Conveyance device and teaching method

Abstract

This conveyance device is for conveying a substrate, and comprises: a first holding section having a placement surface for the substrate; a sensor provided at the tip-end portion of the first holding section; a cable connected to the sensor and attached to only one side from among both width-directional sides of the first holding section; a first fork having a rotating shaft extending in the vertical direction; a second holding section having a placement surface for the substrate; a second fork having a rotating shaft that is coaxial with the first fork; a conveyance robot having the first fork and the second fork; a conveyance chamber which is capable of decompression and is for accommodating the conveyance robot; an optical sensor that is provided in the conveyance chamber and has an optical axis oriented in the vertical direction; and a control device. When the other width-directional side of the first holding section to which the cable is not attached serves as a non-wiring side, the control device rotates the first fork to, by using the optical sensor, detect a first edge position which is the non-wiring side edge position of the first holding section, rotates the second fork to, by using the optical sensor, detect a second edge position which is the edge position of the second holding section on the same side as the non-wiring side, and calculates the difference in rotation angle between the first fork and the second fork on the basis of the first edge position and the second edge position.

Description

Transfer Device and Teaching Method

[0001] The present disclosure relates to a transfer device and a teaching method.

[0002] For example, as described in Patent Document 1, a transfer robot in which a plurality of arms supporting a substrate are coaxially supported is known.

[0003] Japanese Patent Application Laid-Open No. 2020-119927

[0004] In such a transfer device using a transfer robot, for the purpose of expanding the automatic teaching function, mounting a sensor at the tip of the fork has been considered. The technology according to the present disclosure relates to a transfer device and a teaching method that can further improve the transfer accuracy of a substrate in such a transfer device.

[0005] One aspect of the present disclosure is a transfer device for transferring a substrate, including a first holding portion having a placement surface of the substrate, a sensor provided at a tip portion of the first holding portion, a cable connected to the sensor and attached only to one of both sides in the width direction of the first holding portion, a first fork having a rotation axis extending in the vertical direction, a second holding portion having a placement surface of the substrate, a second fork having a rotation axis coaxial with the first fork, a transfer robot having the first fork and the second fork, a depressurable transfer chamber housing the transfer robot, an optical sensor provided in the transfer chamber and having an optical axis directed in the vertical direction, and a control device. When the other side in the width direction of the first holding portion where the cable is not attached is defined as the non-wiring side, the control device rotates the first fork to detect, with the optical sensor, a first edge position that is the non-wiring side edge position in the first holding portion, rotates the second fork to detect, with the optical sensor, a second edge position that is the same-side edge position as the non-wiring side in the second holding portion, and calculates a rotation angle difference between the first fork and the second fork based on the first edge position and the second edge position.

[0006] According to this disclosure, a transport device and a teaching method can be provided that can further improve the transport accuracy of substrates in a transport device equipped with a sensor at the tip of a fork, with the aim of expanding the automatic teaching function.

[0007] This is a plan view showing the schematic configuration of a wafer processing system equipped with a vacuum transfer device as a transfer device according to this embodiment. This is a perspective view showing the schematic configuration of the transfer mechanism of the vacuum transfer device. This is a schematic plan view showing the first fork as seen from above in the vertical direction. This is a diagram showing the A-A cross section of Figure 3. This is a schematic plan view showing the second fork as seen from above in the vertical direction. This is a flowchart for explaining a teaching method by detecting the angular deviation of the forks. This is a diagram for explaining the operation of the first and second forks in the above teaching method. This is a diagram showing the output history of the optical sensor when the first fork rotates. This is a diagram showing the output history of the optical sensor when the second fork rotates. This is a diagram with the output history of Figure 9 superimposed on the output history of Figure 8. This is a diagram showing the first and second forks in a state where angular deviation has occurred. This is a flowchart for explaining a teaching method by detecting other angular deviations. This is a diagram showing the output history of the optical sensor when the first fork rotates in the teaching method of Figure 12. This is a diagram showing another wiring example of the sensor cable. This is a diagram showing another wiring example of the sensor cable.

[0008] The substrate transport device according to this embodiment will be described below with reference to the drawings. In this specification and the drawings, elements having substantially the same functional configuration are denoted by the same reference numerals, and redundant explanations will be omitted.

[0009] <Wafer Processing System> Figure 1 is a schematic plan view showing the configuration of a wafer processing system equipped with a vacuum transfer device as a transfer device according to this embodiment.

[0010] The wafer processing system 1 shown in Figure 1 performs predetermined processes, such as film deposition, diffusion, and etching, on a wafer W, which serves as a substrate, under reduced pressure. This wafer processing system 1 has a configuration in which a carrier station 10, which loads and unloads a carrier C capable of accommodating multiple wafers W, and a processing station 11 equipped with multiple processing devices for performing predetermined processes on the wafers W under reduced pressure are integrally connected. The carrier station 10 and the processing station 11 are connected via two load lock devices 12 and 13.

[0011] The load lock devices 12 and 13 have load lock chambers 12a and 13a configured to switch between atmospheric pressure and vacuum conditions. The load lock devices 12 and 13 are provided to connect the atmospheric pressure conveying device 21 and the vacuum conveying device 30, which will be described later.

[0012] The carrier station 10 includes a carrier mounting platform 20 and an atmospheric pressure conveying device 21 provided adjacent to the carrier mounting platform 20.

