JP7609011B2 - Track Cleaning Device - Google Patents

Description

The present invention relates to a track cleaning device. In particular, the present invention relates to a transport vehicle that transports objects such as FOUPs on a track installed in a clean room in a semiconductor manufacturing factory, and a transport facility equipped with the transport vehicle.

In semiconductor manufacturing plants, for example, the process of manufacturing semiconductor wafers is carried out in a clean room where temperature and humidity are controlled and foreign matter (particles) of a few microns in size are removed, because contamination from the clean room environment reduces product yield. In the clean room, temperature- and humidity-controlled air taken in by an outdoor air conditioner is passed through an Ultra Low Penetration Air (ULPA) filter before being supplied to the work area. If more strict control of the cleanliness of the work area is required, a chemical filter can be added to supply even cleaner air to the work area from which chemical contaminants have been removed.

Meanwhile, in the semiconductor manufacturing process, wafers are transported and stored in sealed containers called FOUPs (Front Opening Unified Pods). In clean rooms, many products come and go during the manufacturing process, and products before and after being placed in manufacturing and inspection equipment for processing are stored in stockers that store these FOUPs. To reach the stocker and processing equipment, a transport vehicle in an overhead transport (OHT) system moves vertically from a track (rail) installed in the ceiling of the clean room, transporting and transferring between the stocker and processing equipment. These OHT systems are constantly transporting FOUPs between the stocker and equipment without stopping.

Patent document 1 describes a three-dimensional installation method for transport and transfer means such as processing equipment, carrier stockers, and OHTs in a clean room.

Patent document 2 describes a gripper that prevents the OHT transport means from falling and is easy to maintain.

Patent document 3 describes a sensor in an OHT that reliably detects obstacles while the vehicle is moving.

JP 2001-267195 A JP 2012-015420 A JP 2012-079153 A

Because the OHT system was also in operation while the clean room was in operation, it was difficult to clean the dust that had accumulated on the tracks (rails), and cleaning could only be done when the clean room and OHT system were stopped (about once every one to two years). In addition, in the OHT system, the transport vehicles were powered by electricity supplied from electric wires laid on the tracks, and since the wires were supplied with high voltage electricity and were exposed, workers had to perform cleaning work after cutting off the power. In addition, in the OHT system, the tracks were laid near the ceiling of the clean room, so when workers performed cleaning work, they had to work at a high altitude, making it a dangerous and time-consuming task.

The present invention has been made to solve the above problems, and aims to provide a track cleaning device that can collect dust that has accumulated on the track along which the transport vehicle travels in the clean room and clean the track without having to stop the operation of the clean room or the transport system.

In order to solve the above problems, the present invention provides a track cleaning device for cleaning a track along which a transport vehicle runs in a clean room, comprising:
A traveling vehicle that travels along the track;
and a dust collecting means for collecting dust accumulated on the track.

This type of track cleaning device can collect dust that has accumulated on the track while traveling along the track in a clean room, so it is possible to collect dust that has accumulated on the track and clean the track in the clean room without having to stop the operation of the clean room or the conveying system.

In addition, even if the track to be cleaned is installed near the ceiling of a clean room, the track cleaning device of the present invention eliminates the need for workers to clean it directly, eliminating the dangers associated with working at heights and significantly shortening the worker's working time.

For example, the dust collecting means may include a roller-shaped brush or sponge that contacts the track and collects dust on the track, and a dust collector that sucks up the collected dust.

Such a track cleaning device can more efficiently collect dust that has accumulated on the track.

Alternatively, the dust collection means may be an adhesive roller.

Such a track cleaning device would make it easier and more cost-effective to collect dust that has accumulated on the track.

As described above, the track cleaning device of the present invention can easily clean the tracks in a clean room by collecting dust that has accumulated on the tracks along which transport vehicles travel within the clean room, without having to stop the operation of the clean room or transport system.

