Conveyance device and control method for conveyance device

Abstract

A transfer robot (1A) comprises: an end effector (20) having a plurality of chuck parts (21) that are arranged in the vertical direction and that each chuck a wafer; two or more photoelectric sensors (31) that are arranged at a pitch (P2) that is less than or equal to half the distance (D1) between an uppermost chuck part (21) located at the uppermost position and a lowermost chuck part (21) located at the lowermost position among the plurality of chuck parts (21), and that detect, on a lateral side of the plurality of chuck parts (21), whether or not an object is present on the lateral side; a location data storage unit; a control unit; and an arithmetic unit.

Description

TRANSPORT DEVICE AND TRANSPORT DEVICE CONTROL METHOD

[0001] The present invention relates to a transport device and a method for controlling the transport device.

[0002] Conventionally, there is known a transport device equipped with multiple chucks for transporting multiple substrates at once. Some of these transport devices measure the height of the chucks or the substrates to chuck the substrates without damaging them with the chucks.

[0003] For example, Patent Document 1 discloses a conveying device that includes a base that is located between the conveying device main body and a cassette that stores substrates and that is raised and lowered by a lifting mechanism, a sensor that is located on the base and measures the height of each of the multiple substrates in the cassette by raising and lowering the base, and an actuator that adjusts the height of a chuck portion based on the height of the substrate measured by the sensor.

[0004] Furthermore, Patent Document 2 discloses a transport device that includes a plurality of chuck sections, each having a lift pad and configured to chuck a substrate with the lift pad, and a lift mechanism that raises and lowers a sensor that detects substrates stored in a cassette. The transport device described in Patent Document 2 uses the lift mechanism to raise and lower the sensor, thereby detecting whether not only the substrate but also the lift pad is in a desired lift state.

[0005] JP 2004-22807 A JP 2017-224658 A

[0006] In the transport device described in Patent Document 1, the lifting mechanism lifts and lowers the base, thereby lifting and lowering the sensor. Therefore, to measure the heights of all the substrates in a cassette, the sensor needs to be lifted and lowered the distance from the bottom to the top of the cassette. As a result, the sensor needs to be lifted and lowered a long distance, which makes measurement time-consuming.

[0007] Furthermore, in the transport device described in Patent Document 2, in order to detect the elevation states of the lift pads of all chuck units and the presence or absence of substrates, the sensor must be raised and lowered the distance from the lowest chuck unit below the bottommost substrate in the cassette to above the topmost substrate in the cassette while the chuck units are inserted into the cassette. As a result, the sensor must be raised and lowered a long distance, which makes measurement time-consuming.

[0008] The present invention has been made to solve the above-mentioned problems, and aims to provide a transport device and a control method for the transport device that can detect in a short time whether there is an abnormality in the height of each chuck portion that chucks a substrate.

[0009] In order to achieve the above object, a transport device according to a first aspect of the present invention comprises: an end effector arranged in a vertical direction and having a plurality of chuck portions each for chucking a substrate; at least two first sensors arranged at a pitch equal to or less than half the distance from an uppermost chuck portion located at the top of the plurality of chuck portions to a lowermost chuck portion located at the bottom, the first sensors detecting whether an object is present at the side of the plurality of chuck portions; a position data storage unit in which a database is stored that stores data on the normal vertical positions of each of the plurality of chuck portions; and a control unit that raises the end effector by at least the pitch relative to the at least two first sensors from a state in which the lowermost chuck portion is located at a first reference position that is lower than the lowermost first sensor of the at least two first sensors by the pitch, or that lowers the end effector by at least the pitch relative to the at least two first sensors from a state in which the uppermost chuck portion is located at a second reference position that is higher than the uppermost first sensor of the at least two first sensors by the pitch. a calculation unit that, while the end effector is being raised or lowered relative to the at least two first sensors, acquires data on the distance traveled by the end effector relative to the first reference position or the second reference position from the control unit, acquires detection data from the at least two first sensors, calculates the vertical position of each of the chuck portions based on the acquired data on the distance traveled and the detection data, calculates the amount of deviation from the normal vertical position of each of the chuck portions based on the database stored in the position data storage unit and each of the calculated vertical positions, and determines whether or not there is an abnormality in each of the plurality of chuck portions based on the calculated amount of deviation.

[0010] The pitch may be equal to a length obtained by dividing the distance from the uppermost chuck portion to the lowermost chuck portion by the number of the first sensors.

[0011] The transport device may further include a base that supports the end effector so that it can move back and forth, and a support column that is provided on the base and supports the at least two first sensors at a position adjacent to the path along which the end effector moves back and forth in a direction perpendicular to the direction of movement and the up-down direction.

[0012] The normal vertical position of each of the chuck portions stored in the database is the position of the tip of the chuck portion; the at least two first sensors detect whether or not an object is present to the side of the tips of the multiple chuck portions; the calculation unit calculates the vertical deviation amount of each of the tips of the multiple chuck portions from the normal vertical position based on the database, the acquired data on the movement distance, and the detection data, and further determines whether the calculated deviation amount of each of the tips exceeds a first allowable value; and the control unit may stop the movement of the end effector when the calculation unit determines that at least one of the deviation amounts of each of the tips exceeds the first allowable value.

[0013] The transport device may further include a warning device that warns of an abnormality when the calculation unit determines that at least one of the deviation amounts of the tip ends exceeds the first allowable value.

[0014] The normal vertical position of each of the chuck portions stored in the database is the position of the tip of the chuck portion; the at least two first sensors detect whether or not an object is present to the side of the tips of the multiple chuck portions; the calculation unit calculates the amount of vertical deviation from the normal vertical position of each of the tips of the multiple chuck portions based on the database, the acquired data on the movement distance, and the detection data, calculates the tilt angle of each of the multiple chuck portions with respect to the horizontal direction from the calculated deviation, and further determines whether the calculated tilt angle of each of the multiple chuck portions exceeds a second allowable value; and the control unit may stop the movement of the end effector when the calculation unit determines that at least one of the tilt angles of each of the multiple chuck portions exceeds the second allowable value.

[0015] The position data storage unit stores data on the thickness of the substrate, and the calculation unit calculates the vertical position of each of the chuck units based on the acquired data on the movement distance and the detection data, and may further determine whether each of the multiple chuck units is chucking the substrate based on the database stored in the position data storage unit, the data on the thickness of the substrate, and the calculated vertical positions.

[0016] The end effector has a clamping section that clamps the substrate collectively from the side when each of the plurality of chuck sections chucks the substrate, and the control section may, when all or some of the plurality of chuck sections chuck the substrate, clamp the substrate by the clamping sections, and while the substrate is clamped by the clamping sections, raise the end effector by at least the pitch relative to the at least two first sensors from a state in which the lowest chuck section is positioned at the first reference position, or lower the end effector by at least the pitch relative to the at least two first sensors from a state in which the highest chuck section is positioned at the second reference position.

[0017] The transport device further includes a base that supports the end effector so that it can move back and forth; a first movement mechanism that supports the base and is movable in a direction perpendicular to the advance / retract direction of the end effector and the up / down direction; a support that movably supports the first movement mechanism; and a second sensor that is provided on the base and detects the inclination of the base in the advance / retract direction relative to an upper surface of the support, wherein the calculation unit determines that there is an abnormality in the inclination of the base in the advance / retract direction relative to the support when the output of the second sensor exceeds a third allowable value, and the control unit may stop the movement of the end effector when the calculation unit determines that there is an abnormality in the inclination in the advance / retract direction.

[0018] The second sensor has: a light-emitting unit provided on the base and emitting light in the forward / backward direction; a light-receiving unit provided on the base and facing the light-emitting unit in the forward / backward direction, receiving the light from the light-emitting unit and measuring the amount of light received; and a light-shielding plate provided on the support body, extending from the support body between the light-emitting unit and the light-receiving unit and blocking a portion of the light from the light-emitting unit; when the inclination of the base relative to the support body in the forward / backward direction changes, the position of the light-shielding plate changes relative to the light-emitting unit and the light-receiving unit, changing the amount of light blocked by the light-emitting unit; and the calculation unit may determine that there is an abnormality in the inclination of the base relative to the support body in the forward / backward direction when the change in the amount of light measured by the light-receiving unit exceeds the third allowable value.

