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Page 1: On a Sampling Decision System using Virtual Metrology

On a Sampling Decision System usingVirtual Metrology

D. Kurz

O. Univ.-Prof. Dr. J. PilzAAU Klagenfurt, Department of Statistics

Dr. C. De LucaInfineon Technologies Austria AG

4 December 2013

D. Kurz On a Sampling Decision System usingVirtual Metrology

Page 2: On a Sampling Decision System using Virtual Metrology

Innovation

Semiconductor process control: the current state-of-the-art

Based on physical measurements

Only certain number of wafers measured

Statical measurement rules

Semiconductor process control with a sampling decisionsystem

Based on virtual measurements

Virtual measurements for every wafer

Dynamical measurement rules

1 2 3

4 5 6

7 8 9

LCL

Target

UCL

a a a a a a a a

D. Kurz On a Sampling Decision System usingVirtual Metrology

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Applied statistical methods

Sampling decision evaluation

Decision-theoretical modeling of virtualmeasurements

Expected utility of measurement information

Lindley information and wafer quality risk values

Monitoring reliability of virtual measurements

Quantification of performance of virtualmeasurements

Detection of unreliable virtual measurements

Update of precision of virtual measurements

PIT

Den

sity

0.0 0.2 0.4 0.6 0.8 1.0

0.0

0.5

1.0

1.5

2.0

VM: N(0,10²)VM: N(0,15²)

µVMk

AAA

yk����

aa

D. Kurz On a Sampling Decision System usingVirtual Metrology

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Results

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0 10 20 30 40 50

−15

0−

5050

150

wafer no.

mea

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real metrologyvirtual metrology

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0 10 20 30 40 50

0.00

0.10

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wafer no.

EV

ofM

I

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0 10 20 30 40 50

0.0

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wafer no.

exp.

loss

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prior riskpreposterior risk

D. Kurz On a Sampling Decision System usingVirtual Metrology