Conveyor 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

Technical Field

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

Background Art

[0002] In a semiconductor manufacturing factory or the like, a conveyance system having a conveyance device for automatically conveying a workpiece to a semiconductor manufacturing device or the like is used. In such a conveyance system, signal exchange is carried out between the conveyance device that conveys the workpiece and a semiconductor manufacturing device or the like. When this signal exchange is not carried out normally for a predetermined period, a timeout abnormality occurs. For example, Patent Document 1 below discloses a communication device connected to a manufacturing device that can accumulate data for analyzing the cause of an error. In this communication device, time data including the time when predetermined packet data received by the communication unit was transmitted and the time when a predetermined port state was detected by the IO monitor unit is stored in the storage unit. By using this time data, it is determined whether correction of conveyance control is necessary.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] With only the time data as shown in Patent Document 1 above, when a timeout abnormality occurs in the signal exchange between the conveyance device that conveys the workpiece and a semiconductor manufacturing device or the like, it has been difficult to determine whether the cause of the timeout abnormality lies in the communication environment or in the signal transmission by the semiconductor manufacturing device or the like.

[0005] An object according to one aspect of the present disclosure is to provide a conveyance system capable of assisting in determining the cause of a timeout abnormality.

Means for Solving the Problems

[0006] A transport system according to an aspect of the present disclosure is a transport system including a transport vehicle that transports an article to a passive device and has a communication unit that wirelessly communicates with the passive device. The transport vehicle includes a counter that generates a counter value according to the elapsed time from the timing when reception becomes 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 transport vehicle. The counter always resets the counter value when reception is possible.

[0007] In the transport system according to an aspect of the present disclosure, an operator can estimate whether the cause of the timeout abnormality is a communication abnormality or an abnormality of the passive device only by checking the counter value output from the output unit (that is, checking whether the counter value is reset). When the counter value is 0 at the time when a timeout abnormality occurs in the transport vehicle, the operator can grasp that the wireless communication has been performed normally, and thus it can be estimated that the cause of the timeout abnormality is in the passive device. On the other hand, when a counter value equal to or greater than a certain value is output at the time when a timeout abnormality occurs in the transport vehicle, the operator can know that the wireless communication has not been performed for a certain period. Therefore, it can be estimated that the cause of the timeout abnormality is a communication failure. According to such a transport system capable of generating and outputting the counter value, it is possible to assist in determining the cause of the occurrence of the timeout abnormality.

[0008] The wireless communication between the transport vehicle and the passive device is wireless communication of an E84 signal defined by an international standard related to semiconductor manufacturing equipment, and the output unit may output the counter value only when a timeout abnormality due to the E84 signal occurs. In this case, generation and output of the counter value during an unnecessary period can be prevented. Thereby, a counter value useful for determining the cause of the occurrence of the timeout abnormality can be surely output.

Advantages of the Invention

[0009] According to one aspect of the present disclosure, a conveyance system capable of assisting in determining the cause of a timeout abnormality can be provided.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0011] Hereinafter, embodiments 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 corresponding elements are denoted by the same reference numerals, and redundant descriptions are omitted.

[0012] First, with reference to FIGS. 1 and 2, the transport system according to this embodiment will be described. FIG. 1 is a plan view of the transport system according to this embodiment. FIG. 2 is a front view of a part of the transport system. As shown in FIG. 1, the transport system 1 is installed in a semiconductor manufacturing factory including a semiconductor processing apparatus 100 which is one of passive apparatuses, and is a system for transporting articles such as a FOUP (article to be transported) 200. The FOUP 200 is a container (FOUP: Front Opening Unified Pod) for storing semiconductor wafers. The semiconductor processing apparatus 100 is a processing apparatus for the semiconductor wafers (for example, a cleaning apparatus, an etching apparatus, a film forming apparatus, etc.) and includes an apparatus 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, the FOUP 200 is transferred to the apparatus port 110 of the semiconductor processing apparatus 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 apparatuses. Each of the HOST and the MCS is an electronic control unit constituted by, for example, 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 can be a MES (Manufacturing Execution System). The HOST outputs a signal (hereinafter simply referred to as "command") including various commands such as a transport command and a travel command to the MCS. When the MCS acquires a command from the HOST, it outputs the command to the overhead transport vehicle 40 etc. at a predetermined timing via a transport vehicle controller.

