E10 Fall, 2009, Prof. Leachman Homework on Queuing Analysis Due at start of class, Wednesday Oct 7 The photolithography department in a semiconductor fabrication plant has 10 identical photo machines. Manufacturing lots pass through a series of 100 steps in the plant, including five photolithography steps. At present, any of the ten machines can be used to perform any of the five photo steps. To improve the process yield, the photo process engineer proposes a “lot-to-lens dedication” policy, whereby each manufacturing lot would be required to visit the same photo machine for processing of photo steps 2, 3, 4 and 5 that the lot visited for photo step 1. It still would be the case that a lot could be processed by any of the ten machines at photo step 1. Suppose the photo machines average 90% availability, the factory works 168 hours per week, and the average total hours of processing work for the ten photolithography machines to perform is 1250 hours per week. a. Assuming utilization of the ten machines is balanced (i.e., each machine is allocated 125 hours
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This note was uploaded on 02/09/2010 for the course ENGIN 10 taught by Professor Johnson during the Fall '08 term at Berkeley.