Oxide                  package:nlme                  R Documentation

Variability in Semiconductor Manufacturing

Description:

     The 'Oxide' data frame has 72 rows and 5 columns.

Format:

     This data frame contains the following columns:

     Source a factor with levels '1' and '2' 

     Lot a factor giving a unique identifier for each lot.

     Wafer a factor giving a unique identifier for each wafer within a
          lot.

     Site a factor with levels '1',  '2', and  '3' 

     Thickness a numeric vector giving the thickness of the oxide
          layer.


Details:

     These data are described in Littell et al. (1996, p. 155) as
     coming ``from a passive data collection study in the semiconductor
     industry where the objective is to estimate the variance
     components to determine the assignable causes of the observed
     variability.'' The observed response is the thickness of the oxide
     layer on silicon wafers, measured at three different sites of each
     of three wafers selected from each of eight lots sampled from the
     population of lots.

Source:

     Pinheiro, J. C. and Bates, D. M. (2000), _Mixed-Effects Models in
     S and S-PLUS_, Springer, New York.  (Appendix A.20)

     Littell, R. C., Milliken, G. A., Stroup, W. W. and Wolfinger, R.
     D. (1996), _SAS System for Mixed Models_, SAS Institute, Cary, NC.