[0019] The transport device further includes a first motor that drives a second moving mechanism that moves the end effector forward and backward, and a second motor that drives a third moving mechanism that raises and lowers the second moving mechanism, wherein the calculation unit acquires torque value data from the first motor and the second motor, determines whether the acquired torque value of the first motor exceeds a first threshold value, and further determines whether the acquired torque value of the second motor exceeds a second threshold value, and the control unit may stop the first motor when the calculation unit determines that the torque value of the first motor exceeds the first threshold value, or stop the second motor when the calculation unit determines that the torque value of the second motor exceeds the second threshold value.

[0020] A control method for a transport device according to a second aspect of the present invention is a control method for a transport device including: an end effector arranged in a vertical direction, having a plurality of chuck portions each for chucking a substrate; and at least two first sensors arranged at a pitch that is equal to or less than half the distance from an uppermost chuck portion located at the top of the plurality of chuck portions to a lowermost chuck portion located at the bottom, the first sensors being arranged at a pitch that is equal to or less than half the distance from an uppermost chuck portion located at the top of the plurality of chuck portions to a lowermost chuck portion located at the bottom, the first sensors being configured to detect whether an object is present at the side of the plurality of chuck portions, the control method comprising the steps of: raising the end effector by at least the pitch relative to the at least two first sensors from a state in which the lowermost chuck portion is located at a first reference position that is lower than a lowermost first sensor of the at least two first sensors by the pitch; or lowering the end effector by at least the pitch relative to the at least two first sensors from a state in which the uppermost chuck portion is located at a second reference position that is higher than an uppermost first sensor of the at least two first sensors by the pitch; The method comprises the steps of: acquiring data on the distance traveled by the end effector relative to the first reference position or the second reference position and acquiring detection data from the at least two first sensors while performing a step of raising or lowering the end effector relative to the at least two first sensors; calculating the vertical position of each of the chuck portions based on the acquired data on the travel distance and the detection data, calculating the amount of deviation from the normal vertical position of each of the chuck portions from a database storing data on the normal vertical position of each of the plurality of chuck portions and each of the calculated vertical positions, and determining whether or not there is an abnormality in each of the plurality of chuck portions based on the calculated amount of deviation; and stopping the movement of the end effector if there is an abnormality in at least one of the plurality of chuck portions.

[0021] According to the configuration of the present invention, the control unit raises or lowers the end effector relative to the at least two first sensors by an amount corresponding to the arrangement pitch of the at least two first sensors. The calculation unit determines whether or not there is an abnormality in each of the multiple chuck units using data on the movement distance of the end effector relative to the first reference position or the second reference position, which data is acquired while the end effector is raised or lowered relative to the at least two first sensors, and the detection data of the at least two first sensors. In this configuration, it is not necessary to raise or lower the end effector by the distance from the uppermost chuck unit to the lowermost chuck unit, and it is sufficient to raise or lower the end effector by an amount corresponding to the arrangement pitch of the at least two first sensors, so that it is possible to quickly detect whether or not there is an abnormality in the height of each chuck unit.

[0022] FIG. 1 is a perspective view of a transport robot according to a first embodiment of the present invention. FIG. 2 is a left side view of a transport system incorporating a transport robot according to the first embodiment. FIG. 3 is an enlarged right side view of a front portion including an end effector of the transport robot according to the first embodiment. FIG. 4 is a hardware configuration diagram of a controller provided in the transport robot according to the first embodiment. FIG. 5 is a block diagram of the controller provided in the transport robot according to the first embodiment. FIG. 6 is a flowchart of an abnormality determination process performed by the controller provided in the transport robot according to the first embodiment. FIG. 7 is a block diagram of a controller provided in the transport robot according to the second embodiment. FIG. 8 is an enlarged left side view of a base and its vicinity provided in the transport robot according to the second embodiment.

[0023] A transfer device and a control method for a transfer device according to an embodiment of the present invention will be described in detail below with reference to the drawings. In the drawings, identical or equivalent parts are designated by the same reference numerals. In the Cartesian coordinate system XYZ shown in the drawings, the Y axis represents the direction of movement of the robot body, and the Z axis represents the direction of elevation of the robot body. The X axis is the direction perpendicular to the Y axis and the Z axis. This coordinate system will be used as appropriate in the following description.

[0024] (Embodiment 1) The transfer device according to embodiment 1 is a transfer robot equipped with multiple chuck units for transferring multiple substrates at once. This transfer robot is equipped with a sensor and a controller for detecting whether the chuck is tilted, since tilting of the chuck unit can damage the wafers. The configuration of the transfer device according to embodiment 1 will be described below using a batch-type transfer robot that transfers multiple wafers at once as an example. First, the configuration of the transfer robot, which is the object of detection by the sensor and the object of control by the controller, will be described with reference to FIGS. 1 and 2.

[0025] FIG. 1 is a perspective view of a transfer robot 1A according to the first embodiment. FIG. 2 is a left side view of a transfer system 2 incorporating the transfer robot 1A. For ease of understanding, FIG. 2 shows the transfer robot 1A and a load port 4 on which a FOUP 3 is placed, among the transfer system 2. In addition to the external appearance, the internal structure is also shown. Also, FIGS. 1 and 2 show the transfer robot 1A chucked with a wafer W.

[0026] As shown in FIG. 1, the transfer robot 1A includes a robot body 10 and an end effector 20 attached to the robot body 10 for chucking a wafer W.

[0027] The transfer robot 1A is a robot for collectively removing a plurality of wafers W from a FOUP 3, which is a type of container for accommodating wafers W, or for collectively placing a plurality of wafers W into the FOUP 3. As shown in Fig. 2, the robot main body 10 has a first linear motion mechanism 11 that linearly moves the end effector 20 in the forward and backward directions to move the end effector 20 in and out of the FOUP 3, and a second linear motion mechanism 12 that linearly moves the end effector 20 in the up and down directions to lift and lower the wafers W in the FOUP 3 with the end effector 20.

[0028] The first linear motion mechanism 11 has a ball screw (not shown) (hereinafter referred to as the first ball screw) that extends in the front-to-rear direction, i.e., the Y direction, a first slider 111 that moves in the Y direction by rotation of the first ball screw, and a motor 112 (also referred to as the first motor) that rotates the first ball screw to move the first slider 111 to a position in the Y direction. In the first linear motion mechanism 11, a controller (described later) rotates the motor 112 in a desired direction by a desired amount, thereby moving the first slider 111 to a desired position in the Y direction. A second linear motion mechanism 12 is mounted above the first slider 111, i.e., on the +Z side.

[0029] The second linear motion mechanism 12 has a ball screw (hereinafter referred to as the second ball screw) not shown in the figure that extends in the vertical direction, i.e., the Z direction, separate from the first ball screw, a second slider 121 that moves in the Z direction by rotating the second ball screw, and a motor 122 (also referred to as the second motor) that rotates the second ball screw to move the second slider 121 to a Z direction position.

[0030] 2, in the second linear motion mechanism 12, a housing 15 that houses equipment for driving the clamp unit 50, electric wires, pipes, etc., is fixed to the front side, i.e., the +Y surface side, of the second slider 121. Furthermore, an end effector 20 is attached to the +Y surface side of the housing 15. Therefore, when the first slider 111 of the first linear motion mechanism 11 moves to a desired position in the Y direction by the above-mentioned controller controlling the rotation of the motor 112 of the first linear motion mechanism 11, not only the second linear motion mechanism 12 mounted on the first slider 111 but also the end effector 20 moves to the desired position in the Y direction.

[0031] Furthermore, in the second linear motion mechanism 12, the controller rotates the motor 122 of the second linear motion mechanism 12 in a desired direction by a desired amount of rotation, thereby moving the second slider 121 to a desired position in the Z direction. Since the end effector 20 is attached to the second slider 121 via the housing 15, when the controller moves the second slider 121 to the desired position in the Z direction, the end effector 20 also moves to the desired position in the Z direction.

[0032] The first slider 111 and the second slider 121 are specific examples of the second movement mechanism and the third movement mechanism defined in the claims, and the motors 112 and 122 are specific examples of the drive unit defined in the claims.

[0033] In this way, the end effector 20 is moved to a desired position in the Y and Z directions by the first linear motion mechanism 11 and the second linear motion mechanism 12. For example, the end effector 20 moves into the FOUP 3. The end effector 20 has multiple chuck portions 21 for chucking and transporting multiple wafers W accommodated in the FOUP 3.