[0014] The first track 10 is a member (travel path) for running the ceiling transfer cart 40 and is suspended from the ceiling. In the present embodiment, the transfer system 1 constitutes a plurality of systems (bays). The transfer system 1 includes a plurality of intra-bay routes that are travel paths within a bay and an inter-bay route that is a travel path connecting different bays. The intra-bay routes are arranged along a plurality of equipment ports 110. The first track 10 includes an intra-bay track 11 arranged on the plurality of intra-bay routes and an inter-bay track 12 arranged on the inter-bay route. The intra-bay track 11 is a track that passes near the storage shelf 30, the semiconductor processing apparatus 100, etc., and is set such that the ceiling transfer cart 40 travels one-way in a clockwise direction. The inter-bay track 12 is also set such that the ceiling transfer cart 40 travels one-way in a clockwise direction, similar to the intra-bay track 11. Note that in the first track 10, the ceiling transfer cart 40 may be set to travel one-way in a counterclockwise direction.

[0015] The second track 20 is a member (travel path) for running the ceiling transfer cart 40 and is suspended from the ceiling. The second track 20 includes an intra-bay track 21 arranged on a part of the plurality of intra-bay routes and an inter-bay track 22 arranged on the inter-bay route. The intra-bay track 21 is a track that passes near the storage shelf 30, the semiconductor processing apparatus 100, etc., and is set such that the ceiling transfer cart 40 travels one-way in a clockwise direction. The inter-bay track 22 is also set such that the ceiling transfer cart 40 travels one-way in a clockwise direction, similar to the intra-bay track 21. Note that in the second track 20, the ceiling transfer cart 40 may be set to travel one-way in a counterclockwise direction.

[0016] As shown in FIG. 2, the first track 10 and the second track 20 are arranged side by side in the vertical (up-and-down) 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 shown by a dashed line and the second track 20 is shown by a solid line.

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

[0018] On a plurality of equipment ports 110, the FOUP 200 transferred from the overhead transfer cart 40 is placed, and the FOUP 200 is transferred to the semiconductor processing equipment 100. Further, when the semiconductor wafers accommodated in the FOUP 200 are processed by the semiconductor processing equipment 100, a plurality of equipment ports 110 transfer the FOUP 200 from the semiconductor processing equipment 100 and are in a state where the FOUP 200 is placed thereon.

[0019] The storage shelf 30 is a member for storing the FOUP 200. A plurality of storage shelves 30 support the FOUP 200. The storage shelf 30 is, for example, suspended from the ceiling. The storage shelf 30 can be an OHB (Overhead Buffer). The area on the storage shelf 30 can place the FOUP 200. The area of the storage shelf 30 is a temporary storage area where the overhead transfer cart 40 stopped on the first track 10 and the second track 20 can transfer the FOUP 200.

[0020] As shown in FIG. 2, a plurality of storage shelves 30 are provided on the other side and below with respect to the first track 10 and the second track 20, on the side opposite to the side where a plurality of equipment ports 110 are provided. That is, a plurality of storage shelves 30 are provided on the side facing a plurality of equipment ports 110 via the first track 10 and the second track 20 when viewed from the vertical direction. The storage shelf 30 is provided inside the intra-bay route having a loop shape.

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

[0022] The gripping portion 41 is a device that grips and releases the FOUP 200. The gripping portion 41 can grip the flange portion 210 of the FOUP 200. The gripping portion 41 grips the flange portion 210 of the FOUP 200 when the ceiling transfer vehicle 40 acquires the FOUP 200 from the device port 110 or the storage shelf 30. The gripping portion 41 releases the flange portion 210 of the FOUP 200 when the ceiling transfer vehicle 40 places the FOUP 200 on the device 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 portion 41 in the vertical direction. The lifting mechanism 42 can raise and lower the gripping portion 41 in the vertical direction. The lifting mechanism 42 has a winding mechanism 42a and a belt 42b. The winding mechanism 42a is held by the moving mechanism 43. The winding mechanism 42a is a device that winds up and winds down the belt 42b in the vertical direction. The winding mechanism 42a can wind up and wind down the belt 42b in the vertical direction. The belt 42b hangs down from the winding mechanism 42a. The belt 42b holds the gripping portion 41 at its lower end. The lifting mechanism 42 can wind up and wind down the belt 42b by a distance such that the FOUP 200 gripped by the gripping portion 41 reaches at least the device port 110 and the storage shelf 30.

