spaMM (version 4.5.0)

wafers: Data from a resistivity experiment for semiconductor materials.

Description

This data set was reported and analyzed by Robinson et al. (2006) and reanalyzed by Lee et al. (2011). The data “deal with wafers in a single etching process in semiconductor manufacturing. Wafers vary through time since there are some variables that are not perfectly controllable in the etching process. For this reason, wafers produced on any given day (batch) may be different from those produced on another day (batch). To measure variation over batch, wafers are tested by choosing several days at random. In this data, resistivity is the response of interest. There are three variables, gas flow rate (x1), temperature (x2), and pressure (x3) and one random effect (batch or day).” (Lee et al 2011).

Usage

data("wafers")

Format

The data frame includes 198 observations on the following variables:

y

resistivity.

batch

batch, indeed.

X1

gas flow rate.

X2

temperature.

X3

pressure.

References

Robinson TJ, Wulff SS, Montgomery DC, Khuri AI. 2006. Robust parameter design using generalized linear mixed models. Journal of Quality Technology 38: 38--65.

Lee, Y., Nelder, J.A., and Park, H. 2011. HGLMs for quality improvement. Applied Stochastic Models in Business and Industry 27, 315-328.

Examples

## see examples in the main Documentation page for the package.