Load port

A load port is provided with a table and a plate. The table is arranged on a side of a front wall of an atmospheric transfer unit for transferring a piece of material under processing and is adapted to mount on it a container with the piece of material received in the same. The plate serves to isolate an interior of the atmospheric transfer unit from an exterior of the atmospheric transfer unit. The load port includes an exhaust duct arranged on a rear side of the plate and a fan arranged in a lower extremity of the exhaust duct. By the exhaust duct and the fan, an internal atmosphere of the atmospheric transfer unit can be exhausted into the atmosphere.

FIELD OF THE INVENTION

This invention relates to a load port suitable for arrangement in a semiconductor fabrication facility, and especially to a load port suitable for arrangement in combination with an atmospheric transfer unit in a semiconductor fabrication facility to handle a container with at least one, generally plural pieces of material such as semiconductor wafers received therein either before or after their processing.

DESCRIPTION OF THE BACKGROUND

In a semiconductor fabrication process, at least one, generally plural pieces of material such as semiconductor wafers (hereinafter simply called “semiconductor wafers” for the sake of brevity) under processing are placed in a container called “FOUP” (Front Opening Unified Pod) or “FOSB” (Front Opening Shipping Box), and are transferred in a substantially-sealed state to a semiconductor fabrication facility by a transfer apparatus.

Until the semiconductor wafers are transferred to a processing chamber in the semiconductor fabrication facility, they are maintained out of contact with the external air. Upon processing, they are taken out of the container by an atmospheric transfer unit such as an atmospheric transfer robot, and are moved into the processing chamber via a transfer chamber.

The atmospheric transfer unit in the semiconductor fabrication facility is, therefore, equipped with a handling apparatus called “load port”. While maintaining them in the substantially sealed state, this load port makes it possible to take the semiconductor wafers out of the container, for example, an FOUP and to transfer them into the processing chamber of the semiconductor fabrication facility, so that in the processing chamber, processing is applied to the semiconductor wafers as needed.

As appreciated from the foregoing, a load port is an apparatus equipped with a function and structure required to bring the interior of a semiconductor fabrication facility into communication with a container and then to take semiconductor wafers out of the container or to place semiconductor wafers in the container while sealing the container from the exterior, and is known conventionally (see, for example, JP-A-2004-165458).

The above-described conventional load ports are, however, configured without taking into consideration a pressure difference between an internal atmosphere of a container and that of a semiconductor fabrication facility. As soon as a door of a load port is opened to bring the interiors of the container and semiconductor fabrication facility into communication with each other, the internal atmosphere of the semiconductor fabrication facility flows into the container due to the pressure difference, thereby developing a problem that particles are carried into the container from a drive unit for the door, an atmospheric transfer robot and the like and deposit on semiconductor wafers to contaminate them.

With a view to eliminating the above-described problem, some other conventional load ports are known to include a fan arranged in an upper or lower part of a transfer chamber as a space through which semiconductor wafers are transferred inside a semiconductor fabrication facility. Even with such a conventional load port, however, it is difficult to produce an air stream to such an extent as reaching inside a container such as an FOUP arranged on the load port. When processing is performed with corrosive gas within the semiconductor fabrication facility, there is a potential problem that the load port may be caused to corrode around the container.

Conventionally-known load ports also include those of the construction that a drive chamber, in which a drive actuator for opening or closing a door of each load port is accommodated, is isolated from a transfer chamber by a partition plate and the partition plate is provided with guide slots to permit movements of a member by which the door itself or a carrier connected to the carrier and the drive chamber are linked to each other. These conventional load ports, however, involve a potential problem that corrosive gas existing in the transfer chamber enters the drive chamber through the slots and may cause corrosion of the carrier around its part connected to the above-mentioned member and also corrosion of the drive actuator to produce particles. There is another problem that such particles may deposit on semiconductor wafers. With respect to these potential problems, no consideration was taken in the above-described conventional art.

SUMMARY OF THE INVENTION

An object of the present invention is, therefore, to provide a load port for the transfer of at least one, generally plural pieces of material such as semiconductor wafers, which is practically free of the potential problem of corrosion development or the potential problem of deposition of particles.

In one aspect of the present invention, there is thus provided a load port provided with a table arranged on a side of a front wall of an atmospheric transfer unit for transferring a piece of material under processing and adapted to mount thereon a container with the piece of material received therein, and a plate for isolating an interior of the atmospheric transfer unit from an exterior of the atmospheric transfer unit. The load port comprises an exhaust duct arranged on a rear side of the plate, and a fan arranged in a lower extremity of the exhaust duct. By the exhaust duct and the fan, an internal atmosphere of the atmospheric transfer unit can be exhausted into the atmosphere.