1 is a schematic side view showing a first embodiment of a track cleaning device of the present invention; FIG. FIG. 2 is a schematic front view of the track cleaning device shown in FIG. 1; FIG. 2 is a schematic side view showing a second embodiment of the track cleaning device of the present invention. FIG. 11 is a schematic side view showing a third embodiment of the track cleaning device of the present invention. FIG. 1 is a schematic diagram showing an example of the positional relationship between an OHT system, a processing device, and an EFEM in a clean room. FIG. 1 is an explanatory diagram showing an example of a typical FOUP. FIG. 1 is a schematic diagram showing an example of an OHT system in a clean room. FIG. 11 is a schematic diagram showing another example of an OHT system in a clean room. FIG. 1 is a schematic diagram prior to transfer of a FOUP from the OHT system to the EFEM. FIG. 13 is a schematic diagram of a FOUP during transfer from the OHT system to the EFEM.

As mentioned above, there was a need for the development of a track cleaning device that could collect dust that had accumulated on the track along which the transport vehicle travels within the clean room and clean the track without having to stop the operation of the clean room or the transport system.

In order to solve the above problems, the inventors have conducted extensive research into methods and devices for cleaning dust that has accumulated on the tracks of vehicles (transport vehicles) in the OHT system of clean rooms in semiconductor factories while the clean rooms and OHT systems are in operation. As a result, they have found that if the OHT system vehicle is equipped with a dust collection means (for example, a combination of a brush or sponge that collects dust and a dust collector that sucks up the dust, or an adhesive roller), it is possible to collect dust while traveling on the tracks, and have completed the present invention.

That is, the present invention is a track cleaning device for cleaning a track along which a transport vehicle runs in a clean room,
A traveling vehicle that travels along the track;
and a dust collecting means for collecting dust accumulated on the track.

The following describes in detail the embodiments of the present invention with reference to the drawings, but the present invention is not limited to these.

Below, as an embodiment of the present invention, a track cleaning device for cleaning the tracks of an OHT system in a clean room will be described. First, the configuration of the OHT system according to this embodiment will be described.

Figure 5 is a side view showing an example of the positional relationship between the OHT transport system, processing equipment, and EFEM (Equipment Front End Module) according to this embodiment.

The OHT system 2 shown in FIG. 5 includes a track 21 and a transport vehicle 3.

The track 21 is laid on the ceiling of the clean room 100, and is made of metal such as stainless steel or aluminum for strength, in order to support the running part 31 of the transport vehicle 3 and the main body 32 containing the FOUP 4 shown in FIG. 6. The shape of the track 21 can be, for example, two rails with an L-shaped cross section facing each other as shown in FIG. 7, or a cross-sectional structure with a mouth-shaped opening with a part cut out at the bottom as shown in FIG. 8.

The transport vehicle 3 is placed on a track 21, and is capable of transporting the transported object, a FOUP 4, by traveling on the track 21. Although not shown here, shelves (storage units) for storing the FOUPs 4 are provided along the track 21.

The transport vehicle 3 consists of a running section 31 and a main body 32. The main body 32 is suspended from the running section 31 by a support 33 disposed between the two tracks 21. The main body 32 is equipped with a FOUP gripper 34. When the transport vehicle 3 is in a state in which a FOUP 4 is contained within the main body 32 as shown in FIG. 9, the lifting belt 35 is unwound from the main body 32 as shown in FIG. 10, and the FOUP 4 is placed on the stand 51a of the EFEM 5.

The EFEM 5 is connected to the processing device 6. The EFEM 5 and the processing device 6 will be described later.

Next, the movement of the transport vehicle 3 on the track 21 will be described. The transport vehicle 3 placed on the track 21 moves with the running part 31 placed on the track 21 and the main body 32 suspended from the track 21. When moving, the plastic wheels 31a placed on the running part 31 come into contact with the track 21, and dust is generated by the wheels 31a being scraped off due to friction, and this dust accumulates on the track 21. In addition, air is circulated within the clean room 100, and a very small amount of dust is also contained therein and accumulates on the track 21.

The present invention has been made in consideration of the above-mentioned problems. Below, we will explain several embodiments of the present invention and a method and device for cleaning dust accumulated on the track 21 while traveling on the track 21.

(First embodiment)
Fig. 1 is a schematic side view of a track cleaning device according to a first embodiment, and Fig. 2 is a schematic front view from viewpoint II in Fig. 1. In Fig. 1 and Fig. 2, the track cleaning device 1 according to the first embodiment is composed of a traveling vehicle 11, a main body 13, and a dust collecting means 12. The traveling vehicle 11 travels on a track 21 by wheels 11a arranged on the front, rear, left and right sides of the traveling vehicle 11, and the driving force for traveling is obtained from a motor (not shown) arranged in the traveling vehicle 11. The traveling vehicle 11 is driven by obtaining electric power from an electric wire (not shown) placed on the track 21 as a power source.

