Patent Application
20090142170
The present invention relates to a load port for use in a minienvironment employed in a semiconductor manufacturing process.
In the course of manufacturing semiconductors, wafer processing is carried out in a clean room in order to improve the yield and quality. However, recent advancements in circuitry miniaturization and higher concentrations of integrated elements, as well as increases in wafer size, and the like, has made it difficult to realize, both in terms of technology and cost, clean room environments that are capable of controlling fine dust and other microcontaminant airborne particulates. Therefore, instead of improving on the clean room, a smaller self-contained clean space called a “minienvironment” has recently been widely adopted as a localized space for enclosing wafers and the peripheral areas around the wafers during conveyance and process treatment steps. When a minienvironment is employed, two important devices are utilized: a FOUP (Front-Opening Unified Pod), which is a wafer storing container that is used to hold wafers during a semiconductor manufacturing process; and a load port that serves both as a port of entry and exit for wafers between the FOUP and the semiconductor processing equipment, and as a portion for interfacing with the transport mechanism for loading and unloading the FOUP from the semiconductor processing equipment. That is to say, clean room construction and operating costs are controlled by maintaining a high-degree clean environment within the FOUP and semiconductor processing equipment, and a low-degree clean environment between the load port and an exterior environment.
The main role normally performed by a load port is that of acting as an intermediary between the FOUP and a wafer loading and unloading device disposed within the semiconductor processing equipment by being brought into close contact with the door on the FOUP so as to be caused to open and close (see, for example, Patent Publication Reference No. 1); and it is therefore sometimes referred to as a “FOUP opener”; however, there are also load ports under development that are provided with a function for mapping the number, position, and the like, of wafers contained within the FOUP (see, for example, Patent Publication Reference No. 2).
Patent Publication Reference No. 1: Japanese Patent Publication 2004-140011
Patent Publication Reference No. 2: Japanese Patent Publication 2006-173510
In the past, wafers were unloaded one at a time from the FOUP and loaded into the semiconductor processing equipment through the load port for processing in the semiconductor processing equipment one at a time; developments in recent years, however, have seen multiple wafers unloaded from the FOUP at once and loaded into the semiconductor processing equipment together for processing as a group in the semiconductor processing equipment, so-called batch processing semiconductor manufacturing. In the case of batch processing such as that described above, a FOUP storage cabinet called a stocker is provided within the clean room in the space outside of the semiconductor processing equipment, a plurality of FOUP are stored in the stocker, wafers are unloaded sequentially from the FOUP through the load port disposed within the stocker into the semiconductor processing equipment for processing, after which the processed wafers are gathered and returned to their original FOUP through the load port, whereby the process is completed. When batch processing such as that described above is performed, an identification number is assigned to each FOUP, each wafer within each FOUP is mapped for easy management, with the aim of further increasing efficiency and reducing costs.
The present invention has been developed based on a consideration of the above-described problems, and the idea that a mapping function can be provided to the load port for mapping the wafers contained within the FOUP. In particular, it is a main object of the present invention to provide a load port that is capable of efficiently facilitating the transfer of FOUP contained within a stocker within a clean room between the stocker and the exterior of the stocker in a batch processing semiconductor manufacturing process.
That is to say, the load port according to the present invention is a load port for use in a semiconductor manufacturing process, comprising a load port main body provided with a main table onto which FOUP which contain wafers are to be placed, and a means for mapping wafers contained in the FOUP; further comprising a displacing mechanism for moving a FOUP that has been placed on the main table between said main table a predetermined position removed a distance from load port main body, wherein the displacing mechanism is provided with adequate open space facilitating the passing of FOUP which contain wafers between the aforementioned predetermined position and another piece of semiconductor manufacturing adjacent to the load port main body.
Here, the FOUP, as described above, refers to a storage container called a “Front-opening Unified Pod” (FOUP) for enclosing and conveying wafers in a clean environment. The load port main body refers to a device that functions as an interface portion between a piece of semiconductor processing equipment and the outside of the semiconductor processing equipment, regardless of whether the load port main body acts in a direct or indirect manner, in a clean room used in a semiconductor manufacturing process. A mapping means provided to a load port main body such as that described above can be, for example, a means provided with a device for detecting, remembering, and so on, the position of each wafer, the total number of wafers contained (including whether or not any wafers are contained), and the like. Normally, a FOUP houses a multi-level cassette for containing a plurality of wafers, and the mapping device maps and remembers the number of wafers contained on each level of the cassette (including whether or not there are wafers present), the position of each wafer, and so on. That is to say, the “predetermined position removed a distance from the load port main body” refers to a position above the main table, to the side the main table, at a diagonal to the main table; just as the phrase states, a position that is that is not the position where the load port main body is located. In other words, the predetermined position refers to a position separated by a distance between said position and the load port main body, excluding positions that are contiguous the load port main body or on the interior of the load port main body. Furthermore, as for the aforementioned open space provided to the displacing mechanism, the aforementioned displacing mechanism may adopt a configuration in which the structural members of the displacing mechanism are provided with a gap for facilitating passage of a FOUP between the structural members, or alternatively, a configuration in which the displacing mechanism is provided with an open space that facilitates passage of the FOUP by circumventing the structural members of the displacing mechanism, or a configuration in which the displacing mechanism has an open space from which structural members of the displacing mechanism present have been excluded.
