Conveyance-container lid fall-off detection device, load port, and conveyance-container lid fall-off detection method

Abstract

As a conveyance-container fall-off detection device, a FOUP lid fall-off detection device 3 comprises a reflector 32 disposed in the vicinity of a FOUP support base 12 of a load port 1, and a reflection-type optical sensor 311 disposed in the vicinity of a load port door 13, and is configured to receive, by the reflection-type optical sensor 311, reflected light L2 resulting from reflection by the reflector 32 of emission light L1 emitted obliquely from the reflection-type optical sensor 311; and detect, by the reflection-type optical sensor 311, the presence of a FOUP lid 22 which has fallen off at the undocking position. Accordingly, a conveyance-container fall-off detection device that can reliably detect fall-off of the conveyance-container lid during undocking and facilitates easy attachment to the load port is provided.

Description

Transfer container lid detachment detection device, load port, and transfer container lid detachment detection method

[0001] The present invention relates to a device for detecting the detachment of a transport container lid when the container is removed (unloaded) from a load port, a load port to which the device is applied, and a method for detecting the detachment of a transport container lid.

[0002] Load ports are widely used at the entrances and exits of substrate processing equipment to transport semiconductor wafers. In a "mini-environment system" that creates a locally highly clean area, semiconductor wafers are transported in a sealable transport container called a FOUP (Front Opening Unified Pod) or a FOSB (Front Opening Shipping Box), which is maintained at a higher level of cleanliness than the external atmosphere.

[0003] To load and unload substrates, the transport container is equipped with an openable / closable transport container lid. The load port is equipped with a transport container support table that supports the transport container so that it can move forward and backward relative to the substrate processing apparatus. The load port is a device that opens and closes the transport container lid relative to the transport container, and by opening the transport container lid, semiconductor wafers, rectangular substrates, etc. can be loaded and unloaded into and from the transport container by a transport robot. The substrates stored in the transport container are then transported to the next process while maintaining a clean environment.

[0004] To maintain a clean environment, the lid of the transport pod must be properly attached to the transport pod body and sealed when the transport pod is closed. However, an abnormality may occur, such as a malfunction of the lid of the transport pod to the transport pod body, causing the lid to be improperly attached to the transport pod body. In this case, the lid of the transport pod may fall off the transport pod body during unloading, when the transport pod is retracted a predetermined distance from the substrate processing apparatus.

[0005] Although conventional load ports are equipped with various sensors, they are not equipped with means for detecting the detachment of a transfer container lid. As a result, there is a possibility that a transfer container may be transported with its lid detached, exposing the substrate to a low-cleanliness atmosphere or that the substrate may escape from the transfer container and fall and be damaged during transport. Therefore, the present applicant has filed a patent application for a load port and a FOUP lid abnormality detection method for a load port that can detect an abnormality in which a FOUP lid is not properly attached to the FOUP body, regarding a load port for FOUPs, and has obtained a patent right (see Patent Document 1).

[0006] JP 2020-061436 A (Patent No. 7228759 A)

[0007] The load port described in Patent Document 1 includes a FOUP lid sensor that is arranged to detect the difference between the normal position of the FOUP lid and the position of the lid (load port door) in a closed state at the time of unloading completion when the FOUP has retreated a predetermined distance from the loading / unloading entrance, and a detection unit that detects detection by the FOUP lid sensor after unloading is complete. Here, an optical sensor is used as the FOUP lid sensor, and specifically, a transmission type optical sensor is used.

[0008] The load port in this document uses a transmission-type optical sensor as a FOUP lid sensor, and is configured to easily detect, for example, the detachment of a FOUP lid from the FOUP body by detecting the interruption of a light beam. However, a transmission-type optical sensor requires two parts, a light-emitting part and a light-receiving part, to be attached to the load port at a distance from each other, which makes it difficult to attach the sensor and adjust its position.

[0009] The present invention has been made in light of these problems, and aims to provide a transport container lid detachment detection device that can simplify the installation work of a sensor for detecting the detachment of a transport container lid when the load port closes and undocks the transport container lid, as well as a load port equipped with such a transport container lid detachment detection device and a transport container lid detachment detection method.

[0010] That is, the present invention provides a transport container lid detachment detection device that is attached to a load port provided at the entrance / exit of a substrate processing apparatus, and includes a reflector located near a transport container support table that supports a transport container having a transport container lid that opens and closes relative to the transport container body and stores substrates inside the transport container body while moving the transport container back and forth relative to the entrance / exit, and a reflective optical sensor located near a load port door that detachably engages with the transport container lid of the transport container placed on the transport container support table to open and close the transport container lid relative to the transport container body, and is configured so that the reflective optical sensor receives reflected light that is emitted from the reflective optical sensor in an oblique direction that includes a component in the forward and backward movement direction of the transport container, and is reflected by the reflector, and is configured so that the reflective optical sensor detects the presence of a detached transport container lid at an undock position where the load port and transport container are released from their docked state.

