Clean stocker and method of storing articles

A reticle rotatable rack is provided at an upper position, and a pod rotatable rack is provided at a lower position in a clean stocker. A clean gas is supplied downwardly. In the stocker, a pod transportation device and a reticle transportation device are elevated and lowered. Load ports, a pod opener, and the pod rotatable rack are connected by the pod transportation device. The pod opener and the reticle rotatable rack are connected by the reticle transportation device.

TECHNICAL FIELD

The present invention relates to a clean stocker for storing articles such as reticles for semiconductor exposure cleanly, and a method of storing the articles in the clean stocker.

BACKGROUND ART

Reticles are used for exposure of semiconductors or the like. The reticles are placed in pods, and transported between a stocker and an exposure apparatus. With respect to storage of the reticles, Japanese Patent No. 3682170 discloses a technique of providing a rack for storing reticles that are not placed in pods, and a rack for storing pods on both sides of a travel route of transportation devices. However, in the technique, the reticles may be contaminated undesirably by the wind generated by the transportation devices moving along the travel route.

SUMMARY OF THE INVENTION

An object of the present invention is to store a large number of articles and containers for the articles in a compact space cleanly.

Another object of the present invention is to store a large number of articles and containers for the articles in a further compact space.

Still another object of the present invention is to make it possible to achieve efficient storage and retrieval of containers containing articles.

Still another object of the present invention is to provide a method of storage and retrieval of a large number of articles and containers for the articles which makes it possible to store the articles and the containers in a compact space cleanly.

The present invention relates to a clean stocker for storing and retrieving an article placed in a container from a storage and retrieval port. A down flow of a clean gas is provided in the clean stocker. The clean stocker comprises an opening and closing device, a storage rack for the article, a storage rack for the container, a container transportation device, and an article transportation device. The opening and closing device places the article into, and takes the article out of the container. The storage rack for the article is disposed on an upper side and the storage rack for the container is disposed on a lower side such that the storage rack for the article and the storage rack for the container are vertically overlapped with each other in a plan view. The container transportation device transports the container among the opening and closing device, the storage and retrieval port, and the storage rack for the container, and the article transportation device transports the article between the opening and closing device and the storage rack for the article.

Preferably, the storage rack for the article and the storage rack for the container are rotatable racks that are horizontally rotatable independently from each other.

In particular, it is preferable that the article transportation device and the container transportation device face each other on one side of the storage rack for the article and the storage rack for the container such that the opening and closing device is interposed between the article transportation device and the container transportation device.

Further, preferably, a fixed rack for storing the container is provided in addition to the storage rack for the container, at a position where the container transportation device can transport the container.

Further, the present invention relates to a method of retrieving and storing an article placed in a container from a retrieval and storage port, and storing the article cleanly by providing a down flow of a clean gas. The method comprises the steps of placing the article into, and taking the article out of the container which is retrieved and stored from the retrieval and storage port; disposing a storage rack for the article taken out from the container on an upper side, and a storage rack for the container on a lower side such that the storage rack for the article and the storage rack for the container are vertically overlapped with each other in a plan view, and supplying the clean gas to the storage rack for the article, and thereafter, to the storage rack for the container; providing a container transportation device for transporting the container and an article transportation device for transporting the article; and transporting the container among the opening and closing device, the retrieval and storage port, and the storage rack for the container using the container transportation device; and transporting the article between the storage rack for the article and the opening and closing device using the article transportation device.

In this specification, unless specifically noted, description about the clean stocker is applicable to the method of storing articles using the clean stocker. Further, unless specifically noted, description about the method of storing articles using the clean stocker is applicable to the clean stocker. Further, in the embodiment, although storage of reticles for semiconductor exposure and pods containing the reticles is taken as an example, the type of stored articles and the type of containers containing the articles can be adopted arbitrarily.

ADVANTAGES OF THE INVENTION

In the present invention, the storage rack for the articles is disposed on the upper side, and the storage rack for the containers is disposed on the lower side. In this state, the down flow of the clean gas is supplied. Therefore, it is possible to store the articles taken out from the containers cleanly. Since the articles are stored after they are taken out from the containers, it is possible to store a large number of articles in a compact space. The number of the stored articles and the number of stored containers need not to be the same. For example, if the number of the containers is smaller than the number of articles, and only the containers in the number required for storage and retrieval of the articles are stored, it is possible to place a large number of articles in a compact space of the rack.

