High efficiency buffer stocker

• US 8,308,418 B2
• Filed: 05/09/2006
• Issued: 11/13/2012
• Est. Priority Date: 05/09/2006
• Status: Active Grant

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Inventors: Lee, Fiona, Ma, Veen, Huang, Chih-Hung, Chiang, Wen-Chung, Hsieh, Goldie
• Primary Examiner(s): Rodriguez, Saul
• Assistant Examiner(s): SNELTING, JONATHAN D
• Application Number:
  US11/431,646
• Publication Number:
  US 20070264114A1
• Time in Patent Office: 2,380 Days
• Field of Search: 1983471-3474, 414/626, 414/940
• US Class Current: 414/626
• CPC Class Codes: B65G 2201/0297 Wafer cassette
• CPC Class Codes: B65G 37/00 Combinations of mechanical conveyors of the same kind, or of different kinds, of interest apart from their application in particular machines or use in particular manufacturing processes series of co-operating belt conveyor units B65G15/22; series of co-operating chain conveyor units B65G17/26; sequence control of combined conveyors B65G43/10
• CPC Class Codes: B65G 37/02 Flow-sheets for conveyor combinations in warehouses, magazines or workshops
• CPC Class Codes: B66C 19/00 Cranes comprising trolleys or crabs running on fixed or movable bridges or gantries B66C17/00 takes precedence; base supporting structures with legs B66C5/00; jib cranes B66C23/00
• CPC Class Codes: H01L 21/67715 Changing the direction of the conveying path
• CPC Class Codes: H01L 21/6773 Conveying cassettes, containers or carriers
• CPC Class Codes: H01L 21/67733 Overhead conveying
• CPC Class Codes: H01L 21/67736 Loading to or unloading from a conveyor
• CPC Class Codes: H01L 21/67769 Storage means

Abstract

A high-efficiency buffer stocker is disclosed. The buffer stocker includes an overhead transport track for supporting overhead transport vehicles carrying wafer containers and at least one conveyor system or conveyor belt provided beneath the overhead transport track for receiving the wafer containers from the overhead transport vehicles on the overhead transport track. The buffer stocker is capable of absorbing the excessive flow of wafer containers between a processing tool and a stocker, for example, to facilitate the orderly and efficient flow of wafers between sequential process tools in a semiconductor fabrication facility, for example.

Claims

1. A buffer stocker comprising:

a longitudinally-extending transport track adapted to move a plurality of transport vehicles horizontally along said transport track, said transport vehicles being configured for carrying, lowering, and raising a container; and

a plurality of conveyor systems associated with said transport track, said plurality of conveyor systems comprising an upper-level conveyor system at a first elevation and a lower-level conveyor system at a second elevation and positioned beneath said upper-level conveyor system;

said transport track including a plurality of track points longitudinally spaced along said transport track positioned for transferring a container from said transport vehicles to said upper-level conveyor system and said lower-level conveyor system, a first track point of said track points being different in location from a second track point of said track points;

each of said upper-level and lower-level conveyer systems comprising a load/unload conveyor belt and a first conveyor belt operably communicating with the load/unload conveyor belt for transferring containers therebetween,

said load/unload conveyor belt of said upper-level conveyor system being vertically aligned with and accessible to said first track point, and said load/unload conveyor belt of said lower-level conveyor system being vertically aligned with and accessible to said second track point, wherein said load/unload conveyor belt of said upper-level conveyor system is longitudinally offset beneath the transport track from said load/unload conveyor belt of said lower-level conveyor system;

said load/unload conveyor belts of said upper-level and lower-level conveyor systems each being configured for receiving and transferring a container between one of said transport vehicles at said first or second track points and said first conveyor belt of each respective upper-level and lower-level conveyor systems,

said first conveyor belts of said upper-level and lower-level conveyor systems overlapping in plan view.

2. The buffer stocker of claim 1 further comprising a controller operably connected to said plurality of conveyor systems and configured to control a direction of travel of said plurality of conveyor systems.