[0013] The carrier mounting table 20 is configured to accommodate multiple carriers C, for example, three carriers side by side. The atmospheric pressure transport device 21 has an atmospheric transport chamber 22 in which the chamber is kept at atmospheric pressure. The atmospheric transport chamber 22 is connected to the load lock chambers 12a and 13a of the load lock devices 12 and 13 via gate valves G1 and G2. A wafer transport mechanism 23 is provided inside the atmospheric transport chamber 22. The wafer transport mechanism 23 is configured to transport wafers W between the carriers C on the carrier mounting table 20 and the load lock chambers 12a and 13a under atmospheric pressure.

[0014] The carrier station 10 further includes an aligner 24 provided adjacent to the atmospheric pressure transport device 21. The aligner 24 recognizes notches and other features on the wafer W and adjusts the orientation of the wafer W.

[0015] (Transportation device) The processing station 11 has a vacuum transport device 30 and processing modules 60 to 63 as transport devices for transporting substrates.

[0016] The vacuum transfer device 30 has a vacuum transfer chamber 31 in which the interior is kept in a reduced-pressure state (vacuum state). The vacuum transfer chamber 31 is made of a sealed housing and is formed to have a substantially polygonal shape (hexagonal in the illustrated example) in plan view. The vacuum transfer chamber 31 is connected to the load lock chambers 12a and 13a of the load lock devices 12 and 13 via gate valves G3 and G4. The vacuum transfer chamber 31 is also connected to each of the vacuum processing chambers 64 to 67, which will be described later, via gate valves G5 to G8. Inside the vacuum transfer chamber 31, there is a wafer transfer mechanism 32 which serves as a transfer mechanism for transporting wafers W between the processing modules 60 to 63 and the vacuum processing chambers 64 to 67, which will be described later.

[0017] The wafer transfer mechanism 32 is a transfer robot having a base 33, arms 34 and 35, a first fork 40, and a second fork 50. Figure 2 is a perspective view showing a schematic configuration of the wafer transfer mechanism 32.

[0018] As shown in Figure 2, one end of arm 34 is rotatably attached to the base 33, and the other end of arm 34 is attached to one end of another arm 35. A first fork 40 and a second fork 50 are attached to the other end of arm 35.

[0019] The first fork 40 has a first arm 41 rotatably attached to the end of the arm 35, and two first holding parts 42 and 43 extending from the first arm 41 as substrate holding parts. The two first holding parts 42 and 43 are formed by branching off from the first arm 41 and face each other. The first fork 40 having this configuration is formed in a U shape in plan view.

[0020] The second fork 50 has a second arm 51 that is rotatably attached to the end of the arm 35, and two second holding parts 52 and 53 that extend from the second arm 51 as substrate holding parts. The two second holding parts 52 and 53 are formed by branching off from the second arm 51 and face each other. The second fork 50 having this configuration is formed in a U shape in plan view.

[0021] Furthermore, the shape of each fork 40, 50 in plan view is not limited to a U-shape, as long as it is possible to transport the wafer W.

[0022] The second fork 50 is located below the first fork 40, and the second arm 51 of the second fork 50 is connected to the end of the arm 35 such that it forms a coaxial axis of rotation with the first arm 41 of the first fork 40. This axis of rotation is a vertically extending axis, and the first fork 40 and the second fork 50 rotate horizontally at different heights around this coaxial axis of rotation.

[0023] The distance between the upper surfaces (wafer mounting surfaces) of the first holding sections 42, 43 and the upper surfaces (wafer mounting surfaces) of the second holding sections 52, 53 is appropriately set to a distance that prevents the wafers held by each holding section 42, 43, 52, 53 from interfering with each other, for example, 10 mm.

[0024] The second fork 50 may be located above the first fork 40.

[0025] (Sensor cable wiring) Figure 3 is a schematic plan view of the first fork 40 as seen from above in the vertical direction. Figure 4 is a view of the A-A cross section of Figure 3. Note that in Figure 3, the hatching indicating the cross section is omitted. Figure 5 is a schematic plan view of the second fork 50 as seen from above in the vertical direction.

[0026] As shown in Figure 3, sensors 44 are provided at the tips of the two first holding portions 42 and 43 of the first fork 40. These two sensors 44 are imaging sensors such as optical sensors and cameras, and are used for various auto-teaching function enhancements, such as teaching the first fork 40 to place wafers on a stage (not shown) in the processing module, and detecting the position of wafers and focus rings placed in the processing module.

[0027] Here, if we refer to the direction perpendicular to the extension direction of the first arm 41 in a plan view as the width direction (lateral direction in Figure 3), then the sensor 44 is located at the outer corner in the width direction of the first holding parts 42 and 43. For this reason, the sensor cable 45, which is connected to the sensor 44, is attached to the outside in the width direction of the first holding parts 42 and 43.

[0028] As shown in Figure 4, a groove 46 capable of accommodating a sensor cable 45 is formed on the outer side surface 42a in the width direction of the first holding portion 42. An adhesive member 47 is filled into the groove 46 with the sensor cable 45 housed inside, thereby fixing the sensor cable 45 in place. The groove 46 is formed, for example, by grinding using a rotating grinding wheel, and extends along the respective sides of the first arm 41 and the first holding portions 42 and 43 shown in Figure 3.

