Y₂O₃ Coatings in Semiconductor Etching Equipment

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Yttrium oxide (Y₂O₃) coatings are widely applied to critical components in plasma etching chambers due to their outstanding resistance to plasma erosion, low particle generation, and ability to maintain process stability.

Key Benefits

1. Plasma Erosion Resistance

   • In fluorine-based plasmas, Y₂O₃ forms stable compounds such as YF₃ and YOF.

   • These act as protective layers, resulting in extremely low etch rates (~11.5 nm/min).

   • Component lifetime is significantly extended, reducing replacement frequency.

2. Contamination Reduction

   • High-purity Y₂O₃ is chemically stable and generates minimal particles.

   • This reduces wafer defects and improves product yield.

3. Process Stability

   • Prevents chamber wall erosion and composition shifts, minimizing process drift.

   • Ensures high repeatability and consistency, boosting production efficiency.

4. Extended Maintenance Cycles

   • Protects aluminum alloy substrates and enhances durability.

   • Extends overhaul intervals from ~15 days to 6 months or more.

Why Y₂O₃ Excels

• Chemical Stability: Reaction byproducts (YF₃/YOF) are inert and protective.

• Low Etch Rate: Dense coatings exhibit slow degradation in fluorocarbon plasmas.

• Dense Microstructure: Low porosity prevents plasma penetration.

Fabrication Process

• Surface Preparation: Substrates are grit-blasted for strong adhesion.

• Powder Engineering: Spherical, spray-granulated Y₂O₃ powders enable uniform melting.

• Plasma Spraying: APS or SPS techniques deposit molten particles under tightly controlled conditions.

• Optimized Coatings: High density, low porosity, and strong adhesion are achieved.

Future Directions

Research is aimed at higher-density, higher-purity coatings, improved multi-gas plasma resistance, modified Y₂O₃ systems, and advanced spraying technologies for greater reliability in next-generation semiconductor manufacturing.

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BDD

 

Aspect	Silicon-based BDD electrode	Nickel-based BDD electrode	Titanium-based BDD electrode
Substrate/interlayer	Heavily doped Si wafers, often with buffer/carbonized layer	Ni foils, meshes, or coatings	Ti plates/foils, often forming TiC/TiN interface
Adhesion of diamond film	Moderate; risk of delamination due to stress (Si/diamond mismatch)	Good; Ni ductility buffers stress, but Ni–C phases may weaken long-term adhesion	Excellent; Ti forms stable TiC/TiN interlayer ensuring strong bonding
Thermal expansion mismatch with diamond	High (leads to residual stress & cracks)	Lower mismatch than Si	Very low mismatch; best stress relief
Electrochemical window (vs. Ag/AgCl)	Wide (up to ~3.5 V)	Wide, but slightly narrower due to Ni interactions	Wide (similar to Si-BDD, ~3.5 V)
Corrosion/chemical stability	Si substrate prone to oxidation/corrosion under long-term anodic polarization	Ni corrodes in chloride-containing wastewater; Ni²⁺ release is problematic	Ti highly corrosion-resistant; TiC/TiN barrier protects substrate
Service lifetime in water treatment	Shorter (substrate degradation limits use)	Moderate (substrate corrosion limits durability)	Longest (excellent lifetime, often >10,000 h reported)
Pollutant degradation efficiency	High (due to strong •OH radical generation)	High, but can drop with Ni dissolution	High, very stable across repeated cycles
Cost & scalability	Lower cost (Si wafers), easy to microfabricate, but limited electrode area	Moderate cost, can be made in larger area (foils/meshes)	Higher cost, but robust and widely adopted for industrial water treatment
Typical applications in water treatment	Lab-scale reactors, sensors, fundamental studies of EAOP	Pilot-scale reactors, electro-Fenton processes, H₂O₂ electrogeneration	Full-scale industrial wastewater treatment, electrochemical oxidation of persistent organic pollutants (POPs)

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