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The OCAP

seldom-used terminators can be moved to the end of the flow or eliminated altogether. If the punt terminator is used fireąuently, the PAT investigates further to obtain morę detail about those occurrences. Another Pareto chart can be madę of the different actions taken under punt terminators, and the morę freąuently occurring causes can be added to the OCAP as specific checkpoints and terminators.

A terminator might not keep its same number once it is moved up or down in the OCAP. For example, if terminator No. 5 “bad wafer” occurs often and is moved up to become the second terminator, it obtains a new number (terminator No. 2) but keeps the same name (“bad wafer”).

•    Analyze activators. The following ąuestions can help the PAT revise the

OCAP: Does the average go out of control morę often than does the rangę? What is the percentage of out-of-control averages vs. out-of-control ranges? Do the average points fali on one side of the target much morę often than on the other side? Are all machines of the same type experiencing the same kinds of out-of-control conditions?

•    Train the point plotters to perform morę of the OCAP tasks. It is often

unreasonable to expect the point plotters to be able to perform every task reąuired by the OCAP. The Pareto analysis of terminators, however, identifies and prioritizes those tasks that the point plotters should be performing. If a revised OCAP moves up to checkpoint or terminator that involves a task for which the point plotter currently isn't responsible, it is a prime candidate for transferal to the point plotter. This maintains the OCAP's efficiency so that as little time as possible is lost in transferring OCAP responsibility between job disciplines.

The Pat regularly performs Pareto reviews for the terminators and revises the control chart and OCAP until a State of stability is achieved. Stability can be measured by looking at:

•    The terminator numbers. The most commonly used terminators should

have the lowest numbers. Ideally, terminator No. 1 should be used the most often, terminator No. 2 should be the next most-often used, and son on.

•    The average amount of time it takes to go through the OCAP process.

This time should approach zero as the OCAP is continually revised and improved.