[0011] In accordance with the transport container lid detachment detection device of the present invention, when the transport container is undocked, a reflective optical sensor located near the load port door emits an obliquely directed light beam toward a reflector located near a transport container support table typically spaced apart in the direction of forward and backward movement of the transport container. If the light reflected by the reflector is received by the reflective optical sensor, the transport container lid is properly attached to the FOUP body. However, if the transport container lid has fallen off the transport container body, blocking the emitted or reflected light, the reflective optical sensor detects the inability to receive the reflected light, thereby detecting the presence of a fallen transport container lid. Note that, in the present invention, "fallen off transport container lid" includes both a state in which the transport container lid has completely detached from the transport container body and fallen, and a state in which the transport container lid has not fallen but is not completely fitted into the transport container body (a state in which the transport container lid is not properly closed).

[0012] Furthermore, the transfer container lid detachment detection device of the present invention is mainly composed of a reflective optical sensor located near the load port door and a reflector located near the transfer container support base, and since the reflector only needs to be capable of reflecting light, the only thing that needs to be firmly attached to the load port is the reflective optical sensor. Therefore, compared to the configuration of Patent Document 1, which requires the installation of at least two parts, a light-emitting unit and a light-receiving unit, the effort required for installing and adjusting the position of the sensor is reduced.

[0013] In addition, in the present invention, by making it possible to change the position of the reflector near the transport container support stand, it becomes possible to appropriately position the reflector near the transport container support stand, which moves back and forth so that transport containers of various types and sizes can be appropriately docked with the load port door, making it possible to reliably detect the detachment of the transport container lid for a variety of transport containers.

[0014] Furthermore, if the present invention is configured with an angle adjustment unit that adjusts the mounting angle of the reflective optical sensor, it becomes easy to fine-tune the angle of the emitted light to the reflector or to adjust it when retrofitting a reflective optical sensor to an existing load port.In addition, even when the position of the reflector is changed, the angle of the emitted light can be appropriately adjusted.

[0015] In particular, by mounting the reflective optical sensor in a position where the optical axis of the light emitted by the reflective optical sensor and the optical axis of the light reflected by the reflector avoid other components mounted on the load port, such as other sensors, suction pads, and load port door latch keys, no major design changes are required to conventional load ports and it is possible to mount the reflective optical sensor on existing load ports with little difficulty.

[0016] Furthermore, the load port of the present invention is a load port provided at an entrance / exit of a substrate processing apparatus, and comprises a transport container support table for supporting a transport container having a transport container lid that opens and closes relative to a transport container body and stores substrates inside the transport container body while moving the transport container back and forth relative to the entrance; a load port door for detachably engaging with the transport container lid relative to the transport container body placed on the transport container support table to open and close the transport container lid relative to the transport container body; and a transport container lid detachment detection device for detecting detachment of the transport container lid from the transport container body, the transport container lid detachment detection device comprising a reflector arranged near the transport container support table and a reflective optical sensor arranged near the load port door, wherein the reflective optical sensor is configured to receive reflected light generated when light emitted from the reflective optical sensor is reflected by the reflector in an oblique direction that includes a component in the forward and backward movement direction of the transport container, and wherein the reflective optical sensor is configured to detect the presence of a detached transport container lid at an undock position where the load port and transport container are released from their docked state.

[0017] With a load port configured in this manner, as with the transport container lid detachment detection device described above, it is easy to attach and adjust the reflective optical sensor to the load port, reducing the effort required, and it is possible to create a load port that can reliably detect when the transport container lid has fallen off the transport container body at the undock position.

[0018] The method for detecting detachment of a transfer container lid of the present invention utilizes a transfer container lid detachment detection device having a reflective optical sensor and a reflector mounted on a load port provided at the entrance / exit of a substrate processing apparatus to detect detachment of a transfer container lid of a transfer container that contains substrates inside the transfer container body and is placed on a transfer container support stand of the load port, and includes a closing step in which the transfer container lid is closed to the transfer container body by a load port door that detachably engages with the transfer container lid; an undock step in which the transfer container support stand is moved away from the load port door to release the docked state between the load port and the transfer container; and an undock sensor provided on the load port detects that the transfer container support stand has moved to an undocked position and is in an undocked state. This method is characterized by including an undock detection process, a detachment detection process in which a reflective optical sensor arranged near the load port door emits light in an oblique direction including a component in the forward and backward movement direction of the transport container support platform, and the reflective optical sensor receives reflected light generated when the emitted light is reflected by a reflector arranged near the transport container support platform, defining the normal state as a state in which the reflective optical sensor receives reflected light, and detects the presence of a detached transport container lid if the reflective optical sensor cannot receive the reflected light or if the amount of reflected light or light reception rate is smaller than a predetermined threshold, and a detachment determination process in which, if the undocked state is detected in the undock detection process and the presence of a detached transport container lid is detected in the detachment detection process, it is determined that the transport container lid has fallen off the transport container body.

