Silicon Carbide (SiC) for Semiconductor Cutting Applications
Silicon carbide (SiC) is a critical abrasive material used in the precision cutting of semiconductor wafers, including silicon (Si), silicon carbide (SiC) substrates, and other hard materials like sapphire (Al₂O₃). Due to its extreme hardness and chemical stability, SiC is widely used in slurry-based multi-wire sawing and diamond wire cutting processes.
1. Why SiC for Semiconductor Cutting?
Hardness (9.2 Mohs): Second only to diamond, making it ideal for slicing hard materials.
Thermal & Chemical Stability: Resists heat and chemical reactions during cutting.
Controlled Particle Shape: Sharp, angular grains enhance cutting efficiency.
High Purity (≥99%): Minimizes contamination in semiconductor manufacturing.
2. Types of SiC Abrasives for Cutting
| Type | Characteristics | Applications |
|---|---|---|
| Green SiC | Higher purity (>99%), sharper grains | Silicon wafers, sapphire, SiC wafers |
| Black SiC | Slightly lower purity (~97-98%), cheaper | General-purpose cutting |
| Coated SiC | Surface-treated for better dispersion | Advanced slurry formulations |
3. Key Specifications for Semiconductor-Grade SiC
Particle Size: Typically 5–50 µm (F200–F1500 mesh).
Purity: ≥99%, with low metallic impurities (Fe, Al, Ca < 100 ppm).
Shape: Blocky or angular for efficient material removal.
Magnetic Particles: <0.1 ppm to avoid defects in wafers.
4. SiC in Different Cutting Methods
A. Slurry-Based Wire Sawing (Traditional Method)
Process: SiC abrasive mixed with PEG (polyethylene glycol) slurry.
Advantage: Cost-effective for silicon ingots.
Disadvantage: Slower, generates more waste.
B. Diamond Wire Cutting (Modern Method)
Process: Diamond-coated wire + coolant (SiC may be used in hybrid processes).
Advantage: Faster, more precise, less kerf loss.