[0034] As shown in FIG. 1 , each chuck unit 21 is formed in the shape of a fork with two blades and a flat plate. The chuck unit 21 has a plate surface facing vertically and the fork-shaped blades facing forward. Furthermore, the chuck unit 21 has gripping claws 211 and 212 on the plate surface at the tips of the blades. The chuck unit 21 also has support pins 213 and 214 on the plate surface at the rear end of the fork. The robot main body 10 is provided with a clamp unit 50 that clamps the rear end of the wafer W from the side when the chuck unit 21 lifts the wafer W. When the clamp unit 50 clamps the wafer W, the chuck unit 21 chucks the wafer W by sandwiching it between the gripping claws 211 and 212 and the support pins 213 and 214. This allows the chuck unit 21 to stably transport the wafer W.

[0035] The end effector 20 has a plurality of such chuck portions 21. Specifically, the end effector 20 has the same number of chuck portions 21 as the maximum number of wafers W (e.g., 25) that can be accommodated in the FOUP 3. This allows the end effector 20 to simultaneously unload all of the wafers W accommodated in the FOUP 3, or simultaneously load the maximum number of wafers W that can be accommodated into the FOUP 3.

[0036] Furthermore, in order for the end effector 20 to simultaneously transport multiple wafers W in the FOUP 3, the chuck portions 21 are vertically arranged at a constant pitch P1 that is the same as the arrangement pitch of the wafers W in the FOUP 3. As described above, the chuck portions 21 are parallel to each other because their plate surfaces are oriented vertically and extend horizontally. This allows the end effector 20 to lift and transport the wafers W stored horizontally in the FOUP 3 without damaging them.

[0037] However, when the chuck portion 21 deteriorates over time due to long-term use of the end effector 20, or when parts such as the chuck portion 21 are replaced depending on the type of FOUP 3, the chuck portion 21 may tilt in the front-rear or left-right direction. Also, the pitch P1 in the up-down direction may change. If the chuck portion 21 tilts or the pitch P1 of the chuck portion 21 deviates from a constant value, the wafer W may be damaged.

[0038] Therefore, the transfer robot 1A is provided with a photoelectric sensor to prevent damage to the wafer W, and the controller determines abnormalities such as tilting and pitch deviation of the chuck portion 21 from the output of the photoelectric sensor.

[0039] In this case, it is also conceivable to use a single photoelectric sensor provided on the side of the end effector 20 to detect the inclination or pitch deviation of the multiple chuck portions 21 arranged in the vertical direction. However, in such a case, it is necessary to raise and lower the end effector 20 relative to the photoelectric sensor by a distance greater than the distance from the bottom surface of the uppermost chuck portion 21 to the bottom surface of the lowermost chuck portion 21 (distance D1 shown in FIG. 3 , which will be described later) plus the thickness T1 of the chuck portions 21. As a result, it takes time for the photoelectric sensor to make measurements, and it also takes time to determine whether there is an abnormality in the chuck portions 21.

[0040] Therefore, the transport robot 1A uses a plurality of photoelectric sensors arranged in the vertical direction to determine abnormalities in the chuck portion 21. Next, the configurations of the photoelectric sensors and controller provided in the transport robot 1A will be described with reference to FIGS.

[0041] FIG. 3 is an enlarged right side view of the front portion of the transport robot 1A, including the end effector 20. FIG. 4 is a hardware configuration diagram of a controller 40 provided in the transport robot 1A. FIG. 5 is a block diagram of the controller 40. Note that, for ease of understanding, FIG. 3 shows the position of the photoelectric sensor 31 on only one of the supports 32 provided on the frame 30; however, in reality, the light-emitting portion and the light-receiving portion of the photoelectric sensor 31 are provided on each of the supports 32 and 33. The same is true for FIGS. 1 and 2. For ease of understanding, FIGS. 4 and 5 also show the configuration of other devices connected to the controller 40 in addition to the controller 40.

[0042] As shown in Figure 3, the transport robot 1A further includes a frame 30 provided at the front end portion of the robot body 10, and a plurality of photoelectric sensors 31 supported by the frame 30 and provided to detect the height of the chuck portion 21 provided on the end effector 20.

[0043] In the transfer robot 1A, the tip end (hereinafter also referred to as the front end) of the end effector 20 is retracted to a plurality of photoelectric sensors 31 attached to the frame 30, and the end effector 20 is raised and lowered in this state, thereby causing the chuck portions 21 of the end effector 20 to be detected by the plurality of photoelectric sensors 31. The frame 30 is formed in a rectangular frame shape so that the end effector 20 can be advanced and retreated and raised and lowered.

[0044] Specifically, as shown in FIG. 1 , the frame 30 has two vertically extending columns 32 and 33 and beam members 34 and 35 extending horizontally and connecting the upper and lower ends of the columns 32 and 33. The columns 32 and 33 are sufficiently longer than the length obtained by adding the vertical distance D1 from the uppermost chuck portion 21 of the end effector 20 to the lowermost chuck portion 21, the thickness T1 of the chuck portion 21 shown in FIG. 3 , and the thickness T2 of the wafer W. The beam members 34 and 35 are also sufficiently longer than the diameter D2 of the wafer W shown in FIG. 1 . As a result, the frame 30 has a rectangular frame shape within which the end effector 20 can advance and retreat. The frame 30 also has a rectangular frame shape within which the end effector 20 can ascend and descend.

[0045] In addition, in order to allow the multiple photoelectric sensors 31 in a stationary state to detect each of the chuck portions 21 of the end effector 20 that is rising and falling, the frame 30 is fixed to a location on the transport robot 1A that does not move as the end effector 20 rises and falls, as shown in Figure 3.

[0046] In detail, the transfer robot 1A includes a base 60 for supporting the first linear motion mechanism 11, and a housing of a linear guide 113 that guides the first slider 111 in the Y direction, which is provided in the first linear motion mechanism 11, is fixed to the base 60. The frame 30 is fixed to the base 60. In this manner, the frame 30 is fixed at a position that is not affected by the advancement and retreat of the end effector 20 by the first slider 111 or the elevation and lowering of the end effector 20 by the second slider 121.

[0047] Furthermore, the frame 30 is disposed in front of and adjacent to the housing of the linear guide 113 so that the front ends of the chuck portions 21 of the end effector 20 can be detected by the multiple photoelectric sensors 31. The length L1 of the frame 30 in the front-rear direction is sufficiently shorter than the distance that the first slider 111, guided by the linear guide 113, can advance. The end effector 20 is positioned ahead of the first slider 111. Due to this positional relationship, when the first slider 111 advances or retreats, (a) the entire chuck portion 21 of the end effector 20, and (b) the entire wafer W when the wafer W is chucked by the chuck portion 21, enter or pass through the internal space of the frame 30. As a result, the support columns 32, 33 of the frame 30 are located on the right or left side of the path (also referred to as the advance / retract path) along which the end effector 20 advances or retreats. The support columns 32 and 33 are provided with a plurality of photoelectric sensors 31 for detecting the height of the chuck portion 21 of the end effector 20 which moves back and forth or rises and falls along the path, and the presence or absence of the wafer W.

[0048] Although not shown, each photoelectric sensor 31 has a light-emitting unit and a light-receiving unit that receives a light beam emitted by the light-emitting unit. The light-emitting unit of the photoelectric sensor 31 is provided on one of the support columns 32 and 33 and emits a light beam in the horizontal direction. The light-receiving unit of the photoelectric sensor 31 is provided on the other of the support columns 32 and 33 at the same height as the light-receiving unit and receives the electron beam. Each photoelectric sensor 31 determines whether or not an object is present between the light-emitting unit and the light-receiving unit based on the amount of light detected by the light-receiving unit, and outputs an indication of the presence or absence of an object. More specifically, each photoelectric sensor 31 outputs an indication of the presence or absence of an object between the support columns 32 and 33. That is, each photoelectric sensor 31 outputs an indication of whether or not the chuck portion 21 of the end effector 20 passes between the support columns 32 and 33, and as a result, whether or not the chuck portion 21 is present between the support columns 32 and 33. Alternatively, each photoelectric sensor 31 outputs an indication of whether or not a wafer W is present between the support columns 32 and 33.