[0019] With this method, it is possible to reliably detect the state in which the lid of the transfer container has fallen off from the main body of the transfer container at the undock position, just as with the transfer container lid falling-off detection device described above.

[0020] According to the present invention, when a transport container is removed from a load port, a sensor can be installed on the load port with a simple configuration and little effort, which can reliably detect if the transport container lid has not closed properly and fallen off while the transport container is in an undocked position with the transport container lid closed by the load port.

[0021] FIG. 1 is a perspective view showing a load port according to an embodiment of the present invention. FIG. 2 is a front view showing the load port of the same embodiment. FIG. 3 is a perspective view showing a state in which a FOUP is placed on the load port of the same embodiment. FIG. 4 is a perspective view showing an example of a FOUP used for the load port of the same embodiment. FIG. 5 is an enlarged perspective view showing the optical axes of the FOUP lid detachment detection device and a reflective optical sensor of the same embodiment. FIG. 6 is a diagram showing an optical sensor unit including a reflective optical sensor applied to the same embodiment. FIG. 7 is an explanatory diagram showing the operation of the load port and FOUP lid detachment detection device in a normal state in the same embodiment. FIG. 8 is an explanatory diagram showing the operation of the load port and FOUP lid detachment detection device in an abnormal detachment state in the same embodiment. FIG. 9 is a diagram showing an example of a FOUP lid detachment pattern in the same embodiment.

[0022] An embodiment of the present invention will be described below with reference to the drawings. A load port 1 according to this embodiment is provided at the entrance of a semiconductor processing apparatus (not shown), which is a type of substrate processing apparatus. The semiconductor processing apparatus is located at the upper right of the load port 1 in FIG. 1 (behind the load port door 13 and panel portion 14). In this embodiment, the load port 1 constitutes part of a transport device (not shown) such as an Equipment Front End Module (EFEM), which is connected to the semiconductor processing apparatus and transports semiconductor wafers (not shown), a type of substrate to be processed. The interiors of the semiconductor processing apparatus and transport device are maintained at a higher level of cleanliness than the external atmosphere. In the following description, the front refers to the direction approaching the semiconductor processing apparatus, which is provided adjacent to the panel portion 14 of the load port 1, and the rear refers to the direction away from the semiconductor processing apparatus. The vertical relationship corresponds to the vertical relationship shown in FIG. 1 .

[0023] In this embodiment, the load port 1 opens and closes a FOUP (Front Opening Unified Pod) 2, a type of transfer container that stores semiconductor wafers, and as shown in Figures 1 and 2, it mainly comprises a main body 11, a FOUP support table (corresponding to the transfer container support table in this invention) 12, a load port door 13, and a panel 14 that supports the load port door 13 so that it can be opened and closed. The basic (mechanical) configuration of the load port 1 is similar to that of a known configuration.

[0024] The main body 11 is shaped like a rectangular box and is disposed at the rear of the transport device. A panel 14 is provided at the front of the main body 11. The panel 14 is fitted into an opening formed in the transport device and is attached to the main body 11. The panel 14 is provided with a display 141 that indicates the operating status of the load port 1, for example.

[0025] The FOUP support table 12, also referred to as a carrier base, is provided on the upper surface of the main body 11 so as to be movable in the front-to-rear direction. As shown in Fig. 3, a FOUP, which has semiconductor wafers stacked in multiple stages, is placed and fixed above the FOUP support table 12. This allows the FOUP support table 12 to support (seat and clamp) the FOUP 2. For this reason, pins and claws for positioning and fixing the FOUP 2 are provided on the upper surface of the FOUP support table 12, as schematically shown in Fig. 1.

[0026] Here, the FOUP 2 is a box-shaped container, such as that shown in FIG. 3 , that mainly comprises a FOUP body 21 with an internal space and a FOUP lid 22 that is detachably attached to the FOUP body 21 and allows the FOUP 2 to be opened and closed. The FOUP 2 is capable of storing multiple semiconductor wafers and is transported between the FOUP support table 12 of the load port 1 and the outside by an external transport device such as an overhead hoist transport (OHT). Although not shown, the FOUP 2 may be provided with an intake port and an exhaust port. In this case, the interior of the FOUP 2 can be purged with nitrogen, for example, using the intake port and the exhaust port. The FOUP 2 is placed on the FOUP support table 12 so that the FOUP lid 22 faces the panel portion 14 of the load port 1 (see FIG. 3 ). Note that FIG. 3 shows the FOUP lid 22 of the FOUP 2 separated rearward from the load port door portion 13 of the load port 1. Furthermore, when the FOUP 2 is moved forward by the FOUP support table 12, the contact portion around the opening of the FOUP body 21 comes into airtight contact with the panel portion 14. This allows semiconductor wafers to be transferred between the FOUP 2 and the transport device and semiconductor processing device in a highly clean environment.

