Trench

Quantum mechanics

Copper interconnect

Tectonics

Engineering

Reliability engineering

Biology

Metallurgy

Materials science

Layer (electronics)

Power (physics)

Computer science

Subduction

Geology

Computer network

Paleontology

Physics

Joule heating

Melting point

Nanotechnology

Interconnection

Reliability (semiconductor)

Composite material

Electromigration

Delamination (geology)

Copper

Engineering physics

Reliability challenges of candidate metal systems to replace traditional Cu wiring in future interconnects are discussed. From a reliability perspective, a key opportunity is electromigration improvement: due to their high melting point and slower self-diffusion kinetics, higher current carrying capabilities are possible. Also, the higher cohesive energy and better resistance to oxidation of some metals potentially allows for barrierless integration, although adhesion properties must be carefully optimized. Besides avoiding small grain pinning and enabling high aspect ratio trench fill, the main processing challenges are identified to be a) avoiding seam voids, b) adhesion, c) CMP and d) disruptive metal etch. Main reliability challenges are related to higher mechanical stresses and higher joule heating which could lead to delamination during further processing and packaging and to enhanced electromigration in nearby metal lines.

Interconnect metals beyond copper: reliability challenges and opportunities