Materials
Fused Quartz Glass
High-purity amorphous silicon dioxide glass with exceptional thermal stability and ultra-low thermal expansion — the core material for semiconductor process components.
What Is Fused Quartz Glass?
Fused quartz glass — also called fused silica — is an amorphous (non-crystalline) form of silicon dioxide (SiO₂) produced by melting high-purity quartz crystal or synthetic silicon compounds at temperatures exceeding 1700°C. Unlike borosilicate glass, fused quartz contains virtually no metallic oxides, giving it a unique combination of properties:
- Thermal stability — reviewed against the operating temperature and thermal cycle
- Low thermal expansion — useful for many thermal-processing components
- Optical transparency — wavelength range depends on grade, thickness, and surface finish
- Chemical resistance — compatibility should be reviewed by chemistry, concentration, and temperature
- Low-metal material options — trace-metal requirements should be confirmed by material certificate
Material Grades Available
Tuguan Semiconductor reviews and machines fused quartz and fused silica grades based on available material source, certificate scope, and application requirements:
Grade 1 · Natural Fused Quartz
| Property | Value |
|---|---|
| SiO₂ Purity | Confirm by supplier certificate |
| OH Content | Confirm by material source |
| Total Metallic Impurities | Confirm by supplier certificate |
| Max Use Temperature | Reviewed by application |
| Thermal Expansion Coefficient | Typical material reference; confirm if critical |
| Softening Point | Typical material reference; confirm if critical |
| Annealing Point | Typical material reference; confirm if critical |
| Refractive Index (589 nm) | Typical material reference; confirm if critical |
| Density | Typical material reference; confirm if critical |
Best for: Standard diffusion tubes, furnace liners, and wafer boats after process temperature and purity requirements are reviewed.
Grade 2 · Synthetic Fused Silica (High Purity)
| Property | Value |
|---|---|
| SiO₂ Purity | Confirm by supplier certificate |
| OH Content | Confirm by material source and grade |
| Total Metallic Impurities | Confirm by supplier certificate or agreed test report |
| Max Use Temperature | Reviewed by application |
| Key Advantage | Lower trace-metal options may be available depending on source |
Best for: CVD chambers, wet-etching components, cleaning tanks, and applications where low trace-metal requirements are reviewed against material certificates.
Grade 3 · Opaque (Milky) Fused Quartz
| Property | Value |
|---|---|
| SiO₂ Purity | Confirm by supplier certificate |
| Appearance | Translucent / milky white |
| IR Reflectivity | Grade-dependent; confirm if critical |
| Max Use Temperature | Reviewed by application |
Best for: Thermal shields, boat holders, and insulation components where high infrared reflectivity is needed rather than optical transparency.
Physical & Optical Properties
| Property | Value | Test Standard |
|---|---|---|
| Density | Typical material reference | Confirm if critical |
| Vickers Hardness | Typical material reference | Confirm if critical |
| Young’s Modulus | Typical material reference | Confirm if critical |
| Poisson’s Ratio | Typical material reference | Confirm if critical |
| Thermal Conductivity | Typical material reference | Confirm if critical |
| Dielectric Constant | Typical material reference | Confirm if critical |
| UV Transmission | Grade, thickness, and surface-finish dependent | Confirm by requirement |
| Birefringence | Annealing and inspection dependent | Confirm by requirement |
Why Fused Quartz for Semiconductor Manufacturing?
Semiconductor wafer fabrication imposes severe requirements on process components:
- Thermal cycling resistance — Diffusion furnaces ramp from room temperature to 1000–1200°C repeatedly; the ultra-low CTE of quartz prevents cracking from thermal shock.
- Metallic purity — Trace-metal requirements should be confirmed against material certificates and process cleanliness targets.
- Chemical inertness — Process gases and cleaning chemicals should be reviewed against concentration, temperature, and exposure time.
- Dimensional stability — At 1000°C continuous operation, quartz maintains dimensional integrity far better than metals or polymers.
Our Machining Capabilities on Fused Quartz
Tuguan Semiconductor applies the following processes to fused quartz billets and tubing:
| Process | Achievable Specification |
|---|---|
| CNC cylindrical grinding | OD/ID requirements reviewed by drawing |
| Face grinding & lapping | Flatness reviewed by part size and inspection method |
| Precision cutting (diamond wire) | Thickness and edge requirements reviewed by material form |
| CNC drilling | Hole diameter and position reviewed by drawing and thickness |
| Optical polishing | Surface finish and surface form reviewed case by case |
| Fusion welding | Leak testing can be arranged for relevant assemblies when specified |
| Flame bending / flaring | Wall uniformity reviewed by geometry |
| Annealing | Birefringence requirements reviewed by application |
Typical Products Machined from Fused Quartz
- Diffusion tubes & furnace liners — straight-bore, flanged, or bell-end configurations
- Wafer boats — horizontal and vertical formats reviewed by wafer and process requirements
- Focus rings & etch rings — tight-tolerance plasma-facing components
- Bell jars & domes — CVD and epitaxy reactor enclosures
- Observation windows & viewports — optically polished flat or curved surfaces
- Cleaning tanks — wet cleaning vessels reviewed by chemistry and exposure requirements
- Gas injectors & showerheads — precision multi-hole gas distribution
Common Components Made from Fused Quartz
Fused quartz is selected when a component needs low thermal expansion, chemical resistance, optical access, or high-purity process compatibility. If you are reviewing a drawing or replacement part, these related pages show common component formats made from the same material family:
- Custom quartz glass fabrication — drawing-based fused quartz component review and RFQ support
- Quartz tubes and furnace tubes — tube, process tube, and furnace tube sourcing context
- Quartz wafer boats — fused quartz carriers for wafer handling and thermal processing
- Quartz plates, discs, and windows — flat fused quartz components for optical, process, and equipment use
- Quartz flanges, fittings, and welded assemblies — fused quartz connection and assembly formats
- Quartz diffusion tube and quartz reactor tube — retained product examples for process tube applications
- Quartz viewport window and custom quartz flange — retained product examples for window and flange applications
Certifications & Documentation
Documentation for fused quartz components can be discussed based on order requirements and may include:
- Material certificates depending on material source and order scope
- Dimensional inspection records for agreed critical features
- Surface condition records where roughness or cleanliness is specified
Certificates or declarations can be requested when they are relevant to the quotation or project scope.