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Reliability
Double Layer Structure
·The stress in the film is a function of Young's modulus (Es)
of the substrate, Young's modulus (Ef) of the film, the
substrate thickness (ts), and film's thickness (tf).
·The strain of the film is thus:
3
t
E
s
=
( s )
f
6Rt
r (t + t ) E
f
s
f
f

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