By the exhaust duct and the fan, an internal atmosphere of the container may also be exhausted to the exterior of the atmospheric transfer unit.

In another aspect of the present invention, there is also provided a load port provided with a table arranged on a side of a front wall of an atmospheric transfer unit for transferring a piece of material under processing and adapted to mount thereon a container with the piece of material received therein, a plate for isolating an interior of the atmospheric transfer unit from an exterior of the atmospheric transfer unit, an opening formed in the plate to permit taking the piece of material out of the container or placing the piece of material in the container, and an accommodation chamber arranged on a side of the front wall of the atmospheric transfer unit and accommodating therein a drive unit for driving a door that opens or closes the opening of the plate. The load port comprises an exhaust duct arranged on a rear side of the plate, and a fan arranged in a lower extremity of the exhaust duct. By the exhaust duct and the fan, an internal atmosphere of the accommodation chamber can be exhausted to the exterior of the atmospheric transfer unit.

By the exhaust duct and the fan, an internal atmosphere of the container may be exhausted to the exterior of the atmospheric transfer unit as mentioned above. A corrosion preventive coating may, therefore, be applied to at least one of a surface of the exhaust duct, a surface of the fan, and a door carrier with the door supported thereon. In addition, the load port may further comprise a closure plate arranged between the door, which has moved to open the opening, and the plate, which isolates the interior of the atmospheric transfer unit and the exterior of the atmospheric transfer unit from each other, such that an interior atmosphere of the atmospheric transfer unit is prevented from flowing into the accommodation chamber.

As described above, the conventional art is accompanied by the problem that, when the door of the load port is opened, deposition of particles and corrosion take place inside the container, in the vicinities of the place where the container is arranged, and also on the door drive unit. According to the present invention, however, an air stream can be produced inside the container such as an FOUP without production of turbulence within the atmospheric transfer unit, and hence, particles and corrosive gas can be carried away from the inside and vicinities of the container and the surface and vicinities of the door drive unit. The present invention can, therefore, lessen or resolve the above-mentioned problems of the conventional art.

Further, the present invention makes it possible to lessen or resolve the above-described problems of the conventional art without requiring any substantial additional cost because it is unnecessary to additionally arrange any large equipment, for example, to additionally arrange a local ventilator in the transfer chamber.

DETAILED DESCRIPTION OF THE INVENTION AND PREFERRED EMBODIMENT

Based on the embodiment illustrated in the accompanying drawings, the load port according to the present invention will be described in more detail. InFIG. 1, a semiconductor processing system1is divided into a processing block on an upper side and an atmospheric block on a lower side thereof as viewed in the drawing. On the side of the processing block, there are plural processing chambers2for processing pieces of material, for example, semiconductor wafers (hereinafter simply called “semiconductor wafers”. A buffer chamber3is arranged in communication with the processing chambers2. On the side of the atmospheric block, there are two load-lock chambers4, via which an atmospheric transfer unit5can be brought into communication with the buffer chambers3.

The buffer chamber3is configured to have a substantially hexagonal shape in plan as viewed from the above. On the individual sides of the buffer chamber3, the processing chambers2and load-lock chambers4are arranged, respectively, such that the processing chambers2and load-lock chambers4can be brought into communication with an interior of the buffer chamber3.

Upon processing, the interiors of the processing chambers2are depressurized, processing gas is fed into the processing chamber2, and the semiconductor wafers are processed with the gas. In the illustrated semiconductor processing system1, the processing chambers2are arranged as many as four, and gas with a corrosive element such as chlorine contained therein can be fed into these processing chambers2.

On the atmospheric side (lower side) of the atmospheric transfer unit5, a plurality of load ports9are arranged. It is to be noted that inFIG. 1, the atmospheric transfer unit5is shown in cross-section to illustrate its internal construction.

Within the atmospheric transfer unit5, a Y-axis unit6is arranged to permit movements of an atmospheric transfer robot14alongside a direction in which the plural load ports9are arranged side by side. This atmospheric transfer robot14is provided with a robot arm7which holds and transfers each semiconductor wafer. On a side of the atmospheric transfer unit5, an alignment unit8is arranged to permit positional and directional adjustments of the robot arm7relative to each semiconductor wafer.

Each load port9is provided in an upper part thereof with an opening and a door for selectively opening or closing the opening. After a container15(seeFIG. 2) is mounted at a position of a predetermined height, the door is opened to bring the interior of the container15and the internal space of the atmospheric transfer unit5into communication with each other in a state that the interior of the container15is maintained sealed from the exterior.