In the case where the storage rack for the articles and the storage rack for the containers are rotatable racks horizontally rotatable independently from each other, it is sufficient that the container transportation device and the article transportation device can move the containers or the articles at predetermined positions of the rotatable racks. In the structure, the operating ranges of these transportation devices are reduced. As a result, it is possible to store a large number of articles or containers in a further compact space. Further, in the rotatable rack, a space is left at the center of the rack. The space can be used as an exhaust gas path of the clean gas.

If the article transportation device and the container transportation device face each other on one side of the storage rack for the article and the storage rack for the container such that the opening and closing device is interposed between the article transportation device and the container transportation device, it is possible to provide these transportation devices in a further compact space. In particular, if each of these transportation devices comprises a transportation device body and its elevation means, even in the case where the rotatable racks for the containers and the articles have upper and lower multiple stages, and the opening and closing device and these racks are provided at different height positions, it is possible to transport the containers and the articles easily.

In addition to the rotatable racks for the containers, by providing a fixed rack for storing the containers, and the container containing the article to be retrieved is stored in advance, it is possible to retrieve the articles efficiently in a short period of time. Further, if articles are stored successively, it is possible to temporarily store the articles in the fixed rack before the container is set in the opening and closing device. Thus, it is possible to carry out storage and retrieval of articles efficiently.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1 to 5show a clean stocker2and a method of storing articles according to an embodiment. In the drawings, a reference numeral2denotes the clean stocker provided in a clean room of, e.g., a semiconductor factory or a liquid crystal factory. A reference numeral4denotes a reticle rotatable rack including a large number of, upper and lower multiple stages. In each stage, reticles for exposure of semiconductors or liquid crystal substrates are stored. The reticle rotatable rack4rotates as a whole, and the stages of the reticle rotatable rack4do not rotate individually. In order to store the reticles in, and retrieve the reticles from the reticle rotatable rack4, the reticle rotatable rack4may be divided into a plurality of upper and lower blocks such that each block can rotate independently. A reference numeral6denotes a pod rotatable rack. After the reticles are taken out from pods, the empty pods are stored in the pod rotatable rack6. The number of the stored pods is smaller than the number of the stored reticles. For example, the number of the stored pods is about 1/100 to 1/100 of the number of the stored reticles. The pod rotatable rack6includes upper and lower multiple stages, and rotates as a whole as the articles. Instead of the reticles, wafers or the like may be stored in the clean stocker.

In the case where the clean stocker2is viewed from the front side (FIG. 1), a pod transportation device8is provided on one of the left and right, and a reticle transportation device is provided on the other of the left and right, on the front side in the clean stocker2. The pod transportation device8and the reticle transportation device10are provided on one side in front of the rotatable racks4,6, and a pod opener12is provided between the pod transportation device8and the reticle transportation device10. Further, pod fixed racks14,15are provided, e.g., above and below the pod opener12. Alternatively, the pod fixed rack may be provided only above or below the pod opener12. Further, the transportation devices8,10are elevated or lowered along elevation guides9,11. For example, the pod transportation device8includes dual arms8a,8b, and a hand8cprovided at the front end of the arms8a,8b. The pod transportation device8has three joints8d,8e,8ffor pivotally moving the arms8a,8band the hand8cin a horizontal plane. For example, the joints8d,8e,8fare operated independently for transporting a pod26in an arbitral direction in a range reachable by the dual arms. Likewise, the reticle transportation device10includes dual arms10a,10bpivotally movable by joints10c,10d, and a hand provided at the front end of the arms10a,10b. The structure of the hand of the reticle transportation device10will be described with reference toFIG. 4.

