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Activity Number:
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359
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Type:
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Contributed
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Date/Time:
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Wednesday, August 6, 2008 : 8:30 AM to 10:20 AM
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Sponsor:
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Section on Quality and Productivity
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| Abstract - #301956 |
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Title:
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A Method for Calculating Control Limits for Multiple Characteristics That Are Skewed and/or Detection Limit Censored
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Author(s):
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Robert Brill*+ and Thomas J. Bzik
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Companies:
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ICL Performance Products and Air Products and Chemicals, Inc.
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Address:
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532 Millstone Drive, Lawrence, KS, 66049,
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Keywords:
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control limits ; skewed data ; detection limit censoring ; family type I error ; individual type I error ; non-distributional
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Abstract:
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There is a trend in industry for producers to require their raw material suppliers to provide materials that not only meet nominal specifications but also that each characteristic be in statistical control. This has the affect of making control limits de facto specifications. In the semi conductor industry a single raw material typically has more than 20 specifications. The data required to calculate control limits are often highly skewed and censored to detection limits. The SEMI trade organization has recently issued a Guideline, SEMI C64-0308 - SEMI Statistical Guidelines for Ship To Control, for calculating control limits for such data that is non-distributional, does not require transformation of the data and approximately maintains a set type I error at the family level. This talk will explain the statistical background of the guideline.
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