Physics / mechanism
Physical vapour deposition via sputtering ejects target atoms by bombarding a solid source with energetic ions (typically Ar⁺ from a plasma). Ejected neutrals traverse a vacuum chamber and condense on the substrate. Key variants: DC sputtering (conductive targets), RF (insulators), magnetron (magnets trap electrons near target, boosting ionisation efficiency and reducing substrate damage), and HiPIMS (high-power impulse magnetron sputtering — peak power densities >kW/cm², near-100% ionisation of flux). Deposition rates: 1–100 nm/min depending on target material and power. Step coverage improves with ionised PVD (iPVD) but remains inferior to CVD/ALD. Dominant materials: Al, Cu, TiN, W, ITO, phase-change alloys, piezoelectrics (AlN, PZT). Used for barrier/seed layers, back-end metallisation, optical coatings, MEMS electrodes.
Competitive landscape
CVD and ALD compete directly for conformal films on high-aspect-ratio features; sputtering wins on throughput, material diversity, and cost for planar or shallow geometries. Evaporation (thermal/e-beam) competes for simpler single-element films but lacks alloy stoichiometry control. Electroplating dominates Cu interconnect fill post-seed. In photonics and advanced packaging, sputtering retains strong position for thick metal stacks and specialty dielectrics.
Companies using
Connected ideas
Sources
Frontier (open questions)
- To be added.