A load port according to the present invention of a configuration such as that described above may operate in a manner so as to: first, load a FOUP that has been conveyed thereto by a convenient conveyance means onto the main table, where the mapping means can carry out mapping of the wafers contained in the FOUP; and next, use the displacement means to move the FOUP to a predetermined position at a distance removed from the load port main body, and transfer the FOUP along with the wafers contained therein through the aforementioned open space to another, adjacent piece of semiconductor processing equipment. Further, the load port main body can receive transfer of the FOUP containing wafers from the aforementioned adjacent other piece of semiconductor processing equipment at the aforementioned predetermined position through the aforementioned open space, return the FOUP to the top of the main table with the displacement means, and have the FOUP transported to a different position with a convenient conveyance means.
For example, a stocker capable of holding a plurality of FOUP can be arranged adjacent to a piece of semiconductor processing equipment capable of batch processing as the aforementioned other piece of semiconductor processing equipment, and if we assume that the stocker is provided with the load port according to the present invention, by use of the load port according to the present invention it becomes possible to directly load and unload FOUP containing wafers that have been mapped by the mapping means, and FOUP containing wafers that have undergone the complete semiconductor processing and been converted into semiconductors (and which, of course, have been subjected to the mapping process beforehand). Note that the transfer of wafers between the stocker and the semiconductor processing equipment can be performed by an appropriate load port (even a conventional load port differing from that according to the present invention) in a hermetically sealed state. That is to say, the environment within the stocker can be maintained at a lower level of cleanliness in comparison to the environment within the semiconductor processing equipment, and the wafers can be transferred to and from the stocker by the load port according to the present invention while remaining contained within the FOUP. Moreover, because wafers contained in a FOUP held within the stocker can be subjected to mapping process in advance by the load port according to the present invention, it becomes possible to shorten the length of time required to carry out a batch processing semiconductor manufacturing process, and to reduce costs, in an efficient manner. Accordingly, the load port according to the present invention can be said to be a load port that is appropriate for application in a batch processing semiconductor manufacturing process employing a minienvironment.
Further, with conventional load ports, it is often the case that two specialized load ports are arranged adjacently next to a piece of semiconductor processing equipment, with one load port used for removing wafers from a FOUP positioned thereon and passing them into the semiconductor processing equipment, and the other load port for receiving processed wafers from the semiconductor processing equipment and returning the processed wafers to the empty FOUP positioned thereon. Considering such conditions in a semiconductor manufacturing process, it can be ascertained that even in the case of batch processing, if two specialized load ports, one for removing wafers from the FOUP and the other for returning wafers to FOUP, respectively, are arranged for use adjacently on the outside of the stocker (on the side opposite that of the semiconductor processing equipment) as load ports according to the present invention, it will be difficult to provide a wide enough open space on either side of either load port. Here, as the load port according to the present invention is provided with a displacing mechanism, if the predetermined position with respect to the main table is set as a position located above the main table, because FOUP can be moved in an up and a down direction by the displacing mechanism so as to enable the loading and unloading of FOUP from a stocker positioned above the load port main body, space can be used more efficiently.
Still further, by providing the displacing mechanism, including a displacing mechanism such as the case of the above-described raising and lowering mechanism, with an auxiliary table on which FOUP are to be loaded at a position removed a distance from the load port main body, including the aforementioned predetermined remote position, it becomes possible to stably move FOUP even to a position located at a distance removed from the main table.
In particular, if the displacing mechanism is provided with an auxiliary table such as that described above, in order to ensure that the main table and auxiliary table do not interfere with each other, it is desirable that the auxiliary table be provided with a depression portion so as to avoid interfering with the main table when FOUP are loaded onto the main table. In this way, it becomes unnecessary to modify the structure of the main table of already existing load ports, or at the least to reduce the need for such modification.