[0029] By housing the sensor cable 45 in the groove 46 shown in Figure 4, interference between the sensor cable 45 and other parts can be suppressed when the first fork 40 rotates. Note that the method of fixing the sensor cable 45 in the groove 46 is not limited to the method using an adhesive member 47. Also, although Figure 4 illustrates the method of fixing the sensor cable 45 in one of the two first holding parts 42, the sensor cable 45 is fixed in the other first holding part 43 in the same way.

[0030] As shown in Figure 5, the second fork 50 does not have a sensor like the sensor 44 mentioned above that is used during teaching. For this reason, no sensor cables are routed on either the outside or inside of the second holding parts 52 and 53 in the width direction.

[0031] Although the second fork 50 does not have a sensor for teaching, the external shape of the first fork 40 and the second fork 50 are the same in plan view. Therefore, the second fork 50 can be taught by utilizing the teaching information of the first fork 40. Specifically, for example, the horizontal coordinate data of the first fork 40 when a wafer is placed on the stage in the processing module, obtained through the teaching of the first fork 40, is reflected in the second fork 50. This allows the horizontal position coordinates of the second fork 50 when a wafer is placed on the stage in the processing module to be set.

[0032] The wafer transport mechanism (transport robot) 32, which includes a first fork 40 and a second fork 50, has been described above.

[0033] As shown in Figure 1, a position detection mechanism 36 is provided inside the vacuum transport chamber 31 for detecting the position of the wafer W held on the first fork 40 or the second fork 50 along the wafer transport path. Based on the detection results from the position detection mechanism 36, the control device 70, described later, calculates the positional deviation of the wafer W from a predetermined position on the first fork 40 or the second fork 50.

[0034] The position detection mechanism 36 is provided for each of the processing modules 60 to 63, which will be described later. Specifically, the position detection mechanism 36 is provided, for example, on the wafer transport path to processing module 60 near gate valve G5, on the wafer transport path to processing module 61 near gate valve G6, on the wafer transport path to processing module 62 near gate valve G7, and on the wafer transport path to processing module 63 near gate valve G8.

[0035] Each position detection mechanism 36 has, for example, a pair of optical sensors 36a and 36b arranged along a corresponding gate valve (any of gate valves G5 to G8). The optical sensors 36a and 36b are, for example, transmissive type and have a light-emitting part and a light-receiving part, respectively, provided on the ceiling side and floor side within the vacuum transport chamber 31. The optical sensors 36a and 36b are installed so that their optical axes are oriented vertically, and the light-receiving part receives light from the light-emitting part.

[0036] While the wafer W passes between the light-emitting and light-receiving sections of the optical sensors 36a and 36b, the light from the light-emitting section is blocked by the wafer W, and light reception by the light-receiving section stops. Once the wafer W has passed between the light-emitting and light-receiving sections, light reception by the light-receiving section resumes. The length of the light reception stop period in the optical sensors 36a and 36b varies depending on the placement position of the wafer W on the first fork 40 or the second fork 50.

[0037] In other words, the orientation in which the wafer W is placed on the first fork 40 or the second fork 50 can be determined from the information on the length of the light-receiving stop period of the optical sensors 36a and 36b. In the control device 70 described later, the positional displacement of the wafer W from a predetermined position on the first fork 40 or the second fork 50 is calculated based on the length of the light-receiving stop period of the optical sensors 36a and 36b. Note that the method for calculating the positional displacement of the wafer W from a predetermined position on the first fork 40 or the second fork 50 is not limited to this method, and other known methods can be used.

[0038] An optical sensor 37 is provided inside the vacuum transfer chamber 31 to detect the presence or absence of a wafer W on the first fork 40 or the second fork 50, which are located in the home position. For example, if the home position of each fork 40, 50 is the position shown by the dashed line in Figure 1, the optical sensor 37 is located in the central part surrounded by the U-shaped portion of each fork 40, 50, which are located in the home position.

[0039] The optical sensor 37 is a transmissive sensor similar to the aforementioned optical sensors 36a and 36b. For example, when the wafer W is present on the first fork 40 located at the home position, the light from the light emitting portion is blocked by the wafer W, and the light reception by the light receiving portion stops. On the other hand, when the wafer W is not present on the first fork 40 located at the home position, the light from the light emitting portion reaches the light receiving portion, and the light reception by the light receiving portion resumes. Therefore, it is possible to detect whether the wafer W is held on the first fork 40 or the second fork 50 based on the detection status of the light reception in the light receiving portion of the optical sensor 37.

[0040] In the above example, transmissive sensors are used as the optical sensors 36a, 36b, and the optical sensor 37. However, a reflective sensor may be used as long as the desired detection function can be obtained.

[0041] As shown in FIG. 1, the processing modules 60 to 63 perform predetermined processes such as film formation processing, diffusion processing, etching processing, etc. on the wafer W under reduced pressure. Further, each of the processing modules 60 to 63 has vacuum processing chambers 64 to 67 in which the above predetermined processes are performed on the wafer W in a chamber under reduced pressure. Note that modules for performing processes according to the purpose of wafer processing can be arbitrarily selected for the processing modules 60 to 63.