[0024] The moving mechanism 43 is a device that moves the gripping part 41 and the lifting mechanism 42 along the side of the overhead transfer cart. That is, the moving mechanism 43 can move the gripping part 41 and the lifting mechanism 42 from the overhead transfer cart 40 in a horizontal direction perpendicular to the traveling direction of the overhead transfer cart 40. The moving mechanism 43 can move the gripping part 41 and the lifting mechanism 42 above the device port 110 and the storage shelf 30 respectively. When the FOUP 200 is gripped by the gripping part 41, the moving mechanism 43 can move the FOUP 200 vertically upward with respect to the device port 110 and the storage shelf 30.

[0025] Each of the plurality of overhead transfer carts 40 stopped at the same position in the traveling direction on each of the first track 10 and the second track 20 can transfer the FOUP 200 to both the device port 110 and the storage shelf 30 located on the side and below the first track 10 and the second track 20. In other words, each overhead transfer cart 40 can transfer the FOUP 200 to the same device port 110 and the same storage shelf 30. That is, in any of the overhead transfer carts 40 on the first track 10 and the overhead transfer carts 40 on the second track 20, the transfer (loading and unloading) of the FOUP 200 with the device port 110 is enabled. And, in any of the overhead transfer carts 40 on the first track 10 and the overhead transfer carts 40 on the second track 20, the transfer of the FOUP 200 with the storage shelf 30 is enabled.

[0026] The overhead transfer cart 40 operates the moving mechanism 43 to move the FOUP 200 above the device port 110 and the storage shelf 30 respectively, from the state where the gripping part 41 grips the flange part 210 of the FOUP 200 directly below the first track 10 and the second track 20. Subsequently, the overhead transfer cart 40 operates the hoisting mechanism 42a to unwind the belt 42b, lower the FOUP 200, and place it on the device port 110 or the storage shelf 30. Thus, the overhead transfer cart 40 transfers (places) the FOUP 200 to the device port 110 and the storage shelf 30.

[0027] In addition, the ceiling transporter 40 grips the flange portion 210 of the FOUP 200 placed on the equipment port 110 or the storage shelf 30 by the gripping portion 41. Subsequently, the ceiling transporter 40 operates the hoisting mechanism 42a to wind up the belt 42b and raise the FOUP 200. Subsequently, the ceiling transporter 40 operates the moving mechanism 43 to move the FOUP 200 directly below the first track 10 and the second track 20. Thus, the ceiling transporter 40 transfers (acquires) 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 ceiling transporter 40. The controller 44 is, for example, an electronic control unit composed of a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. The controller 44 communicates with the target semiconductor processing apparatus 100 in response to a command from the above control device, and controls the traveling of the ceiling transporter 40, the operation of the gripping portion 41, the operation of the elevating mechanism 42, the operation of the moving mechanism 43, and the like.

