BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front view showing a clean stocker according to an embodiment.
FIG. 2 is a horizontal cross sectional view taken along a line II-II in FIG. 1.
FIG. 3 is a horizontal cross sectional view taken along a line III-III in FIG. 1.
FIG. 4 is a view schematically showing reticle hands according to an embodiment.
FIG. 5 is a view showing operating ranges of transportation devices relative to two rotation racks, a pod opener, fixing racks, and load ports.
DESCRIPTION OF THE NUMERALS
2: clean stocker
4: reticle rotatable rack
6: pod rotatable rack
8: pod transportation device
10: reticle transportation device
9, 11: elevation guide
12: pod opener
14, 15: pod fixed rack
16: clean gas supply unit
18, 19: load port for overhead traveling vehicle
20, 21: ground side load port
22: terminal
24: casing
26: pod
28: flange
30: block
31: stage
32, 34: drive unit
36, 38: gas flow path
40, 41: joint
42, 44: hand
46: clean gas supply path
EMBODIMENT
FIGS. 1 to 5 show a clean stocker 2 and a method of storing articles according to an embodiment. In the drawings, a reference numeral 2 denotes the clean stocker provided in a clean room of, e.g., a semiconductor factory or a liquid crystal factory. A reference numeral 4 denotes 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 rack 4 rotates as a whole, and the stages of the reticle rotatable rack 4 do not rotate individually. In order to store the reticles in, and retrieve the reticles from the reticle rotatable rack 4, the reticle rotatable rack 4 may be divided into a plurality of upper and lower blocks such that each block can rotate independently. A reference numeral 6 denotes a pod rotatable rack. After the reticles are taken out from pods, the empty pods are stored in the pod rotatable rack 6. 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 rack 6 includes 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 stocker 2 is viewed from the front side (FIG. 1), a pod transportation device 8 is 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 stocker 2. The pod transportation device 8 and the reticle transportation device 10 are provided on one side in front of the rotatable racks 4, 6, and a pod opener 12 is provided between the pod transportation device 8 and the reticle transportation device 10. Further, pod fixed racks 14, 15 are provided, e.g., above and below the pod opener 12. Alternatively, the pod fixed rack may be provided only above or below the pod opener 12. Further, the transportation devices 8, 10 are elevated or lowered along elevation guides 9, 11. For example, the pod transportation device 8 includes dual arms 8a, 8b, and a hand 8c provided at the front end of the arms 8a, 8b. The pod transportation device 8 has three joints 8d, 8e, 8f for pivotally moving the arms 8a, 8b and the hand 8c in a horizontal plane. For example, the joints 8d, 8e, 8f are operated independently for transporting a pod 26 in an arbitral direction in a range reachable by the dual arms. Likewise, the reticle transportation device 10 includes dual arms 10a, 10b pivotally movable by joints 10c, 10d, and a hand provided at the front end of the arms 10a, 10b. The structure of the hand of the reticle transportation device 10 will be described with reference to FIG. 4.
At the top of the clean stocker 2, a clean gas supply unit 16 is 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 unit 16 includes 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 stocker 2. Reference numerals 18, 19 denote load ports for overhead traveling vehicles, provided at high positions in the clean stocker 2. Overhead traveling vehicles (not shown) store pods 26, e.g., shown in FIG. 3 in, and retrieves the pods 26 from the load ports 18, 19. Reference numerals 20, 21 denote load ports on the ground. For example, the load ports 20, 21 are used when the pods 26 are manually stored, and retrieved. A reference numeral 22 is a terminal used for manually operating the clean stocker 2, inputting and outputting data, or reading IDs of the pods. A reference numeral 24 denotes a casing of the clean stocker 2.
The reticle rotatable rack 4 is divided into a plurality of blocks 30 (FIG. 2), and a flange 28 is provided in the outer region of the reticle rotatable rack 4. The flange 28 is used for lifting vertically overlapped stages 31 of the blocks 30, respectively (FIG. 4). A drive unit 32 rotates the reticle rotatable rack 4, and an open space inside the rotatable rack 4 is used as a gas flow path 36. The clean gas supplied from the clean gas supply unit 16 to the reticle rotatable rack 4 is discharged downwardly through the gas flow path 36 (FIG. 2). The pod rotatable rack 6 has a drive unit 34 at its center. The drive unit 34 rotates the rack 6, and discharges the clean gas of the gas flow path 38 around the drive unit 34. The clean gas in the rack 6 is discharged downwardly (FIG. 3).
