Lot start agent that determines quantity and timing for lot starts

• US 7,043,318 B1
• Filed: 05/23/2002
• Issued: 05/09/2006
• Est. Priority Date: 10/23/2001
• Status: Expired due to Fees

• Current Assignee: GlobalFoundries, Inc.
• Original Assignee: Advanced Micro Devices, Inc.
• Inventors: Li, Yiwei, Barto, Larry D., Nettles, Steven C.
• Primary Examiner(s): PALADINI, ALBERT WILLIAM
• Application Number:
  US10/154,092
• Time in Patent Office: 1,447 Days
• Field of Search: 700/100, 700/101, 700/99, 700/103, 700/95, 703/22
• US Class Current: 700/100
• CPC Class Codes: G06N 5/043 Distributed expert systems; Blackboards

Abstract

An automated system is provided in a facility that manufactures m products, where m>0. The system comprises a software object that provides for calculation of one or more bottleneck delta virtual work in process time (“VWIP”) values. Each of the bottleneck delta VWIP values represents the amount of time until one of n bottleneck workstations begins to risk starvation, where n>0. VWIP is the amount of time a bottleneck will stay busy processing WIP that will reach the bottleneck in less time than new lot starts will reach the same bottleneck. In at least one embodiment, each of the bottleneck delta VWIP values is calculated as a mathematical function of virtual WIP time for the corresponding bottleneck workstation and a lower control limit for the corresponding bottleneck workstation. In at least one other embodiment, n>2 and the software object provides for calculation of a plurality of bottleneck delta VWIP values. The software object contains program code that provides for the foregoing functionality either directly or by invoking one or more other objects.

Claims

1. An automated system in a facility that manufactures m products, where m≧

1, comprising;

a virtual factory, the virtual factory containing objects corresponding to physical elements of the facility that manufacturing m products; and

a software object coupled to the virtual factory, the software object including

means for identifying a selected bottleneck workstation from among a plurality of n bottleneck workstations, each of the plurality of n bottleneck workstations being associated with a distinct one of a plurality of bottleneck delta virtual work in process time (“

VWIP”

) values, each of the plurality of bottleneck delta VWIP values representing the time until the associated bottleneck workstation begins to risk starvation;

means for determining that the selected bottleneck workstation is associated with a lowest bottleneck delta VWIP value from among the plurality of bottleneck delta VWIP values;

means for determining whether products starts should be recommended for the selected bottleneck workstation; and

means for recommending starts if starts should be recommended for the selected bottleneck workstation.

2. The automated system recited in claim 1, wherein:

to determine whether product starts should be recommended for the selected bottleneck workstation, the software object determines whether a minimum delta VWIP value is greater than the bottleneck delta VWIP value for the selected bottleneck workstation.

3. The automated system recited in claim 1, wherein:

to determine whether product starts should be recommended for the selected bottleneck workstation, the software object determines whether a number representing the product starts for a current evaluation cycle is less than a maximum start value.

4. The automated system recited in claim 2, wherein:

to determine whether product starts should be recommended for the selected bottleneck workstation, the software object determines whether a number representing the product starts for a current evaluation cycle is less than a maximum start value.

5. An automated system in a facility that manufactures m products, where m≧

1, comprising;

a virtual factory, the virtual factory containing objects corresponding to physical elements of the facility that manufactures m products; and

a software object coupled to the virtual factory, the software object including

means for calculating a current bottleneck delta virtual work in process time (“

VWIP”

) value for each of a plurality of n bottleneck workstations, where n>

0, each of the plurality of current bottleneck delta VWIP values representing the time until the associated bottleneck workstation begins to risk starvation;

means for determining whether a selected bottleneck workstation requires additional product starts during a current evaluation cycle in order to avoid risk of starvation;

means for determining if the selected bottleneck workstation requires additional product starts in order to avoid risk of starvation, recommending that additional product be started, wherein the recommended additional product starts comprise at least one of the m products; and

means for determining to calculate a new bottleneck delta VWIP value for each of the bottleneck workstations that is expected to process the recommended additional starts.

