Quartz glass consists of silica (SiO2) in amorphous form. It differs from traditional glass in which additives are added to lower the melting point. Due to high purity, Quartz plates have higher melting point. Quartz also offer superior optical properties than ordinary glass like ultraviolet transmittance. Due to these properties, it find applications in semiconductor and optical device fabrication. Also due to its high melting point and low thermal expansion it is used for making crucibles for high temperature furnaces .
Properties of Quartz substrate
| Product type | Quartz glass plate/disc |
|---|---|
| Density | 2.2g/cm3 |
| Hardness | 4.8×107Pa(N/m2) |
| Coefficient of thermal expansion (20℃-300℃) | 5.5×10-7cm/cm℃ |
| Thermal conductivity (20℃) | 1.4W/m℃ |
| Specific heat(20℃) | 660J/kg℃ |
| Softening point | 1730℃ |
| Short time working temperature | 1250℃ |
| Long time working temperature | 1050℃ |
| Optical Transmittance range (JGS1) | 180-2500nm |
| Optical Transmittance range (JGS2) | 200-2500nm |
| Optical Transmittance range (JGS3) | 260-3500nm |