Photoresists in semiconductor manufacturing. Refer to the Quality and Reliability Engineering International (April 2020) study of photoresists in semiconductor manufacturing, Exercise 13.22 (p. 13-33). Recall that in phase 1 of the analysis (where the manufacturer believes the process is in control), five semiconductor wafers were selected each day for 25 consecutive days and the flow resistance (in microns) of the photo resist was measured for each. Now consider constructing an R-chart for the data saved in the file.

a. For each day, compute the flow resistance range. Then verify that the average range for the 25 days is R = .3252.

b. Find the LCL and UCL for the R-chart, as well as the Zone A and Zone B boundaries.

c. Use statistical software to plot the 25 ranges in an R-chart. Is process variation in control? If not, do you recommend creating an x-chart to monitor the process mean?

d. If process variation is in control, plot the ranges for the phase 2 data (saved in the FLOW2 file) on the R-chart, part

c. Is process variation still in control? Applying the Concepts—Intermediate