JPH0447450B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a stocker for three-dimensionally storing a plurality of semiconductor wafer cassettes, and particularly to a stocker for semiconductor wafer cassettes having a mechanism that is easy to drive and has high reliability. .

(Prior Art) Conventionally, semiconductor wafers have been stored by arranging the wafers in boxes called cassettes and storing the cassettes in clean storage shelves. This method has no problems when the number of cassettes to be stored is small, but as the number of cassettes increases, problems arise in terms of storage space and lot management of stored wafers. That is, the height of the storage shelf is limited due to the workability of storing the wafers in the storage shelf, and moreover, a large number of man-hours are required to manage the wafer cassettes stored in a large number of shelves in accordance with the lot numbers.

Therefore, a stocker was devised in which the shelves are arranged three-dimensionally and made rotatable, so that the bottom area is small and cassettes can be easily taken in and taken out. This stocker has two sprocket wheels 1 and 2 as shown in Figs.
A chain 5 is provided between the two sprocket wheels 3 and 4, a chain 6 is provided between the two sprocket wheels 3 and 4,
A plurality of shelves 7 to 18 are provided between the chains 5 and 6.

(Problem to be Solved by the Invention) According to the above configuration, even if the position of each shelf is changed by rotating the sprocket wheel, each shelf board is always kept in a horizontal state. When a wafer cassette 19 is placed on a shelf board, the center of gravity of the shelf shifts and the shelf tilts, making it difficult to take the cassette in and out. Furthermore, since cassettes cannot be inserted or removed from the side of the shelf board, it is difficult to apply this method to automated lines. In addition, chains always require slack when driving, which reduces shelf positioning accuracy, generates a lot of dust due to their structure, and requires oil and fat for lubrication, so they are not suitable for use in clean rooms. It's really inconvenient.

The present invention has been made in view of the above points, and an object of the present invention is to provide a stocker for semiconductor wafer cassettes that is highly accurate and generates less dust.

(Means for Solving the Problems) The present invention provides a storage shelf for storing a plurality of cassettes in which a plurality of wafers are housed, and a storage shelf for a plurality of cassettes which can be kept spaced apart by vertical contact with each other; a first guide means for vertically guiding the cassette storage shelf while keeping the cassette mounting surface horizontal by guiding at least two guides provided at each end of the cassette storage shelf; The cassette storage shelves are horizontally arranged between the upper and lower ends of the first and second guide means, respectively, and a second guide means having the same structure as the guide means and arranged in parallel with the first guide means. two transport means for transporting in the direction;
an elevating means provided corresponding to the guide means, and for elevating and lowering the plurality of cassette storage shelves guided by the guide means by elevating and lowering the lowermost cassette storage shelf. This is a stocker for wafer cassettes.

(Function) The cassette storage shelf can be transferred between the first guide means and the second guide means by the transfer means, and a desired cassette storage shelf can be moved to an arbitrary position.

Further, even if the center of gravity of the cassette storage shelf moves depending on the position where the cassettes are placed, at least two guides provided at each end of the cassette storage shelf are guided by the first guide means or the second guide means. Because of this, the cassette storage shelf will not tilt.
The position of the cassette storage shelf can be set accurately. Moreover, accurate spacing between the plurality of cassette storage shelves is maintained by vertical contact between the cassette storage shelves.

(Example) Hereinafter, an example of the present invention will be specifically described using the drawings.

FIG. 3 is a side view of a stocker according to an embodiment of the present invention, and FIG. 4 is a front view.

Among the shelves 20 to 27, which are cassette storage shelves, the shelves 24 to 26 are connected to a pair of first guide means, e.g.
guide rail 28 and a second guide rail (not shown). The position of each shelf is maintained by the guide fitting into the guide rail, for example, the shelf 24 is held in place by the guides 31 and
is fitted into a first guide rail provided vertically in the length direction, and a guide 36 similarly provided on the opposite side,
37 is saved by fitting into the second guide rail. In this example, each guide is attached to supports 33 and 38 provided at both ends of the cassette storage shelf.

The vertical position of each shelf is determined by the respective supports 33, 3.
8 are held in contact with each other in the vertical direction.
The guide of the shelf 27 is a first guide rail 28 and a second guide rail 28.
It is in a state where it is pushed upward from the guide rail of the shelf 27, but at this time, the guide 3 of this shelf 27
1, 32, 36, and 37 are held down by stoppers (not shown) to the left in FIG. After that, the above-mentioned stopper is released.

