1. Core Definitions
Glass-Ceramic: A composite material prepared through controlled crystallization process, containing crystalline phase (50-95%) and residual glass phase, combining properties of both glass and ceramic.
Fused Silica: Amorphous silicon dioxide (SiO₂), formed by rapid cooling of high-purity molten quartz, resulting in a non-crystalline glass.
2. Common Properties
- Main Composition: Both primarily composed of silicon dioxide (SiO₂)
- Low Thermal Expansion: Both exhibit extremely low thermal expansion coefficients with excellent thermal stability
- Optical Transparency: Both can be manufactured as highly transparent materials
- High-Temperature Applications: Both can be used in high-temperature environments
- Electrical Insulation: Both are excellent electrical insulators
- Semiconductor Applications: Both have important applications in semiconductor manufacturing (wafer carriers, lithography equipment components, etc.)
3. Core Differences Comparison
|
Characteristic |
Glass-Ceramic |
Fused Silica |
|
Microstructure |
Crystalline + Glass phase (multiphase composite) |
Completely amorphous (single-phase glass) |
|
Thermal Expansion Coefficient |
Can be engineered to zero or even negative expansion |
Very low but still positive (~0.5×10⁻⁶/°C) |
|
Thermal Stability |
Superior, withstands severe thermal shock |
Excellent, but with slightly lower limits |
|
Mechanical Strength |
Higher (crystalline phase reinforcement) |
Relatively lower |
|
Hardness |
Higher |
Relatively lower |
|
Thermal Conductivity |
Higher |
Lower |
|
Purity |
Contains various additives, lower purity |
Extremely high SiO₂ purity (99.9%+) |
|
Maximum Service Temperature |
1200-1400°C |
1100-1200°C |
|
Machinability |
Can be formed like glass then crystallized |
Hot formable, cold workable |
|
Cost |
Relatively lower |
High cost for high-purity grades |
|
UV Transmission |
Average |
Excellent (transparent to deep UV) |
4. Typical Semiconductor Industry Applications
Glass-Ceramic (e.g., Zerodur, Astrositall):
- Optical bases and mirror mounts for EUV lithography equipment (utilizing zero expansion characteristics)
- Wafer transfer robot arms
- Precision positioning platforms
- High-temperature process carriers
Fused Silica:
- Deep UV (DUV) lithography optical lenses and prisms
- Wafer carriers and quartz boats
- Plasma etch chamber components
- Semiconductor-grade quartz tubes and crucibles
- Optical windows
5. Key Process Differences
Glass-Ceramic: Material preparation → Melting → Forming → Crystallization heat treatment (two-step process: nucleation + crystal growth) → Post-processing
Fused Silica: High-purity quartz sand → High-temperature melting (arc/plasma/flame) → Rapid cooling forming → Annealing → Post-processing
6. Summary
Both materials are low-expansion high-temperature materials, but with fundamentally different technological approaches: Glass-ceramic achieves performance breakthroughs through crystallization, making it ideal for structural components and precision positioning; Fused silica excels with its high-purity amorphous state, being irreplaceable in optics, particularly in the deep UV range.
In the semiconductor industry supply chain, the two materials are complementary rather than competitive, each leveraging their respective advantages in different application scenarios.
