Interconnects e Packaging

Question 1

Contactos ohmicos tipo-p e tipo-n

Answer 1

-Aluminum to p-type silicon forms
an ohmic contact (Al is p-type
dopant)
– Aluminum to n-type silicon can
form a rectifying contact (Schottky
barrier diode)

Question 2

interconnections- Componentes críticos

Answer 2

– Metal lines
– Contacts (metal/poly-Si or metal/doped-Si)
– Vias (metal/metal)
– Dielectric between metal lines
– Passivation

Question 3

Interconnect- Requisitos

Answer 3

– Low ohmic resistance
– Low contact resistance
– Reliability in operation

Question 4

eletromigração

Answer 4

– High current density causes voids to form in
interconnections
– “Electron wind” causes movement of metal atoms
– Heavier metals (e. g. Cu)
have lower activation
energy
– Copper added to
aluminum to improve
lifetime

Question 5

silicidas

Answer 5

– Silicides of noble and
refractory metals can be
used to reduce sheet
resistance of polysilicon and
diffused interconnections
– Provide shunting layer in
parallel with original
interconnection