At the top of the clean stocker2, a clean gas supply unit16is provided. For example, a clean gas such as a clean air or nitrogen is supplied as a down flow. For example, the clean gas supply unit16includes means for producing the clean gas, a fan filter unit, or a mechanism for taking the down flow of the clean air from the ceiling of the clean room into the stocker2. Reference numerals18,19denote load ports for overhead traveling vehicles, provided at high positions in the clean stocker2. Overhead traveling vehicles (not shown) store pods26, e.g., shown inFIG. 3in, and retrieves the pods26from the load ports18,19. Reference numerals20,21denote load ports on the ground. For example, the load ports20,21are used when the pods26are manually stored, and retrieved. A reference numeral22is a terminal used for manually operating the clean stocker2, inputting and outputting data, or reading IDs of the pods. A reference numeral24denotes a casing of the clean stocker2.

The reticle rotatable rack4is divided into a plurality of blocks30(FIG. 2), and a flange28is provided in the outer region of the reticle rotatable rack4. The flange28is used for lifting vertically overlapped stages31of the blocks30, respectively (FIG. 4). A drive unit32rotates the reticle rotatable rack4, and an open space inside the rotatable rack4is used as a gas flow path36. The clean gas supplied from the clean gas supply unit16to the reticle rotatable rack4is discharged downwardly through the gas flow path36(FIG. 2). The pod rotatable rack6has a drive unit34at its center. The drive unit34rotates the rack6, and discharges the clean gas of the gas flow path38around the drive unit34. The clean gas in the rack6is discharged downwardly (FIG. 3).

FIG. 4shows the block30of the reticle rotatable rack and hands42,44at the front end of the reticle transportation device10. The hand42chucks the flange28, and lifts the flange28upwardly for allowing a reticle (not shown) to move into or move out of the reticle rotatable rack. The hand44for the reticle is provided, e.g., below the hand42. The hands42,44are rotated independently from each other in a horizontal plane. After chucking the flange28using the hand42to lift the stages31a,31bupwardly, the hand44is rotated at the joint41to move the reticle below the stage31binto or out of the reticle rotatable rack4. A reference numeral46denotes clean gas supply paths each made up of an opening or a filter provided in each stage31. The clean gas is supplied through the clean gas supply path toward the reticle.

Operation of the embodiment will be described. After the pods26are transported by the overhead traveling vehicle or manually to the load ports18to21, the pods26are transported by the pod transportation device8to the pod opener12and the pod fixed racks14,15. Since the load ports18,19, the load ports20,21, the pod opener12, and the fixed racks14,15are provided at different height positions, the pod transportation device8is elevated or lowered along the elevation guide9. At this time, in the case of storing a large number of pods successively, the pod fixed racks14,15are used as buffers for compensating the slow operation in the pod opener12. Further, for the reticle which is likely to be used frequently in a light exposure apparatus, and expected to be retrieved soon after its storage, without separating the reticle from the pod26using the pod opener12, the reticle is kept in the pod26, and stored in the pod fixed rack14, or15until it is retrieved. When the reticle is taken out by the pod opener12, the reticle is stored in the reticle rotatable rack4by the reticle transportation device10. The reticle rotatable rack4is rotated, and the reticle transportation device10is elevated or lowered at the same time, and a desired stage of the reticle rotatable rack4is lifted in a manner as shown inFIG. 4to move the reticle into or out of the reticle rotatable rack4. Further, the empty pod left in the pod opener12is stored in the pod rotatable rack6by the pod transportation device8.

At the time of storing a pod, the empty pod is taken out from the pod rotatable rack6using the pod transportation device8, and the pod is set to the pod opener12. Likewise, a desired reticle is taken out from the reticle rotatable rack4using the reticle transportation device10, and the reticle is set in the pod using the pod opener12. After the reticle is set in the pod, the pod may be transported immediately to any of the load ports18to21by the pod transportation device8. If the load ports18to21are occupied, the pod is temporarily stored in the pod fixed rack14,15to wait until any of the load ports18to21becomes empty.

In the clean stocker2, the clean gas from the clean gas supply unit16is initially supplied to the reticle rotatable rack4, and then, the clean gas is supplied to the pod rotatable rack6. Therefore, the atmosphere around the reticle rotatable rack4storing the reticles which are not placed in the pods is kept clean, and it is possible to prevent contamination of the reticles.