[0029] The communication unit 45 is a device capable of communicating with the above control device, the semiconductor processing apparatus 100, etc., and is disposed at a predetermined position of the ceiling transporter 40. FIG. 3 is a schematic diagram showing the communication between the ceiling transporter and the semiconductor processing apparatus. As shown in FIG. 3, the semiconductor processing apparatus 100 includes a communication unit 101 capable of communicating with the transfer 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 the present embodiment, the communication unit 45 of the ceiling transfer vehicle 40 and the communication unit 101 of the semiconductor processing apparatus 100 perform wireless communication with each other. The wireless communication between the ceiling transfer vehicle 40 and the semiconductor processing apparatus 100 is, for example, the transmission and reception of wireless signals performed when the FOUP 200 is transferred. The transfer of the FOUP 200 includes both the transfer of the FOUP 200 from the ceiling transfer vehicle 40 to the semiconductor processing apparatus 100 and the transfer of the FOUP 200 from the semiconductor processing apparatus 100 to the ceiling transfer vehicle 40. During the implementation of the wireless communication between the ceiling transfer vehicle 40 and the semiconductor processing apparatus 100, the wireless signals transmitted and received by the communication units 45 and 101 are, for example, interlock signals for restricting the operation of the semiconductor processing apparatus 100 (particularly, the operation of the apparatus port 110). The interlock signal is, for example, a signal (E84 signal) exchanged according to the procedure defined in E84 of the international standard (SEMI standard: Semiconductor Equipment and Materials International standards) for semiconductor manufacturing apparatuses. By the normal transmission and reception of the E84 signal between the ceiling transfer vehicle 40 and the semiconductor processing apparatus 100, it is possible to prevent interference (contact, collision, etc.) at unintended locations between the gripping unit 41, the elevating mechanism 42, etc. of the ceiling transfer vehicle 40 and the semiconductor processing apparatus 100. The wireless communication between the ceiling transfer vehicle 40 and the semiconductor processing apparatus 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 the above-mentioned E84, the signal transmitted by the semiconductor processing apparatus 100 to the ceiling transfer vehicle 40 changes, and the ceiling transfer vehicle 40 receives the changed signal via the communication unit 45. Hereinafter, the signal transmitted by the semiconductor processing apparatus 100 to the ceiling transfer vehicle 40 is referred to as an output signal, and the signal input from the semiconductor processing apparatus 100 to the ceiling transfer vehicle 40 is referred to as an input signal. In addition, the communication unit 101 and the communication unit 45 always transmit and receive the received signal strengths of each other in addition to the E84 signal. The received signal strength is an index that can confirm the communication environment state.

[0032] When the input signal input to the ceiling transfer vehicle 40 does not change over a predetermined period (timeout determination period), the controller 44 determines that a timeout abnormality has occurred. The timeout abnormality occurs due to, for example, communication abnormalities, device abnormalities, etc. The communication abnormality occurs due to, for example, a communication failure (abnormality of the communication environment) caused by interference of signals generated from other devices. The received signal strength during a communication abnormality is regarded as 0. The device abnormality occurs due to, for example, a failure of the semiconductor processing apparatus 100. When a timeout abnormality occurs, the operations of the ceiling transfer vehicle 40 and the semiconductor processing apparatus 100 (for example, the transfer operation of the FOUP 200) stop. Note that hereinafter, during the E84 communication between the ceiling transfer vehicle 40 and the semiconductor processing apparatus 100, a state where no communication abnormality has occurred may be referred to as a "normal communication state".

[0033] As shown in FIG. 3, the ceiling transfer vehicle 40 includes 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 a part of the controller 44.

[0034] The counter 46 starts counting (generating a counter value) from the timing when a communication abnormality occurs during the wireless communication between the ceiling transfer vehicle 40 and the semiconductor processing apparatus 100. In the present embodiment, the value counted according to the elapsed time corresponds to the counter value. The counter value may be a value that changes according to a predetermined law according to the elapsed time. In the present embodiment, the counter value is the elapsed time itself. When the communication abnormality is resolved after the generation of the counter value (that is, when the received signal strength indicates a value other than 0), the counter 46 resets the counter value. Thereby, the counter value indicates the period of the latest communication abnormality state. In addition, an operator can easily specify the occurrence time of the communication abnormality state from the output counter value. Note that the counter 46 always resets the counter value when reception is possible (for example, in a normal communication state and when the ceiling transfer vehicle 40 can receive a wireless signal 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 or the like. In the present embodiment, a state in which the ceiling transfer vehicle 40 cannot recognize a change in the output signal of the semiconductor processing apparatus 100 within a predetermined period is defined as a timeout abnormality. A state in which the ceiling transfer vehicle 40 cannot 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. Thereby, for example, when the ceiling transfer vehicle 40 and the semiconductor processing apparatus 100 are not exchanging the E84 signal, the output unit 47 does not output the counter value even if the counter value is generated.