[0049] In addition, in order to detect the chuck portion 21 of the end effector 20 moving up and down between the supports 32 and 33, the photoelectric sensors 31 are arranged in the vertical direction along the axis of the supports 32 and 33 at a pitch P2 (also referred to as a second pitch) that is larger than the pitch P1 of the chuck portion 21, as shown in FIGS. 1 to 3 .

[0050] In detail, the photoelectric sensor 31 located at the lowest position among the plurality of photoelectric sensors 31 is disposed at the same height as the reference position (also called the origin, and referred to as the first reference position in the claims) when the end effector 20 is moved to that reference position by the second linear motion mechanism 12, but at a pitch P2 above the height of that reference position (coordinate Z1 in the Z direction shown in FIG. 3). The other photoelectric sensors 31 are then arranged at a pitch P2 above the photoelectric sensor 31 located at the lowest position.

[0051] Here, the pitch P2 is the same length as the distance D1 obtained by dividing the distance from the vertical center of the uppermost chuck portion 21 to the vertical center of the lowermost chuck portion 21 by the number of photoelectric sensors 31.

[0052] Because the photoelectric sensors 31 are arranged in this manner, when the end effector 20 rises by the pitch P2 from the height of the reference position, all of the chuck portions 21 of the end effector 20 pass by the side of one of the photoelectric sensors 31. As a result, all of the multiple photoelectric sensors 31 can detect the height of all of the chuck portions 21 of the end effector 20 and the presence or absence of a wafer W in each of the chuck portions 21.

[0053] Furthermore, the number of photoelectric sensors 31 is preferably a divisor of the maximum number of wafers W that can be accommodated in the FOUP 3. However, it is preferable that this divisor does not include the maximum number. This is because such a number allows the distance by which the end effector 20 is raised from the reference position to be as short as possible. Also, this is because there is no need to raise the end effector 20 any more. In the transfer robot 1A, the maximum number of wafers W that can be accommodated in the FOUP 3 is 25. Therefore, to satisfy the above conditions, only five photoelectric sensors 31 are provided in the transfer robot 1A. As a result, in the transfer robot 1A, the above-mentioned pitch P2 is made shorter than the distance D1, thereby shortening the distance by which the end effector 20 is raised to detect the height of the chuck portion 21 and the presence or absence of wafers W.

[0054] Each photoelectric sensor 31 detects the presence or absence of the chuck portion 21 or the wafer W, i.e., the presence or absence of an object that blocks the light from the light-emitting portion of the photoelectric sensor 31, and transmits the detection data to the controller 40. The photoelectric sensor 31 is a specific example of a first sensor as defined in the claims.

[0055] 4, the controller 40 includes a processor 41, a memory 42, and an interface 43. The processor 41, the memory 42, and the interface 43 are connected to each other via a bus 44.

[0056] The interface 43 connects the processor 41 and the memory 42 to other devices, enabling communication with the other devices. In particular, the interface 43 is connected to a plurality of photoelectric sensors 31 provided in the robot body 10, the motor 112 of the first linear motion mechanism 11, and the motor 122 of the second linear motion mechanism 12. The interface 43 is also connected to a display device 45. This allows the interface 43 to transmit and receive data between the processor 41 and the memory 42 and these devices.

[0057] The processor 41 and the memory 42 constitute a computer. The processor 41 reads and executes various programs stored in the memory 42, thereby causing the controller 40 to perform various processes for controlling various parts of the robot body 10, such as the motor 112 of the first linear motion mechanism 11 and the motor 122 of the second linear motion mechanism 12. For example, the controller 40 reads and executes an abnormality determination program stored in the memory 42, thereby performing an abnormality determination process for the end effector 20, which determines abnormalities such as tilt and pitch deviation of the chuck portion 21 from the output of the above-mentioned photoelectric sensor 31. To perform this process, the controller 40 includes a control unit 46 and a calculation unit 47 shown in FIG. 5 . Next, these components will be described.

[0058] The control unit 46 controls each part of the robot main body 10. For example, the control unit 46 controls the motor 112 of the first linear motion mechanism 11 and the motor 122 of the second linear motion mechanism 12. This moves the first slider 111 and the second slider 121, and moves the end effector 20 forward and backward or up and down to a desired position. The control unit 46 also transmits data on the distance traveled from the reference position (origin) to the calculation unit 47.

[0059] In response to this, the calculation unit 47 receives data on the travel distance of the end effector 20 from the control unit 46. The calculation unit 47 also receives object detection data from each of the photoelectric sensors 31.

[0060] Here, the detection data of the object refers to the detection data of the chuck portion 21 of the end effector 20 or the wafer W. Since the light emitting portion and the light receiving portion of the photoelectric sensor 31 are provided on the supports 32 and 33, respectively, the object that blocks the light beam of the photoelectric sensor 31 is limited to the chuck portion 21 of the end effector 20 or the wafer W chucked to the chuck portion 21. The calculation unit 47 receives such detection data of the chuck portion 21 or the wafer W.

[0061] When the calculation unit 47 receives the movement distance data of the end effector 20 and the object detection data, it determines the position of the chuck portion 21 of the end effector 20 and the presence or absence of an abnormality in the chuck portion 21 based on the received movement distance data of the end effector 20 and the object detection data. In this way, an abnormality determination process for the end effector 20 is performed to determine abnormalities such as tilt and pitch deviation of the chuck portion 21. Next, the abnormality determination process for the end effector 20 will be described in more detail with reference to FIG. 6.

[0062] FIG. 6 is a flowchart of the abnormality determination process performed by the controller 40.

[0063] In the transport robot 1A, when (1) the end effector 20 is advanced to remove a wafer W stored in the FOUP 3, or (2) the end effector 20 is advanced to store the wafer W in the FOUP 3 while the chuck portion 21 is chucking the wafer W, if the chuck portion 21 is inclined or the pitch P1 of the chuck portion 21 is misaligned, the wafer W may be damaged.

[0064] Therefore, the controller 40 performs the abnormality determination process for the end effector 20 shown in FIG. 6 using the photoelectric sensor 31 immediately before the (1) wafer W removal operation and the (2) wafer W accommodating operation. Specifically, the reference position (origin) of the end effector 20 is a position where the front end is forward of the frame 30. The controller 40 retracts the end effector 20 while maintaining the height of the reference position (origin) immediately before the above-described (1) or (2) operation. When the front-rear direction position of the front end of the chuck portion 21, i.e., the Y coordinate, coincides with the Y coordinate of the support columns 32 and 33, the controller 40 determines that the abnormality determination process is possible and executes the abnormality determination process. Specifically, the processor 41 reads and executes the abnormality determination program stored in the memory 42. As a result, the flow of the abnormality determination process for the end effector 20 is started.

[0065] When the flow of the abnormality determination process for the end effector 20 is started, the front end portion of the chuck portion 21 is positioned so as to overlap with the supports 32, 33 when viewed from the left and right, and is in a state where it can be detected by the photoelectric sensor 31. Therefore, the controller 40 first raises the end effector 20 as shown in FIG. 6 and acquires the lift distance data and the detection data of the photoelectric sensor 31 (step S1).

[0066] Specifically, the control unit 46 rotates the motor 122 of the second linear motion mechanism 12 in the forward direction at a constant rotational speed, thereby lifting the second slider 121 at a constant speed. This causes the end effector 20 to lift at a constant speed. In this lifting of the end effector 20, the control unit 46 lifts the end effector 20 by a distance equal to the pitch P2 at which the photoelectric sensors 31 are arranged in the vertical direction. Even when the end effector 20 is lifted by this distance, each of the chuck portions 21 will be detected by one of the photoelectric sensors 31, because the photoelectric sensors 31 are arranged in the vertical direction at the pitch P2.

[0067] In parallel with the lifting of the end effector 20, the calculation unit 47 acquires, from the control unit 46, movement distance data of the end effector 20, i.e., data on the distance that the end effector 20 has lifted from the start of step S1 to the present, every time a certain period of time has elapsed. In addition, the calculation unit 47 acquires detection data from each of the photoelectric sensors 31 every time the certain period of time has elapsed. By shortening the certain period of time, the calculation unit 47 acquires this data almost constantly.

