Method and system for scheduling a stream of products in a manufacturing environment by using process-specific WIP limits

• US 8,185,226 B2
• Filed: 05/12/2008
• Issued: 05/22/2012
• Est. Priority Date: 07/31/2007
• Status: Expired due to Fees

• Current Assignee: GlobalFoundries, Inc.
• Original Assignee: GlobalFoundries, Inc.
• Inventors: Weigang, Joerg, Ringel, Robert, Kalisch, Steffen, Quarg, Thomas
• Primary Examiner(s): HARTMAN JR, RONALD D
• Application Number:
  US12/119,042
• Publication Number:
  US 20090037012A1
• Time in Patent Office: 1,471 Days
• Field of Search: 700/95, 700/97, 700 99-101, 700/103, 700/108, 700/111, 700/102
• 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, in a control system, 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, using the control system, a flow of products to each of said plurality of sections by reducing priorities for releasing substrates from a subset of the plurality of sections into a subsequent section when said comparison result indicates that the current work in progress value of the subsequent section is larger than the respective maximum work in progress value associated with the subsequent section.

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

4. The method of claim 1, further comprising blocking a dispatch of the subset by reducing priorities for releasing the substrates from the subset to zero.

5. 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.

7. The method of claim 5, wherein said manufacturing environment is configured to process microstructure devices.

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

9. The method of claim 8, 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.

6. 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, in a control system, 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, using the control system, a flow of products to each of said plurality of sections by using said comparison result, 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, and 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.

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, in a control system, 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, using the control system, a reduced priority value for each of a plurality of process operations preceding said first process operation; and

processing products according to the plurality of process operations on the basis of said reduced priority values.

11. 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.

12. 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.

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

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

15. 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, in a control system, 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, in the control system, 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, 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.

16. 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, in a control system, 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, in the control system, 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, 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.

17. The method of claim 16, wherein said first process tool is controlled to cease performing said first process operation.

18. A method of automatically controlling a process flow comprising a group of interrelated processes in a manufacturing environment, the method comprising:

determining, in a control system, a cycle time shadow for a first process in the process flow when current work in progress (WIP) material for the first process exceeds a maximum WIP material level assigned to the first process, wherein the cycle time shadow indicates preceding processes that provide WIP material to the first process during a time required to consume a selected amount of WIP material using the first process; and

reducing, using the control system, priorities for releasing WIP material from preceding processes in the cycle time shadow.

19. The method of claim 18, wherein determining the cycle time shadow comprises determining the preceding processes that provide WIP material to the first process during a time required to process WIP material in excess of the maximum WIP material level.

20. The method of claim 18, wherein determining the cycle time shadow comprises determining the preceding processes that provide WIP material to the first process during a time required to process the current WIP material.

21. The method of claim 18, wherein determining the cycle time shadow comprises determining the cycle time shadow using cycle times for processing WIP material in the preceding processes.