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AMAT 0140-12305
Product Name: Single-Crystal Silicon Carbide (SiC) Wafer Clamping Ring
Product Introduction:
This is a high-precision consumable component used in conjunction with Electrostatic Chucks (ESC) to secure the wafer during high-temperature processing. Unlike standard aluminum or anodized aluminum rings, this component is fabricated from single-crystal Silicon Carbide (SiC), a material chosen for its exceptional hardness, high thermal conductivity, and chemical inertness. It prevents wafer slippage, ensures uniform heat transfer from the chuck to the wafer, and defines the “edge exclusion” zone where no film is deposited, which is critical for subsequent lithography and CMP steps.
Detailed content
Technical Specifications:
- Material: Single-Crystal Silicon Carbide (SiC) (Hexagonal 6H-SiC or 4H-SiC polytype)
- Diameter: Available for 200mm and 300mm wafer standards; inner diameter matches the wafer edge exclusion (typically 2mm to 5mm width).
- Thickness: Ranges from 3mm to 10mm depending on the specific chamber configuration.
- Flatness: Total Indicator Reading (TIR) < 0.002 inches (50 microns) across the entire mating surface.
- Thermal Conductivity: > 120 W/m·K (significantly higher than Aluminum), facilitating rapid thermal response.
- Hardness: Vickers Hardness > 2500 HV (Mohs hardness ~9.5), providing extreme wear resistance.
- Surface Roughness: Polished to < 0.2 microns Ra to prevent scratching the wafer backside.
Functional Features:
- Edge Exclusion Definition: The inner lip precisely controls the area where the wafer is not in contact with the chuck, defining the un-deposited edge bead.
- Plasma Confinement: Acts as a dielectric or conductive boundary (depending on coating) that shapes the plasma sheath at the wafer edge, preventing “edge rolling” of deposited films.
- Low Particle Generation: The extreme hardness prevents the generation of metallic particles that would occur with softer metal rings during repeated clamping cycles.
- Chemical Resistance: Impervious to aggressive plasma chemistries (fluorine, chlorine, bromine) and acids used in wet cleans, preventing pitting or corrosion.
- High-Temperature Stability: Maintains dimensional stability and mechanical strength at processing temperatures exceeding 400°C and bake-outs up to 600°C.
Application Scenarios:
- Ionized Metal Plasma (IMP) PVD: Critical for high-power sputtering where plasma bombardment is intense and wafer heating is significant.
- Chemical Vapor Deposition (CVD): Used in tungsten and dielectric CVD processes where precise temperature control is required.
- Rapid Thermal Processing (RTP): Applied in anneal chambers where the wafer undergoes rapid heating and cooling cycles.
- Etch Modules: Used to clamp wafers during high-density plasma etching (e.g., ICP, CCP) to prevent lifting caused by electrostatic forces or gas pressure.