6. The system recited in claim 5, wherein:

the software object calculates the new bottleneck delta VWIP value for each of the bottleneck workstations that is expected to process the recommended additional product starts as a mathematical function of the current bottleneck delta VWIP value for the particular bottleneck workstation and a consumption time associated with the recommended additional product starts.

7. The system recited in claim 6, wherein:

the recommended additional product starts comprise one or more wafers.

8. The system recited in claim 7, wherein:

that at least one of the m products comprises a product i;

the recommended additional product starts comprise a predetermined number, WaferStarts, of wafers of product i.

9. The system recited in claim 8, wherein:

the consumption time represents the projected amount of time required for WaferStarts number of product i to be consumed at a first bottleneck workstation.

10. The system recited in claim 9, wherein:

the selected bottleneck workstation comprises a plurality of bottleneck machines, the plurality of bottleneck machines further comprising M bottleneck machines, wherein M represents the number of the plurality of bottleneck machines that are operational at a given point in time.

11. The system recited in claim 10, wherein:

the software object calculates the new bottleneck delta VWIP value as the sum of the current bottleneck delta VWIP value and (the consumption time multiplied by WaferStarts); and

the consumption time is calculated as the quotient of (the time required for each wafer of product i to be consumed at the first bottleneck workstation) divided by M.

12. The system recited in claim 5, wherein:

the software object determining whether the selected bottleneck workstation requires additional product starts during the current evaluation cycle in order to avoid risk of starvation;

the software object provides for, if the selected bottleneck workstation requires additional product starts in order to avoid risk of starvation, recommending that a second additional product be started, wherein the second additional product comprises at least one of the m products; and

the software object calculating a new bottleneck delta VWIP value for each of the bottleneck workstations that is expected to process the second recommended additional product starts.

13. The system recited in claim 5, wherein:

the software object determining whether a second selected bottleneck workstation requires additional product starts during the current evaluation cycle in order to avoid risk of starvation;

the software object provides for, if the second selected bottleneck workstation requires additional product starts in order to avoid risk of starvation, recommending that a second additional product be started, wherein the second recommended additional product comprises at least one of the m products; and

the software object calculates a new bottleneck delta VWIP value for each of the bottleneck workstations that is expected to process the second recommended additional products starts.

14. An automated system in a facility that manufactures m products, where m≧

1, comprising;

a virtual factory, the virtual factory containing objects corresponding to physical elements of the facility that manufactures m products; and

a software object coupled to the virtual factory, the software object including

means for calculating a current bottleneck delta virtual work in process time (“

VWIP”

) value for each of a plurality of n bottleneck workstations, where n>

0, each of the plurality of current bottleneck delta VWIP values representing the time until the associated bottleneck workstations begins to risk starvation;

means for determining whether any bottleneck workstation requires additional product starts during a current evaluation cycle in order to avoid risk of starvation;

means for determining if no bottleneck workstation requires additional product starts during the current evaluation cycle in order to avoid risk of starvation, whether less than a maximum amount of new product, MaxStarts, has been started during the current evaluation cycle.

15. The system recited in claim 14, wherein:

the software object calculates a wakeup delay.

16. The system recited in claim 14, wherein:

the software object determining which of the current bottleneck delta VWIP values represents a lowest value.

17. The system recited in claim 16, wherein:

the software object calculates a wakeup delay;

wherein, if no bottleneck workstation requires additional product starts during the current evaluation cycle in order to avoid risk of starvation and less than MaxStarts of new product has been started during the current evaluation cycle, the wakeup delay is calculated to have a value associated with the lowest current bottleneck delta VWIP value.

18. The system recited in claim 14, wherein:

the software object provides for calculating each of the plurality of current bottleneck delta VWIP values to take into account the new product that has been started during the current evaluation cycle.

19. The system recited in claim 14, wherein the software object receives MaxStarts as an input value.

20. An automated system in a facility that manufactures m products, where m≧

1, comprising;

a virtual factory, the virtual factory containing objects corresponding to physical elements of the facility that manufactures m products; and

a software object coupled to the virtual factory, the software object including

means for calculating a current bottleneck delta virtual work in process time (“

VWIP”

) value for each of a plurality of n bottleneck workstations, where n>

0, each of the plurality of current bottleneck delta VWIP values representing the time until the associated bottleneck workstation begins to risk starvation;

means for determining whether a selected bottleneck workstation requires additional product starts during a current evaluation cycle in order to avoid risk of starvation;

means for providing for, if the selected bottleneck workstation requires additional product starts in order to avoid risk of starvation, recommending that additional product be started, wherein the recommended additional product starts comprise at least one of the m products;

wherein recommending that recommended additional product be started further includes;

calculating remaining product starts available for a starts period; and

determining an amount of additional product to be started; and

wherein the amount of additional product to be started represents one or more batches, wherein a batch includes a predetermined number, B, of lots.

