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Failure Mechanisms of CMOS Shallow Trench Isolation (STI)
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Table 1295. Shallow trench isolation (STI) failure mechanisms of CMOS.

STI Test polarity Pin pair (stress/reference) Failure mechanism Failure location [1]
N+ diffusion diodes Positive VSS Silicide penetration, metallurgical junction, contacts Junction surface, Metallurgical junction edge, contact-to-silicon surface [1]
P+ diffusion diedes Positive VDD Silicon melting, TiSi2 salicide resistance, CoSi2 agglomeration, contact N-well under shallow tranch isolation, silicide surface [1]
N-well diodes Negative VSS Metallurgical junction failure   [1]
N-well to n-well Negative Well-to-well Molten silicon Shallow trench isolation between wells [1]
N-channel MOSFET Positive Drain-to-source MOSFET second breakdown Molten silicon, MOSFET channel region [1]
Positive Gate Gate dielectric failure MOSFET gate [1]
P-channel MOSFET Negative Drain-to-source MOSFET second breakdown Molten silicon, MOSFET channel region [1]
Negative

MOSFET gate Gate dielectric failure MOSFET gate [1]
N-well resistors     Resistor second breakdown Resistor metallurgical junction, contacts [1]
N-well ballasted Positive Drain-to-source MOSFET second breakdown Molten silicon [1]
N-channel MOSFET Positive
Gate Gate dielectric failure MOSFET channel region and gate [1]
Aluminum wire interconnect Positive   Aluminum melting Aluminum film [1]
Negative   Dielectric cracking Aluminum-ILD interface [1]
Tungsten first level Positive Signal pin ILD (inter-layer-dielectric) breakdown Tungsten film-to-polysilicon fill shape, ILD [1]
Tungsten stud contact     Tungsten melting Tungsten film, silicon surface [1]
Tungsten stud bar contact Positive   Tungsten melting Tungsten film [1]
Negative     Silicon surface [1]
Copper interconnect Positive   Copper melting Copper film [1]
Negative   Dielectric cracking Cracking at the Cu-ILD top surface [1]
Copper via Positive   Copper melting Copper film [1]
Negative     Cracking at the Cu-ILD top surface [1]
Copper dual damascene Positive   Copper film and via Displacement of Cu film and via [1]

 

 

 

 

 

 

 

 

 

 


[1] Steven H. Voldman, ESD: Failure Mechanisms and Models, 2009.

 

 

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