Etching Borofloat 33: Borofloat 33 (CTE 3.25 x 10^-6 /K, 350 nm – 2.0 um); Etching to depth control +/-1 um. Single-piece prototypes to production volumes, quoted from your drawing.
The combination of Borofloat 33 and Etching comes up constantly in RFQs for a reason – the material offers anodic bonding to silicon, and Etching is the right way to get accurate geometry into it. Expect depth control +/-1 um and isotropic smooth walls.
The numbers
| Material | Borofloat 33 (SCHOTT float production, wafer grade) |
|---|---|
| Thermal expansion (CTE) | 3.25 x 10^-6 /K |
| Service temperature | 450 C continuous |
| Transmission range | 350 nm – 2.0 um |
| Density | 2.23 g/cm3 |
| Knoop hardness | 480 kg/mm2 |
| Refractive index | 1.471 @ 587 nm |
| Stock thickness | 0.70 – 25.4 mm |
| Maximum blank size | 500 x 500 mm |
| Process | Etching |
| Working tolerance | depth control +/-1 um |
| Minimum feature | 10 um channel width (masked HF) |
| Surface finish | isotropic smooth walls |
| Thickness window | 0.1 – 5 mm |
| Edge condition | stress-relief etch available |
| RFQ inputs | PDF/DXF/STEP drawing, quantity brackets, surface and edge spec |
Specification advice
Before sending the RFQ, check these against your drawing:
- Material note: float tin side must be tracked when parts see coating or bonding steps.
- Process boundary: isotropic undercut roughly equals depth, so masks are compensated at layout time.
- 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.
Process window
Etching earns its place through microchannels, cavities and frosted textures without mechanical stress. Its boundary condition – isotropic undercut roughly equals depth, so masks are compensated at layout time – is the first thing our DFM review checks.
Beyond this page, Borofloat 33 routinely runs through dicing, edge grinding, grinding, cnc machining in our shop – most real parts combine two or three of these steps.
Who orders this
etching borofloat 33 shows up across microfluidic devices (chips, manifolds, via plates, bonded stacks); led packaging (groove covers, phosphor carriers, package windows); machine vision (camera windows, ring-light diffusers, calibration plates). Background reading on the underlying material science: SCHOTT BOROFLOAT product page.
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 Borofloat 33 selection guide, 4 inch Borofloat wafers, glass wafer bonding.
Frequently asked questions
What equipment runs the etching work?
Buffered HF wet benches and masked lithography line.
Is there a minimum order for etching borofloat 33?
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.
Specifications on this page were last reviewed by our engineering team in September 2026.