[0042] The wafer processing system 1 is provided with at least one control device 70. The control device 70 processes computer-executable instructions that cause the wafer processing system 1 to perform various processes described herein. The control device 70 may be configured to control each element of the wafer processing system 1 to perform the various processes described herein. In one embodiment, some or all of the control device 70 may be included in the wafer processing system 1. The control device 70 may include a processing unit, a storage unit, and a communication interface. The control device 70 is implemented, for example, by a computer. The processing unit may be configured to read a program from the storage unit that provides logic or routines that enable various control operations, and to perform various control operations by executing the read program. This program may be stored in the storage unit in advance, or it may be retrieved via a medium M when needed. The retrieved program is stored in the storage unit and read from the storage unit and executed by the processing unit. The medium M may be various storage media read by a computer, or it may be a communication line connected to a communication interface. The storage medium may be temporary or non-temporary. The processing unit may be a CPU (Central Processing Unit) and may consist of one or more circuits. The storage unit may include RAM (Random Access Memory), ROM (Read Only Memory), HDD (Hard Disk Drive), SSD (Solid State Drive), or a combination thereof. The communication interface may communicate with the wafer processing system 1 via a communication line such as a LAN (Local Area Network).

[0043] For example, the above programs include a program for controlling the rotational movement of each fork 40 and 50, a program for detecting the edge position of each fork 40 and 50 using an optical sensor, and a program for controlling the automatic teaching of each fork 40 and 50.

[0044] <Teaching Method 1> Next, an example of a teaching method for detecting the angular deviation of a fork using a vacuum transfer device will be described. The correction method described below is performed under the control of the control device 70.

[0045] Fig. 6 is a flowchart for explaining the teaching method by detecting the angular deviation. Fig. 7 is a diagram for explaining the operations of the respective forks 40 and 50 when performing the teaching method. When detecting the angular deviation, an optical sensor is used. In the present embodiment, the optical sensor 37 shown in Fig. 1 is utilized.

[0046] (Step S10) First, as shown in Fig. 7(a), the first fork 40 and the second fork are moved to the angular check position. The angular check position is, for example, a position where the optical sensor 37 exists on the turning orbit of the first holding portions 42 and 43 when the first fork 40 rotates, and is a position where the optical axes of the first holding portions 42 and 43 and the light emitting portion of the optical sensor 37 can intersect when the first fork 40 rotates. In Fig. 7(a), since the first fork 40 overlaps the second fork, the second fork is not shown, but the second fork is also in a state of being moved to the angular check position in the same manner as the first fork 40.

[0047] (Step S11) Next, as shown in Fig. 7(b), the first fork 40 is rotated clockwise. At this time, the light of the optical sensor 37 is blocked when the outer portion in the width direction of the first holding portion 42 passes through the optical sensor 37. As a result, as shown in Fig. 8, the optical sensor 37 switches from the non-light-blocking state to the light-blocking state, and a signal is output from the optical sensor 37 toward the control device 70. Based on this signal, the edge position P1 of the outer side in the width direction of the first holding portion 42 can be detected.

[0048] Next, as shown in Figure 7(c), the inner portion of the first holding part 42 in the width direction passes through the optical sensor 37, so that the light from the optical sensor 37 is no longer blocked by the first holding part 42. As a result, the optical sensor 37 switches from a light-shielded state to an unshielded state, and the signal that was being output from the optical sensor 37 to the control device 70 stops. Based on this signal, the inner edge position P2 in the width direction of the first holding part can be detected.

[0049] Next, as shown in Figure 7(d), the first fork 40 rotates further, causing the inner portion of the first holding portion 43 in the width direction to pass the optical sensor 37. As a result, the light from the optical sensor 37 is blocked again, and the optical sensor 37 switches from an unshielded state to a shrouded state, making it possible to detect the inner edge position P3 of the first holding portion 43 in the width direction.

[0050] Next, as shown in Figure 7(e), the outer portion of the first holding part 43 in the width direction passes through the optical sensor 37, so that the light from the optical sensor 37 is not blocked by the first holding part 43. As a result, the optical sensor 37 switches from a light-shielded state to an unshielded state, and the outer edge position P4 of the first holding part in the width direction can be detected.

[0051] By step S11 described above, information on the edge positions P1 to P4 of the two first holding portions 42 and 43 of the first fork 40 can be obtained.

[0052] (Step S12) Next, as shown in Figure 7(f), the second fork 50 is rotated clockwise, similar to the first fork 40. This allows the two second holding portions 52 and 53 of the second fork 50 to pass through the optical sensor 37, enabling the detection of edge positions P1' to P4' as shown in Figure 9.

[0053] (Step S13) Next, the difference in rotation angles between the first fork 40 and the second fork 50 is calculated. Specifically, the difference in rotation angles is calculated from the information of the edge positions P1 to P4 of the first holding parts 42 and 43 of the first fork 40 and the edge positions P1' to P4' of the second holding parts 52 and 53 of the second fork 50, but only the information of specific edge positions is used when calculating the difference in rotation angles. The reason is as follows.

[0054] The sensor cable 45 described above is routed on the widthwise outer side of the first holding portions 42 and 43 of the first fork 40. As explained with reference to Figure 4, the sensor cable 45 is fixed using an adhesive member 47 in a groove 46 on the widthwise outer side of the first holding portion 42, but it is practically difficult to form the adhesive member 47 so that it does not protrude from the groove 46. Therefore, the widthwise outer end position of the sensor cable 45 routed in the first holding portions 42 and 43 is affected by the shape of the adhesive member 47.