Furthermore, the central lower part of the running car 11 is partially open between it and the track 21, and a roller-shaped track dust cleaning brush 12a is arranged in this open position, and the brush 12a rotates in contact with the track 21 in accordance with the running of the running car 11 on the track 21, collecting dust accumulated on the track 21 from the tracks 21 on both sides into the central space between them. The brush 12a can collect dust more efficiently if it is structured so that the spirally formed unevenness rotates in a direction that collects dust in the central space.

The brush 12a can be made of resin, for example. The brush 12a can also be in the shape of a sponge (e.g., a resin sponge), but a brush is preferred because it has better resistance to friction with the track 21 and can accommodate uneven surfaces.

Furthermore, since there is a possibility that the brush 12a may come into contact with the electric wire that is the power source arranged on the track 21, it is preferable that the material of the brush 12a be an insulating material.

The main body 13 is suspended from the running vehicles 11 arranged on the two tracks 21 by a support 14 arranged between the two tracks 21. Inside the main body 13, a dust collector 12b, which is a device for collecting dust, is arranged. Furthermore, the support 14 connecting the running vehicles 11 and the main body 13 is penetrated by a suction port 12c of the dust collector 12b, which sucks up dust collected in the center of the track 21 by the brush 12a below the running vehicles 11. In other words, the brush 12a and the dust collector 12b constitute the dust collection means 12.

In addition, since the OHT system according to this embodiment operates in a clean room, it is preferable to exhaust the air from the dust collector 12b after removing dust using an ULPA (Ultra Low Penetration Air) filter.

Furthermore, as shown in Figures 1 and 2, cameras 11b may be placed in front of and behind the traveling vehicle 11 to photograph the presence or absence of dust on the track 21 and enable monitoring by a wireless system, thereby making it possible to check whether the track cleaning device 1 is cleaning the dust on the track 21.

Second Embodiment
Fig. 3 is a side view of a track cleaning device according to the second embodiment. In Fig. 3, the track cleaning device 1 according to the second embodiment is composed of a traveling vehicle 11, a main body 13, a cleaning vehicle 15, and a dust collecting means 12. In the first embodiment, the traveling vehicle 11 is provided with both a function for traveling on the track 21 and a function for cleaning, but in the second embodiment, in the case where the space for arranging these functions is insufficient, the traveling vehicle 11 and the cleaning vehicle 15 are separated, and the traveling vehicle 11 cleans the track 21 by pulling the cleaning vehicle 15. It is preferable to have the same configuration as the first embodiment except for the above.

Third Embodiment
4 is a side view of a track cleaning device according to a third embodiment. In FIG. 4, the track cleaning device 1 according to the third embodiment is composed of a traveling vehicle 11 and a dust collecting means. In the first embodiment, a main body 13 is hung from the traveling vehicle 11 and a dust collector 12b having a dust collecting function for cleaning the inside of the main body is arranged, but in the third embodiment, in order to make a configuration that is simpler and less costly, an adhesive roller 12d is used as the dust collecting means instead of the brush in the traveling vehicle 11 and the dust collector is omitted, making it possible to collect dust on the track 21 easily and at low cost. It is more preferable to replace this adhesive roller 12d periodically.

The track cleaning device 1 according to the first to third embodiments described above can collect dust accumulated on the track 21 while traveling on the track 21 in the clean room 100, so that the dust accumulated on the track 21 can be collected and the track 21 in the clean room 100 can be cleaned without stopping the operation of the clean room 100 or the OHT system 2.

In addition, by using the track cleaning device 1 according to the first to third embodiments, workers do not need to clean the track 21 directly, eliminating the dangers associated with working at heights and significantly shortening the working time of workers.

Here, the FOUP 4 transported by the OHT system 2 described with reference to Figures 5 and 7 to 10 will be described with reference to Figure 6.

