head that is a light receiving portion changes is switched between an ON signal and an OFF signal. .

  Each photoelectric sensor (the left photoelectric sensor 6L, the central photoelectric sensor 6C, and the right photoelectric sensor 6R) of the present embodiment, when the hand 23 is moved between the transfer start position (S) and the delivery position (E), The peripheral edge of the wafer 7 placed and held on the hand 23 is disposed at a position where all the optical axes of the three photoelectric sensors 6L, 6C, 6R can be blocked.

  As described above, the transfer robot T according to the present embodiment delivers the hand 23 from the transfer start position (S) in a state where the wafer 7 is mounted at the normal mounting position on the hand 23 (see FIG. 1). It is set so that the wafer 7 on the hand 23 can be accurately transferred to a predetermined transfer target position by moving to the position (E) (see FIG. 2). When the movement path from the transfer start position (S) of the hand 23 to the delivery position (E) is defined as a “normal movement path of the hand 23”, the movement direction is orthogonal to the normal movement path of the hand 23. Each photoelectric sensor (left photoelectric sensor 6L, central photoelectric sensor 6C, right photoelectric sensor 6R) is arranged.

  Here, an axis coinciding with the normal movement path of the hand 23 is defined as a first axis (Y axis), and an axis orthogonal to the first axis in the horizontal plane including the first axis is defined as a second axis (X axis). When the orthogonal coordinate system is defined by the first axis and the second axis, the installation positions of the photoelectric sensors 6L, 6C, and 6R can be grasped as coordinates on the orthogonal coordinate system. In this embodiment, as shown in FIG. 3, in this embodiment, the center position of each photoelectric sensor 6L, 6C, 6R is set to the position of each photoelectric sensor (left photoelectric sensor 6L, center photoelectric sensor 6C, right photoelectric sensor 6R). It is taken as the installation position (coordinates).

As shown in FIG. 3, the installation position of the left photoelectric sensor 6L on the orthogonal coordinate system is (x _L , y _L ), and the installation position of the central photoelectric sensor 6C on the orthogonal coordinate system is (x _C , y _C ). The installation position of the right photoelectric sensor 6R on the orthogonal coordinate system is (x _R , y _R ). The transfer robot T according to this embodiment includes installation position information (x _L , y _L ), which are coordinates on the orthogonal coordinate system of each of the photoelectric sensors (left photoelectric sensor 6L, central photoelectric sensor 6C, right photoelectric sensor 6R), Using (x _C , y _C ), (x _R , y _R ) and the passage detection information of the wafer 7 by the photoelectric sensors 6L, 6C, 6R, etc. It is configured so that it can be transported to the transfer position.

  In some cases, notches such as an orientation flat and a notch are formed on the periphery of the wafer 7. In this case, each photoelectric sensor (the left photoelectric sensor 6L, the central photoelectric sensor 6C, and the right photoelectric sensor 6R) can detect a portion where a notch such as an orientation flat or a notch is not formed in the peripheral edge of the wafer 7. The arrangement position of each photoelectric sensor (left photoelectric sensor 6L, central photoelectric sensor 6C, right photoelectric sensor 6R) or the mounting posture (orientation) of the wafer 7 on the hand 23 is set.

  As shown in FIGS. 1 and 2, the arm 2 constituting the transport driving mechanism 1 includes a first link element 21 disposed on the most proximal side (main body 3 side) of the arm 2, and a first link element 21. The second link element 22 is connected to the front end of the second link element 22 so as to be horizontally rotatable, and the hand 23 is an end effector connected to the front end of the second link element 22 so as to be horizontally rotatable. The arm 2 has a link structure (multiple shapes) whose shape changes between a folded state (see FIG. 1) in which the arm length is minimum and an extended state (see FIG. 2) in which the arm length is longer than in the folded state. Joint structure). Further, in the internal space of the first link element 21, a power transmission mechanism (for example, a pulley and a belt) that transmits power to the second link element 22 to rotate the second link element 22 is provided. A power transmission mechanism (for example, a pulley and a belt) that transmits power to the hand 23 to rotate the hand 23 is also provided in the internal space (not shown). Although FIG. 1 shows a hand 23 that is formed in a fork shape having a bifurcated tip, it interferes with sensing processing by each photoelectric sensor (left photoelectric sensor 6L, central photoelectric sensor 6C, right photoelectric sensor 6R). If the condition that does not occur is satisfied, a hand having another shape such as a tip formed in a substantially rectangular shape in plan view may be applied.

  In such an arm 2, the base 23 is horizontally swiveled around the turning shaft 31, or the link elements 21, 22 are horizontally swiveled at the joint portions to appropriately deform the shape of the entire arm 2, and the hand 23 is illustrated. 2 is moved from the transfer start position (S) shown in FIG. 1 (the position of the hand 23 in the arm 2 in the folded state) to the delivery position 23 (E) (the position of the hand 23 of the arm 2 in the extended state) shown in FIG. Thus, the wafer 7 is transferred to a predetermined transfer target position (regular transfer position). Here, as shown in FIG. 1, the Y axis (first axis) overlapping the regular movement path of the hand 23 is a coordinate axis passing through the center 31 a of the turning shaft 31, and the X axis (second axis) orthogonal to the Y axis. Axis) is a coordinate axis orthogonal to the Y axis and passing through the center 31a of the swivel axis 31 in a horizontal plane including the Y axis, and the arm 2 including the hand 23 has an XY coordinate system defined by these coordinate axes (the present invention). It can be considered as moving on the plane of (orthogonal coordinate system).

The motion coordinate system of the turning shaft 31 and the arm 2 can be shown as a robot motion polar coordinate system (r, θ). “R” is the traveling direction (r-axis direction) of the hand 23 passing through the center 31 a of the turning shaft 31, and “θ” is the rotation angle of the r-axis around the turning shaft 31. Then, the center position of the wafer 7 at the time when the wafer 7 is transferred to the regular transfer position (in this embodiment, a predetermined transfer target position set in the processing chamber or the load lock chamber B) by the transfer drive mechanism 1 ( r ₀ , θ ₀ ), the Y axis coincides with the r axis direction when θ is θ ₀ (see FIG. 2).

  As shown in FIG. 4, if the hand 23 is moved from the transfer start position (S) to the delivery position (E) in a state where the wafer 7 is placed at a position shifted from the normal placement position on the hand 23. Then, the center position 7a of the wafer 7 on the hand 23 after the movement is shifted from the center position 7a of the wafer 7 when the wafer 7 is transferred to a predetermined transfer target position (regular transfer position). Displaces according to the amount. In FIG. 4, the wafer 7 placed and held at a position displaced from the normal placement position in the hand 23 is indicated by a solid line, and the wafer 7 placed and held at a regular placement position in the hand 23 is indicated by a broken line.

  As a specific arrangement of each photoelectric sensor (left photoelectric sensor 6L, central photoelectric sensor 6C, right photoelectric sensor 6R) on the XY coordinate system, for example, the left photoelectric sensor 6L is in the second quadrant (X coordinate is a negative value). And the right photoelectric sensor 6R is placed in the first quadrant (the region consisting of points where both the X coordinate and the Y coordinate take a positive value), A standard arrangement in which the central photoelectric sensor 6C is arranged at a position that matches the Y axis can be adopted. However, in this embodiment, the central photoelectric sensor 6C is different from the standard arrangement in that the central photoelectric sensor 6C is arranged in the first quadrant. An arrangement mode is adopted.