[0036] Next, an example (normal example) in which the ceiling transfer vehicle 40 and the semiconductor processing apparatus 100 can perform normal wireless communication will be described with reference to FIGS. 4(a), 4(b), 5(a), and 5(b). Each of FIGS. 4(a), 4(b), 5(a), and 5(b) is a timing chart for explaining a normal example of wireless communication between the ceiling transfer vehicle 40 and the semiconductor processing apparatus 100. In each of FIGS. 4(a), 4(b), 5(a), and 5(b), the timing T0 indicates the start timing of the timeout determination period, the timing T1 indicates the end timing of the timeout determination period, each of the timings Ts, Ts1, and Ts2 indicates the occurrence timing of a communication abnormality, the timing Te indicates the end timing of the communication abnormality, the dashed arrow indicates a normal communication state, and the region surrounded by the dashed line indicates a communication abnormality state. In each of FIGS. 4(a), 4(b), 5(a), and 5(b), the initial value of the output signal is the value PL, and the initial value of the input signal is the value CL. The value of the output signal changes from the value PL to the value PH at the timing Tp between the timing T0 and the timing T1. This change from the value PL to the value PH is made, for example, by the controller 102 of the semiconductor processing apparatus 100. Also, the change of the input signal from the value CL to the value CH is implemented by receiving the output signal having the value PH. Therefore, the ceiling transfer vehicle 40 does not update the input signal unless it receives the output signal having the value PH.

[0037] In the first normal example shown in FIG. 4(a), wireless communication between the ceiling transfer vehicle 40 and the semiconductor processing apparatus 100 is normally performed throughout the entire timeout determination period. In this case, at timing Tp, in response to the change in the value of the output signal from value PL to value PH, the input signal normally changes from value CL to value CH. In this case, the controller 44 determines that no timeout abnormality has occurred.

[0038] In the second normal example shown in FIG. 4(b), a normal communication state continues at least from timing T0 to timing Tp. Also, a communication abnormality state occurs after timing Tp and before timing T1. In this case, similar to the first normal example, in response to the change in the value of the output signal from value PL to value PH, the input signal changes from value CL to value CH, and the input signal changes normally. Then, similar to the first normal example, the controller 44 determines that no timeout abnormality has occurred. Note that from timing Ts after timing Tp, the counter 46 generates a counter value. However, in the second normal example, since it is determined that no timeout abnormality has occurred, the output unit 47 does not output the counter value. Note that even after passing timing T1, the counter 46 may continue to count while the communication abnormality continues.

[0039] In the third normal example shown in Fig. 5(a), a communication abnormal state occurs between timing T0 and timing Tp. The communication abnormal state continues until timing Te 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, when the output signal indicating value PH is received by the ceiling carrier 40, the input signal changes normally. And, similar to the first normal example and the second normal example, the controller 44 determines that no timeout abnormality has 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. 5(b), similar to the third normal example, a communication abnormal state occurs from timing Ts1 which is between timing T0 and timing Tp. Also, the communication abnormal state continues until timing Te which is between timing Tp and timing T0. In addition, another communication abnormal state occurs from timing Ts2 after timing Te until timing T1. In this case, similar to the third normal example, the input signal is not updated at timing Tp. However, in the normal communication state existing between timing Te and timing Ts2, the output signal indicating value PH is received by the overhead transfer vehicle 40. Thereby, the input signal changes normally. And, similar to the first to third normal examples, the controller 44 determines that no timeout abnormality has occurred. Note that the counter value is generated by the counter 46 between timing Ts1 and timing Te, but the counter value is reset at timing Te. However, a new counter value is newly generated by the counter 46 from timing Ts2. However, in the fourth normal example, since it is determined that no timeout abnormality has occurred, the new counter value is not output. Note that the generation of the new counter value by the counter 46 can continue until the communication abnormality that occurred at timing Ts2 is resolved.

[0041] Next, with reference to Figs. 6(a), (b) and Figs. 7(a), (b), an example (abnormal example) when the overhead transfer vehicle 40 and the semiconductor processing apparatus 100 cannot perform normal wireless communication will be described. Each of Figs. 6(a), (b) and Figs. 7(a), (b) is a timing chart for explaining an abnormal example of the wireless communication between the overhead transfer vehicle 40 and the semiconductor processing apparatus 100.

