METHOD AND SYSTEM FOR SCHEDULING A STREAM OF PRODUCTS IN A MANUFACTURING ENVIRONMENT BY USING PROCESS-SPECIFIC WIP LIMITS

• US 20090037012A1
• Filed: 05/12/2008
• Published: 02/05/2009
• Est. Priority Date: 07/31/2007
• Status: Active Grant

• Current Assignee: GlobalFoundries, Inc.
• Original Assignee: GlobalFoundries, Inc.
• Inventors: Kalisch, Steffen, Quarg, Thomas, Weigang, Joerg, Ringel, Robert
• Granted Patent: US 8,185,226 B2
• Time in Patent Office: Days
• US Class Current: 700/101
• CPC Class Codes: G05B 19/41865 characterised by job scheduling, process planning, material flow
• CPC Class Codes: G05B 2219/31449 Monitor workflow, to optimize business, industrial processes
• CPC Class Codes: G05B 2219/32266 Priority orders
• CPC Class Codes: G05B 2219/32293 Minimize work in progress, system at maximum productivity
• CPC Class Codes: G05B 2219/45031 Manufacturing semiconductor wafers
• CPC Class Codes: Y02P 90/02 Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]

Abstract

By defining a section-related WIP limit or a throughput-related WIP limit, an efficient “look ahead” characteristic may be established to efficiently control the WIP in a complex manufacturing environment, such as a semiconductor facility. The respective critical WIP values may enable efficient reduction of priority of products moving towards an increased WIP queue, thereby reducing or substantially avoiding the release of products that are expected to run into the WIP queue. In this way, the efficiency of shared tools may be increased, since process capacity no longer required for the processing products running into WIP queues may be allocated for other operations.

Claims

1. A method of automatically controlling a process flow in a manufacturing environment, the method comprising:

determining a plurality of sections of said process flow performed in said manufacturing environment by using a plurality of process tools for processing products, each of said plurality of sections corresponding to a group of interrelated processes;

determining a maximum work in progress value for each of said plurality of sections on the basis of at least a section-specific characteristic and a characteristic relating to a production target value of said process flow;

for each of the plurality of sections, comparing a current work in progress value of a respective section with a respective maximum work in progress value associated with said respective section to provide a comparison result; and

controlling a flow of products to each of said plurality of sections by using said comparison result.

2. The method of claim 1, wherein controlling said flow of products to each of said plurality of sections comprises assigning a priority to each product of said flow of products and controlling dispatching of each product in the flow into a first process tool corresponding to a first process of a respective section on the basis of said priority.

3. The method of claim 1, further comprising blocking a dispatch of a product dedicated for processing into a specific one of said plurality of sections when said comparison result indicates that the current work in progress value of said specific one of said plurality of sections is greater than said maximum work in progress value.

4. The method of claim 1, wherein at least one process tool is used to perform a first process in a first one of said plurality of sections and a second process in a second one of said plurality of sections.

5. The method of claim 4, wherein said process tool is controlled to perform said second process while rejecting requests for said first process when the work in progress values of said first and second sections are higher and lower, respectively, compared to said maximum work in progress value.

6. The method of claim 4, wherein said manufacturing environment is configured to process microstructure devices.

7. The method of claim 6, wherein each of said plurality of sections corresponds to processes performed on the basis of a different lithography mask set.

8. The method of claim 7, wherein said maximum work in progress value is determined on the basis of an overall production target output per time unit of said manufacturing environment and a cycle time of a product for passing through a respective section.

9. The method of claim 2, further comprising scheduling said flow of products through said plurality of sections on the basis of said priorities.

10. A method of automatically controlling a process flow comprising a plurality of process operations in a manufacturing environment, the method comprising:

determining a critical work in progress value for each process operation on the basis of a characteristic related to a production target value of said process flow, said critical work in progress value indicating a required work in progress value at each process operation to support said production target value;

comparing each critical work in progress value with a current work in progress value of each process operation to provide a comparison result;

when said comparison result indicates that a first process operation has a first current work in progress value that is greater than a critical work in progress value associated with said first process operation, generating a reduced priority value for each of one or more process operations preceding said first process operation; and

processing products according to said one or more process operations on the basis of said reduced priority values.

11. The method of claim 10, wherein generating a reduced priority value for each of said one or more preceding process operations comprises estimating a number of preceding process operations on the basis of said comparison result and a cycle time of process operations preceding said first process operation.

12. The method of claim 10, wherein said first process operation and a second process operation are performed by a first process tool and wherein the method further comprises reducing priority for performing said first process operation and increasing priority for performing said second process operation, when said second operation is not one of said one or more preceding process operations.

13. The method of claim 12, wherein said first process tool is controlled to cease performing said first process operation.

14. The method of claim 10, further comprising establishing a dispatch list for at least some of said process operations on the basis of said comparison result.

15. The method of claim 10, further comprising performing at least one further process flow by using process tools used in said process flow and increasing a priority for performing specific process operations of said at least one further process flow when said specific process operations are performed by one or more process tools that perform said one or more process operations preceding said first process operation.

16. The method of claim 10, wherein said manufacturing environment is configured to process semiconductor devices.

17. The method of claim 10, further comprising automatically updating said work in progress value for each of said process operations on a regular basis.

18. A work in progress control system, comprising:

a process monitor configured to receive process information relating to a plurality of products and a plurality of process tools of a manufacturing environment and to determine a current work in progress value for each of a plurality of process operations performed by said plurality of process tools;

a comparator configured to determine a comparison result indicating a deviation between said current work in progress values and a plurality of limit work in progress values corresponding to said plurality of process operations, said limit work in progress values indicating an upper limit for a work in progress value required to meet a production target of said process flow; and

a process priority estimator configured to reduce a priority for at least some of said process operations by using said comparison result.

19. The work in progress control system of claim 18, wherein each of said limit work in progress values represents a maximum value for a mean work in progress value of a respective one of a plurality of sections of interrelated process operations of said process flow.

20. The work in progress control system of claim 18, wherein each of said limit work in progress values represents a target work in progress value for each of said plurality of process operations.