At this time, the associated load-lock chamber4is located between the atmospheric transfer unit5and the buffer chamber3, and serves to permit a transfer of the semiconductor wafer under reduced pressure between a wafer transfer robot (not shown) arranged in the buffer chamber3and the robot arm7arranged in the atmospheric transfer unit5. In this embodiment, the load lock chambers4are used as many as two.

Each load port9will hereinafter be described more specifically with reference toFIGS. 2, 3 and 4. As illustrated inFIG. 2, the atmospheric transfer unit5is internally provided with a transfer chamber12, which serves as a space in which each semiconductor wafer is transferred under atmospheric pressure by the atmospheric transfer robot14equipped with the robot arm7.

In an upper part of the transfer chamber12, a fan unit13is arranged to produce a flow of air in a downward direction within the transfer chamber12. In association with the fan unit13, plural exhaust channels11are arranged below the atmospheric transfer robot14such that the air inside the transfer chamber12can be caused to downwardly flow from the interior of the transfer chamber12into the atmosphere as indicated by arrows.

This fan unit13serves to feed the air from the exterior of the atmospheric transfer unit5into the transfer chamber12and hence, to make the air pressure inside the transfer chamber12slightly higher than the atmospheric chamber.

As also illustrated inFIG. 1, the plural exhaust channels11are arranged in a lower part of the transfer chamber12and alongside the direction in which the load ports9are arranged side by side, in other words, along the direction in which the Y-axis unit6extends. Owing to the arrangement of the exhaust channels11, the air inside the transfer chamber12is allowed to evenly flow in the downward direction. It is to be noted that, although the plural exhaust channels11are arranged in the illustrated atmospheric transfer unit5, a single exhaust channel with a plurality of openings may be arranged and may be modified as needed in accordance with the specifications required.

Owing to the construction described in the above, a flow of air within the transfer chamber12is controlled to run in a substantially downward direction, and therefore, can serve to release and separate particles and processing gas, which have deposited on semiconductor wafers and are still remaining in the vicinities of the semiconductor wafers, respectively, and the like from the surfaces and vicinities of the semiconductor wafers.

Even when the door of the load port9is opened, the maintenance of the internal pressure of the transfer chamber12at a level slightly higher than the atmospheric pressure makes it possible to prevent the surrounding air of the atmospheric transfer unit5from flowing into the transfer chamber12, and hence, to prevent contaminants, particles, foreign matter and the like from entering the transfer chamber12so that the system and semiconductor wafers are protected from adverse effects.

Owing to the above-described construction, it is also facilitated to produce within the container15an air flow useful for the movement and ventilation of particles and corrosive gas both of which exist within the container15.

As illustrated inFIG. 2, each load port9according to this embodiment is arranged on the side of the atmosphere (on the left side as viewed inFIG. 2) relative to the transfer chamber12of the atmospheric transfer unit5, and is provided with a Box Opener/Loader to Tool Standard (BOLTS) plate16such that the BOLTS plate16is located facing the transfer chamber12. The BOLTS plate16is provided on the side of the transfer chamber12with a mapping unit18, a door19and an exhaust duct20, which are arranged along a surface of the BOLTS plate16as shown in detail inFIG. 3.

On the opposite side (outer side) of the BOLTS plate16relative to the transfer chamber12, there are arranged an accommodation chamber23and a table unit24located above the accommodation chamber23. Drive equipment for driving the load port9is accommodated in the accommodation chamber23. The sealable container15with semiconductor wafers received therein, such as an FOUP, can be mounted on the table unit24.

The BOLTS plate16is a plate which isolates the interior of the transfer chamber12of the atmospheric transfer unit5from the exterior, and has a surface facing the transfer chamber12. The BOLTS plate16has, in an upper part thereof, an opening which is opened or closed by the door19. This opening is formed at a level higher than the table24such that the opening is in registration with the position of the container15and is opposite to the container15.

Accordingly, the semiconductor wafers either before or after their processing can be carried through the opening of the BOLTS plate16, thereby making it possible to transfer the semiconductor wafers between the interior of the container15mounted on the table unit24and the transfer chamber12. At this time, the door19is moved up or down by a drive unit17to close or open the opening formed in the upper part of the BOLTS plate16. In this manner, the interior of the transfer chamber12and its exterior can be brought into communication with each other or can be shut off from each other.

In this embodiment, the load port9is provided on the side of the transfer chamber12with the exhaust duct20, and a fan21is arranged on a lower portion of the exhaust duct20. Arranged underneath the fan21is the corresponding one of the exhaust channels10. The exhaust channel10has an opening. These exhaust duct20, fan21and exhaust channel10make up an exhaust route on the side of the load port9.

