Conveyance system

Abstract

This conveyance system comprises a conveyance vehicle that conveys articles with respect to a passive apparatus and that has a communication unit which communicates wirelessly with the passive apparatus. The conveyance vehicle has a counter that generates a counter value according to the amount of time passed since a time at which reception became impossible due to a communication failure during wireless communication with the passive apparatus, and an output unit that outputs the counter value when a time-out malfunction has occurred in the conveyance vehicle. When reception is possible, the counter perpetually resets the counter value.

Description

Transport System

[0001] The present disclosure relates to a transport system.

[0002] Semiconductor manufacturing plants and the like use conveyance systems that include conveyance devices for automatically conveying workpieces to semiconductor manufacturing equipment. In such conveyance systems, signals are exchanged between the conveyance device that conveys the workpieces and the semiconductor manufacturing equipment. If this signal exchange is not performed normally for a predetermined period of time, a timeout error occurs. For example, Patent Document 1 listed below discloses a communication device connected to manufacturing equipment that can accumulate data for analyzing the cause of an error. In this communication device, time data including the time when a predetermined packet data received by a communication unit was transmitted and the time when a predetermined port state was detected by an IO monitor unit is accumulated in a memory unit. This time data is used to determine whether or not correction of conveyance control is necessary.

[0003] JP 2016-118845 A

[0004] When a timeout abnormality occurs in the signal exchange between a transport device that transports workpieces and a semiconductor manufacturing device or the like, it is difficult to determine, using only the time data as disclosed in Patent Document 1, whether the cause of the timeout abnormality is the communication environment or the transmission of signals by the semiconductor manufacturing device or the like.

[0005] An object according to one aspect of the present disclosure is to provide a transport system that can assist in determining the cause of a timeout abnormality.

[0006] A conveying system according to one aspect of the present disclosure is a conveying system including a conveying vehicle that conveys items to a passive device and has a communication unit that communicates wirelessly with the passive device, wherein the conveying vehicle has a counter that generates a counter value corresponding to the elapsed time from the time when reception became impossible due to a communication failure during wireless communication with the passive device, and an output unit that outputs the counter value when a timeout abnormality occurs in the conveying vehicle, and the counter always resets the counter value when reception is possible.

[0007] In a conveyance system according to one aspect of the present disclosure, an operator can estimate whether the cause of a timeout abnormality is a communication abnormality or an abnormality in a passive device simply by checking the counter value output from the output unit (i.e., checking whether the counter value has been reset). If the counter value is 0 when a timeout abnormality occurs in a transport vehicle, the operator can determine that wireless communication was occurring normally, and can therefore estimate that the cause of the timeout abnormality is the passive device. On the other hand, if a counter value above a certain level is output when a timeout abnormality occurs in a transport vehicle, the operator can determine that wireless communication has not occurred for a certain period of time. Therefore, the operator can estimate that the cause of the timeout abnormality is a communication failure. A conveyance system capable of generating and outputting such counter values ​​can assist in determining the cause of a timeout abnormality.

[0008] The wireless communication between the transport vehicle and the passive device is wireless communication using the E84 signal specified in the international standard for semiconductor manufacturing equipment, and the output unit may output the counter value only when a timeout abnormality occurs due to the E84 signal. In this case, it is possible to prevent the generation and output of counter values ​​during unnecessary periods. This ensures that counter values ​​useful for determining the cause of the timeout abnormality can be output.

[0009] According to one aspect of the present disclosure, it is possible to provide a transport system that can assist in determining the cause of a timeout abnormality.

[0010] FIG. 1 is a plan view of a transport system according to an embodiment. FIG. 2 is a front view of a portion of the transport system. FIG. 3 is a schematic diagram showing communication between an overhead transport vehicle and a semiconductor processing apparatus. FIGS. 4A and 4B are timing charts for explaining a normal example of wireless communication between an overhead transport vehicle and a semiconductor processing apparatus. FIGS. 5A and 5B are timing charts for explaining a normal example of wireless communication between an overhead transport vehicle and a semiconductor processing apparatus. FIGS. 6A and 6B are timing charts for explaining an abnormal example of wireless communication between an overhead transport vehicle and a semiconductor processing apparatus. FIGS. 7A and 7B are timing charts for explaining an abnormal example of wireless communication between an overhead transport vehicle and a semiconductor processing apparatus.