  In the transfer robot T according to the present embodiment, the control unit 4 that controls the operation of the transfer drive mechanism 1 includes a peripheral position detection unit 41, a center position calculation unit 42, and a displacement amount calculation unit 43, as shown in FIG. And an operation command generation means 44 and a position correction execution means 45. 1 and 2 exemplify a mode in which the control unit 4 is built in or attached to the main body unit 3, the control unit 4 is connected to the main body unit 3 by connecting an information processing device or the like separate from the control unit 4. 4 can also be configured.

  The peripheral position detection means 41 passes the wafer 7 on the hand 23 that has started to move from the conveyance start position (S) in the stopped state toward the delivery position (E) to each photoelectric sensor 6L, 6C, 6R. By detecting changes in the output signals of the respective photoelectric sensors 6L, 6C, 6R, it is detected that three different positions at the peripheral position of the wafer 7 have passed through the respective photoelectric sensors 6L, 6C, 6R. Specifically, the peripheral edge position detection means 41 moves each of the photoelectric sensors 6L, 6C, and 6C when the hand 23 holding the wafer 7 is moved from the transfer start position (S) toward the delivery position (E). By detecting a change in the binarized signal output from the 6R light receiving unit (sensor head), it is detected that the three peripheral edges of the wafer 7 have passed through the photoelectric sensors 6L, 6C, and 6R, respectively. When the hand 23 on which the wafer 7 is placed and held starts to move from the transfer start position (S) in the stopped state toward the delivery position (E), the light receiving portions (sensor heads) of the photoelectric sensors 6L, 6C, 6R. ) Output is changed when the peripheral edge of the wafer 7 starts to pass through the photoelectric sensors 6L, 6C, 6R (passing start time) and when the peripheral edge of the wafer 7 is changed to the photoelectric sensors 6L, This is the point in time when passing through 6C and 6R (passing end point). Note that the timing at which the periphery of the wafer 7 passes through the photoelectric sensors 6L, 6C, and 6R may be simultaneous or substantially simultaneous, or may not be simultaneous according to the amount of displacement of the mounting position of the wafer 7 on the hand 23. In some cases. Further, when the arrangement of the photoelectric sensors 6L, 6C, and 6R is appropriately changed, the peripheral edge of the wafer 7 can be obtained even when the wafer 7 is placed on the placement reference position on the hand 23 by the arrangement configuration. It is also assumed that the timing of passing through the photoelectric sensors 6L, 6C, 6R becomes uneven.

  The transport robot T according to the present embodiment includes a hand movement amount detection unit 5 that can detect at least the movement amount of the hand 23 in the transport driving mechanism 1. The hand movement amount detection unit 5 is attached to the transport driving mechanism 1 and, for example, based on the detected value of the rotation direction and the rotation amount of the motor, the movement amount of the hand 23 of the transport driving mechanism 1 and the turning shaft 31. The rotation angle may be calculated indirectly. Alternatively, the position detector such as an encoder is not attached to the transport drive mechanism 1 but directly attached to the link rotation shaft of the arm 2 or the hand 23, and the rotation amount of the link rotation shaft or the movement amount of the hand 23 is directly measured. It may be detectable. Further, as a hand movement amount detection unit, the first axis (not shown in the transfer robot T itself) is detected by a laser displacement sensor disposed in a peripheral device of the transfer robot T or a peripheral space (for example, the processing chamber or the load lock chamber B). A device that can detect only the amount of movement of the hand 23 in the (Y-axis) direction can also be applied. In the present embodiment, the position of the hand 23 at the transport start position is used as a reference point, and the amount of movement of the hand 23 relative to this reference point is detected.

  The center position calculation means 42 is the photoelectric sensor 6L, 6C among the photoelectric sensor position information which is the installation position of each photoelectric sensor 6L, 6C, 6R on the XY coordinate system and the detection information detected by the peripheral position detection means 41. , 6R is used to calculate the center position of the wafer 7 by using the amount of movement of the wafer 7 that can be obtained in association with the detection information at the start of passage of the peripheral position of the wafer 7 relative to 6R. In this embodiment, the center position of each photoelectric sensor 6L, 6C, 6R is used as the photoelectric sensor position information of each photoelectric sensor 6L, 6C, 6R. In order to eliminate the installation error of the photoelectric sensors 6L, 6C, 6R, Position coordinates estimated based on data acquired by calibration processing to be described later can be used as photoelectric sensor position information of each photoelectric sensor 6L, 6C, 6R.

In the transfer robot T according to the present embodiment, out of the detection information detected by the peripheral position detection means 41, detection information when the peripheral edge of the wafer 7 starts to cross the sensor optical axes of the photoelectric sensors 6L, 6C, 6R, That is, when the three peripheral edges of the wafer 7 begin to cross the sensor optical axes of the photoelectric sensors 6L, 6C, 6R, the three peripheral edges of the wafer 7 are detected by detecting changes in the output signals of the photoelectric sensors 6L, 6C, 6R. When the peripheral position of the wafer 7 starts to pass in units of each photoelectric sensor 6L, 6C, 6R based on the detection information that can specify that the sensor has started passing the photoelectric sensors 6L, 6C, 6R (the peripheral edge of the wafer 7 is The hand at the time when the binarized signal output of the sensor head changes and the change is detected at the moment when the sensor optical axes of the photoelectric sensors 6L, 6C and 6R start to cross. The third moving amount acquired from the hand movement amount detection unit 5, the photoelectric sensors 6L, 6C, movement amount [Delta] y _Li hand 23 in the pass beginning of the periphery of the wafer 7 relative 6R, Δy _Ci, Δy _Ri (unit: mm) in a predetermined storage area. Here, the movement amounts Δy _Li , Δy _Ci , and Δy _Ri are the positions where the photoelectric sensors 6L, 6C, and 6R are detected from the peripheral edge of the wafer 7 placed and held on the hand 23. The amount of movement (movement amount) along the first axis (Y axis) up to the point when it starts to pass through each photoelectric sensor 6L, 6C, 6R as it moves from the transfer start position (S) to the delivery position (E) ). That is, the movement amount Δy _Li , Δy _Ci , Δy _Ri (unit: mm) of the hand 23 at the start of passage of the periphery of the wafer 7 with respect to each photoelectric sensor 6L, 6C, 6R is expressed as “the start time of passage of the peripheral position of the wafer 7”. This is synonymous with “amount of wafer movement that can be acquired in association with the detection information”.

As described above, as shown in FIG. 3, the coordinates of the photoelectric sensors 6L, 6C, 6R on the XY coordinate system are respectively (x _L , y _L ), (x _C , y _C ), (x _R , y _R ). , Based on the information detected by each photoelectric sensor 6L, 6C, 6R, the movement amount at each of three different positions on the periphery of the wafer 7 is the installation position of each photoelectric sensor 6L, 6C, 6R (x _L , Y _L ), (x _C , y _C ), (x _R , y _R ) as reference positions, respectively, can be specified and acquired as Δy _Li , Δy _Ci , Δy _Ri (unit: mm).