[0027] The load port door 13 is a plate-shaped portion that can open and close a loading / unloading entrance (a part of the opening described above) provided in the transport device for loading and unloading semiconductor wafers. In this embodiment, the load port door 13 has a substantially rectangular shape, as shown in FIGS. 1 and 2 . The load port door 13 is movable (e.g., forward and backward and up and down) relative to the panel 14 by an opening / closing device 15 (see FIGS. 7 and 8 ) provided on the load port 1. For example, when fitted into the panel 14, the load port door 13 can airtightly close the loading / unloading entrance when raised and can open the loading / unloading entrance when lowered. During lowering, the load port door 13 first advances (moves toward the transport device) and then descends along the panel 14 to avoid interference with the panel 14. The surface of the load port door 13 facing the FOUP 2 is provided with a mating portion (e.g., a latch mechanism) 131 that matingly engages with the FOUP lid 22. The FOUP lid 22 is provided with a mating portion 221 corresponding to the mating portion. The FOUP 2 is then moved forward while held on the FOUP support platform 12, with the FOUP lid 22 and the load port door section 13 overlapping each other, and the suction pad 132 is brought into close contact with the FOUP lid 22. The fitting portion 131 of the load port door section 13 is fitted into the fitted portion 221 of the FOUP lid 22, thereby integrating the FOUP lid 22 and the load port door section 13. In this state, the load port door section 13 can be moved forward and downward relative to the panel section 14 to remove the FOUP lid 22 from the FOUP body 21, opening the load port door section 13 to the loading / unloading entrance of the transport device. In this open state, the loading / unloading entrance and the interior of the FOUP body 21 are in communication, allowing semiconductor wafers to be loaded and unloaded into the FOUP body 21 using, for example, a robot arm provided inside the transport device.

[0028] The load port 1 is provided with various sensors, and in this embodiment in particular, a FOUP lid detachment detection device 3 is provided for detecting abnormal detachment of the FOUP lid 22. In this embodiment, the FOUP lid detachment detection device 3 is designed to be retrofitted to an existing load port 1. This FOUP lid detachment detection device 3 is primarily composed of an optical sensor unit 31 and a reflector 32. This FOUP lid detachment detection device 3 is installed so as to detect an object between the normal position of the FOUP lid 22 and the position of the load port door unit 13 in the closed state, when the FOUP lid 22 is undocked from the load port door unit 13 and the FOUP support base 12 is slightly retracted to place the FOUP 2 in an undocked position where it is separated from the loading / unloading entrance. For object detection by this FOUP lid drop detection device 3, a detection unit (not shown) is provided at the undocked position, which detects detection by the optical sensor unit 31 (when it does not detect reflected light reflected by the reflector 32 (when emitted light L1 (the optical axis of the emitted light is shown as L1) does not reach the reflector 32 due to obstruction by an object in the first place, reflected light L2 (the optical axis of the reflected light is shown as L2) is not generated), or when the amount or attenuation rate of reflected light L2 falls below a predetermined value). This detection unit can be provided in a control unit provided in the load port 1. To detect the detachment of the FOUP lid 22, in this embodiment, in addition to the FOUP lid detachment detection device 3, an undocking sensor (not shown) that is linked to the operation of the fitting portion (latch mechanism, etc.) 131 and the fitted portion 221, a presence sensor 16 (see FIGS. 2 and 5) that detects whether semiconductor wafers are loaded inside the FOUP 2, and a seating sensor 17 (see FIGS. 2 and 5) that detects whether the FOUP 2 is seated on the FOUP support base 12 are used. The undocking sensor, presence sensor 16, and seating sensor 17 are the same as those conventionally equipped in known load ports 1, and are managed by a control unit provided in the load port 1.

[0029] In this embodiment, a reflective optical sensor 311 is used as the optical sensor unit 31. As shown in Figures 5 and 6, the reflective optical sensor 311 is a typical type equipped with both a light-emitting unit 311b and a light-receiving unit 311c. Taking into consideration retrofitting to an existing load port 1, the reflective optical sensor 311 is provided in the panel unit 14, avoiding an area near the load port door 13 where other sensors and other components are located. Furthermore, the reflective optical sensor 311 and reflector 32 are positioned so that the emitted light L1 and reflected light L2 are not obstructed by other sensors, fittings (such as latch mechanisms) 131, suction pads, etc. Specifically, the optical sensor unit 31 is primarily composed of a first bracket 312 attached to the panel unit 14 at the upper edge of the opening in the panel unit 14 into which the load port door 13 is fitted, a second bracket 313 attached to the first bracket 312 so that its angle can be adjusted, and the reflective optical sensor 311 fixedly supported by the second bracket 313. The first bracket 312 and the second bracket 313 function to support the reflective optical sensor 311 and also function as an angle adjuster for the reflective optical sensor 311. The first bracket 312 is attached by screwing one L-shaped piece (fixing piece 312a) to an attachment portion (not shown) provided on the panel portion 14 for attaching various sensors and parts. The remaining piece (support piece 312b) of the first bracket 312 has a round hole 312b1 formed on the base end and an elliptical long hole 312b2 formed on the tip end. The second bracket 313 has one L-shaped piece (standing piece 313a) attached to the support piece 312b of the first bracket 312, and the reflective optical sensor 311 attached to the remaining piece (attaching piece 313b).