[0011] Hereinafter, an embodiment according to one aspect of the present disclosure will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same or equivalent elements are designated by the same reference numerals, and duplicated explanations will be omitted.

[0012] First, a transfer system according to this embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a plan view of the transfer system according to this embodiment. FIG. 2 is a front view of a portion of the transfer system. As shown in FIG. 1, the transfer system 1 is installed in, for example, a semiconductor manufacturing plant equipped with a semiconductor processing apparatus 100, which is a type of passive equipment, and is a system for transferring an object such as a FOUP (front opening unified pod) 200. The FOUP 200 is a container (FOUP: Front Opening Unified Pod) that stores semiconductor wafers. The semiconductor processing apparatus 100 is a processing apparatus for the semiconductor wafers (e.g., a cleaning apparatus, an etching apparatus, a film forming apparatus, etc.) and includes an equipment port 110 for loading and unloading the FOUP 200.

[0013] As shown in FIGS. 1 and 2 , the transport system 1 includes a first track 10, a second track 20, a storage shelf 30, and a plurality of overhead transport vehicles 40 (transport vehicles). In the transport system 1, for example, a FOUP 200 is transferred to an equipment port 110 of a semiconductor processing equipment 100 by the overhead transport vehicle 40 moving along the first track 10 or the second track 20. Although not shown, the transport system 1 further includes, for example, a HOST and an MCS (Material Control System) as control devices. Each of the HOST and the MCS is an electronic control unit configured, for example, with a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc. The HOST is a higher-level controller. The HOST may be a MES (Manufacturing Execution System). The HOST outputs signals including various commands, such as transport commands and travel commands (hereinafter simply referred to as "commands") to the MCS. When the MCS receives a command from the HOST, it outputs the command to the overhead transport vehicle 40 or the like at a predetermined timing via the transport vehicle controller.

[0014] The first track 10 is a member (traveling path) along which the overhead transport vehicle 40 travels, and is suspended from the ceiling. In this embodiment, the transport system 1 comprises multiple systems (bays). The transport system 1 includes multiple intra-bay routes, which are traveling paths within the bays, and inter-bay routes, which are traveling paths connecting different bays. The intra-bay routes are arranged along multiple equipment ports 110. The first track 10 includes intra-bay tracks 11 arranged along the multiple intra-bay routes and inter-bay tracks 12 arranged along the inter-bay routes. The intra-bay tracks 11 are tracks that pass near the storage shelves 30, semiconductor processing equipment 100, etc., and are configured so that the overhead transport vehicle 40 travels in a one-way clockwise direction. Like the intra-bay tracks 11, the inter-bay tracks 12 are also configured so that the overhead transport vehicle 40 travels in a one-way clockwise direction. Note that the first track 10 may also be configured so that the overhead transport vehicle 40 travels in a one-way counterclockwise direction.

[0015] The second track 20 is a member (traveling path) along which the overhead transport vehicle 40 travels, and is suspended from the ceiling. The second track 20 includes an intrabay track 21 located in a portion of the multiple intrabay routes, and an interbay track 22 located in the interbay route. The intrabay track 21 is a track that passes near the storage shelves 30, semiconductor processing equipment 100, etc., and is set up so that the overhead transport vehicle 40 travels in a one-way clockwise direction. Like the intrabay track 21, the interbay track 22 is also set up so that the overhead transport vehicle 40 travels in a one-way clockwise direction. Note that the second track 20 may also be set up so that the overhead transport vehicle 40 travels in a one-way counterclockwise direction.

[0016] As shown in Fig. 2, the first track 10 and the second track 20 are arranged side by side in the up-down (vertical) direction. The first track 10 is located below the second track 20. In other words, the second track 20 is located above the first track 10. In Fig. 1, the first track 10 is indicated by a dashed line, and the second track 20 is indicated by a solid line.

[0017] 1, in the transport system 1, the equipment ports 110 of each semiconductor processing equipment 100 are arranged outside the intra-bay route along the direction in which the first track 10 and the second track 20 extend. Each equipment port 110 is provided so as to be located below and to one side of the first track 10 and the second track 20 that are arranged side by side one above the other.

[0018] The FOUPs 200 transferred from the ceiling transport vehicle 40 are placed on the plurality of equipment ports 110, and the FOUPs 200 are transferred to the semiconductor processing equipment 100. Furthermore, when the semiconductor wafers stored in the FOUPs 200 are processed in the semiconductor processing equipment 100, the plurality of equipment ports 110 transfer the FOUPs 200 from the semiconductor processing equipment 100, and the FOUPs 200 are placed on the plurality of equipment ports 110.