[0055] In other words, of the edge positions P1 to P4 of the first holding parts 42 and 43, the outer edge positions P1 and P4 in the width direction, which correspond to the wiring side of the sensor cable 45, are detected as the end face of the adhesive member 47 and not as edge positions corresponding to the sides of the first holding parts 42 and 43. Therefore, high positional accuracy cannot be guaranteed as positional data for determining the fork's swivel angle detection position. In particular, when teaching is performed in a relatively high-temperature environment, which is the actual transport environment, the adhesive member 47 is affected by thermal expansion, which may lead to a deterioration in positional accuracy. On the other hand, the inner edge positions P2 and P3 in the width direction, which correspond to the non-wired side of the sensor cable 45, can be detected with high accuracy as the edge positions corresponding to the inner sides of the first holding parts 42 and 43 in the width direction, because the sensor cable is not wired there.

[0056] Therefore, in the teaching method according to this embodiment, when calculating the rotation angle difference between the forks 40 and 50, information on edge positions P2 and P3 where the sensor cable 45 is not wired is used. In the following description, the edge positions P2 and P3 on the non-wired side of the first holding parts 42 and 43 will be referred to as the "first edge position". In addition, among the edge positions P1' to P4' of the second holding parts 52 and 53, the edge positions P2' and P3' on the inside in the width direction of the second holding parts 52 and 53 that correspond to the same side as the non-wired side of the first holding parts 42 and 43 will be referred to as the "second edge position".

[0057] In step S13, the rotation angle difference is calculated from the set value of the rotation angle of the first fork 40 when the first edge positions P2 and P3 are detected, and the set value of the rotation angle of the second fork 50 when the second edge positions P2' and P3' are detected. The following will be explained in detail with reference to Figure 10. Figure 10 is a diagram that superimposes the output history of the optical sensor 37 during the rotation of the first fork shown in Figure 8 and the output history of the optical sensor 37 during the rotation of the second fork shown in Figure 9.

[0058] The first fork 40 and the second fork 50 rotate based on the control signal output from the control device 70, which is a set value of the rotation angle. Therefore, if there is no angular misalignment, the set value of the rotation angle of the first fork 40 when the first edge position P2 is detected and the set value of the rotation angle of the second fork 50 when the second edge position P2' is detected will coincide at angle DEG1 as shown in Figure 10.

[0059] On the other hand, during the assembly process of the wafer transport mechanism 32 shown in Figure 1, assembly errors of each fork 40, 50 may occur. In this case, as shown in Figure 10, a discrepancy occurs between the detection timing of the first edge position P2 and the detection timing of the second edge position P2'. Specifically, for example, the first edge position P2 is detected when the set value of the rotation angle of the first fork 40 reaches angle DEG1, while the second edge position P2' is detected when the set value of the rotation angle of the second fork 50 reaches angle DEG2.

[0060] In other words, the second edge position P2' should be detected when the set value of the rotation angle becomes angle DEG1, assuming no angular misalignment occurs, but it is detected at DEG2. Therefore, even if a set value of angle DEG1 is assigned to the second fork 50, the actual rotation angle of the second fork 50 may be different from angle DEG1.

[0061] In that case, even if the same rotation angle setting is applied, the second fork 50 exhibits an angular difference of rotation angle θ relative to the first fork 40, as shown in Figure 11. In step S13, the rotation angle difference θ is calculated based on the difference between the angle DEG1 when the first edge position P2 of the first fork 40 is detected and the angle DEG2 when the second edge position P2' of the second fork 50 is detected.

[0062] Since the first fork 40 and the second fork 50 have the same external shape in plan view, it is possible to calculate the rotation angle difference θ from the information of the first edge position P2 of the first holding part 42 and the second edge position P2' of the second holding part 52 of one of the two. However, from the viewpoint of improving the accuracy of calculating the rotation angle difference θ, it is preferable to use the information of the first edge position P3 of the other first holding part 43 and the second edge position P3' of the other second holding part 53. This allows for the acquisition of multiple pieces of information on the first and second edge positions, thereby improving the accuracy of calculating the rotation angle difference θ.

[0063] In the teaching method by detecting angular misalignment according to this embodiment described above, the first edge position, which is the edge position of the first holding part 42, 43 on the non-wired side of the sensor cable 45, and the second edge position, which is the edge position of the second holding part 52, 53 on the same side as the non-wired side, are detected. The first edge position and the second edge position detected in this way can be said to be the side surface of the first holding part and the side surface of the second holding part. Therefore, by calculating the rotation angle difference θ between each fork 40, 50 based on these first edge position and second edge position, the second fork 50 can be detected relative to the first fork 40.

[0064] The rotation angle difference θ calculated using the method described above is used, for example, for teaching the second fork 50. Specifically, after teaching the first fork 40, when using that teaching information for teaching the second fork 50, the coordinate data of the second fork 50 is corrected by taking into account the rotation angle difference θ. This allows teaching to be performed while taking into account the angular deviation due to assembly errors of each fork 40 and 50, thereby improving teaching accuracy. This makes it possible to further improve the transport accuracy of substrates in a transport device having a fork 40 equipped with a sensor 44 at its tip, with the aim of expanding the automatic teaching function.

[0065] Furthermore, detection of fork angle deviations, correction of coordinate data, and teaching of each fork can all be performed automatically under the control device 70. Therefore, teaching of each fork can be performed without human intervention, making it possible to perform teaching in high-temperature environments similar to those during actual wafer processing. This allows teaching to be performed while taking into account the thermal expansion of components such as gears used in the transport mechanism, thereby improving teaching accuracy.