[0042] In the first abnormal example shown in Fig. 6(a), wireless communication between the ceiling transfer vehicle 40 and the semiconductor processing apparatus 100 is normally performed throughout the entire timeout determination period. For this reason, the counter 46 does not change its counter value from 0. On the other hand, from timing T0 to timing T1, the value of the output signal remains at PL. For this reason, the input signal does not show 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 the counter value 0. The controller 44 outputs, for example, the counter value as log information.

[0043] In the second abnormal example shown in Fig. 6(b), a communication abnormal state exists throughout the entire timeout determination period. The counter 46 generates a counter value from the point when reception stops until reception is performed again. On the other hand, the value of the output signal changes to the value PH at timing Tp, but the value of the input signal remains at the value CL from timing T0 to timing T1. For this reason, similarly to the first abnormal 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 abnormal example corresponds to the elapsed time from timing T0 to timing T1. When the communication abnormality occurs before timing T0, the counter value is larger than the elapsed time from timing T0 to timing T1. Even when both an apparatus abnormality and a communication abnormality occur, generation of the counter value starts from the point when the communication abnormality occurs.

[0044] In the third abnormal example shown in Fig. 7(a), the communication abnormal 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. On the other hand, from timing T0 to timing T1, similar to the first and second abnormal examples, the value of the input signal remains at value CL. For this reason, similar to the first and second abnormal 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 abnormal example corresponds to the elapsed time from timing Ts to timing T1. Note that even when a device abnormality occurs after timing Ts, the output counter value corresponds to the elapsed time from the time (timing Ts) when the communication abnormality occurred to timing T1.

[0045] In the fourth abnormal example shown in Fig. 7(b), a plurality of communication abnormal states occur intermittently from timing T0 to timing T1. In the fourth abnormal example, the first communication abnormal state continues from timing Ts1 to timing Te, and the second communication abnormal state continues from timing Ts2 after timing Te to timing T1. In this case, the counter value generated by the counter 46 in the first communication abnormal state is reset at timing Te. Also, the counter 46 generates a new counter value from timing Ts2. On the other hand, from timing T0 to timing T1, similar to the first to third abnormal examples, the value of the input signal remains at value CL. For this reason, similar to the first to third abnormal examples, 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 example corresponds to, for example, the elapsed time from timing Ts2 to timing T1.

[0046] When a timeout abnormality occurs in each abnormal case, the counter value output can be used as an indicator for estimating the cause of the timeout abnormality. For example, when the counter value output by the output unit 47 is 0 (i.e., in the case of the first abnormal case), the operator can easily understand that there is no problem with the communication environment between the ceiling transfer vehicle 40 and the semiconductor processing apparatus 100. Thereby, the operator can presume that the timeout abnormality has occurred due to an apparatus abnormality.

[0047] When the counter value output by the output unit 47 is other than 0 (i.e., in the case of the second to fourth abnormal cases), 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 such an estimation, the operator can estimate whether the cause or main cause of the timeout abnormality in each of the second to fourth abnormal cases is a communication abnormality or an apparatus abnormality.

[0048] Specifically, when a timeout abnormality occurs, the operator can grasp the length of the timeout determination period (from timing T0 to timing T1), the output counter value, and the signal state (value CL, value CH) of the ceiling transfer vehicle 40 at the time of the timeout abnormality occurrence. Although timing Tp is illustrated for convenience in FIGS. 6 and 7, the operator cannot grasp timing Tp. When the output counter value is 0 (first abnormal case), the operator can presume that no communication abnormality has occurred and an apparatus abnormality has occurred. When the output counter value is equal to or greater than the timeout determination period (second abnormal case), the operator can presume that a communication abnormality has always occurred during the timeout determination period, or that a communication abnormality has occurred before the timeout determination started. In this case, an apparatus abnormality may also have occurred during the communication abnormality. When the output counter value is smaller than the timeout determination time (third and fourth abnormal cases), the length of the period during which a communication abnormality has occurred can be understood from the magnitude of the output counter value, and the degree of possibility of an apparatus abnormality can be estimated.

[0049] In the transport 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 apparatus abnormality of the semiconductor processing apparatus 100 only by checking the counter value output from the output unit 47. Therefore, according to the transport system 1, it is possible to assist in determining the cause of the occurrence of the timeout abnormality.