[0019] The storage shelf 30 is a component that stores the FOUP 200. A plurality of storage shelves 30 support the FOUP 200. The storage shelves 30 are, for example, suspended from the ceiling. The storage shelves 30 may be an OHB (Overhead Buffer). The FOUP 200 can be placed in an area above the storage shelf 30. This area of ​​the storage shelf 30 is a temporary storage area where the ceiling guided vehicle 40 stopped on the first track 10 and the second track 20 can transfer the FOUP 200.

[0020] 2, the multiple storage shelves 30 are provided on the side and below the first track 10 and the second track 20, opposite the side on which the multiple equipment ports 110 are provided. In other words, when viewed vertically, the multiple storage shelves 30 are provided on the side opposite the multiple equipment ports 110 via the first track 10 and the second track 20. The storage shelves 30 are provided inside the loop-shaped intra-bay route.

[0021] The overhead transport vehicle 40 is a device that transports the FOUP 200 in an area where it may interfere with passive equipment such as the storage shelf 30 and the semiconductor processing equipment 100, and moves along the first track 10 or the second track 20. The overhead transport vehicle 40 includes, for example, a ceiling-suspended crane, an OHT (Overhead Hoist Transfer), etc. The overhead transport vehicle 40 has a gripping unit 41, a lifting mechanism 42, a moving mechanism 43, a controller 44, and a communication unit 45.

[0022] The gripping unit 41 is a device that grips and releases the FOUP 200. The gripping unit 41 is capable of gripping the flange portion 210 of the FOUP 200. The gripping unit 41 grips the flange portion 210 of the FOUP 200 when the ceiling transport vehicle 40 acquires the FOUP 200 from the equipment port 110 or the storage shelf 30. The gripping unit 41 releases the flange portion 210 of the FOUP 200 when the ceiling transport vehicle 40 places the FOUP 200 on the equipment port 110 or the storage shelf 30.

[0023] The lifting mechanism 42 is a device (such as a hoist) that raises and lowers the gripping unit 41 in the vertical direction. The lifting mechanism 42 is capable of raising and lowering the gripping unit 41 in the vertical direction. The lifting mechanism 42 has a hoisting mechanism 42a and a belt 42b. The hoisting mechanism 42a is held by the moving mechanism 43. The hoisting mechanism 42a is a device that vertically hoists and lowers the belt 42b. The hoisting mechanism 42a is capable of vertically hoisting and lowering the belt 42b. The belt 42b hangs down from the hoisting mechanism 42a. The belt 42b holds the gripping unit 41 at its lower end. The lifting mechanism 42 is capable of hoisting and lowering the FOUP 200 gripped by the gripping unit 41 a distance sufficient to at least reach the equipment port 110 and the storage shelf 30.

[0024] The moving mechanism 43 is a device that moves the gripping unit 41 and the lifting mechanism 42 along the side of the ceiling transport vehicle. That is, the moving mechanism 43 can move the gripping unit 41 and the lifting mechanism 42 from the ceiling transport vehicle 40 in a horizontal direction perpendicular to the traveling direction of the ceiling transport vehicle 40. The moving mechanism 43 can move the gripping unit 41 and the lifting mechanism 42 above the equipment port 110 and the storage shelf 30, respectively. When a FOUP 200 is gripped by the gripping unit 41, the moving mechanism 43 can move the FOUP 200 vertically above the equipment port 110 and the storage shelf 30.

[0025] Each of the multiple overhead transport vehicles 40 stopped at the same position in the traveling direction on each of the first track 10 and the second track 20 can transfer a FOUP 200 to both the equipment port 110 and the storage shelf 30 located to the side of and below the first track 10 and the second track 20. In other words, each overhead transport vehicle 40 can transfer a FOUP 200 to the same equipment port 110 and the same storage shelf 30. That is, both the overhead transport vehicle 40 on the first track 10 and the overhead transport vehicle 40 on the second track 20 can transfer (transfer) the FOUP 200 to and from the equipment port 110. Furthermore, both the overhead transport vehicle 40 on the first track 10 and the overhead transport vehicle 40 on the second track 20 can transfer the FOUP 200 to and from the storage shelf 30.