FOUP4 in Figure 6 is a sealed storage container that stores wafers. FOUP4 comprises a container body 41 and a lid 42. The container body 4 is formed so that it can store multiple wafers, and has an opening on the front. Wafers are inserted and removed through this opening. In Figure 6, the front of the container body 41 is the right side. The lid 42 is used to open and close the opening on the front of the container body 41. When the lid 42 closes via a gasket (not shown), the inside of the container body 4 is sealed.

Figure 5 and Figures 7 to 10 show the case where wafers W are stored and transported in a FOUP 4. Normally, the FOUP 4 is fully filled with wafers W. Note that a full filling usually consists of, for example, 25 wafers, but for simplicity, the drawings show only 8 wafers.

In the above, a FOUP 4 has been described as an example of the object to be transported by the OHT system 2, but the object to be transported is not limited to a FOUP. The object to be transported can also be, for example, a sealed storage container of the FOSB (Front Opening Shipping Box) type.

Furthermore, the wafers W stored in the FOUP or FOSB are not particularly limited, and examples thereof include various semiconductor wafers such as semiconductor silicon wafers and compound semiconductor wafers, and in particular may be polished silicon wafers or silicon wafers formed by epitaxial growth.
In addition, wafer-like objects such as glass substrates can also be transported.

Next, we will explain the EFEM 5 and processing device 6 shown in Figures 5, 9, and 10.

The EFEM 5 transports the wafers W stored in the FOUP 4 from the FOUP 4 to the processing device 6 using a mini-environment system. The EFEM 5 includes a transport robot 52, a transport chamber 53, and a load port 51.

The transport robot 52 retrieves and transports the wafers W stored in the FOUP 4. The transport robot 52 can also place the wafers W in the FOUP 4 and store them there.

The transfer chamber 53 houses the transfer robot 52. The wafer W removed from the FOUP 4 by the transfer robot 52 is transferred to the processing device 6 via the transfer chamber 53. Conversely, the wafer W processed in the processing device 6 can also be transported and placed in the FOUP 4 via the transfer chamber 53. A wafer transfer entrance 54 is provided in the wall of the transfer chamber 53 for transferring the wafer W to and from the FOUP 4.

The load port 51 is an interface for transferring wafers W between the FOUP 4 and the transfer chamber 53. When transferring wafers W between the FOUP 4 and the transfer chamber 53, the transfer is via the load port 51.

This load port 51 comprises a load port stand (stand) 51a and a load port door (door) 51b.

As shown in Figures 5 and 10, the stand 51a is where the FOUP 4 is placed. The height and position are adjusted so that the FOUP 4's lid 42 can be placed facing the wafer loading/unloading entrance 54.

The door 51b is for opening and closing the wafer loading/unloading entrance 54. That is, the door 51b can be fitted into the wafer loading/unloading entrance 54 and can close the opening. The door 51b can also be removed from the wafer loading/unloading entrance 54 and can open the opening. Figures 5, 9, and 10 show the state in which the opening of the wafer loading/unloading entrance 54 is closed by the door 51b.

The processing device 6 processes the wafer W that is transported to the processing device 6.

The present invention is not limited to the above-described embodiment. The above-described embodiment is merely an example, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and exhibits similar effects is included within the technical scope of the present invention.

1...track cleaning device, 2...OHT system, 3...transport vehicle, 4...FOUP, 5...EFEM, 6...processing device, 11...traveling vehicle, 11a...wheels, 11b...camera, 12...dust collection means, 12a...track dust cleaning brush, 12b...dust collector, 12c...suction port, 12d...adhesive roller, 13...main body, 14...support, 15...cleaning vehicle, 21...track, 31...traveling part, 31a...wheels, 32...main body, 33...support, 34...FOUP gripper, 35...lifting belt, 41...container body, 42...lid, 51...load port, 51a...frame, 51b...door, 52...transport robot, 53...transport chamber, 54...wafer loading/unloading entrance, 100...clean room, W...wafer.

Claims (1)

A track cleaning device for cleaning a track along which a transport vehicle runs in a clean room, comprising:
A traveling vehicle that travels along the track;
and a dust collecting means for collecting dust accumulated on the track ,
the dust collecting means includes a roller-shaped brush that contacts the track and collects dust on the track, and a dust collector that sucks up the collected dust,
The track cleaning device is characterized in that the roller-shaped brush has a structure that rotates the spirally formed unevenness in a direction that collects the dust into the space at the center of the track .

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