6. (20 points} A brication facility operates a single process ow. The process ow includes four polish steps performed by a particular type of Elly-[P machine. Data about the EMF machines of this type is as follows: Ayailability: 69.U% Utilization of ayailability: eases MTIR: 10 hours EUR: 413 hours Tel-ct time (TED: 0.2- hours (for each of the four polish steps) Standard cycle time {SCI}: 0.4 hours (for each of the four polish steps] Number of qualied machines: 3 (for each of the four polish steps) After each polish step there is a cleaning step performed by a particular type of single-wafer clean (SEE-TY) machine. Data about the SWIG machines of this type is as follows: Ayailability: 93.13% Utilization of availability: 32.0% MTIR: 4.4 hours SITE: 5.3 hours Talct time (TED: 0.1455 hours (for each ofthe four cleanafterpolish steps as u-'ell as for 3 other cleaning steps performed by this machine type) Standard cycle time (SCI): [12 hours (for each of the four clean-aer-polish steps as well as for 3 ether cleaning steps performed by this machine type) Number of qualied machines: 4 (for each of the four cleanaerpelish steps as well as for 3 other cleaning steps performed by this machine type) Assume cg = 1 and CE = 1 for all steps on both machine types. Recent data shop.r that incoming wafer uniformity at two of the four polish steps has improved considerably) so the process engineering director is censiderin g eliminating these two polishing steps and the subsequent two cleanafterpelish steps from the process ow. (a) (3 points} Estimate the reduction in entitlement cycle time if the two polish steps and the two clean-aerpolish steps are eliminated from the process ow. {bl (T points} Assuming the above-mentioned two polish steps and the two clean-after-polish steps are eliminated, estimate the percentage increase in wafer starts l[to the nearest percentage point) that could be made such that the new total ECT for the CM? machine type and the SWC machine type aboye would not exceed the total EST for those machine types before the steps are eliminated. (c) {3 points} Now suppose there are many other equipment types in the fabrication facility. Briefly explain how to determine the percentage increase in wafer starts that could be made if the above-mentioned two polish steps and two clean-aer-poltsh steps are eliminated such that the new total EST for the process flow would not exceed the total ECT for the process flow before the steps are eliminated. (d) {2 points} Suppose there is a slight decrease in yield that would occur if the above-mentioned steps are eliminated. Briey explain how you would determine if fab output would go up or go down it" the steps are eliminated and wafer starts are increased by the percentage calculated according to your proposed method in part (c)