[0026] The ceiling transport vehicle 40, with the gripping section 41 gripping the flange section 210 of the FOUP 200 directly below the first track 10 and the second track 20, operates the movement mechanism 43 to move the FOUP 200 above the equipment port 110 and the storage shelf 30. Next, the ceiling transport vehicle 40 operates the hoisting mechanism 42a to lower the belt 42b, thereby lowering the FOUP 200 and placing it on the equipment port 110 or the storage shelf 30. In this way, the ceiling transport vehicle 40 transfers (places) the FOUP 200 to the equipment port 110 or the storage shelf 30.

[0027] Furthermore, the ceiling transport vehicle 40 uses the gripping portion 41 to grip the flange portion 210 of the FOUP 200 placed on the equipment port 110 or the storage shelf 30. Next, the ceiling transport vehicle 40 operates the hoisting mechanism 42a to hoist the belt 42b and raise the FOUP 200. Next, the ceiling transport vehicle 40 operates the moving mechanism 43 to move the FOUP 200 to directly below the first track 10 and the second track 20. In this manner, the ceiling transport vehicle 40 transfers (obtains) the FOUP 200 from the equipment port 110 or the storage shelf 30.

[0028] The controller 44 is a device that controls the operation of the overhead transport vehicle 40. The controller 44 is an electronic control unit that is configured, for example, with a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc. The controller 44 communicates with the target semiconductor processing apparatus 100 in response to commands from the control device, and controls the travel of the overhead transport vehicle 40, the operation of the gripper 41, the operation of the lifting mechanism 42, the operation of the moving mechanism 43, etc.

[0029] The communication unit 45 is a device capable of communicating with the control device, the semiconductor processing apparatus 100, etc., and is disposed at a predetermined position on the ceiling transport vehicle 40. FIG. 3 is a schematic diagram showing communication between the ceiling transport vehicle and the semiconductor processing apparatus. As shown in FIG. 3, the semiconductor processing apparatus 100 has a communication unit 101 capable of communicating with the transport system 1, and a controller 102 connected to the communication unit 101. The controller 44 and the communication unit 45 transmit and receive data to and from each other. Similarly, the communication unit 101 and the controller 102 also transmit and receive data to and from each other.

[0030] The communication unit 45 transmits and receives signals to and from the semiconductor processing apparatus 100 via wireless communication. In this embodiment, the communication unit 45 of the ceiling transport vehicle 40 and the communication unit 101 of the semiconductor processing apparatus 100 communicate wirelessly with each other. The wireless communication between the ceiling transport vehicle 40 and the semiconductor processing apparatus 100 is, for example, transmission and reception of wireless signals performed when transferring the FOUP 200. Transfer of the FOUP 200 includes both transferring the FOUP 200 from the ceiling transport vehicle 40 to the semiconductor processing apparatus 100 and transferring the FOUP 200 from the semiconductor processing apparatus 100 to the ceiling transport vehicle 40. During wireless communication between the ceiling transport vehicle 40 and the semiconductor processing apparatus 100, the wireless signal transmitted and received by the communication units 45 and 101 is, for example, an interlock signal for restricting the operation of the semiconductor processing apparatus 100 (particularly, the operation of the equipment port 110). The interlock signal is, for example, a signal (E84 signal) exchanged in accordance with the procedure defined in E84 of the Semiconductor Equipment and Materials International Standards (SEMI Standards) for semiconductor manufacturing equipment. Normal transmission and reception of the E84 signal between the ceiling transport vehicle 40 and the semiconductor processing equipment 100 can prevent interference (contact, collision, etc.) between the gripper 41, the lifting mechanism 42, etc. of the ceiling transport vehicle 40 and the semiconductor processing equipment 100 at unintended locations. The wireless communication between the ceiling transport vehicle 40 and the semiconductor processing equipment 100 is, for example, ANT communication using frequencies in the 2.4 GHz band or the 5.8 GHz band, but is not limited thereto.

[0031] According to the procedure defined in E84 described above, the signal transmitted from the semiconductor processing apparatus 100 to the ceiling transport vehicle 40 changes, and the ceiling transport vehicle 40 receives the changed signal via the communication unit 45. Hereinafter, the signal transmitted from the semiconductor processing apparatus 100 to the ceiling transport vehicle 40 will be referred to as an output signal, and the signal input from the semiconductor processing apparatus 100 to the ceiling transport vehicle 40 will be referred to as an input signal. Furthermore, the communication units 101 and 45 constantly transmit and receive the strength of the received signal to each other in addition to the E84 signal. The received signal strength is an indicator that can be used to check the state of the communication environment.