Here, the photoelectric sensor position information is the position coordinates (x _L , y _L ), (x _C , y _C ), (x _R , y _R ) of the photoelectric sensors 6L, 6C, 6R shown in FIG. The coordinates (x _L , y _L ), (x _C , y _C ), (x _R , y _R ), and the peripheral position of the wafer 7 acquired by the sensing processing of the photoelectric sensors 6L, 6C, 6R are detected. The coordinates (x _L , y _Li ), (positions where the photoelectric sensors 6L, 6C, 6R and the peripheral position of the wafer 7 intersect in plan view are determined by the movement amounts Δy _Li , Δy _Ci , Δy _Ri of the wafer 7 at the time of x _C , y _Ci ), (x _R , y _Ri ) are coordinates represented by the following Equation 1.

The center coordinates of the wafer 7 placed on the hand 23 in the stopped state at the transfer start position (S) are (x _i , y _i ), and the wafer 7 is a circle having a radius R _i (unit: mm). Assuming that, the equation shown by the following formula 2 holds from the three-square theorem.

The position coordinates (x _L , y _L ), (x _C , y _C ), and (x _R , y _R ) of each photoelectric sensor may be known coordinates (designed position coordinates) or calibration described later. The coordinates may be estimated in advance by the processing process. Further, the movement amounts Δy _Li , Δy _Ci , Δy _Ri are values detected each time the hand 23 moves from the transfer start position (S) toward the delivery position (E), and the above equations are the center coordinates of the wafer 7. Solving for (x _i , y _i ) gives the equation shown in Equation 3 below.

In the center position calculation means 42 in this embodiment, the center position 7a of the wafer 7 placed on the hand 23 is calculated as coordinates (x _i , y _i ) on the XY coordinate system by the arithmetic processing shown in Equation 3. It is configured. In addition, the said Numerical formula 3 is an example of the numerical solution which solved the equation shown by the said Numerical formula 2, and may become the type | formula further rearranged or deform | transformed depending on the derivation method of the solution.

The displacement amount calculation means 43 is calculated by the reference center position on the XY coordinate system, which is the center position of the wafer 7 when the wafer 7 is placed at the normal placement position on the hand 23, and the center position calculation means 42. The difference (displacement amount) from the center position of the wafer 7 is calculated. Specifically, in the displacement amount calculating means 43, the reference center position on the XY coordinate system is set to (x ₀ , y ₀ ), and the center position (x _i ) of the wafer 7 with respect to the reference center position (x ₀ , y ₀ ). , Y _i ), the displacement amount (Δx, Δy) is calculated by the equation (4).

  The operation command generation unit 44 is based on the difference (displacement amount) calculated by the displacement amount calculation unit 43 and is required to transfer the wafer 7 on the hand 23 to a predetermined transfer destination position. The operation command which prescribes | regulates is produced | generated. The transfer robot T according to the present embodiment employs a transfer drive mechanism 1 that includes a turning shaft 31 and an arm 2. As described above, the operation coordinate system of the turning shaft 31 and the arm 2 is a robot operation polar coordinate system. It can be shown as (r, θ). Then, the wafer 7 at the time when the hand 23 is moved from the transfer start position (S) to the delivery position (E) along the normal transfer path in a state where the wafer 7 is mounted on the normal load position on the hand 23. The displacement amount (Δx, Δy) calculated by the displacement amount calculation means 43 can be expressed by the following Equation 5 where the Y coordinate of the center position of “n” is “r”.

  Since the normal transfer position (predetermined transfer target position) is a positive value on the Y axis in the XY coordinates, the operation command generation unit 44 in this embodiment uses the first quadrant and the second in the coordinates. The correction amount (Δr, Δθ) of the transport drive mechanism 1 on the robot motion polar coordinate system (r, θ) is limited to the position correction within the two quadrants (condition: r + Δr> 0), and the calculation shown in the following Equation 6 is performed. Seeking by processing.

  Note that the computing capacity of the device for calculating the correction amount (Δr, Δθ) of the transport drive mechanism 1 is not sufficient, and the “r” is added to Δy among the displacement amounts (Δx, Δy) calculated by the displacement amount calculation means 43. When the added distance (r + Δy) is sufficiently larger than Δx of the displacement amount (Δx, Δy) calculated by the displacement amount calculating means 43, the arithmetic processing shown in the following formula 7 obtained by the first order approximation of Taylor expansion Thus, the correction amount (Δr, Δθ) of the transport drive mechanism 1 on the robot operation polar coordinate system (r, θ) may be calculated.

  The position correction execution unit 45 controls the operation of the turning shaft 31 and the arm 2 based on the operation command of the transport drive mechanism 1 calculated by the operation command generation unit 44, so that the wafer 7 placed on the hand 23 is moved. Position correction processing for moving to a predetermined transfer target position (regular transfer position) is executed.

  Next, using the transfer robot T and each photoelectric sensor (left photoelectric sensor 6L, central photoelectric sensor 6C, right photoelectric sensor 6R), the center position 7a of the wafer 7 placed on the hand 23 and the reference About a method and an action of detecting a difference from the center position and actually reflecting the detected value on the operation of the turning shaft 31 and the arm 2 to transfer the wafer 7 to a predetermined transfer target position (regular transfer position). explain.

  In this embodiment, when detecting the difference between the center position 7a of the wafer 7 placed on the hand 23 and the reference center position, each photoelectric sensor (left photoelectric sensor 6L, central photoelectric sensor 6C, right photoelectric sensor 6R). ) And position information on the coordinates of the photoelectric sensors 6L, 6C, 6R themselves are used. However, the photoelectric sensors 6L, 6C, and 6R are accurately arranged at design positions due to various influences such as assembly accuracy of a device that supports the photoelectric sensors 6L, 6C, and 6R at predetermined positions and processing accuracy of parts. This is difficult, and some errors occur between the actual positions of the photoelectric sensors 6L, 6C, and 6R and the designed positions. When the transfer process of the wafer 7 is executed without considering this error, it is assumed that the accuracy of transferring the wafer 7 to the regular transfer position is lowered.

  Therefore, in the present embodiment, calibration processing is performed in advance for each photoelectric sensor (the left photoelectric sensor 6L, the central photoelectric sensor 6C, and the right photoelectric sensor 6R), and data (a plurality of calibration data) acquired by the calibration processing is used. The position coordinates of the photoelectric sensors 6L, 6C, and 6R are estimated by use.

  The calibration process is based on one placement position of the wafer 7 on the hand 23, and from the transfer start position (S) to the delivery position (E) in a state where the wafer 7 is placed on the reference placement position. A reference movement amount that is an amount of movement along the first axis (Y-axis) until the three peripheral edges of the wafer 7 on the hand 23 that have started to move pass through the photoelectric sensors 6L, 6C, 6R; Delivery from the transfer start position (S) in a state where the wafer 7 used for extracting the reference movement amount is placed on the calibration placement position displaced from the reference placement position (by an arbitrary amount different from each other). It moves along the first axis (Y-axis) until the three peripheral edges of the wafer 7 on the hand 23 that have started moving toward the position (E) start passing through the photoelectric sensors 6L, 6C, 6R. A plurality of sets of calibration movement amounts that are the same amount as the photoelectric sensor and a relative position coordinate of each calibration placement position with respect to the reference placement position, This is a process for estimating the position coordinates of the photoelectric sensors 6L, 6C, 6R.

  Here, a procedure for acquiring a reference movement amount and a plurality of calibration movement amounts used in the process of estimating the position coordinates of each photoelectric sensor 6L, 6C, 6R will be described.

  First, the center position 7a of the wafer 7 on the port B1 in the load lock B chamber, which is the transfer destination of the wafer 7, is approximately the center position of the wafer 7 transferred to the regular transfer position (predetermined transfer target position). Place it in a matching position in advance.