[0068] Next, the calculation unit 47 calculates the height of each of the chuck portions 21 (step S2).

[0069] In step S1, the end effector 20 rises at a constant speed a distance equal to the pitch P2, causing the front end of the chuck 21 to move relative to each of the photoelectric sensors 31. Alternatively, if the chuck 21 is chucking a wafer W, the wafer W moves relative to each of the photoelectric sensors 31. Therefore, by acquiring the lift distance data and the detection data of the photoelectric sensors 31 in step S1, the calculation unit 47 obtains object presence / absence data for a length obtained by multiplying the number of photoelectric sensors 31 by the distance of the pitch P2 in the vertical direction at the front-to-rear position where each photoelectric sensor 31 is located (position Y1 shown in FIG. 3 ). From this data, the calculation unit 47 creates mapping data indicating the presence or absence of an object in the vertical direction. The calculation unit 47 then calculates the height of the top or bottom surface of each of the chucks 21 from the height of the top or bottom surface of the portion of the mapping data where an object is present.

[0070] Next, as shown in FIG. 6, the calculation unit 47 determines whether or not there is an abnormality in the height of any of the chuck units 21 (step S3).

[0071] 5, the memory 42 includes a position data storage unit 421 and a determination parameter storage unit 422. The position data storage unit 421 stores data on the normal height of each of the upper and lower surfaces of the chuck portion 21 (also referred to as a database in the claims) and data on the normal thickness T2 of the wafer W (also referred to as substrate thickness data in the claims). The determination parameter storage unit 422 stores a threshold value (also referred to as a first allowable value in the claims) of the deviation amount from the ideal height of the chuck portion 21 that should be determined to be normal.

[0072] The calculation unit 47 reads out the normal height data of the upper or lower surface of each of the chuck portions 21 and the normal thickness data of the thickness T2 of the wafer W from the position data memory unit 421, and compares the read-out normal height data of the upper or lower surface of each of the chuck portions 21 with the height data of the upper or lower surface of each of the chuck portions 21 calculated in step S2 to calculate the deviation amount of the height of the upper or lower surface of each of the chuck portions 21 from the normal height.

[0073] Furthermore, the calculation unit 47 reads out the deviation threshold from the judgment parameter storage unit 422 and determines whether any one of the deviations from the normal height of the upper or lower surface of each of the chuck portions 21 is greater than the read deviation threshold. If the calculation unit 47 determines that the deviation is greater than the read deviation threshold, it determines that one of the chuck portions 21 has a height abnormality. Then, the calculation unit 47 determines that the chuck portion 21 determined to have an abnormality is tilted or has a misaligned pitch P1. On the other hand, if the calculation unit 47 determines that the deviation is equal to or less than the read deviation threshold, it determines that none of the chuck portions 21 has a height abnormality. In this way, the calculation unit 47 determines whether any of the chuck portions 21 has a height abnormality in step S3.

[0074] In step S3, if any of the data on the height of the upper surface of each of the chuck portions 21 calculated in step S2 is higher than the normal height of the upper surface of each of the chuck portions 21 by the read-out normal thickness value of the thickness T2 of the wafer W, the calculation unit 47 determines that the wafer W is chucked to that chuck portion 21. Here, when the height of the upper surface of each of the chuck portions 21 is higher than the normal height by the read-out normal thickness value of the thickness T2 of the wafer W, this includes variations within the above-mentioned deviation threshold. Then, the calculation unit 47 outputs the determination result of the presence or absence of the wafer W to another device (for example, the display device 45 shown in FIG. 5).

[0075] If it is determined in step S3 that any of the chucks 21 has a height abnormality (Yes in step S3), the calculation unit 47 sends an abnormality signal to the control unit 46, and the control unit 46 stops the movement of the end effector 20. This prevents the end effector 20 from penetrating the FOUP 3 and damaging the wafer W. The calculation unit 47 also sends an abnormality signal to the display device 45 to display a warning (step S4). This prompts the user to replace or adjust the chuck 21. At this time, it is preferable that the number of the chuck 21 determined to have a height abnormality (e.g., the number counted from the top) be displayed on the display device 45. The display device 45 is an example of a warning device for warning of an abnormality as defined in the claims, and may be, for example, a warning light.

[0076] Subsequently, the calculation unit 47 ends the abnormality determination process. After the abnormality determination process ends, the control unit 46 keeps the operation of the transport robot 1A stopped until the user of the transport robot 1A returns the transport robot 1A to the origin, replaces and adjusts the chuck unit 21, and cancels the warning.

[0077] On the other hand, if it is determined in step S3 that there is no height abnormality in any of the chuck units 21 (No in step S3), the calculation unit 47 transmits the result to the control unit 46, and the control unit 46 lowers the end effector 20 to return it to the state before the end effector 20 was raised in step S1. Then, the calculation unit 47 ends the abnormality determination process. The control unit 46 determines that there is no abnormality in the chuck units 21 and that there is no risk of damage to the wafer W, and controls the robot body 10 to perform the wafer W removal operation (1) or the wafer W accommodation operation (2) described above.

[0078] As described above, in the transport robot 1A according to the first embodiment, the control unit 46 controls the motor 122 of the second linear motion mechanism 12 to lift the end effector 20 by a pitch P2 that is smaller than the distance D1 from the uppermost chuck unit 21 to the lowermost chuck unit 21 among the plurality of chuck units 21. The calculation unit 47 then determines whether or not there is an abnormality in each of the chuck units 21 using the lift distance data and detection data of the end effector 20 acquired while the end effector 20 is being lifted by the pitch P2. In the transport robot 1A, it is not necessary to lift the end effector 20 by the pitch P1; it is sufficient to raise and lower the end effector 20 by at least the pitch P2. Therefore, the transport robot 1A can quickly detect whether or not there is an abnormality in the height of each of the chuck units 21.

[0079] Specifically, the transport robot 1A is provided with five photoelectric sensors 31, and as a result, the pitch P2 is 1 / 5 of the above-mentioned distance D1. Therefore, the transport robot 1A can detect whether or not there is an abnormality in the height of each chuck portion 21 in a short time, compared to a configuration in which the end effector 20 is raised by the pitch P1 and the photoelectric sensors 31 detect the chuck portions 21.

[0080] Furthermore, in the transfer robot 1A, when the calculation unit 47 determines that there is a height abnormality in any of the chuck units 21, the transfer robot 1A stops the movement of the end effector 20. As a result, the transfer robot 1A can prevent the abnormal chuck unit 21 from entering the FOUP 3 and damaging the wafer W. For example, the wafer W is less likely to be scratched.

[0081] In the transport robot 1A, the photoelectric sensor 31 is fixed via the frame 30 to a base 60 that supports the first linear motion mechanism 11. In the transport robot 1A, the base 60 is part of the robot body 10, so it takes less time to detect an abnormality in the height of the chuck portion 21 than when the transport robot is moved to another device and the height of the chuck portion is measured thereon.

[0082] Furthermore, since the frame 30 is located in front of and adjacent to the first linear motion mechanism 11, the distance over which the end effector 20 is moved to detect an abnormality in the height of the chuck portion 21 is short, and therefore the time required to detect an abnormality in the height of the chuck portion 21 is shorter.

[0083] In the transfer robot 1A, the front end portion of the chuck portion 21 of the end effector 20 is detected by the photoelectric sensor 31, so if the chuck portion 21 is tilted, the tilt can be easily detected.

[0084] In the first embodiment, the abnormality determination process of the end effector 20 determines the amount of deviation of the height of the upper or lower surface of each of the chuck portions 21 from the normal height, and determines whether or not there is an abnormality in the height of the chuck portion 21 based on the amount of deviation. However, the presence or absence of an abnormality in the height of the chuck portion 21 may also be determined based on the inclination angle of the chuck portion 21.

[0085] For example, the calculation unit 47 may calculate the inclination angle of each chuck portion 21 based on the deviation of the height of the upper or lower surface of each chuck portion 21 from the normal height and the length from the front end portion of the chuck portion 21, which is the measurement point of the photoelectric sensor 31, to the base end of the chuck portion 21, and may determine that there is an abnormality in the chuck portion 21 if the inclination angle exceeds an allowable value (referred to as a second allowable value in the claims).

