Chemical Mechanical Planarisation

Physics / mechanism

Chemical Mechanical Planarization (CMP) removes material from a wafer surface via simultaneous chemical etching and mechanical abrasion. A rotating wafer is pressed against a polishing pad flooded with slurry—abrasive nanoparticles (typically silica or ceria, 50–200 nm) suspended in a pH-controlled chemical solution. Material removal follows Preston’s equation: MRR = k × P × v, where pressure and velocity are the primary control levers. Target planarity: <1 nm Ra across 300 mm wafers. CMP is mandatory at STI, ILD, metal interconnect, and high-k/metal gate steps. Leading equipment: Applied Materials Reflexion, Ebara, Entegris (consumables). Global CMP consumables market ~$3B; equipment ~$2B.

Competitive landscape

CMP competes with dry etch-back planarization (inferior global planarity) and electrochemical mechanical planarization (eCMP, lower pressure for soft metals like Cu). Adjacent approaches: atomic layer etching for sub-nm removal, stress-engineered films that self-planarize, sacrificial spin-on dielectrics. For advanced nodes and photonics, eCMP is gaining ground for damage-sensitive III-V or low-k surfaces.

Where the value sits

Value concentrates in the consumables, not the tool. GlobalFoundries’ process portfolio (22FDX, 45CLO for photonics) relies on CMP at multiple integration steps, and consumables qualification is a recurring capex decision rather than a one-off purchase, which is what makes the slurry and pad layer a repeat-revenue position. The differentiated wedges are slurry chemistry for compound semiconductors (SiC, GaN, InP), pad conditioning, and end-point detection (AI/optical) that reduces yield loss. Downstream this touches any ferroelectric process and any photonic integrated circuit foundry bet needing damascene waveguide planarization.

Companies using

Connected ideas

Sources

Frontier (open questions)

• To be added.