[0066] In steps S11 and S12 described above, the first fork 40 and the second fork 50 were rotated clockwise, but they may also be rotated counterclockwise. Furthermore, for example, the order of steps S11 and S12 may be reversed. Additionally, if the rotation angle difference θ calculated in step S25 exceeds a predetermined threshold (e.g., ±1°), the operation of the vacuum conveying device 30 may be stopped and a warning signal may be sent to the operator.

[0067] <Teaching Method 2> Next, we will describe another example of a teaching method that uses angular deviation detection. Figure 12 is a flowchart illustrating this method. Figure 13 is a schematic diagram showing the output history of the optical sensor during the first fork rotation in this teaching method.

[0068] (Step S20) First, as in step S10 described above, the first fork 40 and the second fork 50 are moved to the angle check position.

[0069] (Step S21) Next, similar to step S11 described above, the first fork 40 is rotated clockwise to detect the edge positions P1 to P4 of the first holding parts 42 and 43. This obtains the first edge positions P2 and P3, which are the edge positions on the non-wired side of the sensor cable.

[0070] (Step S22) Next, the first fork 40 is rotated counterclockwise. This moves the edge position P of the first holding parts 42 and 43. 11 ~P 14 The first edge position P is detected when the first fork 40 is rotated counterclockwise. 12 , P 13 Obtain it.

[0071] As a result of steps S21 and S22 described above, the information of the first edge position is obtained as follows: the first edge positions P2 and P3 when the first fork 40 is rotated clockwise, and the first edge position P when the first fork 40 is rotated counterclockwise. 12 , P 13 It can be detected.

[0072] Gears are used as components to rotate the first fork 40, but when switching the direction of rotation, the angle deviation may change due to the effect of gear backlash. Therefore, the first edge positions P2, P3, P when the first fork 40 is rotated in different directions. 12 , P 13 By detecting this, it becomes possible to detect angular deviations that take into account the effects of backlash.

[0073] (Step S23) Next, similar to step S12 described above, the second fork 50 is rotated clockwise to detect the edge positions of the second holding parts 52 and 53, and information on the second edge position, which is the same edge position as the non-wired side of the sensor cable, is obtained.

[0074] (Step S24) Next, the second fork 50 is rotated counterclockwise, and the second edge positions of the second holding parts 52 and 53 are detected at this time.

[0075] By steps S23 and S24 described above, the second edge position can be detected as information about the second edge position, specifically the second edge position when the second fork 50 is rotated clockwise and the second edge position when the second fork 50 is rotated counterclockwise.

[0076] (Step S25) Next, the rotation angle difference between forks 40 and 50 is calculated based on the first edge position and the second edge position detected by the method described above. The rotation angle difference calculated here takes into account the effect of gear backlash.

[0077] Therefore, the accuracy of detecting angular deviations is improved, and the teaching accuracy of each fork can also be further improved. In the example shown in Figure 12, each fork was rotated clockwise and then counterclockwise, but the rotation order may be reversed. Also, the order of steps S21 to S24 is not particularly limited, and the flow may proceed in the order of steps S21, S23, S22, and S24.

[0078] <Modification> The optical sensor used to detect the angular displacement may be the optical sensor 36a or optical sensor 36b of the position detection mechanism 36 shown in Figure 1. Each optical sensor 36a and 36b is installed in close proximity within the processing modules 60 to 63. Therefore, when the optical sensors 36a and 36b detect the first edge position and the second edge position, the state of the wafer transport mechanism 32 becomes close to the state in which the wafer W is transported into the processing modules 60 to 63.

[0079] Therefore, by using optical sensor 36a or optical sensor 36b, the angular deviation of the fork can be detected in a state similar to when the wafer W is being transported into the processing modules 60-63. This improves detection accuracy and also improves teaching accuracy.

[0080] Furthermore, when detecting angular deviation, both optical sensor 36a and optical sensor 36b may be used. This increases the number of edge positions detected as first edge positions and the number of edge positions detected as second edge positions, thereby improving detection accuracy.

[0081] Furthermore, when using the optical sensor 37 as the optical sensor for detecting angular misalignment, angular misalignment can be detected when the arms 34 and 35 of the wafer transport mechanism 32 are in their home position. This allows for the detection of angular misalignment while minimizing the influence of the posture of the arms 34 and 35.

[0082] In the above example, as shown in Figure 4, the sensor cable 45 was housed in the groove 46, but it may also be exposed and routed from the side surface 42a of the first holding portion 42, for example, as shown in Figure 14. In the example of Figure 14, the sensor cable 45 is fixed to the side surface 42a of the first holding portion 42 by an adhesive member 47 filled in the groove 46. Alternatively, for example, as shown in Figure 15, the sensor cable 45 may be routed to the bottom surface 42c of the first holding portion 42. In the example of Figure 15, since the fixing point of the sensor cable 45 is the bottom surface 42c near the side surface 42a, a part of the sensor cable 45 is located outside the side surface 42a.