Similar to the exhaust channels11, this exhaust channel10communicates the atmosphere around the atmospheric transfer unit5with the space inside the exhaust duct20so that by operating the fan21, the air in the transfer chamber12can be caused to flow into the exhaust duct20, through the exhaust duct20, through the opening formed below the fan21, toward the floor, and then to the exterior of the transfer chamber12.

As the load port9according to this embodiment is provided on the rear side of the BOLTS plate16with the exhaust duct20and the fan21, an air stream inside the transfer chamber12can be controlled on the side of the load port9. The exhaust duct20is arranged such that an air stream vertically flows through its interior.

The exhaust duct20is configured to be attached to the BOLTS plate16by bolts. The exhaust duct20is dimensioned to avoid any interference with the drive unit17for the door19, an open/closure unit for the door19or the mapping unit18upon its attachment.

The fan21is equipped with such fan capacity that, even when the door19is opened, no disturbance occurs in an air stream around the container15and a sufficient flow rate can also be obtained in the vicinity of the drive unit17to permit the exhaustion of air from the vicinity of the drive unit17. Plural fans may, therefore, be arranged as needed in some instances.

The exhaust duct20has, in its wall (front wall) on the side of the accommodation chamber23, slots22along which a carrier (not shown) for driving the door19and the mapping unit18is movable. The accommodation chamber23, which is arranged on opposite side of the BOLTS plate16relative to the transfer chamber12and accommodates the drive unit17therein, and the interior of the exhaust duct20are, therefore, in communication with each other via the slots22. By moving the carrier vertically in and along the slots22, the mapping unit18and door19supported on the carrier are vertically moved.

In this embodiment, the slots22extend from the vicinity of the fan21in the exhaust duct20to a height around the middle of the BOLTS plate16, and on the side of the transfer chamber12, the slots22are covered by its wall (rear wall) of the exhaust duct20on the side of the transfer chamber12.

When the fan21is operated, the air in the transfer chamber12flows into the exhaust duct20through an opening formed at an upper portion of the exhaust duct20and communicating the transfer chamber12and the interior of the exhaust duct20with each other, and at the same time, the air in the accommodation chamber23also flows into the exhaust duct20through the slots22. The air from the transfer chamber12and the air from the accommodation chamber23then flow together through the exhaust channels11, and finally flow out of the atmospheric transfer unit5.

Corrosive gas, particles, contaminants and the like, which exist in the accommodation chamber23, have separated and flowed in during the transfer of the semiconductor wafers, or have moved from the interior of the container15, can therefore be caused to flow out of the atmospheric transfer unit5.

To facilitate an efficient intake of particles and gas from the container15, the exhaust duct20extends upwards to the vicinity of the lower extremity of the container15mounted on the upper wall of the table unit24, and as described above, the opening is formed in the upper portion of the exhaust duct20so that the air in the transfer chamber12flows in through the opening. Further, one or more openings are also formed through the rear wall of the exhaust duct20at a height around the vertical center of the rear wall to facilitate an intake of air from a lower part of the transfer chamber12.

To prevent corrosion with the corrosive gas, corrosion preventive coatings of a predetermined thickness are applied to a surface of the exhaust duct20, a surface of the fan21and a surface of the carrier supporting thereon the door19of the load port9.

As described above, the BOLTS plate16serves to isolate the transfer chamber12of the atmospheric transfer unit5from the exterior. In addition, a closure plate25is arranged between the BOLTS plate16and the downwardly-moved door19. The closure plate25serves to prevent the internal atmosphere of the transfer chamber12of the atmospheric transfer unit5from flowing into the accommodation chamber23, in which the drive unit17of the load port9is accommodated, even when the door19is moved downwards to open the opening of the load port9.

According to this embodiment, an air stream can be produced inside the container15without production of turbulence in the transfer chamber12of the atmospheric transfer unit5even when the door19of the load port9is opened. It is, therefore, possible to prevent the deposition of particles and the development of corrosion inside the container15or in the vicinities of the place where the container15is arranged and also to prevent the deposition of particles and the development of corrosion on the drive unit positioned within the accommodation chamber23.

Since an air stream can be produced inside the container15without production of turbulence inside the transfer chamber12of the atmospheric transfer unit5as described above, the load port9according to this embodiment can lessen or resolve the above-described problems of the conventional art without requiring any additional arrangement of large equipment such as the arrangement of a local ventilator in the transfer chamber12of the atmospheric transfer unit5, and hence, without requiring any substantial additional cost.