Wright Williams & Kelly

TECHNICAL ALERT #4 FOR ALL USERS OF TWO COOL®


The advanced features of TWO COOL® v2.0 allows analysis of a single tool using multiple process recipes. The process recipe section of v2.0 uses a simple weighted average based on percentage of use for all inputs. For cases where throughput or equipment yield differs greatly among process recipes, a simple weighted average may underestimate yield loss.

This issue does not impact analyses of process recipes with similar throughputs and yields or analyses using single process recipes. The equations on the following page are incorporated into TWO COOL® v2.1.1. The equations extend process recipe weighting to include percentage of use and throughput. Should you have additional input or suggestions, please contact Wright Williams & Kelly directly.

Equipment Yield (Wafer Fab and Assembly and Packaging)

Defect Density (Wafer Fab Only)

Probability of Failure (Wafer Fab Only)

where:
EY = equipment yield
%Use = the percentage use of a process recipe
TPT = throughput at capacity
DD = defect density
POF = probability of failure.

Techalert4-9601


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