[0030] The upright piece 313a has round holes 313a1 and 313a2 formed at positions corresponding to the round holes 312b1 and the elongated holes 312b2, and is fixed with a bolt (not shown) and a nut (not shown) inserted through the round holes 312b1 and 313a1, thereby positioning the upright piece 313a relative to the fixed piece 312a. On the other hand, the angle of the upright piece 313a relative to the fixed piece 312a can be adjusted by adjusting the position of the round hole 313a2 within the range of the elongated hole 312b2 and then fixing it with a bolt (not shown) and a nut (not shown) inserted through the round holes 313a2. Furthermore, the mounting piece 313b has an insertion hole (not shown) formed therein through which the cylindrical sensor body 311a of the reflective optical sensor 311 is inserted, and with the sensor body 311a passing through this insertion hole, the body of the sensor body 311a is fastened and fixed by a nut 313c and a washer 313d that are paired above and below the mounting piece 313b. A light-emitting unit 311b and a light-receiving unit 311c are provided on the underside of the sensor body 311a, and a cord 311d extending from the top side is connected to a control unit and a sensor amplifier provided in the load port 1. If a sensor amplifier is provided to amplify the signal from the sensor, the sensor amplifier can be placed in a position where it does not interfere with other parts, such as on the back side of the top surface of the load port main body 11, and the sensor body 311a and the sensor amplifier can be connected by wiring.

[0031] 1 and 5 , the reflector 32 is disposed on the upper surface of the main body 11 of the load port 1 near the FOUP support table 12 and is a member capable of emitting light. In this embodiment, the reflector 32 is formed of a rectangular sticker piece having a reflective surface 32a on its front surface that can appropriately scatter and reflect light and a removable adhesive surface on its back surface, and a release sheet (not shown) is attached to the back surface for protection before being affixed to the upper surface of the main body 11. Specifically, the reflector 32 is disposed on the upper surface of the main body 11, closer to the panel unit 14 than the FOUP support table 12. However, because the FOUP support table 12 is moved back and forth to adjust its position for each type of FOUP 2, the reflector 32 is attached to a front portion that is very close to the FOUP support table 12 at the undock position of the FOUP support table 12 corresponding to each FOUP 2. The optimum position for the reflector 32 is on the top surface of the load port main body 11, slightly closer to the load port door 13 than the front of the FOUP lid 22 in the undocked position. The position of the reflector 32 can be changed by replacing the reflector 32 depending on the type of FOUP 2 and the undocked position of the FOUP support base 12. When changing the position of the reflector 32, or when attaching the reflective optical sensor 311 to the load port 1, the mounting angle of the reflective optical sensor 311 (the angle of the optical axis of the emitted light L1 and the angle at which light reception efficiency for the reflected light L2 is good) can be adjusted or fine-tuned by adjusting the positions of the elongated hole 312b2 and the round hole 313a2 described above.

[0032] The light beam for detecting the detachment of the FOUP lid 22 is emitted from the light-emitting unit 311b of the reflective optical sensor 311 downward, and is reflected by the reflecting surface 32a of the reflector 32, resulting in reflected light L2 that reaches the light-receiving unit 311c from bottom to top. The optical axes of the emitted light L1 and reflected light L2 are inclined in the front-to-rear direction based on the relative positions of the reflective optical sensor 311 and the reflector 32. Specifically, as shown in FIG. 5 , the reflector 32 located below is positioned further rearward (away from the load port door 13) than the reflective optical sensor 311 located above. In other words, the optical axes of the emitted light L1 and reflected light L2 are inclined relative to the surface direction (vertical direction) of the FOUP lid 22. By providing the reflective optical sensor 311 and the reflector 32 so that the optical axis is inclined in this manner, the detection range of the FOUP lid 22 in the front-to-rear direction can be made wider compared to when the optical axis is parallel to the surface direction of the FOUP lid 22. This improves the reliability of detection when the FOUP lid 22 falls off the FOUP body 21.