  In the transfer robot T of the present embodiment, the transfer drive mechanism 1 is operated without position correction by the operation control by the control unit 4 in accordance with dedicated teaching data used at the time of calibration, and the wafer 7 placed on the port B1. Is transferred onto the hand 23 positioned at the delivery position (E), and the hand 23 is moved to the transport start position (S). When the wafer 7 is transferred between the hand 23 and the port B1, the entire transport driving mechanism 1 may be moved up and down by an appropriate lifting mechanism (not shown), or the transport driving mechanism 1 may be moved. It may be configured so that it cannot be moved up and down, and the port B1 may be moved up and down by a lifting mechanism provided in the processing chamber or the load lock chamber B.

In the transfer robot T of the present embodiment, the hand 23 that has taken out the wafer 7 from the processing chamber or the load lock chamber B, positioned at the transfer start position (S), and once stopped from the hand 23 has started moving toward the delivery position (E). The upper wafer 7 passes through each photoelectric sensor (left photoelectric sensor 6L, central photoelectric sensor 6C, right photoelectric sensor 6R), so that three locations on the periphery of the wafer 7 on the hand 23 are the photoelectric sensors 6L, 6C. , 6R are detected by the photoelectric sensors 6L, 6C, 6R, and the movement amount (Δy _L1 *, Δy) of the hand 23 in the positive direction of the first axis (Y axis) at the detected passage start time is detected. _C1 *, Δy _R1 *) are extracted. This extracted movement amount (Δy _L1 *, Δy _C1 *, Δy _R1 *) is synonymous with the movement amount until each photoelectric sensor 6L, 6C, 6R detects the three peripheral edges of the wafer 7 on the hand 23, respectively. The movement amount (Δy _L1 *, Δy _C1 *, Δy _R1 *) and the center position of the wafer 7 at the time of detection are the above-mentioned reference center position (the transfer start position (S) hand 23 in the stopped state). Displacement amount (displacement amount) (Δx ₁ *, the center position 7a of the wafer 7 when the wafer 7 is placed at the normal placement position on the upper side) A pair with Δy ₁ *) is stored in a predetermined storage unit as the first calibration data. Here, the amount of deviation (Δx ₁ *, Δy ₁ *) at the time of obtaining the first calibration data is (0, 0). The placement position of the wafer 7 on the hand 23 at the time of the first calibration data acquisition is the “reference placement position” at the time of the calibration process, and three peripheral edges of the wafer 7 placed at this reference placement position are shown. The amount of movement (Δy _L1 *, Δy _C1 *, Δy _R1 *) up to the same meaning detected by each photoelectric sensor 6L, 6C, 6R becomes the “reference movement amount”. The reference movement amount extraction process is completed by the above procedure.

Subsequent to the extraction processing of the reference movement amount, the transfer robot T according to the present embodiment can extract the wafer 7 that can be extracted based on detection information by each photoelectric sensor (left photoelectric sensor 6L, central photoelectric sensor 6C, right photoelectric sensor 6R). A process of acquiring a plurality of sets of calibration peripheral positions (a set of movement amounts (Δy _Ln *, Δy _Cn *, Δy _Rn *) at three peripheral edges and having the same amount of movement as the photoelectric sensor as one set (for calibration) (Peripheral position extraction process). In the present embodiment, the movement amounts (Δy _Ln *, Δy _Cn *, Δy _Rn *) of each set are combined with a shift amount (Δx _n *, Δy _n *) = (Δx _n , Δy _n ) described later. A process of acquiring a plurality of sets of data (calibration data) is performed. In addition, “n” in the coordinate value means what number of calibration data. In the present embodiment, 49 sets of calibration data are set to be acquired.

A procedure for extracting a plurality of sets of calibration movement amounts (in other words, a procedure for acquiring the second and subsequent calibration data) will be described below. Subsequently to the acquisition of the first calibration data, the control unit 4 adjusts the position correction amount (Δx for calibration) to the XY coordinate position (x _hand , y _hand ) of the hand 23 shown in FIG. 6 based on the teaching data. _{n 2} , Δy _n ), the arm 2 and the turning shaft 31 are actuated to move the hand 23 from the transfer start position (S) toward the delivery position (E), and the wafer 7 is transferred to the processing chamber. Alternatively, after transporting to the load lock chamber B and transferring to the port B1, the hand 23 is moved to the transport start position (S). As a result, the center position 7a of the wafer 7 on the port B1 is a position correction amount for calibration (Δx _n , Δy _n ) with respect to the center position of the wafer 7 transferred to the regular transfer position on the port B1. It is displaced by the minute. That is, the above-mentioned “deviation amount” means the position correction amount for this calibration. Note that “n” in the calibration position correction amount (Δx _n , Δy _n ) means the position correction amount at the time of calibration data acquisition. The position correction amounts (Δx _n , Δy _n ) of the hand 23 at the time of the calibration process are set so as to be different from each other in the order of numbers in the order of spiral displacement from the center one shown in FIG. Note that the position correction amount for calibration is not an equal interval, and may be an arbitrary value in the transport area where the position correction operation is performed in actual transport. Further, the acquisition order of calibration data is not limited to a spiral shape, and may be an appropriate order.

Subsequently, in the transport robot T of the present embodiment, the transport drive mechanism 1 is operated without performing position correction by the control unit 4, and the transport start position (S) in the stopped state is directed toward the delivery position (E). The photoelectric sensor 6L, 6C, 6R detects when the three peripheral edges of the wafer 7 on the hand 23 that has started to move pass through the photoelectric sensor 6L, 6C, 6R. A movement amount (Δy _L2 *, Δy _C2 *, Δy _R2 *) of the hand 23 in the positive direction of the first axis (Y axis) is extracted as a movement amount for calibration. The detected value (Δy _L2 *, Δy _C2 *, Δy _R2 *) and the deviation amount (Δx ₂ *, Δy ₂ *) = (Δx ₂ , Δy) of the center position of the wafer 7 with respect to the above-mentioned reference center position at the time of detection. ₂ ) is stored in a predetermined storage unit as second calibration data. In the present embodiment, the procedure according to the procedure for acquiring the second calibration data is repeated until the 49th calibration data is acquired. Here, the placement position and movement amount of the wafer 7 in the second and subsequent calibration data are the “calibration placement position” and “calibration movement amount” in the present invention. As described above, the number of calibration movement amounts in each group is the same as the number of photoelectric sensors (when the position of the photoelectric sensor is estimated by an optimization problem as will be described later, The number is the same as the number of parameters to be estimated, that is, the number of photoelectric sensors, and is “3” in this embodiment. The number of calibration data to be acquired is not limited to “49”, and can be set to an appropriate number.

  Based on the plurality of calibration data acquired by the above procedure, the position coordinates of the photoelectric sensors 6L, 6C, 6R are estimated.

