An article in Solid State Technology, "Orthogonal Design for Process Optimization and Its Application to Plasma Etching" by G. Z. Yin and D. W. Jillie (May, 1987) describes an experiment to determine the effect of the C₂F₆ flow rate on the uniformity of the etch on a silicon wafer used in integrated circuit manufacturing. Data for two flow rates are as follows:

 

(a) Does the C₂F₆ flow rate affect average etch uniformity? Use α = 0.05.

(b) What is the P-value for the test in part (a)?

(c) Does the C₂F₆ flow rate affect the wafer-to-wafer variability in etch uniformity? Use α = 0.05.

(d) Draw box plots to assist in the interpretation of the data from this experiment.

Uniformity Observation CF. Flow (SCCM) 1 2 3 4 5 6. 125 2.7 4.6 2.6 3.0 3.2 3.8 200 4.6 3.4 2.9 3.5 4.1 5.1