# Homework5 -S09

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## Homework5 -S09

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- Pages:
- 2
- School:
- Iowa State University
- Course:
- Stat 496 - Applied Statistics for Industry II

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STAT 496 Spring 2009 Homework Assignment 5 Due by Friday March 13 1 A factorial experiment is performed as part of the development of a nitride etching process on a single wafer plasma etcher The process uses C2F6 as the reactant gas For factors are manipulated in the experiment The factors and levels are given below Factor A Anode Cathode Gap cm B Pressure mTorr C C2F6 gas flow SCCM D Power applied to cathode W Low 1 0 8 450 125 275 High 1 1 2 550 200 325 The response is the etch rate for silicon nitride in Angstroms per minute The data are given below Note that coded levels of the factors are given in the data table Trmt Comb 1 a b ab c ac bc abc d ad bd abd cd acd bcd abcd XA 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 XB 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 XC 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 XD 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Etch Rate 550 669 604 650 633 642 601 635 1037 749 1052 868 1075 860 1063 729 Run 13 8 12 9 4 15 16 3 1 14 5 10 11 2 7 6 a For each factor calculate the mean etch rate when that factor is at the high level and at the low level Display these means in four main effects plots one for each factor Comment on the apparent size of each main effect b Construct interaction plots for the four factors Pay particular attention to the combinations of A Anode Cathode Gap with B Pressure A Anode Cathode Gap with C C2F6 gas flow and A Anode Cathode Gap with D Power applied to the cathode Comment on the apparent presence or absence of interaction for these three combinations c Compute the overall grand sample mean and the 15 estimated effects Be sure to indicate whether you are computing estimated full effects of half effects 1 d Construct a normal probability plot for the 15 estimated full effects Label on your plot effects that appear to be significant e You should be able to pick up some pseudo replication by eliminating a factor and all its interactions with the other three factors This should give you a 23 experiment with 2 replicates With this reduced model compute

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