Qzvalues describe: synthetic fused quartz
Semiconductor equipment & lithographyChipmakers (foundries & IDMs)
Why it wins
Furnace tubes, boats, bell jars, plasma windows: fused quartz is the transparent consumable of the fab.
Why not the alternative
Ceramics are opaque and metals contaminate; quartz is pure SiO2, its erosion is process-native on silicon.
Watch out
Devitrifies with cycling and alkali contamination; OH content sets the IR and thermal behavior.
Properties
The values below are candidate: compiled from the sources named, not yet individually validated.
Provisional provenance: Semiconductor chamber materials and plasma-resistant coating literature.
Wet cleaning
| Recipe | the fab standard: HF etch to strip deposits and the devitrified skin, DI cascade rinse, dry |
|---|
| Forbidden | letting devitrification advance: the part crazes and sheds |
|---|
| Limit | HF etch budget: each clean removes wall, and the part has a countable number of cleans |
|---|
Vacuum and outgassing
| Outgassing, unbaked (10 h) | 1e-9 mbar·L/s/cm² |
|---|
| Outgassing, baked | 1e-12 mbar·L/s/cm² |
|---|
| Vapour pressure | none |
|---|
Temperature
| Bake, assembled | 450 °C |
|---|
| Vacuum degas | 1000 °C |
|---|
| Braze / H2 firing | 1200 °C |
|---|
| Metallurgical limit | devitrifies above 1200 °C in service |
|---|
Thermal
| CTE | 0.55 ppm/K |
|---|
| Thermal conductivity | 1.4 W/m·K |
|---|
| Specific heat | 740 J/kg·K |
|---|
| Emissivity | 0.9 |
|---|
| Melting / softening | 1665 soft. °C |
|---|
Mechanical
| Strength | 50 flex MPa |
|---|
| Elongation | nil |
|---|
| Young's modulus | 73 GPa |
|---|
| Hardness | 600–700 HV |
|---|
| Density | 2.2 g/cm3 |
|---|
Electrical and magnetic
| Relative permeability | 1.0 |
|---|
| Resistivity | >1e18 Ω·cm |
|---|
Engineering
| Corrosion | inert except HF |
|---|
| Joining | flame-worked |
|---|
| Process notes | a consumable with a finite service life |
|---|
| Availability and cost | commodity in the fab supply chain |
|---|
Grades
| GE 214 class | standard low-OH furnace grade |
|---|
| Heraeus HSQ / Suprasil | purity and optical grades per position |
|---|
Sources · 1
- Heraeus fused silica data
← The Matter