Specifically, at each placement position (reference placement position and calibration placement position) where the center position (x _i , y _i ) of the wafer 7 is placed on the hand 23 different from each other, In the present embodiment, data of movement amounts (reference movement amount and movement amount for calibration) until the sensors 6L, 6C, and 6R detect the three peripheral edges of the wafer 7 are acquired by the calibration process. The position coordinates of the respective photoelectric sensors to be estimated (the left photoelectric sensor 6L, the central photoelectric sensor 6C, and the right photoelectric sensor 6R) are set as coordinates shown in the following formula 8, and the photoelectric sensors 6L, 6C, and 6R before the calibration process are executed. However, three peripheral edges of the wafer 7 on the hand 23 that has started to move from the transport start position (S) in the stopped state toward the delivery position (E) were detected. The wafer peripheral position estimated from the movement amount of the hand 23 in the positive direction of the first axis (Y axis) and the sensor position coordinates at the time of the start of passage and the radius of the wafer 7 are set to values shown in Equation 9 below. Focusing on the fact that the error ε of the sensor can be expressed by the following equation 10, the coordinates shown in the equation 8 that minimizes the evaluation function J shown in the following equation 11 are obtained by an optimization method. Each coordinate can be a position coordinate of each photoelectric sensor (left photoelectric sensor 6L, central photoelectric sensor 6C, right photoelectric sensor 6R). Here, in order to make an optimization problem that minimizes the evaluation function J, ε ² is used in which the error ε, which takes a positive or negative value, is squared to be a positive value.

  Since the process of acquiring calibration data is performed using the same wafer 7, the radius of the wafer 7 is a value that does not depend on the number of measurements. Here, Formula 11 can be expressed as an evaluation function shown in Formula 12 below based on Formula 10.

Then, the deviation amount of the center position coordinates (x _i , y _i ) of the wafer 7 at each placement position (calibration placement position) with respect to the reference center position (x ₀ , y ₀ ) of the wafer 7 on the hand 23 is calculated. (Δx _i *, Δy _i *) and movement of the hand 23 (wafer 7) until each of the three peripheral edges of the wafer 7 is detected by each photoelectric sensor (left photoelectric sensor 6L, central photoelectric sensor 6C, right photoelectric sensor 6R). If the amounts are Δy _Li *, Δy _Ci *, Δy _Ri *, the evaluation function J can be organized into the following equation (13).

  Then, by substituting a plurality of sets of calibration data acquired by the calibration process into the equation 13, the coordinates shown in the equation 12 are obtained by an optimization method, and the obtained coordinates are obtained from each photoelectric sensor (left photoelectric sensor 6L). , Central photoelectric sensor 6C, right photoelectric sensor 6R).

  For the optimization problem in which the evaluation function J is an extreme value (minimized in this case), a steepest descent method, a quasi-Newton method, a conjugate gradient method, or the like, which is a general nonlinear optimization solution, can be used.

  Note that as the amount of deviation of the wafer 7 increases, the calculation accuracy of the center position of the wafer 7 using the estimated position coordinates of each photoelectric sensor (left photoelectric sensor 6L, central photoelectric sensor 6C, right photoelectric sensor 6R) tends to deteriorate. If there is, an evaluation function J ′ multiplied by a weight W proportional to the amount of deviation is used to estimate the position coordinates of each photoelectric sensor (left photoelectric sensor 6L, central photoelectric sensor 6C, right photoelectric sensor 6R). Processing may be performed. An example of weighting is shown in Equation 14 below.

  Further, when it takes time to estimate the position coordinates of the photoelectric sensors 6L, 6C, and 6R, and the calculation result is a local solution, the calculation accuracy of the estimated value with respect to the true value (the actual coordinate position of the photoelectric sensor) is high. In order to avoid the reduction, the optimization problem may be solved by giving the mounting position range of each photoelectric sensor 6L, 6C, 6R as a constraint condition in advance.

  The transport robot T of this embodiment estimates the position coordinates of each photoelectric sensor (the left photoelectric sensor 6L, the central photoelectric sensor 6C, and the right photoelectric sensor 6R) through such arithmetic processing, and then detects the peripheral position shown in FIG. Each process after step S1 is performed.

  That is, after carrying out the photoelectric sensor position coordinate estimation process, the transfer robot T according to the present embodiment first performs a predetermined receiving destination (for example, a FOUP placed on a load port (not shown) by the operation control of the control unit 4. At the timing when the hand 23 on which the wafer 7 received from the inside is moved from the transfer start position (S) in a stationary state toward the delivery position (E), the three peripheral edges of the wafer 7 are The photoelectric sensors 6L, 6C, 6R are passed. At this time, three different positions at the peripheral position of the wafer 7 passed through the photoelectric sensors 6L, 6C, 6R by detecting the output change of the binary signals of the photoelectric sensors 6L, 6C, 6R. Is detected by the peripheral position detection means 41 (peripheral position detection step S1, see FIG. 7).

Subsequently, the transport robot T according to the present embodiment uses the photoelectric sensor position information and the detection information detected in the peripheral position detection step S1 by the center position calculation unit 42 of the control unit 4 to detect the photoelectric sensors 6L, 6C, and 6R. A center position calculation step S2 is performed to calculate the center position 7a of the wafer 7 based on the detection information at the start of passage of the peripheral position of the wafer 7 relative to (see FIG. 7). In the present embodiment, the calibration described above is used as the position coordinates (x _L , y _L ), (x _C , y _C ), (x _R , y _R ) of the photoelectric sensors 6L, 6C, 6R which are the photoelectric sensor position information. The position coordinates of the photoelectric sensors 6L, 6C, 6R estimated through the processing can be used. Further, as shown in FIG. 3, detection information at the start of passage of the peripheral position of the wafer 7 with respect to each photoelectric sensor 6L, 6C, 6R, that is, three different positions in the peripheral position of the wafer 7 are the photoelectric sensors 6L, 6C, The movement amount of the hand 23 at that time is acquired from the hand movement amount detection unit 5 based on the information that the fact that it has started to pass through 6R is detected by the change in the output signal of each photoelectric sensor 6L, 6C, 6R. The amount of movement of the hand 23 at the start of passage of the periphery of the wafer 7 relative to 6L, 6C, 6R is stored in a predetermined storage area as Δy _Li , Δy _Ci , Δy _Ri (unit: mm). The movement amounts Δy _Li , Δy _Ci , Δy _Ri of the hand 23 are synonymous with the movement amount of the wafer 7 placed and held on the hand 23. That is, the movement amounts Δy _Li , Δy _Ci , and Δy _Ri of the hand 23 are determined when each of the photoelectric sensors 6L is transferred when the wafer 7 is transferred along with the movement of the hand 23 from the transfer start position (S) toward the delivery position (E). , 6C, 6R means the amount of movement of the wafer 7 until it detects the periphery of the wafer 7 that starts to pass immediately after approaching the photoelectric sensors 6L, 6C, 6R.

In the center position calculating step S2, the photoelectric sensor position information and the photoelectric sensors 6L, 6C, 6C, 6C, 6C, 6C, 6C, 6C, 6C, 6C, 6C, 6C, 6C, 6C, 6D Using the movement amounts Δy _Li , Δy _Ci , and Δy _Ri of the wafer 7 until the output signal of 6R changes, the calculation processing shown in Equation 3 above is performed on the hand 23 positioned at the transfer start position (S). The center position 7a of the placed wafer 7 is calculated as coordinates (x _i , y _i ) on the XY coordinate system.

Next, the transfer robot T according to the present embodiment uses the displacement amount calculation unit 43 of the control unit 4 to determine the reference center position of the wafer 7 (this wafer when the wafer 7 is placed at a regular placement position on the hand 23). 7) and the difference (displacement amount) between the center position 7a (x _i , y _i ) of the wafer 7 calculated in the center position calculation step S2 (displacement amount calculation step S3, see FIG. 7). In this displacement amount calculation step S3, the reference center position on the XY coordinate system is set to (x ₀ , y ₀ ), and the center position (x _i , y _i ) of the wafer 7 with respect to this reference center position (x ₀ , y ₀ ). The displacement amount (Δx, Δy) is calculated by the equation shown in Equation 4.