Thereafter, the transfer means 40 moves to the third guide rail 29 and the fourth guide rail (not shown).
A pair of second guide means, for example, the fifth guide rail 30, are guided by the guide rail 30 and moved to the right in FIG.
and stops on a sixth guide rail (not shown). The fifth guide rail 30 and the sixth guide rail are stored on the shelves 20 to 22,
After the shelf 23 located at the lowest level is moved toward the front of the stocker by the same transfer means as described above, the entire shelves 20 to 22 are lowered by one level by the lowering of the second shelf raising and lowering mechanism 35. As a result, a shelf 27 is stored at the top of the fifth and sixth guide rails.

The shelf 23 that has moved toward the front of the stocker is pushed up by the first shelf raising and lowering mechanism 34. As a result, each guide of the shelf 23 is engaged with the first guide rail 28 and the second guide rail, and the shelves 24 to 26 are pushed upward, and each guide of the shelf 26 is released from the first and second guide rails. be done. By repeating these operations, each shelf can be moved freely.

Note that by reversing the operations of the first shelf raising/lowering mechanism 34, the second shelf raising/lowering mechanism 35, and the transfer means 40, the moving direction of each shelf can be reversed.

The feature of the above embodiment is that the stocker for semiconductor wafer cassettes is equipped with a plurality of shelves for semiconductor wafer cassettes that can be raised and lowered in multiple stages, and each shelf is provided with a supporting portion with a guide at both ends thereof.
The guide fits into and slides over each of the first and second guide rails, and includes a length corresponding to at least one shelf guide at at least one end of each of the first and second guide rails. Third and fourth guide rails are provided, and the transport means is located in a stocker for semiconductor wafer cassettes that is laterally movable guided by the third and fourth guide rails.

By providing fifth and sixth guide rails of equal length and parallel to the first and second guide rails, each shelf is moved by the moving means while being guided by the third and fourth guide rails. By doing so, each shelf can be moved from the first and second guide rails to the fifth and sixth guide rails.
Note that each shelf has second, fourth, and
and one of the sixth guide rails.

According to this embodiment, the position of each shelf can be set extremely accurately, and since no chain is used, less dust is generated from each linkage. Furthermore, since the drive mechanism is independent of the number of shelves, a stocker with any number of shelves can be easily realized by simply changing the lengths of the first, second, fifth, and sixth guide rails. Furthermore, since each shelf can be removed regardless of the drive mechanism, its maintenance is extremely simple.

In addition, in order to stop each shelf guided by the first guide means and the second guide means from falling, it is necessary to provide a stopper for fixing at least the lowest shelf, and each shelf is raised and lowered. In this case, it is necessary to release the stopper.

(Effects of the Invention) According to the present invention, since each shelf is moved without using a chain, less garbage is generated.
In addition, a semiconductor wafer cassette stocker with high shelf positioning accuracy can be realized.

[Brief explanation of the drawing]

1 and 2 are a side view and a front view, respectively, of a conventional stocker for semiconductor wafer cassettes, and FIG.
The figure is a side view of a stocker for semiconductor wafer cassettes according to an embodiment of the present invention, and FIG. 4 is a front view. 1 to 4... Sprocket wheel, 5, 6...
Chain, 7-18...Shelf, 19...Wafer cassette, 20-27...Shelf, 28...First guide rail, 29...Third guide rail, 30...
Fifth guide rail, 31, 32, 36, 37...
...Guide, 33, 38...Support, 34...First
The shelf raising/lowering mechanism, 32... is the second shelf raising/lowering mechanism.

Claims (1)

[Claims] 1. A storage shelf for a plurality of cassettes that can hold a plurality of cassettes containing a plurality of wafers, and that maintains spacing by vertical contact with each other;
a first guide means for vertically guiding the cassette storage shelf while keeping the cassette mounting surface horizontal by guiding at least two guides provided at each end of the cassette storage shelf;
a second guide means having the same configuration as the guide means and arranged in parallel with the first guide means;
and two transport means for horizontally transporting the cassette storage shelf between the upper and lower ends of the second guide means, respectively, and a lowermost stage provided corresponding to the first and second guide means. and a lifting means for raising and lowering the plurality of cassette storage shelves guided by the guide means by raising and lowering the plurality of cassette storage shelves.