[0083] In both wiring examples shown in Figure 14 and Figure 15, the edge position of the wiring side of the first holding portion 42 detected by the optical sensor is the outer shape of the sensor cable 45, and the outer side surface 42a in the width direction of the first holding portion 42 cannot be detected as an edge position. On the other hand, the edge position of the non-wiring side of the first holding portion 42 detected by the optical sensor is the inner side surface 42b in the width direction of the first holding portion 42. In other words, in both wiring examples shown in Figure 14 and Figure 15, angular misalignment can be detected by utilizing the information of the edge position on the non-wiring side of the sensor cable 45, similar to the teaching method using angular misalignment detection described above.

[0084] In the above example, the sensor cable 45 was routed on the outside in the width direction of the first holding part 42, but it may also be routed on the inside in the width direction. In this case, the routed side will be on the inside in the width direction, and the unrouted side will be on the outside in the width direction. Therefore, when detecting angular displacement, the edge positions on the outside in the width direction of the first and second holding parts can be obtained as the first edge position and the second edge position.

[0085] In other words, if the sensor cable 45 is wired to one side of the widthwise side of the first holding parts 42 and 43, and no such sensor cable is wired to the other side, the teaching method by detecting the angular displacement described above can be applied. However, when forming a groove 46 in the first holding part, it is easier to form the groove 46 on the outer side than on the inner side in the widthwise direction. For this reason, from the viewpoint of ease of processing the groove 46, it is preferable that the sensor cable 45 is wired on the outside in the widthwise direction of the first holding part.

[0086] In the above example, sensor cables are not wired to the second holding parts 52 and 53. However, sensor cables may be wired to the second holding parts 52 and 53 on the same side as the wired side of the first holding parts 42 and 43. Even in this case, if sensor cables are not wired to the same side of the second holding parts 52 and 53 as the unwired side of the first holding parts 42 and 43, the first edge position on the unwired side of the first holding parts 42 and 43 and the second edge position on the unwired side of the second holding parts 52 and 53 can be detected. Therefore, the teaching method by detecting the angular deviation described above can be applied.

[0087] Furthermore, the cables wired to the first holding parts 42 and 43, or the cables that can be wired to the second holding parts 52 and 53, may not be sensor cables, but rather cables used for other purposes.

[0088] The embodiments disclosed herein should be considered in all respects as illustrative and not restrictive. The embodiments described above may be omitted, replaced, or modified in various ways without departing from the scope of the appended claims, the examples of configurations within the technical scope of this disclosure described below, and the spirit thereof. For example, the constituent elements of the embodiments described above can be combined in any way. Such any combination will naturally yield the effects and benefits of each constituent element in the combination, as well as other effects and benefits that will be apparent to those skilled in the art from the description herein.

[0089] Furthermore, the effects described herein are merely descriptive or illustrative and not limiting. In other words, the technology relating to this disclosure may produce other effects that are obvious to those skilled in the art from the description herein, in addition to or instead of the effects described herein.

[0090] The following configuration examples also fall within the technical scope of this disclosure. (1) A transport device for transporting a substrate, comprising: a first holding part having a substrate mounting surface; a sensor provided at the tip of the first holding part; a cable connected to the sensor and attached only to one of the two sides in the width direction of the first holding part; and a rotating shaft extending in the vertical direction; a second holding part having a substrate mounting surface; and a rotating shaft coaxial with the first fork; a transport robot having the first fork and the second fork; a depressurized transport chamber housing the transport robot; an optical sensor provided in the transport chamber with its optical axis oriented in the vertical direction; and a control device, wherein the other side of the first holding part in the width direction to which the cable is not attached is the non-wired side. A transport device comprising: (1) the control device which rotates the first fork to detect a first edge position, which is the non-wiring side edge position of the first holding portion, with the optical sensor, rotates the second fork to detect a second edge position, which is the same side edge position as the non-wiring side of the second holding portion, with the optical sensor, and calculates the difference in rotation angle between the first fork and the second fork based on the first edge position and the second edge position. (2) The transport device according to (1), wherein a groove for which the cable is arranged is formed on the wiring side surface of the cable in the first holding portion. (3) The transport device according to (2), wherein the wiring side is the outside in the width direction of the first holding portion. (4) The transport device according to any one of (1) to (3), wherein the optical sensor is a sensor that detects whether or not the substrate is held in the first holding portion or the second holding portion at the home positions of the first fork and the second fork. (5) The transport device according to any one of (1) to (3), wherein the optical sensor is a sensor that detects a displacement of the substrate held in the first holding part or the second holding part from a predetermined position.(6) The conveying device according to any one of (1) to (5), wherein the control device detects the first edge position when the first fork is rotated clockwise and the first edge position when the first fork is rotated counterclockwise, and when the second edge position is detected, the control device detects the second edge position when the second fork is rotated clockwise and the second edge position when the second fork is rotated counterclockwise. (7) A teaching method for a transport device for transporting substrates, the transport device comprising: a first holding portion having a substrate mounting surface; a sensor provided at the tip of the first holding portion; a cable connected to the sensor and attached only to one of the two sides in the width direction of the first holding portion; a rotating shaft extending vertically; a second holding portion having a substrate mounting surface; a second fork having a rotating shaft coaxial with the first fork; a transport robot having the first fork and the second fork; a depressurized transport chamber housing the transport robot; an optical sensor provided in the transport chamber with its optical axis oriented vertically; and a control device, wherein when the other side of the first holding portion in the width direction to which the cable is not attached is considered the non-wiring side, the first fork is rotated and the first edge position, which is the non-wiring side edge position of the first holding portion, is detected by the optical sensor; A teaching method comprising the steps of: rotating the second fork and detecting with the optical sensor a second edge position which is the same side edge position as the non-wired side of the second holding portion; and calculating the difference in rotation angle between the first fork and the second fork based on the first edge position and the second edge position. (8) The teaching method according to (7), wherein a groove for accommodating the cable is formed on the wiring side of the first holding portion. (9) The teaching method according to (8), wherein the wiring side is the outside in the width direction of the first holding portion. (10) The teaching method according to any one of (7) to (9), wherein the optical sensor is a sensor that detects whether or not the substrate is held in the first holding portion or the second holding portion at the home positions of the first fork and the second fork.(11) The teaching method according to any one of (7) to (9), wherein the optical sensor is a sensor that detects a positional deviation of the substrate held in the first holding part or the second holding part from a predetermined position. (12) The teaching method according to any one of (7) to (11), wherein in the step of detecting the first edge position, the first edge position when the first fork is rotated clockwise and the first edge position when the first fork is rotated counterclockwise are detected, and in the step of detecting the second edge position, the second edge position when the second fork is rotated clockwise and the second edge position when the second fork is rotated counterclockwise are detected.