According to the load port of the present invention, because it becomes possible to directly load and unload FOUP which contain wafers that have been subjected to a mapping process from a piece of equipment used in a semiconductor manufacturing process, such as a stocker disposed adjacent to another piece of semiconductor processing equipment for use in a batch processing semiconductor manufacturing process, that is located adjacent to a position removed a distance from the load port main body, it is not necessary to subject wafers to a mapping process when the wafers are extracted and inserted from a piece of semiconductor processing equipment such as the stocker, and the environment within the stocker and the like can be maintained in a relatively low degree of cleanliness in comparison to that of semiconductor processing equipment; whereby, beneficial effects such as reduction in the time and costs of the semiconductor manufacturing process can be efficiently achieved. Therefore, according to the present invention, it is possible to provide a load port that is extremely well suited for advantageous application in batch processing semiconductor manufacturing processes.
Hereinafter a preferred embodiment of the present invention will be described with reference to the drawings.
As shown in
Further, as shown in
The raising and lowering mechanism 3 is provided with a auxiliary table onto which FOUP 4 may be placed instead of on the main table 27 of the load port main body 2, and the auxiliary table 31 is provided with a raising and lowering mechanism 32, which is a type of displacing mechanism for raising and lowering the auxiliary table 31 between a lowered position of the raising and lowering mechanism mounted near the main table 27 and a predetermined position set at a position higher than the upper end of the load port main frame 21, and a guide 33 for stabilizing the operation of the raising and lowering mechanism 32. The auxiliary table 31 overlaps the upper face of the support plate 22 when the support plate 22 is in the lowered position shown in
The raising and lowering device 32 according to the current embodiment is formed from a plurality (two are shown in the drawings) of hydraulic cylinders or gas pressure cylinders 320. More specifically, each of the cylinders 320 is provided with a cylindrical main body 321 interposed in a vertical orientation between the carriage 25 of the load port main body 2 and the support plate 22, and a rod 322 protruding upward from the cylinder main body 321 and passing through the support plate 22 the upper end thereof being fixed in place at the auxiliary table 31. The cylinder main body 321 also functions as a support member for supporting the support plate 22 of the load port main body 2. Further, by extending upward or retracting downward the cylinder main body 321 by applying or releasing hydraulic pressure or gas pressure to the rod 322, the auxiliary table 31 may be moved up and down between the lowered position (
Further, in the raised position shown in
Further, the loading and unloading of FOUP 4 from the stocker C is performed according to a procedure such as that described below.
First, the wafers contained in a FOUP 4 that has been placed on the main table 27 of the load port main body 2 by the conveying device in the preceding step are subjected to a mapping process by the mapping means while the FOUP 4 is maintained in an airtight state such as that described above. Next, once a FOUP 4 that has been placed on the auxiliary table 31 by the raising and lowering device is raised up to the raised position (refer to the imaginary lines in
As described above, without loss or degradation of any of the functionality provided by conventional load ports, if the load port 1 according to the current embodiment of the present invention is employed, it becomes possible to move a FOUP 4, which has placed temporarily on the main table 27 and then transferred to the auxiliary table 31 by the raising and lowering device (a displacing mechanism) and subsequently moved while on the auxiliary table 31, to a position removed a distance from the load port main body 2, to carry the wafers contained in each FOUP 4, which have already been subjected to a mapping process, to the adjacent stocker C, and to unload FOUP 4 containing wafers that have completed processing and been converted to semiconductors from the stocker C as is; therefore, it is possible to greatly improve operational efficiency and reduce costs in a batch processing semiconductor manufacturing process that employs a minienvironment.
Note that the present invention is not limited to the above-described preferred embodiments. For example, the displacing mechanism is not limited to being a raising and lowering device 3 such as that of the above-described embodiment, but can be a displacing mechanism for moving FOUP on the auxiliary table 31 to the right and left, or diagonal direction. In addition, the actual parts used to form each portion of the load port main body, displacing mechanism, and the like, are not limited to being those use in the above-described embodiment; so far as the gist of the present invention is not deviated from or transgressed, a wide range of variations is possible.
Load port 1
Load port main body 2
Displacing mechanism 3 (raising and lowering device)
FOUP 4
Mapping means 24
Main table 27
Auxiliary table 31
Depression portion 31a
Raising and lowering device 31
Open space 34
Clean room A
Semiconductor processing equipment B
Stocker C
| Number | Date | Country | Kind |
|---|---|---|---|
| 2007-309350 | Nov 2007 | JP | national |