[0086] In the first embodiment, when the clamp unit 50 clamps the wafer W, the chuck unit 21 chucks the wafer W by sandwiching it between the gripping claws 211, 212 and the support pins 213, 214. However, the clamp unit 50 is not only used when the wafer W is chucked by the chuck unit 21.

[0087] When performing the abnormality determination process for the end effector 20 with the chuck unit 21 chucked with the wafer W, the clamp unit 50 is preferably used when the end effector 20 is raised in step S1. That is, the clamp unit 50 advances and retreats in the forward and backward directions by a linear motion mechanism (not shown), and before the end effector 20 is raised in step S1, the control unit 46 preferably controls the linear motion mechanism (not shown) to move the clamp unit 50 forward to clamp the wafer W. Then, the end effector 20 is preferably raised in step S1 while the wafer W remains clamped. If the end effector 20 is raised in this manner, the wafer W will not shift, allowing the photoelectric sensor 31 to accurately detect the wafer W.

[0088] Second Embodiment In the first embodiment, the calculation unit 47 determines whether or not there is an abnormality in each of the chuck units 21 in order to prevent damage to the wafer W. However, the present invention is not limited to this. In the present invention, the calculation unit 47 may further determine whether or not there is an inclination of the base 60 that supports the first linear motion mechanism 11 in order to prevent damage to the wafer W.

[0089] The transfer robot 1B according to the second embodiment is provided with an inclination detection sensor that detects the inclination of the base 60. The calculation unit 47 determines whether the inclination of the base 60 is acceptable or not based on the detection result of the inclination detection sensor.

[0090] 7 and 8, a description will be given of the configuration of a transfer robot 1B according to the second embodiment. In the second embodiment, the description will focus on the configuration that is different from the first embodiment.

[0091] Fig. 7 is a block diagram of the controller 40 provided in the transport robot 1B. Fig. 8 is an enlarged left side view of the base 60 provided in the transport robot 1B and its vicinity. For ease of understanding, Fig. 7 also shows the configuration of other devices connected to the controller 40 in addition to the controller 40. Fig. 8 also shows an enlarged view of region VIII shown in Fig. 2 provided in the transport robot 1B.

[0092] As shown in FIG. 7, the transport robot 1B includes a photoelectric sensor 31 provided on the robot body 10, and further includes an inclination detection sensor 61.

[0093] First, the inclination of the base 60, which is the detection target of the inclination detection sensor 61, will be described. As described in the first embodiment, the base 60 supports the first linear motion mechanism 11. Specifically, as shown in FIG. 2 , the base 60 is formed in a flat plate shape and is further supported by a support frame 62 provided below. The support frame 62 is supported by a third slider 64 of a third linear motion mechanism 63, also referred to simply as a slider. The third linear motion mechanism 63 has a rail fixed to a base 65 and extending in the left-right direction, i.e., the X direction. The third slider 64 moves linearly along the rail. The third slider 64 moves linearly in the X direction, thereby linearly moving the transport robot 1B supported by the base 60 in the X direction. This realizes the transport system 2 that moves the end effector 20 in the X, Y, and Z directions.

[0094] However, the housing 15 and the end effector 20 are moved on the base 60 by the first linear motion mechanism 11 and the second linear motion mechanism 12. As a result, problems such as deformation and misalignment are likely to occur due to aging. This may cause the base 60 to tilt relative to the third slider 64. If the base 60 tilts relative to the third slider 64, not only will the chuck portion 21 of the end effector 20 tilt, but the frame 30 supporting the photoelectric sensor 31 described in the first embodiment will also tilt. As a result, it is difficult for the photoelectric sensor 31 to detect the tilt of the chuck portion 21 caused by the tilt of the base 60. Therefore, the transport robot 1B is provided with a tilt detection sensor 61. The tilt detection sensor 61 is a specific example of the second sensor defined in the claims.

[0095] As shown in Figure 8, the tilt detection sensor 61 has an emitter 611 and a receiver 612 provided on the base 60, and a light-shielding plate 613 provided on the stand 65 between the emitter 611 and the receiver 612 to block light from the emitter.

[0096] The light emitting unit 611 is provided at the bottom of the base 60 and emits a light beam backward. On the other hand, the light receiving unit 612 is provided behind the light emitting unit 611 at the bottom of the base 60 and receives the light beam emitted by the light emitting unit 611.

[0097] The light emitting unit 611 emits a light beam in the horizontal direction when the surface of the base 60 is horizontal. The light receiving unit 612 faces the light emitting unit 611 in the Y direction.

[0098] On the other hand, the light-shielding plate 613 is provided on the +Z plane of the base 65. It has a tip that extends parallel to the YZ plane. The tip extends to between the light-emitting unit 611 and the light-receiving unit 612. The light-shielding plate 613 blocks half of the light beam from the light-emitting unit 611 when the surface of the base 60 is horizontal. When the surface of the base 60 is tilted in the Y direction from this state, the tip of the light-shielding plate 613 blocks more of the light beam. In other words, the light-shielding rate of the light beam by the light-shielding plate 613 changes. The light-receiving unit 612 measures this amount of light and transmits it to the calculation unit 47 shown in FIG. 7.

[0099] The calculation unit 47 receives light intensity data measured by the light receiving unit 612 from the tilt detection sensor 61. Meanwhile, the judgment parameter storage unit 422 stores data on the normal value of light intensity and the allowable value of light intensity change (referred to as the third allowable value in the claims). The calculation unit 47 reads out the data on the normal value of light intensity and the allowable value of light intensity change, and calculates the amount of change in the received light intensity data from the normal value of light intensity. The calculation unit 47 then determines whether the calculated amount of change exceeds the allowable value. This allows the calculation unit 47 to determine whether the base 60 is tilted with respect to the +Z plane of the mount 65.

[0100] If the calculated amount of change exceeds the allowable value, the calculation unit 47 determines that the inclination of the base 60 with respect to the stand 65 is large, and transmits an abnormality signal to the control unit 46. When the control unit 46 receives the abnormality signal, it stops the movement of the end effector 20 and transmits an abnormality signal to the display device 45 to display a warning, similar to step S4 of the abnormality determination process for the end effector 20 described in the first embodiment. The transfer robot 1B according to the second embodiment constantly executes the determination by the calculation unit 47 while it is activated. As a result, damage to the wafer W caused by the inclination of the base 60 is suppressed in the transfer robot 1B.

[0101] The tilt detection sensor 61 is provided at the rear portion of the base 60 in the front-rear direction. Specifically, as shown in FIG. 2 , the base 60 is supported by a third slider 64 via a support frame 62. The third slider 64 is located below the center of the base 60 in the front-rear direction. Meanwhile, as can be seen from the fact that region VIII in FIG. 2 is located at the rear portion of the base 60, the tilt detection sensor 61 is provided at a rear portion of the base 60 relative to the third slider 64. As a result, the tilt detection sensor 61 is more susceptible to the influence of tilt of the base 60 in the front-rear direction and can easily detect the tilt. As a result, in the transfer robot 1B, damage to the wafer W due to tilt of the base 60 is more effectively suppressed.

[0102] The third slider 64 is a specific example of a first moving mechanism as defined in the claims, and the base 65 is a specific example of a support as defined in the claims.

[0103] As described above, in the transfer robot 1B according to the second embodiment, the calculation unit 47 determines whether or not the base 60 is inclined relative to the upper surface of the pedestal 65 based on the outputs of the tilt detection sensors 61 provided on the base 60 and the pedestal 65. As a result, in the transfer robot 1B, damage to the wafer W caused by the tilt of the base 60 is unlikely to occur.

[0104] (Embodiment 3) In embodiment 1, the calculation unit 47 determines whether or not there is an abnormality in each of the chuck units 21 in order to prevent damage to the wafer W. In embodiment 2, the calculation unit 47 determines whether or not there is an inclination of the base 60. However, the present invention is not limited to this. In the present invention, in order to prevent damage to the wafer W, the calculation unit 47 may determine whether or not there is an abnormality in the motor 112 of the first linear motion mechanism 11 and the motor 122 of the second linear motion mechanism 12.

[0105] In addition to the configuration of the transport robot according to the second embodiment, the calculation unit 47 determines whether or not there is an abnormality in the motor 112, the motor 122, etc. The configuration of the transport robot according to the third embodiment will be described below. In the third embodiment, the configuration different from the first and second embodiments will be mainly described.