[0032] If the input signal input to the ceiling transport vehicle 40 does not change over a predetermined period (timeout determination period), the controller 44 determines that a timeout abnormality has occurred. A timeout abnormality occurs, for example, due to a communication abnormality, an equipment abnormality, or the like. A communication abnormality occurs, for example, due to a communication failure (an abnormality in the communication environment) caused by interference from signals generated by other devices. When a communication abnormality occurs, the received signal strength is considered to be 0. An equipment abnormality occurs, for example, due to a malfunction of the semiconductor processing equipment 100. When a timeout abnormality occurs, operation between the ceiling transport vehicle 40 and the semiconductor processing equipment 100 (e.g., the transfer operation of the FOUP 200) stops. Note that, hereinafter, a state in which no communication abnormality occurs during E84 communication between the ceiling transport vehicle 40 and the semiconductor processing equipment 100 may be referred to as a "normal communication state."

[0033] 3, the ceiling transport vehicle 40 has a counter 46 and an output unit 47 in addition to the controller 44 and the communication unit 45. The counter 46 and the output unit 47 may be part of the controller 44.

[0034] The counter 46 starts counting (generating a counter value) when a communication abnormality occurs during wireless communication between the ceiling transport vehicle 40 and the semiconductor processing apparatus 100. In this embodiment, the counter value corresponds to a value counted according to elapsed time. The counter value may be any value that changes according to the elapsed time in accordance with a predetermined rule. In this embodiment, the counter value is the elapsed time itself. The counter 46 resets the counter value when the communication abnormality is resolved after the counter value is generated (i.e., when the received signal strength indicates a value other than 0). This allows the counter value to indicate the period of the most recent communication abnormality. In addition, the operator can easily identify the time when the communication abnormality occurred from the output counter value. Note that the counter 46 always resets the counter value when reception is possible (e.g., when communication is normal and the ceiling transport vehicle 40 can receive wireless signals from the semiconductor processing apparatus 100).

[0035] When a timeout abnormality occurs, the output unit 47 outputs the counter value generated by the counter 46 to the controller 44, etc. In this embodiment, a timeout abnormality is defined as a state in which the ceiling transport vehicle 40 is unable to recognize a change in the output signal of the semiconductor processing apparatus 100 within a predetermined period of time. A state in which the ceiling transport vehicle 40 is unable to recognize a change in the output signal of the semiconductor processing apparatus 100 corresponds to a state in which the input signal has not changed. The output unit 47 outputs the counter value only when a timeout abnormality occurs. As a result, for example, when the ceiling transport vehicle 40 and the semiconductor processing apparatus 100 are not exchanging E84 signals, the output unit 47 will not output the counter value even if a counter value has been generated.

[0036] Next, with reference to (a) and (b) of Figure 4 and (a) and (b) of Figure 5, an example (normal example) when wireless communication between the ceiling transport vehicle 40 and the semiconductor processing apparatus 100 is normal will be described. (a) and (b) of Figure 4 and (a) and (b) of Figure 5 are timing charts for explaining a normal example of wireless communication between the ceiling transport vehicle 40 and the semiconductor processing apparatus 100. In (a) and (b) of Figure 4 and (a) and (b) of Figure 5, timing T0 indicates the start timing of the timeout determination period, timing T1 indicates the end timing of the timeout determination period, and timings Ts and Ts １ , Ts ２ Each of the arrows indicates the timing at which a communication abnormality occurs, timing Te indicates the timing at which the communication abnormality ends, the dashed arrow indicates a normal communication state, and the area surrounded by the dashed line indicates a communication abnormality state. In each of FIGS. 4A and 4B and 5A and 5B, the initial value of the output signal is value PL, and the initial value of the input signal is value CL. The value PL of the output signal changes to value PH at timing Tp between timing T0 and timing T1. This change from value PL to value PH is made, for example, by the controller 102 of the semiconductor processing apparatus 100. Furthermore, the change from value CL of the input signal to value CH is made by receiving an output signal with value PH. Therefore, the overhead transport vehicle 40 does not update the input signal unless it receives an output signal with value PH.

