Signal Propagation Along Interconnects

1. interconnect device Signal PropagationAlong Interconnects 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 +25-30%/yr Springboard for the IT revolution • But… Factory costs escalating +20%/yr Increasing technology challenges, possible show-stoppers Market diversifying, segmenting, and reconfiguring • 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. Cu seed + Cu fill Metal barrier Low-K dielectric Polish stops Etch stops drawing to scale within  10% W plug BPSG dielectric KA Monnig, Sematech 09/02/96 Advanced Si ULSI Technology