These activities focus on data
analysis in the context of statistical
process control (SPC) in the
semiconductor industry. One stage
in the manufacturing process of
microchips is the production of polished
silicone wafers. In Activity 1 students
examine data on wafer thickness and
represent distributions of sample data
with histograms. Students are presented
with a set of histograms representing
data for polished wafers produced under
a variety of control settings. Using
information from the histograms,
students decide how each of three
controls affects wafer thickness and make
recommendations on appropriate settings
for these controls.
Mathematics Prerequisites and Discussion:
Activity 1 assumes that students know how
to (1) create frequency distributions and (2)
draw histograms for quantitative data. If
histograms and frequency distributions are
new to students, present an example similar
to the one in the Lesson Notes before they
begin Activity 1.
Histograms can be tedious to draw by hand,
particularly when data sets are large, as is
generally the case in process control. Hence,
in Activity 2 all histograms should be created
using technology, either graphing calculators
or spreadsheets. (The Lesson Notes include
instructions for TI83/84 graphing
calculators.) In addition, students should be
familiar with plotting points and making
scatter plots.
Materials Needed:
Graph paper, graphing calculators (or
spreadsheet software).