[0091] 30 Vacuum transfer device 31 Vacuum transfer chamber 32 Wafer transfer mechanism (transfer robot) 36a, 36b Optical sensor 37 Optical sensor 40 First fork 41 First arm 42, 43 First holding part 44 Sensor 45 Sensor cable 50 Second fork 51 Second arm 52, 53 Second holding part 70 Control device W Wafer

Claims

1. A transport device for transporting substrates, comprising: a first holding part having a substrate mounting surface; a sensor provided at the tip of the first holding part; a cable connected to the sensor and attached only to one of the two sides in the width direction of the first holding part; a first fork having a vertically extending rotating shaft; a second holding part having a substrate mounting surface; a second fork having a rotating shaft coaxial with the first fork; a transport robot having the first fork and the second fork; a depressurized transport chamber housing the transport robot; an optical sensor provided in the transport chamber with its optical axis oriented vertically; and a control device, wherein the other side of the first holding part in the width direction to which the cable is not attached is the non-wired side. The control device rotates the first fork to detect a first edge position, which is the non-wiring side edge position in the first holding portion, using the optical sensor; rotates the second fork to detect a second edge position, which is the same side edge position as the non-wiring side in the second holding portion, using the optical sensor; and calculates the difference in rotation angle between the first fork and the second fork based on the first edge position and the second edge position, as a conveying device.

2. The conveying device according to claim 1, wherein a groove for the cable to be placed is formed on the wiring side of the first holding portion.

3. The conveying device according to claim 2, wherein the wiring side is on the outside in the width direction of the first holding portion.

4. The transport device according to any one of claims 1 to 3, wherein the optical sensor is a sensor that detects whether or not the substrate is held in the first holding part or the second holding part at the home position of the first fork and the second fork.

5. The transport device according to any one of claims 1 to 3, wherein the optical sensor is a sensor that detects a positional displacement of the substrate held in the first holding part or the second holding part from a predetermined position.

6. The conveying device according to any one of claims 1 to 3, wherein the control device detects the first edge position when the first fork is rotated clockwise and the first edge position when the first fork is rotated counterclockwise, and when detecting the second edge position, it detects the second edge position when the second fork is rotated clockwise and the second edge position when the second fork is rotated counterclockwise.

7. A teaching method for a transport device for transporting substrates, the transport device comprising: a first holding portion having a substrate mounting surface; a sensor provided at the tip of the first holding portion; a cable connected to the sensor and attached only to one of the two sides in the width direction of the first holding portion; a rotating shaft extending vertically; a second holding portion having a substrate mounting surface; a second fork having a rotating shaft coaxial with the first fork; a transport robot having the first fork and the second fork; a depressurized transport chamber housing the transport robot; an optical sensor provided in the transport chamber with its optical axis oriented vertically; and a control device, wherein when the other side of the first holding portion in the width direction to which the cable is not attached is considered the non-wiring side, the first fork is rotated and the first edge position, which is the non-wiring side edge position of the first holding portion, is detected by the optical sensor; A teaching method comprising the steps of: rotating the second fork and detecting the second edge position, which is the same side edge position as the non-wired side of the second holding portion, with the optical sensor; and calculating the difference in rotation angle between the first fork and the second fork based on the first edge position and the second edge position.

8. The teaching method according to claim 7, wherein a groove for accommodating the cable is formed on the wiring side of the first holding portion.

9. The teaching method according to claim 8, wherein the wiring side is on the outside in the width direction of the first holding portion.

10. The teaching method according to any one of claims 7 to 9, wherein the optical sensor is a sensor that detects whether or not the substrate is held in the first holding part or the second holding part at the home position of the first fork and the second fork.

11. The teaching method according to any one of claims 7 to 9, wherein the optical sensor is a sensor that detects a positional deviation of the substrate held by the first holding portion or the second holding portion from a predetermined position.

12. The teaching method according to any one of claims 7 to 9, wherein in the step of detecting the first edge position, the first edge position when the first fork is rotated clockwise and the first edge position when the first fork is rotated counterclockwise are detected, and in the step of detecting the second edge position, the second edge position when the second fork is rotated clockwise and the second edge position when the second fork is rotated counterclockwise are detected.

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