[0050] In the present embodiment, the wireless communication between the overhead transport vehicle 40 and the semiconductor processing apparatus 100 is wireless communication of an E84 signal defined by an international standard related to semiconductor manufacturing apparatuses, and the output unit 47 may output a counter value only when a timeout abnormality of the E84 signal occurs. In this case, generation and output of the counter value during an unnecessary period can be prevented. Thereby, it is possible to surely output a counter value useful for determining the cause of the occurrence of the timeout abnormality.

[0051] As described above, the transport system according to one aspect of the present disclosure is as described in [1] to [6] below, and these have been described in detail based on the above embodiment. [1] A transport system including a transport vehicle having a communication unit that transports an article to a passive device and wirelessly communicates with the passive device, wherein the transport vehicle includes a counter that generates a counter value according to the elapsed time from the timing when reception becomes 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 transport vehicle, wherein the counter always resets the counter value when reception is possible, a transport system. [2] The wireless communication between the transport vehicle and the passive device is wireless communication of an E84 signal defined by an international standard related to semiconductor manufacturing apparatuses, and the output unit outputs the counter value only when a timeout abnormality due to the E84 signal occurs. The transport system according to [1]. [3] The counter value is the elapsed time itself, the conveying system according to [1] or [2]. [4] The timing corresponds to the timing at which a communication abnormality occurs between the carrier vehicle and the passive device, the conveying system according to any one of [1] to [3]. [5] The timeout abnormality occurs when the carrier vehicle fails to recognize a change in the output signal of the passive device within a predetermined period, the conveying system according to any one of [1] to [4]. [6] The counter always resets the counter value during wireless communication between the carrier vehicle and the passive device, the conveying system according to any one of [1] to [5].

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

[0053] In the above-described embodiment, the first track and the second track are arranged side by side in the vertical direction, but it is not limited thereto. The track of the overhead carrier vehicle may be only one track, or a plurality of tracks of three or more may be arranged side by side. Also, only a part of the plurality of tracks may be arranged so as to overlap in the vertical direction, or the plurality of tracks having different heights may not overlap in the vertical direction.

[0054] In the above-described embodiment, the plurality of storage shelves are provided on the side facing the plurality of equipment ports via the first track and the second track when viewed from the vertical direction, but the present invention is not limited to this. The processing port and the storage shelf may be arranged on the same side with respect to the track. Further, the storage shelf may be provided inside or outside the intra-bay route having a loop shape.

[0055] In the above-described embodiment, the carrier is a ceiling carrier that travels on a track laid on the ceiling of the semiconductor processing factory, but the present invention is not limited to this. It may be a carrier that travels on a track laid on the floor surface, or a carrier that travels directly on the floor surface.

Description of Signs

[0056] 1…Conveying system, 10…First track, 20…Second track, 30…Storage shelf, 40…Ceiling carrier, 41…Gripping part, 42…Lifting mechanism, 43…Moving mechanism, 44…Controller, 45…Communication part, 100…Semiconductor processing apparatus, 101…Communication part, 102…Controller, 110…Equipment port, 200…FOUP (article).

Claims

1. A conveying system comprising a carrier for conveying an article to a passive device, wherein the carrier has a communication unit that transmits and receives a wireless signal different from the received signal strength to and from the passive device while constantly transmitting and receiving the received signal strength to and from the passive device during transfer of the article; a counter that generates a counter value according to the elapsed time from the timing when the communication unit stops receiving the received signal strength transmitted from the passive device during transfer of the article; an output unit that outputs the counter value when a timeout abnormality occurs, which is a state where the communication unit cannot recognize the wireless signal output from the passive device for a predetermined period of time; and the counter always resets the counter value when receiving the received signal strength. A conveying system.

2. The wireless signal includes an E84 signal defined by an international standard related to semiconductor manufacturing equipment, and the output unit outputs the counter value only when the timeout abnormality occurs. The conveying system according to Claim 1.

3. The counter value is the elapsed time itself. The conveying system according to Claim 1 or 2.

4. The counter always resets the counter value during wireless communication between the carrier and the passive device. The conveying system according to Claim 1 or 2.

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