12 Inch (300 mm) Fused Silica Wafers – Fused Silica (CTE 0.55 x 10^-6 /K, 185 nm – 2.5 um); 300 mm format, TTV <5 um. No minimum order; DFM review included with every RFQ.
12 inch (300 mm) fused silica wafers are supplied as finished substrates: edge-rounded, cleaned and packed in wafer cassettes. The material brings near-zero thermal expansion and deep-UV transmission; the format brings SEMI-compatible handling.
Specification envelope
| Material | Fused Silica (JGS1 (UV), JGS2 (standard), JGS3 (IR)) |
|---|---|
| Thermal expansion (CTE) | 0.55 x 10^-6 /K |
| Service temperature | 1,100 C continuous |
| Transmission range | 185 nm – 2.5 um |
| Density | 2.20 g/cm3 |
| Knoop hardness | 500 kg/mm2 |
| Refractive index | 1.458 @ 587 nm |
| Stock thickness | 0.10 – 50 mm |
| Maximum blank size | 450 x 450 mm |
| Diameter / format | 300 mm |
| Thickness | 0.7 – 1.1 mm |
| TTV | <5 um |
| Flat / notch | SEMI notch |
| RFQ inputs | PDF/DXF/STEP drawing, quantity brackets, surface and edge spec |
Capabilities and limits
One material, many routes: on Fused Silica we also quote dicing, edge grinding, double-side polishing, sandblasting, and multi-step drawings are the norm rather than the exception.
Getting the drawing right
Before sending the RFQ, check these against your drawing:
- Material note: its hardness and brittleness demand diamond tooling and controlled feeds.
- Specify flat or notch orientation relative to your device layout – regrinding orientation later scraps the wafer.
- Over-specification is the quiet budget killer: a 20/10 scratch-dig face costs roughly three times an 80/50 face, so grade each surface individually.
For the complete framework, see the tolerance design guide and the holes and edges design guide.
Application context
The recurring buyers of 12 inch (300 mm) fused silica wafers: scientific instruments (reference flats, cells, prism mounts, stage inserts); ccd inspection equipment (CCD cover plates, reference grids, stage glass); semiconductor equipment (view ports, wafer carriers, plasma rings, chamber windows). Background reading on the underlying material science: RP Photonics: fused silica.
Dimensions still moving? Configure this part live in the 3D + 2D builder below, or open the full custom glass machining 3D + 2D builder to start from a blank canvas.
For adjacent specifications, see fused silica wafers 2-12 inch, fused silica wafer applications, custom ITO glass.
Buyer questions, answered
How does Fused Silica behave under heat?
CTE is 0.55 x 10^-6 /K and continuous service reaches 1,100 C continuous, which is what drives its use where near-zero thermal expansion matters.
Is there a minimum order for 12 inch (300 mm) fused silica wafers?
No. Single prototypes are accepted, and pricing steps down at 10, 100 and 1,000 pieces.
How fast can prototypes ship?
Machined prototypes ship in 5 – 10 working days. Coated or bonded parts add 1 – 2 weeks depending on queue slots.
What files do you need for a quote?
A dimensioned PDF plus DXF or STEP geometry. If only a sketch exists, our drawing review service formalizes it before quoting.
Do parts ship with inspection data?
Dimensional reports, surface certificates and material certs per melt are available; specify the level on the RFQ.
Specifications on this page were last reviewed by our engineering team in August 2026.