[0033] Next, a method for detecting an abnormality in the FOUP lid 22 in the load port 1 and FOUP lid detachment detection device 3 of this embodiment will be described with reference to Figures 7 and 8. First, Figure 7 shows the process from closing the FOUP lid 22 to releasing (unclamping) the clamped state of the FOUP 2 by the FOUP support base 12 under normal conditions when the FOUP lid 22 has not fallen off. When the FOUP body 21 is open and in close contact with the panel 14, the FOUP body 21 is in communication with the interior of the transport device, and the FOUP lid 22 is engaged with the load port door 13 and positioned in a lowered position (0.LOAD) by the opening / closing device 15 (see Figure 5). From this state, the opening / closing device 15 is raised (1. DOOR UP), and then the opening / closing device 15 is retracted toward the panel section 14 to fit the load port door section 13 into the opening of the panel section 14, thereby closing the FOUP body 1 with the FOUP lid 22 (2. DOOR CLOSE, closing process). Next, the mating section 131 of the load port door section 13 and the mated section 221 of the FOUP lid 22 are released from their mated state (3. LATCH, circle in the figure), and the suction state by the suction pad 132 is released (4. SUCCTION OFF, circle in the figure). In the process up to this point, in the FOUP lid detachment detection device 3, if the FOUP 2 (FOUP body 21 and FOUP lid 22) is not translucent, the emitted light L1 emitted from the light-emitting unit 311b of the reflective optical sensor 31 is blocked before reaching the reflector 32, so no reflected light L2 is generated, and the reflected light L2 cannot be received by the light-receiving unit 311c (there is an obstacle), and the reflective optical sensor 31 continues to detect this (Sensor detect). In addition, if the FOUP2 (FOUP body 21 and FOUP lid 22) is translucent, such as being made of a transparent material, the emitted light L1 emitted from the light-emitting unit 311b reaches and is reflected by the reflector 32, and the reflected light L2 reaches the light-receiving unit 311c. However, as the emitted light L1 and reflected light L2 pass through the translucent FOUP2, the amount of light decreases, and the reflective optical sensor 311 continues to detect that the light-receiving rate of the reflected light L2 has decreased (that an obstacle is present).Next, the FOUP support base 12 is retracted to release the docking between the peripheral edge of the FOUP body 21 and the panel section 14 of the load port 1 (undocking process), and when the FOUP 2 moves to the undock position (5. UNDOCK), a space of a predetermined distance is created in the front-to-rear direction between the panel section 14 and the FOUP lid 22. As a result, the emitted light L1 projected from the light-projecting section 311b reaches and is reflected by the reflector 32, and this reflected light L2 reaches the light-receiving section 311c with a sufficient light-receiving rate, so that the reflective optical sensor 311 is no longer able to detect an obstacle (sensor not detect), and it is determined that the FOUP lid 22 is normally closed to the FOUP body 21. At this time, the undock sensor determines whether the FOUP 2 is undocked based on the position of the FOUP support base 12 on which it is placed, and if it determines that the FOUP 2 is undocked, it detects the undocked state (undock sensor ON, undock process). Furthermore, even if the FOUP 2 is released from the clamped state by the FOUP support base 12 (6. UNCLAMP), the reflective optical sensor 311 cannot detect an obstacle (sensor not detect), and the state in which it is determined that the FOUP lid 22 is normally closed on the FOUP body 21 is maintained. Note that the presence sensor 16 and the seating sensor 17 are both detecting (ON) until the FOUP 2 is lifted off the FOUP support base 12.

[0034] On the other hand, a case where the FOUP lid 22 is not properly closed against the FOUP body 21 when the FOUP 2 is moved to the undock position, causing a detachment abnormality, will be described with reference to Figure 8 in accordance with Figure 7. In this case, the process from when the opening / closing device 15 places the FOUP lid 22 and load port door 13 in the lowered position (0. LOAD) to when suction to the internal atmosphere of the FOUP body 21 is released (4. SUCCTION OFF) is the same as under normal circumstances, and during this time the reflective optical sensor 311 in the FOUP lid detachment detection device 15 continues to detect the presence of an obstacle (Sensor detect). Subsequently, when the FOUP support base 12 is retracted and the FOUP lid 22 is released from the load port door 13 (undocking step), and the FOUP 2 is moved to the undock position (5. UNDOCK), if the FOUP lid 22 falls off the top surface of the load port body 11 without closing the FOUP body 21, the emitted light L1 emitted from the light-emitting unit 311b will be blocked without reaching the reflector 21 (if the FOUP lid 22 is translucent, the light-receiving rate of the reflected light L2 will be lower than normal), and the reflective optical sensor 311 will continue to detect the presence of an obstacle (sensor detect). Furthermore, even when the clamped state of the FOUP 2 by the FOUP support base 12 is released (6. UNCLAMP), the reflective optical sensor 311 continues to detect the presence of an obstacle (sensor detect, detachment detection step). At this time, the undock sensor detects the undocked state (undock sensor ON) (undocking process), and it is determined that an abnormality has occurred in the FOUP lid 22 falling off while the FOUP 1 is separated from the panel portion 14 (fall-off determination process). Furthermore, if both the presence sensor 16 and the seating sensor 17 are in a detection (ON) state, it is possible to reliably determine that an abnormality has occurred in the FOUP lid 22 falling off before the FOUP 2 is lifted off the FOUP support base 12 by the external transport device, making it possible to stop the FOUP 2 before it is released by the external transport device.