[0037] 4A, wireless communication between the ceiling transport vehicle 40 and the semiconductor processing apparatus 100 is performed normally throughout the timeout determination period. In this case, at timing Tp, the input signal changes normally from value CL to value CH in response to the output signal changing from value PL to value PH. In this case, the controller 44 determines that a timeout abnormality has not occurred.

[0038] In the second normal example shown in FIG. 4B, a normal communication state continues at least from timing T0 to timing Tp. Furthermore, a communication abnormality occurs after timing Tp but before timing T1. In this case, as in the first normal example, the input signal changes from value CL to value CH in response to the change in the output signal from value PL to value PH, and the input signal changes to normal. Then, as in the first normal example, the controller 44 determines that a timeout abnormality has not occurred. Note that the counter 46 generates a counter value from timing Ts, which is after timing Tp. However, in the second normal example, it is determined that a timeout abnormality has not occurred, and therefore the output unit 47 does not output the counter value. Note that the counter 46 may continue counting even after timing T1 has passed while the communication abnormality continues.

[0039] In the third normal example shown in FIG. 5A, a communication abnormality occurs between timing T0 and timing Tp. This communication abnormality continues until timing Te, which is between timing Tp and timing T0. In addition, a normal communication state continues from timing Te to timing T1. In this case, the input signal does not change from timing Tp to timing Te. However, in the normal communication state after timing Te, an output signal indicating the value PH is received by the ceiling transport vehicle 40, causing the input signal to change to normal. Then, as in the first and second normal examples, the controller 44 determines that a timeout abnormality has not occurred. Note that a counter value is generated by the counter 46 between timing Tp and timing Te, but the counter value is reset at timing Te. The counter value may be reset between timing Te and timing T1. The same applies to the following examples.

[0040] In the fourth normal example shown in FIG. 5B, similarly to the third normal example, the timing Ts between the timing T0 and the timing Tp １ The communication abnormality state occurs from the timing Tp to the timing T0. The communication abnormality state continues until the timing Te between the timing Tp and the timing T0.２ Another communication abnormality occurs from timing T1 to timing T2. In this case, as in the third normal case, the input signal is not updated at timing Tp. However, between timing Te and timing Ts ２ In a normal communication state between the controller 40 and the control unit 41, an output signal indicating the value PH is received by the ceiling transport vehicle 40. This causes the input signal to change to normal. As in the first to third normal cases, the controller 44 determines that no timeout abnormality has occurred. １ The counter value is generated by the counter 46 from the timing Ts to the timing Te, but the counter value is reset at the timing Te. ２ However, in the fourth normal case, it is determined that no timeout abnormality occurs, so no new counter value is output. The counter 46 generates a new counter value at timing Ts ２ This may continue until the communication error that occurred is resolved.

[0041] Next, with reference to (a) and (b) of Figure 6 and (a) and (b) of Figure 7, an example (abnormal example) when normal wireless communication cannot be performed between the ceiling transport vehicle 40 and the semiconductor processing equipment 100 will be described. (a) and (b) of Figure 6 and (a) and (b) of Figure 7 are timing charts for explaining an abnormal example of wireless communication between the ceiling transport vehicle 40 and the semiconductor processing equipment 100.

[0042] In the first abnormality example shown in (a) of Figure 6, wireless communication between the ceiling transport vehicle 40 and the semiconductor processing apparatus 100 is performed normally throughout the entire timeout determination period. Therefore, the counter value of the counter 46 does not change from 0. Meanwhile, the value of the output signal remains PL from timing T0 to timing T1. Therefore, the input signal does not indicate the value CH by timing T1, and the controller 44 determines that a timeout abnormality has occurred. In this case, the output unit 47 outputs a counter value of 0. The controller 44 outputs the counter value as log information, for example.

[0043] In the second abnormality example shown in FIG. 6B, a communication abnormality occurs throughout the entire timeout determination period. The counter 46 generates a counter value from the time when reception ceases until reception resumes. Meanwhile, the value of the output signal changes to value PH at timing Tp, but the value of the input signal remains at value CL from timing T0 to timing T1. Therefore, as in the first abnormality example, the controller 44 determines that a timeout abnormality has occurred. In this case, the output unit 47 outputs the counter value at timing T1. Note that the minimum counter value assumed in the second abnormality example corresponds to the elapsed time from timing T0 to timing T1. If a communication abnormality occurs before timing T0, the counter value is greater than the elapsed time from timing T0 to timing T1. Even if both a device abnormality and a communication abnormality occur, counter value generation begins from the time when the communication abnormality occurs.

