Balancing work release based on both demand and supply variables

• US 20040186605A1
• Filed: 03/21/2003
• Published: 09/23/2004
• Est. Priority Date: 03/21/2003
• Status: Active Grant

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Inventors: Wu, Kan, Chien, Ming-Cheng, Lai, Po-Chun, Hung, Wei-Jai, Lo, Chiang-Chou, Chen, Hsu-Jen
• Granted Patent: US 6,892,106 B2
• Time in Patent Office: Days
• US Class Current: 700/102
• CPC Class Codes: G06Q 10/087 Inventory or stock management, e.g. order filling, procurement or balancing against orders

Abstract

A systematic approach for generating a work release plan that considers both demand and supply variables. The approach comprises prioritizing scheduled lots in order of their critical ratios, estimating an initial daily release quota for the scheduled lots based on both pull and push requirements, and determining detailed capacity constraints for the manufacturing system. The approach further comprises testing whether the initial daily release quota complies with the detailed capacity constraints, and, if the detailed capacity constraints are violated, rearranging the lots in the initial daily release quota so that the detailed capacity constraints are met.

Claims

1. A method of generating a work release plan for a manufacturing system, said method comprising:

prioritizing scheduled lots in order of their critical ratios;

estimating an initial daily release quota for the scheduled lots based on both pull and push requirements;

determining detailed capacity constraints for the manufacturing system;

testing whether the initial daily release quota complies with the detailed capacity constraints; and

if the detailed capacity constraints are violated, rearranging the lots in the initial daily release quota so that the detailed capacity constraints are met.

2. The method of claim 1, wherein the critical ratio is determined by the formula:

Critical Ratio=(Master Production Schedule Date−

Today'"'"'s Date)/(Forecast Out Date−

Today'"'"'s Date).

3. The method of claim 1, wherein the initial daily release quota is estimated as minimum(overall system capacity constraints, front end line balance).

4. The method of claim 3, wherein the overall system capacity constraints indicate an overall manufacturing system bottleneck loading.

5. The method of claim 3, wherein the front end line balance indicates a front end bottleneck loading.

6. The method of claim 1, wherein the initial daily release quota is estimated as minimum(overall system capacity constraints, front end line balance, fab output target requirement).

7. The method of claim 6, wherein the fab output target requirement is determined using material requirements planning.

8. The method of claim 1, wherein the detailed capacity constraints are selected from the group consisting of:

specific tool group capacity, batch size optimization, limited quantity tool capacity, and combinations thereof.

9. The method of claim 8, wherein the batch size optimization includes grouping similar recipe parts together, and includes making lot size the same as a batch process'"'"' batch size.

10. A method of generating a wafer start plan for a semiconductor fabrication facility, said method comprising:

prioritizing scheduled wafer lots in order of their critical ratios;

estimating an initial daily wafer start quota based on both pull and push requirements;

determining detailed capacity constraints for the semiconductor fabrication facility;

testing whether the initial daily wafer start quota complies with the detailed capacity constraints; and

if the detailed capacity constraints are violated, rearranging the wafer lots in the initial daily wafer start quota so that the detailed capacity constraints are met.

11. The method of claim 10, wherein the initial daily wafer start quota is estimated as minimum(overall system capacity constraints, front end line balance, fab output target requirement).

12. The method of claim 11, wherein the front end line balance indicates a front end furnace bottleneck loading.

13. The method of claim 10, wherein one of the detailed capacity constraints is photolithography load balancing.

14. The method of claim 13, wherein the photolithography load balancing is no more than 6 lots per tool per day.

15. The method of claim 10, wherein one of the detailed capacity constraints is furnace batch size optimization.

16. The method of claim 15, wherein the furnace batch size optimization includes grouping similar recipe parts together, and includes making lot size the same as the furnace batch size.

17. The method of claim 10, wherein one of the detailed capacity constraints is photo mask capacity.

18. The method of claim 17, wherein the photo mask capacity is no more than 12 lots per part per mask per day.

19. A system for generating a work release plan for a manufacturing system, said system comprising:

means for prioritizing scheduled lots in order of their critical ratios;

means for estimating an initial daily release quota using both demand and supply requirements;

means for determining detailed capacity constraints for the manufacturing system;

means for testing whether the initial daily release quota complies with the detailed capacity constraints; and

if the detailed capacity constraints are violated, means rearranging the lots in the initial daily release quota so that the detailed capacity constraints are met.

20. A computer-readable medium having computer code recorded thereon executable by a computer, said computer code for generating a work release plan for a manufacturing system, said computer code comprising instructions for causing the computer to:

order scheduled lots according to their critical ratios;

estimate an initial daily release quota for the scheduled lots using both supply and demand requirements;

determine detailed capacity constraints for the manufacturing system;

test whether the initial daily release quota complies with the detailed capacity constraints; and

if the detailed capacity constraints are violated, rearrange the lots in the initial daily release quota so that the detailed capacity constraints are met.