[0106] The block diagram of the transport robot according to the third embodiment is the same as that of the transport robot 1B according to the second embodiment, and therefore is not shown.

[0107] The motor 112 of the first linear motion mechanism 11 and the motor 122 of the second linear motion mechanism 12 each have a torque measurement unit and transmit measured torque value data to the calculation unit 47. The third linear motion mechanism 63 described in the second embodiment is also provided with a motor for moving the third slider 64. The motor of the third linear motion mechanism 63 also has a torque measurement unit and transmits measured torque value data to the calculation unit 47.

[0108] Meanwhile, the judgment parameter storage unit 422 stores first, second, and third thresholds at which the torque values ​​of the motor 112 of the first linear motion mechanism 11, the motor 122 of the second linear motion mechanism 12, and the motor of the third linear motion mechanism 63 are determined to be abnormal. The calculation unit 47 reads the first, second, and third thresholds from the judgment parameter storage unit 422. Thereafter, when the calculation unit 47 receives torque value data from the motor 112 of the first linear motion mechanism 11, the motor 122 of the second linear motion mechanism 12, and the motor of the third linear motion mechanism 63, the calculation unit 47 determines whether each of the data exceeds the first, second, and third thresholds, respectively.

[0109] When the torque value data of the motor 112 of the first linear motion mechanism 11 exceeds the first threshold value, the calculation unit 47 transmits a first torque abnormality signal to the control unit 46. Upon receiving the first torque abnormality signal, the control unit 46 stops the operation of the first linear motion mechanism 11 and causes the display device 45 to display a warning that an abnormality has occurred in the first linear motion mechanism 11.

[0110] Similarly, when the torque value data of the motor 122 of the second linear motion mechanism 12 exceeds the second threshold value, the calculation unit 47 transmits a second torque abnormality signal to the control unit 46. Upon receiving the second torque abnormality signal, the control unit 46 stops the operation of the second linear motion mechanism 12 and displays a warning on the display device 45 that an abnormality has occurred in the second linear motion mechanism 12.

[0111] Furthermore, when the torque value data of the motor of the third linear motion mechanism 63 exceeds the third threshold value, the calculation unit 47 transmits a third torque abnormality signal to the control unit 46. Upon receiving the third torque abnormality signal, the control unit 46 stops the operation of the third linear motion mechanism 63 and causes the display device 45 to display a warning that an abnormality has occurred in the third linear motion mechanism 63.

[0112] As described above, the transfer robot according to the third embodiment detects an abnormality in each of the first linear motion mechanism 11, the second linear motion mechanism 12, and the third linear motion mechanism 63 from the torque values ​​of the motor 112 of the first linear motion mechanism 11, the motor 122 of the second linear motion mechanism 12, and the motor of the third linear motion mechanism 63. The transfer robot according to the third embodiment stops operation when an abnormality is detected, thereby preventing damage to the wafer W during transfer.

[0113] The transport apparatus and the control method for the transport apparatus according to the first to third embodiments of the present invention have been described above using the transport robots 1A and 1B as an example, but the transport apparatus and the control method for the transport apparatus are not limited to this.

[0114] For example, in Embodiments 1-3, the photoelectric sensor 31 is attached to the frame 30, but the present invention is not limited thereto. In the present invention, the photoelectric sensors 31 are arranged at a pitch P2 that is less than half the distance D1 from the uppermost chuck portion 21 located at the top of the plurality of chuck portions 21 to the lowermost chuck portion 21 located at the bottom, and at least two first sensors are provided on the sides of the plurality of chuck portions 21 to detect whether an object is present on the side. Since the photoelectric sensor 31 only needs to be located on the side of the plurality of chuck portions 21, it may be attached to the support columns 32, 33 without the beam members 34, 35. Furthermore, the photoelectric sensor 31 may be attached to either of the support columns 32, 33. In this configuration, the photoelectric sensor 31 will be located on the side of the plurality of chuck portions 21 as the end effector 20 advances and retreats. As a result, the photoelectric sensor 31 can detect the presence or absence of the chuck portions 21.

[0115] Furthermore, in embodiments 1-3, the photoelectric sensor 31 includes a light-emitting unit and a light-receiving unit that are provided separately, but the present invention is not limited to this. As described above, in the present invention, the photoelectric sensor 31 may be any sensor that detects whether or not an object is present to the side. For example, the photoelectric sensor 31 may be a so-called reflective sensor in which the light-emitting unit and the light-receiving unit are provided in an integrated housing, and the light-receiving unit receives light reflected from the object to be detected. Furthermore, the photoelectric sensor 31 may be a so-called retro-reflective sensor in which the light-emitting unit and the light-receiving unit are provided in an integrated housing, and further includes a reflecting unit provided separately from the light-emitting unit and the light-receiving unit.

[0116] Furthermore, in the first to third embodiments, only five photoelectric sensors 31 are provided. However, the present invention is not limited to this. As described above, the present invention requires at least two photoelectric sensors 31. For example, there may be two photoelectric sensors 31. Even in such a case, it is sufficient that the end effector 20 rises by half the distance D2 from the height of the origin (coordinate Z1 in the Z direction shown in FIG. 3). As explained in the first embodiment, it is desirable that the number of photoelectric sensors 31 is a divisor of the maximum capacity of wafers W that can be accommodated in the FOUP 3. However, it is desirable that this divisor does not include the maximum capacity.

[0117] In the first to third embodiments, when the photoelectric sensor 31 detects the chuck portion 21, the end effector 20 is elevated from the height of the origin (coordinate Z1 in the Z direction shown in FIG. 3 ). However, the present invention is not limited to this. In the present invention, when the photoelectric sensor 31 detects the chuck portion 21, the end effector 20 is elevated by at least the pitch P2 relative to the at least two first sensors from a state in which the lowest chuck portion 21 is positioned at a first reference position that is lower than the lowest first sensor of the plurality of photoelectric sensors 31, i.e., of the at least two first sensors in the present invention. Therefore, the end effector 20 may be elevated from above the origin.

[0118] In the present invention, when the chuck portion 21 is detected by the photoelectric sensor 31, the end effector 20 may be lowered as well as raised. That is, in the present invention, the uppermost chuck portion 21 may be positioned at a second reference position that is higher by the pitch P2 than the uppermost first sensor of the plurality of photoelectric sensors 31, i.e., of the at least two first sensors in the present invention, and the end effector 20 may be lowered by at least the pitch P2 relative to the at least two first sensors.

[0119] In the embodiment, the chuck units 21 and 22 include gripping claws 211 and 212 and support pins 213 and 214. The chuck units 21 and 22 chuck the wafer W. However, the present invention is not limited to this. In the present invention, the chuck units 21 and 22 may each be capable of chucking a substrate. Therefore, in the present invention, the specific means by which the chuck units 21 and 22 chuck a substrate is arbitrary. For example, the chuck units 21 and 22 may chuck the wafer W using a vacuum chuck. The specific shape of the chuck units 21 and 22 is also arbitrary. For example, instead of being fork-shaped, the chuck units 21 and 22 may have a rectangular shape on which a substrate can be mounted. Furthermore, the wafer W to be chucked may be another substrate, such as a glass substrate.

[0120] The present invention allows various embodiments and modifications without departing from the broad spirit and scope of the present invention. Furthermore, the above-described embodiments are intended to illustrate the present invention and do not limit the scope of the present invention. In other words, the scope of the present invention is defined by the claims, not the embodiments. Various modifications made within the scope of the claims and within the scope of the meaning of the invention equivalent thereto are considered to be within the scope of the present invention.