21. The system recited in claim 20, wherein:

the software object receives the value of B as an input.

22. The system recited in claim 20, wherein calculating the remaining product starts available for a starts period further comprises:

determining a total planned starts value for the starts period;

determining an actual starts-to-date value for the starts period; and

calculating the remaining product starts available as a mathematical function of the total planned starts value and the actual starts-to-date value.

23. The system recited in claim 22, wherein calculating the remaining product starts available for a starts period further comprises:

summing the difference of (total planned starts value for the starts period−

actual starts-to-date for the starts period) for each of the m products.

24. The system recited in claim 21, wherein:

each lot comprises a predetermined number, WafersPerLot, of wafers.

25. The system recited in claim 24, wherein:

the software object receives the value of WafersPerLot as an input.

26. The system recited in claim 21, wherein determining an amount of additional product to be started further comprises:

initializing the number of product starts to zero; and

iteratively incrementing the number of product starts by one batch of wafers until the current bottleneck VWIP value for the selected bottleneck workstation is greater than a minimum delta VWIP value.

27. An automated system in a facility that manufactures m products, where m≧

1, comprising;

a virtual factory, the virtual factory containing objects corresponding to physical elements of the facility that manufactures m products; and

a software object coupled to the virtual factory, the software object including

means for calculating a current bottleneck delta virtual work in process time (“

VWIP”

) value for each of a plurality of n bottleneck workstations, where n>

0, each of the plurality of current bottleneck delta VWIP values representing the time until the associated bottleneck workstation begins to risk starvation;

means for determining whether a selected bottleneck workstation requires additional product starts during a current evaluation cycle in order to avoid risk of starvation;

means for providing for, if the selected bottleneck workstation requires additional product starts in order to avoid risk of starvation, recommending that additional product be started, wherein the recommended additional product starts comprise at least one of the m products;

wherein recommending that additional product be started further includes;

determining a total planned starts value for the starts period;

determining an actual starts-to-date value for the starts period; and

calculating the remaining product starts available as a mathematical function of the total planned starts value and the actual starts-to-date value.

28. The system recited in claim 27, wherein recommending that additional WIP be started further comprises:

summing the difference of (total planned starts value for the starts period−

actual starts-to-date for the starts period) for each of the m products.

29. The system recited in claim 28, wherein the actual starts-to-date value for the starts period reflects any manual starts that have occurred during the starts period.

30. The system recited in claim 28, wherein a starts plan is associated with the starts period.

31. The system recited in claim 30, wherein the starts plan identifies the total planned starts value for the starts period.

32. The system recited in claim 27, wherein a plurality of starts plans is associated with the starts period, the plurality of starts plans including a most current starts plan.

33. The system recited in claim 32, wherein the most current starts plan identifies the total planned starts value for the starts period.

34. An automated system in a facility that manufactures m products, where m≧

1, comprising;

a virtual factory, the virtual factory containing objects corresponding to physical elements of the facility that manufactures m products; and

a software object coupled to the virtual factory, the software object including

means for calculating a current bottleneck delta virtual work in process time (“

VWIP”

) value for each of a plurality of n bottleneck workstations, where n>

0, each of the plurality of current bottleneck delta VWIP values representing the time until the associated bottleneck workstation begins to risk starvation;

means for determining whether any bottleneck workstation requires additional products starts during a current evaluation cycle in order to avoid risk of starvation;

means for determining whether less than a maximum amount of new product, MaxStarts, has been started during the current evaluation cycle if the maximum amount of new product has been started during the current evaluation cycle, then waiting a minimum wakeup delay before starting another evaluation cycle.

35. The system recited in claim 34, wherein the minimum wakeup delay is configurable.