1. Signal Propagation Along Interconnects
device
interconnect
Signal propagation along wires (interconnects) can’t keep up with the devices
Time to propagate signal along interconnect between devices is an RC delay
R = electrical resistance of wire
Depends on metal resistivity
Depends on wire length & width
C = capacitance of wire relative to its surroundings
Depends on insulator dielectric constant
Depends on wiring geometries
Interconnect wire with resistance R
and capacitance C to rest of circuit
device B receives trigger
to switch at t=RC
device A switches at t=0

2. Microelectronics Silicon ULSI, and more
Amazing success
Market +15%/yr for >30 yrs
Productivity %/yr
Springboard for the IT revolution
But…
Factory costs escalating +20%/yr
Increasing technology challenges, possible show-stoppers
Market diversifying, segmenting, and reconfiguring
Motorola – Jim Durham (Moto) w/ G. W. Rubloff, contam ctrl in gas supply
Key questions
Maintaining productivity growth curve
New technologies for end of roadmap
Semiconductor International Jan 1998

3. Advanced Interconnect Technology
Cu seed +
Cu fill
Metal barrier
Low-K dielectric
Polish stops
Etch stops
drawing to scale
within  10%
ITRS Interconnect 1999, Fig. 28
W plug
BPSG dielectric
KA Monnig, Sematech 09/02/96

4. Advanced Si ULSI Technology
KA Monnig, Sematech 09/02/96
drawing to scale
within  10%
Etch stops
Polish stops
Low-K dielectric
Metal barrier
Cu seed +
Cu fill
BPSG dielectric
W plug