[0044] In the third abnormality example shown in FIG. 7A, a communication abnormality state continues from before timing Tp to timing T1. In this case, the counter 46 generates a counter value from timing Ts between timing T0 and timing Tp. Meanwhile, as in the first and second abnormality examples, the value of the input signal remains at value CL from timing T0 to timing T1. Therefore, as in the first and second abnormality examples, the controller 44 determines that a timeout abnormality has occurred. In this case, the output unit 47 outputs the counter value at timing T1. The counter value output in the third abnormality example corresponds to the elapsed time from timing Ts to timing T1. Note that even if a device abnormality occurs after timing Ts, the output counter value corresponds to the elapsed time from the time when the communication abnormality occurred (timing Ts) to timing T1.

[0045] In the fourth abnormality example shown in FIG. 7B, a plurality of communication abnormalities occur intermittently between timing T0 and timing T1. １ The first communication abnormality state continues from time Te to time Ts ２The second communication abnormality state continues from timing T1 to timing T2. In this case, the counter value generated by the counter 46 in the first communication abnormality state is reset at timing Te. ２ A new counter value is generated from the counter value Ts. On the other hand, the value of the input signal remains at the value CL from timing T0 to timing T1, as in the first to third abnormal cases. Therefore, as in the first to third abnormal cases, the controller 44 determines that a timeout abnormality has occurred. In this case, the output unit 47 outputs the new counter value at timing T1. The counter value output in the fourth abnormal case is, for example, the value CL from timing Ts ２ This corresponds to the elapsed time from timing T1 to timing T2.

[0046] The counter value output when a timeout abnormality occurs in each abnormality example can be used as an index for estimating the cause of the timeout abnormality. For example, if the counter value output by the output unit 47 is 0 (i.e., in the case of the first abnormality example), the worker can easily understand that there is no problem with the communication environment between the ceiling transport vehicle 40 and the semiconductor processing equipment 100. This allows the worker to estimate that the timeout abnormality occurred due to an equipment abnormality.

[0047] If the counter value output by the output unit 47 is other than 0 (i.e., in the cases of the second to fourth abnormality examples), the operator can estimate the cause of the timeout abnormality by checking the output counter value. For example, by checking the output counter value, the operator can easily estimate whether a normal communication state existed between timing T0 and timing T1. Based on this estimation, the operator can estimate whether the cause or main factor of the timeout abnormality in each of the second to fourth abnormality examples is a communication abnormality or a device abnormality.

[0048] Specifically, when a timeout abnormality occurs, the worker can grasp the length of the timeout determination period (from timing T0 to timing T1), the output counter value, and the signal state (values ​​CL and CH) of the ceiling transport vehicle 40 at the time of the timeout abnormality. Although timing Tp is illustrated in Figures 6 and 7 for convenience, the worker cannot grasp timing Tp. When the output counter value is 0 (first abnormality example), the worker can infer that no communication abnormality occurred and that an apparatus abnormality occurred. When the output counter value is equal to or greater than the timeout determination period (second abnormality example), the worker can infer that the communication abnormality occurred throughout the timeout determination period or that the communication abnormality occurred before the timeout determination began. In this case, it is possible that an apparatus abnormality also occurred while the communication abnormality was occurring. When the output counter value is smaller than the timeout determination period (third abnormality example, fourth abnormality example), the magnitude of the output counter value indicates the length of the period during which the communication abnormality occurred, and the degree of the possibility of an apparatus abnormality can be estimated.

[0049] In the conveyance system 1 according to the present embodiment described above, an operator can estimate whether the cause of the timeout abnormality is a communication abnormality or an abnormality in the semiconductor processing apparatus 100, simply by checking the counter value output from the output unit 47. Therefore, the conveyance system 1 can assist in determining the cause of the timeout abnormality.

[0050] In this embodiment, the wireless communication between the ceiling transport vehicle 40 and the semiconductor processing equipment 100 is wireless communication using the E84 signal defined in the international standard for semiconductor manufacturing equipment, and the output unit 47 may output a counter value only when a timeout abnormality occurs in the E84 signal. In this case, it is possible to prevent the generation and output of counter values ​​during unnecessary periods. This ensures that a counter value useful for determining the cause of the timeout abnormality can be output.

