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2. Measurement Process Characterization
2.6. Case studies
2.6.2. Check standard for resistivity measurements
2.6.2.2. Analysis and interpretation

2.6.2.2.1.

Repeatability and level-2 standard deviations

Example The table below illustrates the computation of repeatability and level-2 standard deviations from measurements on a check standard. The check standard measurements are resistivities at the center of a 100 ohm.cm wafer. There are J = 6 repetitions per day and K = 5 days for this example.
Table of data, averages, and repeatability standard deviations
Measurements on check standard #137

Repetitions per day
Days 1 2 3 4 5 6
1 96.920 97.054 97.057 97.035 97.189 96.965
2 97.118 96.947 97.110 97.047 96.945 97.013
3 97.034 97.084 97.023 97.045 97.061 97.074
4 97.047 97.099 97.087 97.076 97.117 97.070
5 97.127 97.067 97.106 96.995 97.052 97.121
6 96.995 96.984 97.053 97.065 96.976 96.997
Averages 97.040 97.039 97.073 97.044 97.057 97.037
Repeatability
Standard
Deviations
0.0777 0.0602 0.0341 0.0281 0.0896 0.0614
Pooled
Repeatability
Standard
Deviation
0.0625
30 df
Level-2
Standard
Deviation
0.0139
5 df
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