[0035] FIG. 8 shows a state in which the FOUP lid 22 has fallen off while tilting forward between the FOUP body 21 and the load port door section 13, but various modes of falling are conceivable, such as when the FOUP lid 22 falls off while tilting backward between the FOUP body 21 and the load port door section 13 and panel section 14, as exemplified in FIG. 9 (a1: the FOUP lid 22 is tilted forward towards the load port door section 13 and panel section 14, a2: the FOUP lid 22 is tilted backward towards the FOUP body 21), when it falls off in a vertical position along the FOUP body 21 (b), or when it falls off in a vertical position along the load port door section 13 (panel section 14) (c). In the load port 1 and FOUP lid detachment detection device 3 of this embodiment, the light-emitting unit 311b of the reflective optical sensor 311 emits emitted light L1 obliquely toward the reflecting surface 32a of the reflector 32, and the reflected light L2 reflected by the reflecting surface 32a is reflected obliquely and received by the light-receiving unit 311c, so that in any of these detachment modes, either the emitted light L1 or the reflected light L2 is blocked by the fallen FOUP lid 22, making it possible to reliably detect an abnormal detachment of the FOUP lid 22. Even if the FOUP lid 22 is translucent, the emitted light L1 and the reflected light L2 pass through the fallen FOUP lid 22 a total of two times, so that a large decrease in the amount of reflected light L2 received by the light-receiving unit 311c is detected (a low light-receiving rate), making it possible to reliably detect an abnormal detachment of the FOUP lid 22. Such advantages can be obtained even when the position of the reflector 17 is changed or the mounting angle of the reflective optical sensor 161 is changed or adjusted in accordance with the movement of the FOUP support table 12 in the forward and backward directions due to a change in the type of FOUP 2.

[0036] It should be noted that the present invention is not limited to the above-described embodiment. For example, the FOUP lid detachment detection device 3 in the above-described embodiment has been described as being retrofitted to the load port 1, but it may also be installed on the load port 1 from the beginning as a standard or optional feature. Since it is difficult to retrofit the two light-emitting and light-receiving parts of a transmission-type optical sensor separately to an existing load port, it is realistic to install it on the load port as standard equipment. However, the FOUP lid detachment detection device 3 in this embodiment can easily be retrofitted to the load port 1 or provided as standard equipment on the load port 1.

[0037] Furthermore, in the case of a load port employing a transmission-type optical sensor as in Patent Document 1, if the FOUP lid is opaque, the light emitted from the light-emitting unit is blocked by the fallen FOUP lid and cannot be received by the light-receiving unit, making it possible for the sensor to detect an abnormality. However, if a light-transmitting FOUP lid such as a transparent lid is used, the light emitted from the light-emitting unit may pass through the fallen FOUP lid and be received by the light-receiving unit. Moreover, since the light only passes through the FOUP lid once, the reduction in light intensity is small, so it is possible that an abnormality will not be detected. Furthermore, in the load port of this document, the sensor is configured to detect an abnormality after the FOUP has been unloaded, and therefore, due to issues with detection timing, an external transport device such as an OHT (Overhead Hoist Transport) or AGV (Automatic Guided Vehicle) may move the FOUP even after an abnormality has been detected, which could cause the FOUP lid to fall or detach. In contrast, the transport container lid detachment detection device of the present invention can reliably detect when a transport container lid has not closed properly and has fallen off, whether the transport container lid is opaque or translucent.

[0038] Furthermore, instead of placing the reflector 32 on the upper surface of the load port main body 11 near the FOUP support table 12, it is also acceptable to place the reflector 32 by, for example, attaching it to the FOUP support table 12 so that it is not hidden when a FOUP 2 is placed on it. The area 32S where the reflector 32 can be placed is shown as a shaded area in Figure 5. This area 32S where the reflector 32 can be placed is the combined area of ​​the area on the upper surface of the load port main body 11 between the front edge of the FOUP support table 12 and the panel section 14 and the front wall surface (which is an inclined wall surface in the illustrated example) facing the panel section 14 of the FOUP support table 12. The position of the FOUP support table 12 in the front-to-rear direction varies depending on the type and size of the FOUP 2 being used, but points to note regarding the placement of the reflector 32 include placing the reflector 32 in a position where it will not be hidden when a FOUP 2 is placed on the FOUP support table 12 in an undocked state, and determining the height (thickness) of the reflector 32 so as not to interfere with the movement of the FOUP support table 12, since the FOUP support table 12 passes over the reflector 32 and approaches the panel section 14 when the FOUP 2 is docked with the panel section 14. Furthermore, the reflector can be attached to the transport container support table in a variety of appropriate ways depending on the relationship with the load port, such as by attaching it with a sticker, by using a magnet, or by fastening it with screws.