Subsequently, the transfer robot T of this embodiment is necessary for transferring the wafer 7 on the hand 23 to a predetermined transfer target position based on the displacement amounts (Δx, Δy) calculated in the displacement amount calculation step S3. An operation command that defines the operation amount of the transport drive mechanism 1 is generated by the operation command generation means 44 of the control unit 4 (operation command generation step S4, see FIG. 7). In this operation command generation step S4, the hand 23 is moved from the transfer start position (S) to the delivery position (E) along the normal transfer path in a state where the wafer 7 is mounted at the normal position on the hand 23. The Y coordinate of the center position of the wafer 7 at the time of this is set to “r”, and the robot operation polar coordinate system (limited to the position correction in the first quadrant and the second quadrant (condition: r + Δr> 0) on the coordinates ( The correction amount (Δr, Δθ) of the transport driving mechanism 1 on (r, θ) is obtained by the arithmetic processing shown in the equation 6. When the displacement amount of the center position (x _i , y _i ) of the wafer 7 with respect to the reference center position (x ₀ , y ₀ ) on the XY coordinate system is _zero in the displacement amount calculation step S3, that is, the reference center position. When (x ₀ , y ₀ ) and the center position (x _i , y _i ) of the wafer 7 coincide with each other, in the operation command generation step S5, the regular movement amount of the transport drive mechanism 1 (movement amount in the case of no position correction). ) Is generated with an amount of correction for zero.

The transfer robot T according to the present embodiment is placed on the hand 23 by controlling the operation of the turning shaft 31 and the arm 2 based on the operation command of the transfer drive mechanism 1 calculated in the operation command calculation step S4. A position correction process for transferring the wafer 7 being transferred to a predetermined transfer target position (regular transfer position) is executed (see position correction execution step S5, FIG. 7). In the present embodiment, an operation command for the transport driving mechanism 1 is generated while the hand 23 is being moved from the transport start position (S) toward the delivery position (E), and based on this operation command, the delivery position is temporarily set. After moving to (E), the turning shaft 31 is turned by the amount reduced by the correction amount (Δθ), and the hand 23 is moved by the amount reduced by the correction amount (Δr), whereby the wafer 7 is moved to the wafer transfer chamber A. In the processing chamber or the load lock chamber B which is the transfer destination, a position correction process for transferring to a predetermined transfer target position (regular transfer position) set in advance is executed. Here, when the reference center position (x ₀ , y ₀ ) and the center position (x _i , y _i ) of the wafer 7 actually placed and held on the hand 23 match, the transport drive mechanism 1 The hand 23 moves from the transfer start position (S) to the delivery position (E) along the normal movement path, and is added in accordance with the subsequent correction amount. Does not work. On the other hand, if the reference center position (x ₀ , y ₀ ) and the center position (x _i , y _i ) of the wafer 7 actually placed and held on the hand 23 do not match, the transport drive mechanism 1 is The position correction operation is performed based on the operation command including the correction amount in the movement amount, and the hand 23 moves from the transfer start position (S) to the delivery position (E) and then moves to the delivery position (E). Then, it moves to a position shifted by the amount of correction amount (Δr, Δθ). In any case, the wafer 7 placed and held on the hand 23 can be transported to a predetermined transport target position (regular transfer position).

  The transfer robot T of the present embodiment transfers the wafer 7 to a predetermined transfer target position in the processing chamber or the load lock chamber B, and then operates the above-described lifting mechanism (lifting means) to move the wafer 7 on the hand 23. The wafer 23 is transferred to the port B1 in the processing chamber or the load lock chamber B, and the hand 23 on which the wafer 7 is not placed and held is moved to the transfer start position (S).

  With the above procedure, the wafer 7 placed and held on the hand 23 can be transferred to the regular transfer position. Then, when there is a wafer 7 to be transferred next, that is, when the next transferred wafer 7 is placed on the hand 23, the above steps S1 to S5 are repeated, and each wafer 7 is transferred to the regular transfer. It can be transported to the loading position.

  As described above, the transfer robot T according to the present embodiment uses the photoelectric sensors 6L, 6C when the three peripheral edges of the wafer 7 placed on the hand 23 pass through the photoelectric sensors 6L, 6C, 6R. , 6R based on the change in the output signal, the timing when the hand 23 starts to move from the transport start position (S) in the stopped state toward the delivery position (E), that is, the hand 23 is at the initial speed. Since it is set to be a time point or a time point close to the initial speed, the probability of being affected by variations in scan timing can be made closer to zero compared to a mode in which the passage of the wafer 7 in a high speed state is detected by a sensor. This can prevent and suppress the problem that the accuracy of detecting when the peripheral position of the wafer 7 passes the sensor as the conveyance speed of the wafer 7 increases. Can.

  In particular, in the transfer robot T according to the present embodiment, as information used when calculating the center position of the wafer that is actually placed on the hand 23, Since the detection information at the start of passage of the peripheral position of the wafer 7 relative to the photoelectric sensors 6L, 6C, 6R is used, the hand 23 is accelerated from the transport start position (S) in the stopped state toward the delivery position (E). Even when the configuration is moved, the detection information at the passage end time is relatively slow, and the detection information at the passage end time is relatively fast and easily affected by variations in scan timing. By not using it, for example, by using detection information that includes an error with respect to the true value due to variations in scan timing, It is possible to avoid the situation that calculates the center position of the object. Further, by adopting such a configuration, the transfer robot T according to the present embodiment moves the hand 23 holding the wafer 7 while accelerating from the transfer start position (S) toward the delivery position (E). A problem that may occur if the configuration is such that the point at which the wafer 7 begins to pass through the sensor and the point at which the wafer 7 has passed are detected and the center position of the wafer 7 is calculated based on the linear distance between the detected points. In other words, due to variations in scan timing, the sensing accuracy decreases as the wafer transfer speed increases, and the transfer speed is relatively high compared to the sensing accuracy at the beginning of passage where the transfer speed is relatively low. The sensing accuracy at the end of the passage is inferior, and an error occurs with respect to the true value of the peripheral position of the wafer, and the wafer calculated based on the detected value including the error The center position of the lens also becomes a value deviated from the true value, and the amount of deviation with respect to the normal placement position calculated based on the center position is corrected to avoid the problem that the accuracy of transport to the predetermined transport target position is reduced. be able to.

  Furthermore, since the transfer robot T according to the present embodiment does not use the diameter size of the wafer 7 placed on the hand 23 as a known value when calculating the center position 7a of the wafer 7, for example, Even in the case of wafers 7 having different diameter sizes for each individual due to high temperature processing or the like, the center position of each wafer 7 can be calculated with high accuracy.

  The transfer robot T according to the present embodiment actually calculates the center position 7a of the wafer 7 actually placed on the hand 23 on the hand 23 by accurately calculating the center position 7a with respect to the true value without error. An accurate difference between the center position 7a of the wafer 7 placed on the wafer 7 and the reference center position, which is the center position when the wafer 7 is placed at the regular placement position on the hand 23, can be obtained. Including this difference, an operation command that defines the amount of movement of the transport drive mechanism 1 necessary for transporting the wafer 7 on the hand 23 to a predetermined transport target position (the normal placement position of the wafer 7 on the hand 23). When the device is placed at a position deviated from the position, an operation command including a correction operation amount is generated, and the conveyance drive mechanism 1 is operated based on the operation command. Have Correct the deviation amount between the center position and the reference center position of the wafer 7, it is possible to transport the wafers 7 are placed on the hand 23 to a predetermined transport destination position.