[0121] DESCRIPTION OF SYMBOLS 1A, 1B Transfer robot 2 Transfer system 3 FOUP 4 Load port 10 Robot body 11 First linear motion mechanism 12 Second linear motion mechanism 15 Housing 20 End effector 21 Chuck section 30 Frame 31 Photoelectric sensor (first sensor) 32, 33 Supports 34, 35 Beam member 40 Controller 41 Processor 42 Memory 43 Interface 44 Bus 45 Display device (warning device) 46 Control section 47 Arithmetic section 50 Clamp section 60 Base 61 Tilt detection sensor 62 Support frame 63 Third linear motion mechanism 64 Third slider (first movement mechanism) 65 Base (support) 111 First slider (second movement mechanism) 112 Motor (drive section) 113 Linear guide 121 Second slider (third moving mechanism) 122 Motor (driving unit) 211, 212 Grip jaws 213, 214 Support pins 421 Position data storage unit 422 Judgment parameter storage unit 611 Light emitting unit 612 Light receiving unit 613 Light shielding plate D1 Distance D2 Diameter L1, L2 Length P1, P2 Pitch T1, T2 Thickness W Wafer (substrate) Y1 Position

Claims

1. An end effector having a plurality of chuck portions arranged in the vertical direction, each of which chucks a substrate, at least two first sensors arranged at a pitch equal to or less than half of the distance from the uppermost chuck portion located at the top to the lowermost chuck portion located at the bottom among the plurality of chuck portions, for detecting whether an object is present laterally on the sides of the plurality of chuck portions, a position data storage unit storing a database storing data on the normal vertical positions of the plurality of chuck portions, a control unit for raising the end effector by at least the pitch with respect to the at least two first sensors from a state where the lowermost chuck portion is positioned at a first reference position that is lower than the pitch from the lowermost first sensor among the at least two first sensors, or lowering the end effector by at least the pitch with respect to the at least two first sensors from a state where the uppermost chuck portion is positioned at a second reference position that is higher than the pitch from the uppermost first sensor among the at least two first sensors, while the end effector is being raised or lowered with respect to the at least two first sensors, the control unit obtains data on the moving distance by which the end effector has relatively moved from the first reference position or the second reference position, obtains detection data from the at least two first sensors, calculates the vertical positions of the respective chuck portions based on the obtained moving distance data and the detection data, further calculates the deviation amount from the normal vertical positions of the respective chuck portions from the database stored in the position data storage unit and the calculated vertical positions, and determines the presence or absence of abnormality of each of the plurality of chuck portions based on the calculated deviation amount, a conveying device comprising the above components.

2. The conveying device according to claim 1, wherein the pitch is the same as the length obtained by dividing the distance from the uppermost chuck portion to the lowermost chuck portion by the number of the first sensors.

3. A base that supports the end effector so as to be movable back and forth, and a support column provided on the base that supports the at least two first sensors at positions adjacent to each other from the side in a direction perpendicular to the forward / backward direction and the vertical direction in the forward / backward path along which the end effector moves back and forth. The conveying device according to claim 1 or 2, further comprising the support column.

4. The normal vertical position of each of the chuck portions stored in the database is the position of the tip of the chuck portion. The at least two first sensors detect whether an object is on the side, on the side of the tips of the plurality of chuck portions. The calculation unit calculates the vertical deviation amount of each of the tips of the plurality of chuck portions with respect to the normal vertical position based on the database, the acquired data of the moving distance, and the detection data, and further determines whether the deviation amount of each of the calculated tips exceeds a first allowable value. When the calculation unit determines that at least one of the deviation amounts of each of the tips exceeds the first allowable value, the control unit stops the movement of the end effector. The conveying device according to claim 1 or 2.

5. The conveying device according to claim 4, further comprising a warning device that warns of an abnormality when the calculation unit determines that at least one of the deviation amounts of each of the tips exceeds the first allowable value.

6. The normal vertical position of each of the chuck parts stored in the database is the position of the tip of the chuck part. The at least two first sensors detect whether an object is on the side, on the side of the tips of the plurality of chuck parts. The calculation unit calculates the amount of vertical deviation of each of the tips of the plurality of chuck parts with respect to the normal vertical position based on the database, the acquired data of the moving distance, and the detection data, calculates the inclination angle of each of the plurality of chuck parts with respect to the horizontal direction from the calculated amount of deviation, and further determines whether the inclination angle of each of the plurality of chuck parts calculated exceeds a second allowable value. The control unit stops the movement of the end effector when the calculation unit determines that at least one of the inclination angles of the plurality of chuck parts exceeds the second allowable value. The conveying device according to claim 1 or 2.

7. The position data storage unit stores data on the thickness of the substrate. The calculation unit calculates the vertical position of each of the chuck parts based on the acquired data of the moving distance and the detection data, and further determines whether each of the plurality of chuck parts is chucking the substrate based on the database, the data on the thickness of the substrate, and the calculated vertical positions stored in the position data storage unit. The conveying device according to claim 1 or 2.

8. The end effector has a clamping part that clamps the substrate collectively from the side when each of the plurality of chuck parts chucks the substrate. The control unit, when all or part of the plurality of chuck parts chuck the substrate, causes the clamping part to clamp the substrate, and with the substrate clamped by the clamping part, raises the end effector by at least the pitch with respect to the at least two first sensors from the state where the lowermost chuck part is positioned at the first reference position, or lowers the end effector by at least the pitch with respect to the at least two first sensors from the state where the uppermost chuck part is positioned at the second reference position. The conveying device according to claim 1 or 2.

9. A base that supports the end effector so as to be movable back and forth, a first moving mechanism that supports the base and is movable in a direction perpendicular to the back-and-forth direction and the up-and-down direction of the end effector, a support body that movably supports the first moving mechanism, and a second sensor that is provided on the base and detects the inclination of the base in the back-and-forth direction with respect to the upper surface of the support body. Further provided, when the output of the second sensor exceeds a third allowable value, the arithmetic unit determines that there is an abnormality in the inclination of the base in the back-and-forth direction with respect to the support body, and when the arithmetic unit determines that there is an abnormality in the inclination in the back-and-forth direction, the control unit stops the movement of the end effector. The conveying device according to claim 1 or 2.

10. The second sensor includes a light emitting unit provided on the base and emitting light in the back-and-forth direction, a light receiving unit provided on the base, facing the light emitting unit in the back-and-forth direction, receiving the light of the light emitting unit, and measuring the amount of the received light, and a light shielding plate provided on the support body and extending from the support body between the light emitting unit and the light receiving unit to block a part of the light of the light emitting unit. The light shielding plate changes the amount of light blocked by the light emitting unit by changing the position with respect to the light emitting unit and the light receiving unit when the inclination of the base in the back-and-forth direction with respect to the support body changes. When the change in the amount of light measured by the light receiving unit exceeds the third allowable value, the arithmetic unit determines that there is an abnormality in the inclination of the base in the back-and-forth direction with respect to the support body. The conveying device according to claim 9.

11. A first motor that drives a second moving mechanism for moving the end effector forward and backward, and a second motor that drives a third moving mechanism for moving the second moving mechanism up and down are further provided. The arithmetic unit acquires data on torque values from the first motor and the second motor, respectively, determines whether the torque value of the acquired first motor exceeds a first threshold value, and further determines whether the torque value of the acquired second motor exceeds a second threshold value. The control unit stops the first motor when the arithmetic unit determines that the torque value of the first motor exceeds the first threshold value, or stops the second motor when the arithmetic unit determines that the torque value of the second motor exceeds the second threshold value. The conveying device according to claim 1 or 2.

12. A control method for a transfer device, comprising: an end effector having a plurality of chuck portions arranged in the vertical direction, each of which chucks a substrate; at least two first sensors arranged at a pitch equal to or less than half of the distance from the uppermost chuck portion located at the uppermost position among the plurality of chuck portions to the lowermost chuck portion located at the lowermost position, for detecting whether an object is present laterally on the side of the plurality of chuck portions; A step of raising the end effector by at least the pitch with respect to the at least two first sensors from a state where the lowermost chuck portion is positioned at a first reference position that is lower than the pitch from the lowermost first sensor among the at least two first sensors, or lowering the end effector by at least the pitch with respect to the at least two first sensors from a state where the uppermost chuck portion is positioned at a second reference position that is higher than the pitch from the uppermost first sensor among the at least two first sensors; While executing the step of raising or lowering the end effector with respect to the at least two first sensors, acquiring data on the moving distance by which the end effector has relatively moved from the first reference position or the second reference position, and acquiring detection data from the at least two first sensors; Based on the acquired moving distance data and the detection data, calculating the vertical positions of the respective chuck portions, calculating the deviation amount from the normal vertical positions of the respective chuck portions from the normal vertical position data stored in a database for each of the plurality of chuck portions and the calculated vertical positions, and determining the presence or absence of abnormality for each of the plurality of chuck portions based on the calculated deviation amount; When at least one of the plurality of chuck portions is abnormal, a step of stopping the movement of the end effector.

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