An experiment was run in a semiconductor fabrication plant in an effort to increase yield. Five factors, each at two levels, were studied. The factors (and levels) were A = aperture setting (small, large), B = exposure time (20% below nominal, 20% above nominal), C = development time (30 and 45 seconds), D = mask dimension (small, large), and E = etch time (14.5 and 15.5 minutes). The following unreplicated 25 design was run:

(a) Construct a normal probability plot of the effect estimates. Which effects appear to be large?

(b) Conduct an analysis of variance to confirm your findings for part (a).

(c) Construct a normal probability plot of the residuals. Is the plot satisfactory?

(d) Plot the residuals versus the predicted yields and versus each of the five factors. Comment on the plots.

(e) Interpret any significant interactions.

(f) What are your recommendations regarding process operating conditions?

(g) Project the 25 design in this problem into a 2r for r < 5 design in the important factors. Sketch the design and show the average and range of yields at each run. Does this sketch aid in data interpretation?

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(1) = 12 = 35 = 52 = 15 = 22 45 = 65 9. a ae = 34 = 55 = 16 = 20 = 40 = 60 be abe ab ce ac ace bc abc bce abce = 6 de = 10 = 10 ad ade bde = 32 abd = 50 cd = 30 abde = 53 cde bd = 15 acde = 20 bcde = 41 abcde = 63 18 acd = 21 bcd = 44 abcd = 61