3. The buffer stocker of claim 1 wherein said first conveyor belt of said each conveyor system comprises a conveyor belt loop.

4. The buffer stocker of claim 1 wherein said plurality of conveyor systems further comprises a mid-level conveyor system between said upper-level conveyor system and said lower-level conveyor system.

5. The buffer stocker of claim 1 wherein said each conveyor system further comprises a second conveyor belt arranged in transverse relationship to said first conveyor belt.

6. The buffer stocker of claim 1 wherein said container to be transferred between said transport vehicle and said first conveyor belt is configured to contain a wafer.

7. The buffer stocker of claim 1 wherein said transport vehicles are configured to sequentially stop at the plurality of track points along said transport track.

8. The buffer stocker of claim 1 wherein at least a portion of said first conveyor belt of said lower-level conveyor system occupies a position that is vertically directly beneath said first conveyor belt of said upper-level conveyor system.

9. The buffer stocker of claim 1 wherein each conveyor system comprises a second conveyor belt arranged in parallel relationship to said first conveyor belt and a pair of parallel third and fourth conveyor belts arranged in transverse relationship to said first and second conveyor belts.

10. A buffer stocker comprising:

a longitudinally-extending transport track adapted to move a plurality of transport vehicles horizontally along said transport track, said transport vehicles being configured for carrying, lowering, and raising a wafer container; and

a plurality of conveyor systems associated with said transport track for temporarily storing said wafer containers, said plurality of conveyor systems comprising;

an upper-level conveyor system at a first elevation positioned beneath said transport track; and

a lower-level conveyor system at a second elevation positioned beneath said upper-level conveyor system and said transport track;

said transport track including a plurality of track points longitudinally spaced along said transport track positioned for transferring a container from said transport vehicles to said upper-level conveyor system and said lower-level conveyor system, a first track point being associated with said upper-level conveyor system and a second track point being associated with said lower-level conveyor system, the first track point having a different longitudinal position on said transport track than said second track point;

each of said upper-level and lower-level conveyer systems comprising a load/unload conveyor belt and at least one first conveyor belt operably communicating with the load/unload conveyor belt for transferring containers therebetween,

said load/unload conveyor belt of said upper-level conveyor system being vertically aligned with and accessible to said first track point, and said load/unload conveyor belt of said lower-level conveyor system being vertically aligned with and accessible to said second track point, wherein said load/unload conveyor belt of said upper-level conveyor system is longitudinally offset beneath the transport track from said load/unload conveyor belt of said lower-level conveyor system to provide access for said load/unload conveyor belt of said lower-level conveyor system to said second track point of said transport track; and

said load/unload conveyor belts of said upper-level and lower-level conveyor systems each being configured for receiving and transferring a container between one of said transport vehicles at said first or second track points and said first conveyor belt of each respective upper-level and lower-level conveyor systems;

wherein at least a portion of said first conveyor belt of said lower-level conveyor system occupies a position that is vertically directly beneath said first conveyor belt of said upper-level conveyor system.

11. The buffer stocker of claim 10 further comprising a controller operably connected to said upper-level conveyor system and said lower-level conveyor system and configured to control a direction of travel of said upper-level conveyor system and said lower-level conveyor system.

12. The buffer stocker of claim 10 wherein

said load/unload conveyor belt of said upper-level conveyor system is overlapped with said first conveyor belt of said upper-level conveyor system, said first conveyor belt configured to move first containers of said upper-level conveyor system;

and

said load/unload conveyor belt of said lower-level conveyor system is overlapped with said first conveyor belt of said lower-level conveyor system, said first conveyor belt configured to move second containers of said lower-level conveyor system.

13. The buffer stocker of claim 10 wherein said transport vehicles are configured to transport wafers.

14. The buffer stocker of claim 10 wherein said transport vehicles are configured to sequentially stop at said first track point and said second track point.

15. The buffer stocker of claim 10 wherein each conveyor system comprises a second conveyor belt arranged in parallel relationship to said first conveyor belt and a pair of parallel third and fourth conveyor belts arranged in transverse relationship to said first and second conveyor belts.