Page 232 - The Six Sigma Project Planner

Figure 39. Lithography Inspection Station Table, Stool, and Magnifying Glass

Each inspector checks each sheet once in the morning and again in the afternoon. After
each inspection, the inspector classifies the sheet as either acceptable or unacceptable.
The entire study is repeated the following week. The results are shown in Table 20.

Table 20. Results of Lithography Attribute Inspection Study

A B C D E F G H I
1 Part Standard InspA InspB InspC Date Time Reproducible Accurate
2 1 1 1 1 1 Today Morning 1 1
3 1 1 0 1 1 Today Afternoon 0 0
4 2 0 0 0 0 Today Morning 1 0
5 2 0 0 0 1 Today Afternoon 0 0
6 1 1 1 1 1 Last Week Morning 1 1
7 1 1 1 1 0 Last Week Afternoon 0 0
8 2 0 0 0 1 Last Week Morning 0 0
9 2 0 0 0 0 Last Week Afternoon 1 0

In Table 20, the “Part” column identifies which sheet is being inspected and the
“Standard” column is the classification for the sheet based on the journeymen’s
evaluations. A 1 indicates that the sheet is acceptable, a 0 that it is unacceptable. The
columns labeled “InspA,” “InspB,” and “InspC” show the classifications assigned by
the three inspectors respectively. The “Reproducible” column is a 1 if all three inspectors
agree on the classification, whether their classification agrees with the standard or not.
The “Accurate” column is a 1 if all three inspectors classify the sheet correctly as shown
in the “Standard” column.

Individual Inspector Accuracy
Individual inspector accuracy is determined by comparing each inspector’s
classification with the standard. For example, in cell C2 of Table 20, Inspector A
classified the unit as acceptable and the “Standard” column in the same row indicates
that the classification is correct. However, in cell C3 the unit is classified as unacceptable

215