FIG. 4 shows the block 30 of the reticle rotatable rack and hands 42, 44 at the front end of the reticle transportation device 10. The hand 42 chucks the flange 28, and lifts the flange 28 upwardly for allowing a reticle (not shown) to move into or move out of the reticle rotatable rack. The hand 44 for the reticle is provided, e.g., below the hand 42. The hands 42, 44 are rotated independently from each other in a horizontal plane. After chucking the flange 28 using the hand 42 to lift the stages 31a, 31b upwardly, the hand 44 is rotated at the joint 41 to move the reticle below the stage 31b into or out of the reticle rotatable rack 4. A reference numeral 46 denotes clean gas supply paths each made up of an opening or a filter provided in each stage 31. The clean gas is supplied through the clean gas supply path toward the reticle.
Operation of the embodiment will be described. After the pods 26 are transported by the overhead traveling vehicle or manually to the load ports 18 to 21, the pods 26 are transported by the pod transportation device 8 to the pod opener 12 and the pod fixed racks 14, 15. Since the load ports 18, 19, the load ports 20, 21, the pod opener 12, and the fixed racks 14, 15 are provided at different height positions, the pod transportation device 8 is elevated or lowered along the elevation guide 9. At this time, in the case of storing a large number of pods successively, the pod fixed racks 14, 15 are used as buffers for compensating the slow operation in the pod opener 12. 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 pod 26 using the pod opener 12, the reticle is kept in the pod 26, and stored in the pod fixed rack 14, or 15 until it is retrieved. When the reticle is taken out by the pod opener 12, the reticle is stored in the reticle rotatable rack 4 by the reticle transportation device 10. The reticle rotatable rack 4 is rotated, and the reticle transportation device 10 is elevated or lowered at the same time, and a desired stage of the reticle rotatable rack 4 is lifted in a manner as shown in FIG. 4 to move the reticle into or out of the reticle rotatable rack 4. Further, the empty pod left in the pod opener 12 is stored in the pod rotatable rack 6 by the pod transportation device 8.
At the time of storing a pod, the empty pod is taken out from the pod rotatable rack 6 using the pod transportation device 8, and the pod is set to the pod opener 12. Likewise, a desired reticle is taken out from the reticle rotatable rack 4 using the reticle transportation device 10, and the reticle is set in the pod using the pod opener 12. After the reticle is set in the pod, the pod may be transported immediately to any of the load ports 18 to 21 by the pod transportation device 8. If the load ports 18 to 21 are occupied, the pod is temporarily stored in the pod fixed rack 14, 15 to wait until any of the load ports 18 to 21 becomes empty.
In the clean stocker 2, the clean gas from the clean gas supply unit 16 is initially supplied to the reticle rotatable rack 4, and then, the clean gas is supplied to the pod rotatable rack 6. Therefore, the atmosphere around the reticle rotatable rack 4 storing the reticles which are not placed in the pods is kept clean, and it is possible to prevent contamination of the reticles.
FIG. 5 schematically shows operating ranges of the pod transportation device 8 and the reticle transportation device 10. The pod transportation device 8 transports the pod among the positions of the pod rotatable rack 6, the pod opener 12, the pod fixed racks 14, 15, and the load ports 18 to 21, and elevates or lowers the transportation device body having multiple arms and a plurality of joints along the elevation guide to efficiently transport the pod to various height positions in a compact space. The reticle transportation device 10 transports the reticle between the reticle rotatable racks 4 and the pod opener 12. In the same manner as in the case of the pod transportation device 8, the reticle transportation device 10 elevates or lowers the transportation device body having multiple arms and a plurality of joints along the elevation guide to efficiently transport the reticle to various height positions in a compact space. The rotatable racks 4 and 6 are overlapped with each other vertically, and the transportation devices 8, 10 are provided around the pod opener 12, in the empty-space in front of the rotatable racks 4, 6. In the structure, transportation in the stocker is carried out efficiently. Further, pod fixed racks 14, 15 are provided in open spaces above and below the pod opener 12, and it is possible to use the pod fixed racks 14, 15 as buffers used at the time of storage and retrieval of the pods.
In the embodiment, the following advantages can be obtained.
(1) The clean gas is supplied from the clean gas supply unit 16 to the pod rotatable rack 6 through the reticle rotatable rack 4. In this manner, the atmosphere in the reticle rotatable rack 4 is kept particularly clean.
(2) The number of pods stored in the pod rotatable rack 6 is smaller than the number of stored reticles. Therefore, it is possible to store a large number of reticles in a compact space of the reticle rotatable rack 4.
(3) Since the rotatable racks 4, 6 are used, it is not necessary to move the articles or containers into, or out of the entire surfaces of the racks 4, 6. Thus, the transportation devices 8, 10 do not use large spaces.
(4) The transportation devices 8, 10 are provided on one side of the rotatable racks 4, 6 which are overlapped vertically with each other, such that the pod opener 12 is interposed between the transportation devices 8, 10. In the structure, it is possible to transport the pod in the range from the load port to the pod rotatable rack in a compact space. Further, it is possible to transport the reticle between the pod opener and the reticle rotatable rack.
Patent Application
20080023417