  In addition, the transfer robot T according to the present embodiment uses the calibration acquired by the calibration process as photoelectric sensor position information (position coordinates of the photoelectric sensors 6L, 6C, and 6R) used by the center position calculation unit 42 of the control unit 4. Since the estimated value based on the operation data is applied, the slightest installation error that cannot be avoided even if each photoelectric sensor 6L, 6C, 6R is attached with high accuracy is eliminated and placed on the hand 23. Thus, the center position of the wafer 7 can be accurately calculated.

  In particular, in the present embodiment, as a procedure for acquiring calibration data and estimating the position coordinates of the photoelectric sensors 6L, 6C, 6R, one mounting position of the wafer 7 on the hand 23 is used as a reference, and the reference mounting is performed. Three positions on the periphery of the wafer 7 on the hand 23 that have started to move from the transfer start position (S) to the delivery position (E) in the state of being placed at the placement position pass through the photoelectric sensors 6L, 6C, 6R. A set of reference movement amounts, which are amounts moved along the first axis (Y axis) up to the start point, and the wafer 7 used to extract the reference movement amount are displaced from the reference placement position on the hand 23. The three peripheral edges of the wafer 7 on the hand 23 that have started to move from the transfer start position (S) to the delivery position (E) in the state of being placed at the calibration placement position thus formed are the photoelectric sensors. A plurality of sets of calibration movements that have moved along the first axis (Y-axis) until the start of passing through 6L, 6C, and 6R, and the number of movements in each group is the same as the photoelectric sensor The photoelectric sensor position coordinates are estimated using the amount and the relative position coordinates of each calibration placement position with respect to the reference placement position. Therefore, even when the position of each photoelectric sensor is not accurately adjusted at the time of sensor installation (not accurately adjusted), the position of each photoelectric sensor can be defined by the above-described method. It becomes possible to accurately calculate the center position of the wafer using the position of each defined photoelectric sensor.

  Furthermore, in the transfer robot T according to the present embodiment, the wafer 7 is placed on the hand 23 after the reference movement amount extraction process or after the n-th set (n is an integer of 1 or more) calibration movement amount extraction process. The position where the hand 23 is displaced by an arbitrary amount of displacement with respect to the delivery position (E) by the calibration position correction operation of the first group or the m-th group (m is n + 1) to which an arbitrary amount of displacement is added. The wafer 23 is transferred to the predetermined transfer destination (port B1), and the hand 23 returned to the transfer start position (S) is moved to the delivery position (E) without performing the position correction operation. At the timing when the transferred wafer 7 is placed on the hand 23 and returned to the transfer start position (S) and starts moving toward the delivery position (E) without the position correction operation, the first set or m sets Calibration of eyes (m is n + 1) The control unit 4 controls the operation of the transport drive mechanism 1 so as to perform the process of extracting the movement amount for the calibration, and the relative position coordinates of each calibration placement position with respect to the reference placement position are set as the calibration peripheral edge of each set. Since the configuration is obtained based on the amount of displacement during the calibration position correction operation to extract the position, for each calibration with respect to the reference mounting position used when estimating the photoelectric sensor position coordinates Accurate relative position coordinates of the mounting position can be obtained efficiently.

  In addition, this invention is not limited to embodiment mentioned above. For example, the disk-shaped conveyance object may be other than a wafer, such as a liquid crystal.

  In addition, the disk actually placed on the hand based on the operation command (command generated by the motion command generation means (motion command generation step)) after operating the transport drive mechanism by the normal amount of motion. When the position correction operation is additionally performed according to the amount of deviation between the center position of the object to be transported and the reference center position, the timing for generating the operation command of the transport drive mechanism is from the transport start position to the delivery position. It may be at any time during the movement, or after moving the hand from the transfer start position to the delivery position.

  Moreover, the number of photoelectric sensors should just be three or more, and the number of the peripheral positions of the disk-shaped conveyance target detected by a photoelectric sensor becomes the same as the number of photoelectric sensors. The arrangement of the three or more photoelectric sensors is not particularly limited as long as the arrangement can detect different positions on the periphery of the disc-shaped conveyance target.

  For example, a detection value by a detection device (sensor or camera) that can directly detect the movement of the disk-shaped conveyance object itself is applied as the “movement amount of the disk-shaped conveyance object” used in the calculation processing in the center position calculation means. Can do.

  Further, the installation position (position coordinates) of each photoelectric sensor used in the center position calculation means (center position calculation step) may be a design installation position (position coordinates) instead of a value estimated by the calibration process. Absent.

  Further, the installation position (position coordinates) of each photoelectric sensor that can be estimated or acquired by an appropriate process or method other than the calibration process can be used in the center position calculation means (center position calculation step).

  When estimating the installation position (positional coordinates) of each photoelectric sensor by calibration processing, the marker position on the disk-shaped conveyance object is measured by an image processing apparatus such as an area sensor, or used as a drive source for the conveyance drive mechanism. Based on the information of an attached position detector such as an encoder, the displacement (relative position coordinates) of each calibration placement position with respect to the reference placement position may be calculated directly or indirectly.

  Moreover, the conveyance drive mechanism should just be what can convey the disk-shaped conveyance thing mounted and hold | maintained on the hand along a linear movement path | route, and the number and shape of the link elements which comprise an arm, a joint part (axis | shaft). ) Can be changed as appropriate. Furthermore, the link elements may be connected so as to be slidable instead of or in addition to the horizontal turning operation.

  Furthermore, as shown in FIG. 8, the transport drive mechanism has an axis center 31a of the pivot shaft 31 of the arm 2 that is not on the first axis (Y axis), but in the second axial direction with respect to the first axis ( It may be at a position displaced by an arbitrary value in the X-axis positive direction or the X-axis negative direction). FIG. 8 is a view showing the transport drive mechanism according to this modified example corresponding to FIG. 4, and the parts corresponding to those shown in FIG. 4, dimension display, angle display, etc. are given the same reference numerals. ing. In FIG. 8, the photoelectric sensor is omitted. The arm 2 shown in FIG. 8 is set to a position in which the axis center 31a of the turning shaft 31 is displaced by an arbitrary value in the negative direction of the second axis with respect to the first axis, as compared with the arm 2 shown in FIG. The third link element 24 having a longitudinal dimension corresponding to the amount of displacement in the X-axis direction relative to the Y-axis of the pivot axis 31a is interposed between the second link element 22 of the arm 2 and the hand 23. In addition, the distal end portion of the second link element 22 and the proximal end portion of the third link element 24 are connected so as to be capable of relative swiveling, and the distal end portion of the third link element 24 and the proximal end portion of the hand 23 can be relatively swiveled. It is different in that it is connected to. The tip shape of the hand 23 and the number and dimensions of the link elements interposed between the second link element and the hand can be appropriately changed.

  The transport drive mechanism may be a multi-arm type having a plurality of arms. As an example, a two-arm robot in which arms as shown in FIG. 8 are arranged symmetrically about the first axis (Y axis) can be mentioned. Of course, a multi-arm robot in which the pivot axes of the arms are set at the same position may be used.