[0051] As described above, a conveying system according to one aspect of the present disclosure is as described in the following [1] to [6], and has been described in detail based on the above embodiments. [1] A conveying system including a conveying vehicle that conveys an article to a passive device and has a communication unit that wirelessly communicates with the passive device, wherein the conveying vehicle has: a counter that generates a counter value corresponding to the elapsed time since reception became impossible due to a communication failure during wireless communication with the passive device; and an output unit that outputs the counter value when a timeout abnormality occurs in the conveying vehicle, and the counter always resets the counter value when reception is possible. [2] The conveying system described in [1], wherein the wireless communication between the conveying vehicle and the passive device is wireless communication using an E84 signal specified in an international standard for semiconductor manufacturing equipment, and the output unit outputs the counter value only when a timeout abnormality occurs due to the E84 signal. [3] The conveying system described in [1] or [2], wherein the counter value is the elapsed time itself. [4] The transport system according to any one of [1] to [3], wherein the timing corresponds to a timing when a communication abnormality occurs between the transport vehicle and the passive device. [5] The transport system according to any one of [1] to [4], wherein the timeout abnormality occurs when the transport vehicle fails to recognize a change in the output signal of the passive device within a predetermined period. [6] The transport system according to any one of [1] to [5], wherein the counter always resets the counter value during wireless communication between the transport vehicle and the passive device.

[0052] However, one aspect of the present disclosure is not limited to the above embodiment and the above [1] to [6]. One aspect of the present disclosure can be further modified without departing from the spirit thereof. For example, in the above embodiment, the conveyance system is installed in a semiconductor processing factory, but this is not limited thereto and the conveyance system may be installed in other facilities. In this case, a processing device that performs some processing on the article is installed in the other facility as a passive device. In other facilities, the interlock signal is not limited to the E84 signal. Therefore, in the above embodiment, the passive device is a semiconductor processing device, but this is not limited thereto.

[0053] In the above embodiment, the first track and the second track are arranged side by side in the up-down (vertical) direction, but this is not limited to this. The overhead transport vehicle may have only one track, or three or more tracks arranged side by side. Also, only a portion of the tracks may be arranged to overlap in the up-down (vertical) direction, or the tracks at different heights may not overlap in the up-down (vertical) direction.

[0054] In the above embodiment, the storage shelves are provided on the sides facing the equipment ports across the first and second tracks when viewed vertically, but this is not limited to this. The processing ports and the storage shelves may be located on the same side of the tracks. Furthermore, the storage shelves may be provided inside or outside the loop-shaped intra-bay route.

[0055] In the above embodiment, the transport vehicle is a ceiling transport vehicle that runs on a track laid on the ceiling of the semiconductor processing factory, but this is not limited to this. It may also be a transport vehicle that runs on a track laid on the floor surface, or a transport vehicle that runs directly on the floor surface.

[0056] 1...Transport system, 10...First track, 20...Second track, 30...Storage shelf, 40...Ceiling transport vehicle, 41...Gripping unit, 42...Lifting mechanism, 43...Moving mechanism, 44...Controller, 45...Communication unit, 100...Semiconductor processing device, 101...Communication unit, 102...Controller, 110...Device port, 200...FOUP (item).

Claims

1. A transport system including a transport vehicle that transports an article to a passive device, The transport vehicle is a communication unit that transmits and receives wireless signals to and from the passive device while constantly transmitting and receiving a received signal strength to and from the passive device during the transfer of the article; a counter that generates a counter value corresponding to an elapsed time from a timing when the communication unit stopped receiving the received signal strength transmitted from the passive device during the transfer of the article; an output unit that outputs the counter value when a timeout abnormality occurs in which the communication unit is unable to recognize the wireless signal output by the passive device for a predetermined period of time, The counter always resets the counter value when the received signal strength is received. Conveying system.

2. The wireless signal includes an E84 signal defined in the international standard for semiconductor manufacturing equipment. The transport system according to claim 1 , wherein the output unit outputs the counter value only when the timeout abnormality occurs.

3. The transport system according to claim 1 , wherein the counter value is the elapsed time itself.

4. (delete)

5. (delete)

6. The transportation system according to claim 1 or 2, wherein the counter constantly resets the counter value during wireless communication between the transportation vehicle and the passive device.