Solutions to IEOR 130 Midterm Examination Spring, 2001 Prof. Leachman 1. (a) The down time is 2 hours. A= 22 / 24 = 0.9167 35 lots were run, but 5 lots were run twice. Thus there 40 machine cycles yesterday. The average process time per lot is 0.5 hours.

IEOR130 Midterm Examination Spring, 2009 Prof. Leachman Open notes. Work all problems. Each problem is worth 20 points. 1. At a particular manufacturing step, the important parameter for process control is the deposition thickness. This is measured at fiv

IEOR130 Midterm Examination Spring, 2009 Prof. Leachman Open notes. Work all problems. Each problem is worth 20 points. 1. At a particular manufacturing step, the important parameter for process control is the deposition thickness. This is measured at fiv

IEOR 130 Methods of Manufacturing Improvement Midterm Examination Spring, 2001 Prof. Leachman Open book and notes. Work all problems. 20 points each problem. 1. In a 24-hour period, a particular photo exposure machine had 2 hours of down time. Its rate ef

IEOR 130 Methods of Manufacturing Improvement Spring, 2008, Prof. Leachman Homework assignment 9, due May 5, 2009.
As discussed in class, one means of controlling the WIP level and the cycle time in a factory is by controlling the release of new work into

IEOR 130 Methods of Manufacturing Improvement Spring, 2009, Prof. Leachman Homework assignment 8, due April 21, 2009.
1. Consider a fab producing a NAND flash device. Production volume is 50,000 wafer starts per week. Accounting for line yield and die yie

Solutions to HW #8 IEOR 130 1. (a) The revenue gain from a one-day reduction in cycle time is expressed as
1 - e - H R = e - 1 WYP0 e -CT
(
)
.
The value of satisfies
0.50 = e - 365 or = 0.001899. The value of one day of cycle time is then R = e 0.001

IEOR 130 Methods of Manufacturing Improvement Spring, 2009 Prof. Leachman Homework Assignment 7 Due April 9, 2008 1. For a particular semiconductor product, the customer orders received are as follows, sorted by date due to ship to customer: Delivery date

IEOR 130 Methods of Manufacturing Improvement Spring, 2009 Prof. Leachman Homework Problems #6 Due Tuesday, March 17, 2009
1. Data in a factory has been collected on the performance of five types of machines, as displayed in the following table. The machi

IEOR 130 Spring, 2009, Prof. Leachman Solutions to HW 5 1. (a) We use the observed best yield to make a 3- estimate of YR: 0.82 - YR = 3 YR (1 - YR ) / 400
0.6724 - 1.64YR + YR = (9 / 400)[YR - YR ]
2 2
0.6724 - 1.6625YR + 1.0225YR = 0
2
YR =
1.6625 2.763

IEOR 130 - Methods of Manufacturing Improvement Spring, 2009 Prof. Leachman Homework Assignment 5 - Due Tuesday, March 10 1. A product with 400 die per wafer has an average die yield of 60% and a die area of 0.5 cm2. The best die yield observed near the c

Solutions to HW 4 IEOR 130 Prof. Leachman
1. Computing die yield DY according to Poisson, Murphy and Seeds yield models. Given a die area A and a defect density D per unit area, the models are as follows: Poisson Model: DY = exp cfw_ -AD Murphy Model: DY

IEOR 130 Methods of Manufacturing Improvement Spring, 2009. Prof. Leachman. HW #4, due Tuesday March 3. 1. It has been claimed that all defect density models basically predict the same yield if the average number of defects per die is less than one. To te

IEOR 130 Solutions to HW 3 Spring, 2008, Prof. Leachman
1. Using a p-chart, the control limit is
UCL = p + 3 p( 1 - p ) where p = 0.04. n
Shift Number 1 2 3 4
# of wafers processed 500 650 550 600
# of wafers reworked 20 39 36 18
rework fraction (p) .04 .

IEOR 130 Spring, 2009, Prof. Leachman Homework #3 due Thursday Feb. 26 1. The average rework rate for photolithography at a particular fab is 4%. Recent data on the photo rework is as follows. Shift # 1 2 3 4 # of wafers processed 500 650 550 600 # of waf

IEOR 130 Methods of Manufacturing Improvement Spring, 2009 Prof. Leachman Second homework assignment - due Thursday Feb. 19. 1. A control chart is being set up to track the resistivity after the ion implantation process step. Five sample measurements are

Solutions to IEOR 130 HW 1 Spring 2009 Prof. Leachman 1. Line yield (LY) is the fraction of wafers started that become wafer outs from the wafer fabrication (wafer fab) factory. Die yield (DY) is the fraction of chips (dice) printed on wafers coming out o

IEOR 130 Methods of Manufacturing Improvement Spring, 2009 Prof. Leachman First homework assignment - due Tuesday, Feb. 3. 1. Briefly define the following terms: line yield, die yield, defect density, stepper throughput, overall equipment efficiency, on-t

IEOR130 Midterm Examination Spring, 2009 Prof. Leachman Open notes. Work all problems. Each problem is worth 20 points. 1. At a particular manufacturing step, the important parameter for process control is the deposition thickness. This is measured at fiv