  In addition, as the transport driving mechanism, a Cartesian coordinate system robot that can move the hand straightly along two axes orthogonal to each other (the first axis and the second axis in the present invention) can be applied.

  In addition, as a mode of holding the disk-shaped transport object in a state of being placed on the hand, “vacuum suction holding” for holding by vacuum suction, so-called “Bernoulli holding” using the Bernoulli effect, mechanical nails, “Mechanical holding” that holds the disk-shaped transport object in physical contact with a roller, “Static holding” that holds the disk-shaped transport object with electrostatic force, and holds by the gravity of the disk-shaped transport object itself. (For example, the hand is provided with a groove or three or more notches, and the disc-shaped conveyance object is held in the groove or the plurality of notches) “gravity holding”, any of these mounting and holding modes may be used. .

  Further, the transfer destination of the disk-shaped transfer object is not limited to the port in the processing chamber or the load lock chamber, but may be in the FOUP on the load port or an appropriate port.

  In addition, the specific configuration of each part is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Conveyance drive mechanism 23 ... Hand 4 ... Control part 41 ... Perimeter position detection means 42 ... Center position calculation means 43 ... Correction amount calculation means 44 ... Operation command generation means 45 ... Position correction execution means 5 ... Hand movement amount detection part 6L , 6C, 6R ... photoelectric sensor (left photoelectric sensor, central photoelectric sensor, right photoelectric sensor)
7 ... Disc-shaped transfer object (wafer)
T ... Transport robot

Claims (5)

A transport drive mechanism capable of transporting the disk-shaped transport object on the hand to a predetermined transport target position by moving the hand from a transport start position to a delivery position along a linear movement path; and the transport drive mechanism A control unit for controlling the operation of
The control unit is
The disk-shaped transport object on the hand that has started to move from the transport start position in the stopped state to the delivery position is passed through three or more photoelectric sensors, and changes in the output signals of these photoelectric sensors are detected. Peripheral position detecting means for detecting that three or more different peripheral positions of the disc-shaped transport object have passed through the photoelectric sensors,
The installation position of each photoelectric sensor on an orthogonal coordinate system defined by a first axis along a normal movement path of the hand and a second axis orthogonal to the first axis in a horizontal plane including the first axis. The disc-shaped transport that can be obtained in association with the detection information at the start of passage of the peripheral position of the disc-shaped transport target with respect to each photoelectric sensor among the photoelectric sensor position information and the detection information detected by the peripheral position detecting means. Center position calculating means for calculating the center position of the disc-shaped transport object on the orthogonal coordinate system based on the amount of movement of the object;
Calculated by the center position calculation means and the reference center position on the Cartesian coordinate system, which is the center position of the disk-shaped transport object when the disk-shaped transport object is placed at a regular placement position on the hand Displacement amount calculating means for calculating a difference from the center position of the disc-shaped transport object,
Based on the difference calculated by the displacement amount calculation means, an operation command is generated that defines an operation amount of the transport drive mechanism necessary for transporting the disc-shaped transport object on the hand to the predetermined transport target position. Operation command generating means for
A transport robot characterized in that the operation of the transport drive mechanism is controlled based on the motion command generated by the motion command generation means. A hand movement amount detection unit capable of detecting a movement amount of the hand along at least the first axis;
The movement amount of the disc-shaped transport object used in the calculation process in the center position calculating means is the time when the start of passage of the peripheral position of the disc-shaped transport object with respect to each photoelectric sensor is detected by the peripheral position detecting means. The transfer robot according to claim 1, wherein the transfer robot is acquired based on a detection value of a hand movement amount detection unit. On the hand that has started to move from the transfer start position toward the delivery position in a state of being placed at the reference placement position with reference to one placement position of the disc-shaped transport object on the hand A reference movement amount that is an amount moved along the first axis until the time when the peripheral positions of the three or more places in the disk-shaped conveyance object start to pass through the photoelectric sensors, respectively;
The delivery from the transfer start position in a state in which the disc-shaped transfer object used for extracting the reference movement amount is placed on the hand at the calibration placement position displaced from the reference placement position. The amount of movement along the first axis until the three or more peripheral positions of the disc-shaped transport object on the hand that have started to move toward the position start to pass through the photoelectric sensors. And a plurality of sets of calibration movement amounts, each having the same number of movement amounts as the photoelectric sensor,
Using the relative position coordinates of the calibration mounting positions with respect to the reference mounting position, the position coordinates of the photoelectric sensors are estimated,
The transport robot according to claim 1 or 2, wherein the center position calculation unit uses the photoelectric sensor position information based on the estimated position coordinates of the photoelectric sensors. After the reference movement amount extraction process or after the n-th set (n is an integer greater than or equal to 1), the calibration movement amount extraction process, the disc-shaped transport object is placed on the hand with any displacement. The disc-shaped conveyance is performed by moving the hand to a position shifted by an arbitrary displacement amount with respect to the delivery position by the calibration position correcting operation of the first group or m-th group (m is n + 1) to which the amount is added. The object is transferred to a predetermined transfer destination, the hand returned to the transfer start position is moved to the delivery position without a position correction operation, and the disk-shaped transfer object transferred to the transfer destination is moved to the transfer destination. The first set or the m-th set (m is n + 1) for the calibration at the timing when it returns to the transfer start position while being placed on the hand and starts to move toward the delivery position without a position correction operation. Movement amount extraction processing The controller controls the operation of the transport driving mechanism to extract the relative position coordinates of the calibration placement positions with respect to the reference placement position, and to extract the calibration movement amounts of the sets. The transfer robot according to claim 3, wherein the transfer robot is acquired based on a displacement amount during a calibration position correction operation performed in a step. Utilizing a transport robot having a transport drive mechanism capable of transporting the disc-shaped transport object on the hand to a predetermined transport target position by moving the hand from a transport start position to a delivery position along a linear movement path And a transport method for transporting the disc-shaped transport object,
The disk-shaped transport object on the hand that has started to move from the transport start position in the stopped state to the delivery position is passed through three or more photoelectric sensors, and changes in the output signals of these photoelectric sensors are detected. A peripheral position detection step of detecting that three or more different peripheral positions of the disc-shaped transport object have passed through the photoelectric sensors,
It is an installation position of each photoelectric sensor on an orthogonal coordinate system defined by a first axis that is a normal movement path of the hand and a second axis that is orthogonal to the first axis in a horizontal plane that includes the first axis. The movement of the wafer that can be acquired in association with the detection information at the start of passage of the peripheral position of the disc-shaped transport object with respect to each photoelectric sensor among the detection information detected in the peripheral position detection step and the photoelectric sensor position information A center position calculating step for calculating a center position of the disc-shaped transport object on the orthogonal coordinate system based on an amount;
Calculated by the center position calculation step and the reference center position on the Cartesian coordinate system, which is the center position of the disk-shaped transport object when the disk-shaped transport object is placed at a regular placement position on the hand. A displacement amount calculating step for calculating a difference from the center position of the disc-shaped transport object,
Based on the difference calculated in the displacement amount calculating step, an operation command that defines an operation amount of the transport driving mechanism necessary for transporting the disc-shaped transport object on the hand to the predetermined transport target position is generated. Through the operation command generation step to
A method for transporting a disk-shaped transport object, wherein the operation of the transport drive mechanism is controlled based on the motion command generated in the motion command generation step.

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