HPFS® Standard Grade 7980, is a high purity synthetic amorphous silicon dioxide manufactured by flame hydrolysis. The noncrystalline, colorless, silica glass combines a very low thermal expansion coefficient with excellent optical qualities and exceptional transmittance in ultraviolet. It is available various grades for different applications.
Coresix produces HPFS® Standard Grade Wafers to all SEMI Standards including dimensional, flat and notch specifications. Additionally, we offer custom specifications designed to your unique needs including, alignment marks, holes, pockets, edge profile, thickness, flatness, surface quality, cleanliness or other details critical to your application.

Electrical Properties
| Property | Condition | Value |
|---|---|---|
| Log10 Volume Resistivity | (250°C, 482°F) | 11.8 ohm·cm |
Thermal Properties
| Property | Value |
|---|---|
| Softening Point* | 1585 °C |
| Annealing Point* | 1042 °C |
| Strain Point* | 893 °C |
| Specific Heat | 0.770 J/(g·K) |
| Thermal Conductivity | 1.38 W/mk |
| Thermal Diffusivity | 0.0075 cm²/s |
Thermal Expansion ** (ppm/C)
| Temperature Range | Value |
|---|---|
| 5°C to 35°C | 50.52 x 10⁻⁶ |
| 0°C to 200°C | 0.57 x 10⁻⁶ |
| -100°C to +200°C | 0.48 x 10⁻⁶ |
Mechanical Properties
| Property | Value |
|---|---|
| Density (25°C) | 2.20 g/cm³ |
| Elastic (Young's) Modulus | 73 GPa |
| Shear Modulus (25°C) | 31 GPa |
| Modulus of Rupture, abraded | 52.4 MPa |
| Bulk Modulus | 35.9 GPa |
| Knoop Hardness (100g load) | 522 kg/mm² |
| Poisson's Ratio | 0.16 |
| Tensile Strength | 54 MPa |
| Compressive Strength | 1.14 GPa |
Optical Properties
| Property | Value |
|---|---|
| Abbe Constraints Vₑ | 67.6 |
| Abbe Constraints Vd | 67.8 |
| Stress Coefficient | 35.0 nm/cm MPa |
Refractive Index (Conditions: 22°C, 760 mm Hg, N₂)
| Wavelength | Refractive Index 2n | Thermal Coefficient Δn/ΔT3 [ppm/C] |
|---|---|---|
| @435.957nₘ | 1.466691 | 10.6 |
| @587.725nₘ | 1.458461 | 10.1 |
| @656.454nₘ | 1.456364 | 9.9 |