[0039] Furthermore, in the above-described embodiment, an example has been shown in which when the reflective optical sensor 311 detects the detachment of the FOUP lid 22, it is confirmed that the undock sensor, the presence sensor 16, and the seating sensor 17 are all ON, and then a determination is made as to whether or not the FOUP lid 22 has detached. However, it is not necessarily necessary to use all of the undock sensor, the presence sensor 16, and the seating sensor 17; it is possible to determine whether or not the FOUP lid 22 has detached by using at least the undock sensor alone, and in addition, by using one or both of the presence sensor 16 and the seating sensor 17, the reliability and safety of detecting an abnormality in detachment can be improved.

[0040] Furthermore, the optical axis (emitted light L1, reflected light L2) of the reflective optical sensor 311 may be set obliquely in the front-to-back direction as in the above-described embodiment, or may be set obliquely in the front-to-back and left-to-right directions as long as a front-to-back component is included. Even if the positions of the reflective optical sensor 311 and the reflector 32 are interchanged, the same effect as in this embodiment can be obtained.

[0041] Furthermore, the specific configuration of each part is not limited to the above embodiment, and various modifications are possible within the scope of the present invention.

[0042] DESCRIPTION OF SYMBOLS 1... Load port 2... Transfer container (FOUP) 12... Transfer container support base (FOUP support base) 13... Load port door (load port door portion) 21... Transfer container body (FOUP body) 22... Transfer container lid (FOUP lid) 3... Transfer container lid detachment detection device (FOUP lid detachment detection device) 31... Reflective optical sensor 32... Reflector 312, 313... Angle adjustment unit (first bracket, second bracket)

Claims

1. A transport container lid detachment detection device that is attached to a load port provided at the entrance / exit of a substrate processing apparatus and is used to detect the detachment of a transport container lid, comprising: a reflector located near a transport container support table that supports a transport container having a transport container lid that opens and closes relative to the transport container body and stores substrates inside the transport container body, and that moves the transport container back and forth relative to the entrance / exit; and a reflective optical sensor located near a load port door that detachably engages with the transport container lid for the transport container placed on the transport container support table to open and close the transport container lid relative to the transport container body; the reflective optical sensor is configured to receive reflected light generated when light emitted from the reflective optical sensor is reflected by the reflector in an oblique direction that includes a component in the forward and backward movement direction of the transport container; and the reflective optical sensor is configured to detect the presence of the detached transport container lid at an undock position where the docking state between the load port and the transport container is released.

2. A transfer container lid detachment detection device according to claim 1, wherein the position of the reflector is changeable in the vicinity of the transfer container support base.

3. A transfer container lid detachment detection device according to claim 1 or 2, further comprising an angle adjustment unit for adjusting the mounting angle of said reflective optical sensor.

4. A transfer container lid detachment detection device according to claim 1, wherein the reflective optical sensor is mounted at a position where the optical axes of the emitted light and the reflected light avoid other components mounted on the load port.

5. A load port provided at the entrance / exit of a substrate processing apparatus, comprising: a transport container support stand that supports a transport container having a transport container lid that opens and closes relative to a transport container body and stores substrates inside the transport container body, and moves the transport container back and forth relative to the entrance / exit; a load port door that opens and closes the transport container lid relative to the transport container body by detachably engaging with the transport container lid for the transport container placed on the transport container support stand; and a transport container lid detachment detection device that detects the detachment of the transport container lid from the transport container body, a load port characterized in that the transport container lid detachment detection device comprises a reflector arranged near the transport container support table and a reflective optical sensor arranged near the load port door, and is configured so that the reflective optical sensor receives reflected light generated when light emitted from the reflective optical sensor is reflected by the reflector in an oblique direction that includes a component of the forward and backward movement direction of the transport container, and the reflective optical sensor is configured to detect the presence of a detached transport container lid at an undock position where the load port and the transport container are released from their docked state.

6. A method for detecting the detachment of a transport container lid of a transport container that contains substrates inside the transport container body and is placed on a transport container support stand of the load port, using a transport container lid detachment detection device having a reflective optical sensor and a reflector equipped on a load port provided at the entrance / exit of a substrate processing apparatus, comprising: a closing step in which the transport container lid is closed to the transport container body by a load port door that detachably engages with the transport container lid; an undock step in which the transport container support stand is moved back in a direction away from the load port door to undock the load port and the transport container; and an undock detection step in which an undocked state in which the transport container support stand has moved to an undock position is detected by an undock sensor provided on the load port. A method for detecting detachment of a transport container lid, comprising: a detachment detection process in which the reflective optical sensor arranged near the load port door emits light in an oblique direction including a component in the forward and backward movement direction of the transport container support platform, and the reflective optical sensor receives reflected light generated by the emitted light being reflected by the reflector arranged near the transport container support platform, defining a normal state as the state in which the reflective optical sensor receives the reflected light, and detects the presence of a detached transport container lid if the reflective optical sensor cannot receive the reflected light or if the amount of reflected light or light reception rate is smaller than a predetermined threshold; and a detachment determination process in which, if the undocked state is detected in the undock detection process and the presence of a detached transport container lid is detected in the detachment detection process, the method determines that the transport container lid has fallen off from the transport container body.

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