Ultra-Thin Polishing: Wafers and Substrates as Thin as 10–15 µm
Fused silica, glass, silicon, sapphire and ceramics, polished as thin as 10-15 microns
When your design calls for a wafer thinner than anyone else will quote, Valley Design delivers. We polish fused silica, optical glass, ceramics, silicon and sapphire to thicknesses as low as 10-15 microns, depending on material and size, with optical surface finishes, micron-level tolerances, and thousands of finished wafers in stock.
Ultra-thin polishing removes material from a wafer or substrate in controlled, microscopic increments until it reaches a target thickness measured in tens of microns, while holding tight tolerances on thickness, flatness and surface finish. Valley Design polishes fused silica, optical glass, silicon, sapphire, aluminum nitride and alumina wafers to as thin as 10–15 µm. It is the process behind components in smartphones, sensors, MEMS devices, optics and microelectronics, where every micron of package height matters.
Ultra-thin polishing capabilities
Depending on your material and part configuration, we may be able to meet one or more of the following specifications. Thinnest values apply to small parts (for example 1 cm geometries); larger diameters have higher minimums, as shown in the sizes table below.
10–15 µm
Smallest thickness
±1 µm
Thickness tolerances
<1 µm TTV
Total thickness variation
1/4 Wave
Surface flatness
<5 Å Ra
Polished surface roughness
Quick definitions: TTV (total thickness variation) is the difference between the thickest and thinnest points on a wafer. Flatness is how far the surface departs from a perfect plane, given here in fractions of a wavelength of light. Ra is surface roughness, given here in angstroms (1 Å = 0.1 nm). Flatness and roughness are separate specifications.
We’re the experts in ultra-thin.
With over 50 years of industry-leading expertise, our techniques enable us to reach true ultra-thin specifications — down to as small as 10–15 µm thick — across several material types.
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How thin can we go?
Minimum achievable thickness depends on the material and part geometry. Here is where we stand today:
| Material |
Minimum thickness |
| Fused silica and fused quartz |
10–15 µm |
| Optical glass (AF45, Borofloat, B270, D263, Eagle, BK7) |
10–15 µm |
| Silicon |
15–20 µm |
| Aluminum nitride (AlN) |
15–20 µm |
| 96% and 99.6% alumina |
20 µm |
| Sapphire, A-plane |
25 µm |
| Sapphire, R-plane |
50 µm |
| Sapphire, C-plane |
75 µm |
Sapphire is an anisotropic crystal, so its mechanical response, and the thickness we can reach, varies by orientation plane. Need to compare materials first? See our full materials list, or our sapphire wafers page.
Polished surface finish by material
| Ultra-thin fused silica and glass |
Optical polish to 10/5 scratch-dig, <5 Å Ra |
| Ultra-thin sapphire |
<5 Å Ra |
| Ultra-thin aluminum nitride and alumina |
<0.3 µin Ra (about 7.6 nm) |
These are surface-roughness (Ra) figures. Flatness is specified separately. For polishing processes and other finish options, see lapping and polishing, glass polishing services and CMP polishing.
Standard ultra-thin wafer sizes
For fused silica, glass, ceramics and sapphire, we produce some of the thinnest wafers in the industry, many available from stock for immediate shipment:
| Wafer diameter |
Standard thickness (depending on material) |
| 10 mm |
10–15 µm |
| 1″ (25.4 mm) |
25 µm |
| 50.8 mm |
50 µm |
| 75.6 mm |
60 µm |
| 100 mm |
75 µm |
| 125 mm |
85 µm |
| 150 mm |
100 µm |
| 200 mm |
125 µm |
| 300 mm |
150 µm |
Need a custom size or thickness? Contact us. Custom diameters, squares and thicknesses are routine work for us.
Handling, backing plates and customer-supplied material
At the thicknesses above, ultra-thin wafers remain relatively easy to handle with standard care. Parts can be thinned further, but below these limits they must be adhered to a supportive backing plate, and the end user dismounts and cleans the wafer at their facility. Thin wafers lose mechanical stability, which is why thinning and handling are usually planned together.
Already have material? We routinely thin and polish customer-supplied wafers and die to ultra-thin thicknesses, including finished devices that need backside thinning. For silicon backside thinning, see wafer thinning. For flat, parallel parts, see flat lapping.
Why engineers choose Valley Design
For over 50 years, we’ve been the shop that research labs and manufacturers call when a part is too thin, too flat or too precise for anyone else. We’re AS9100D and ISO 9001:2015 certified, ITAR registered, and we keep thousands of finished wafers and substrates in stock, so prototypes ship in days, not months.
Frequently asked questions about ultra-thin polishing
What is ultra-thin polishing?
Ultra-thin polishing is the controlled removal of material from a wafer or substrate, in microscopic increments, until it reaches a target thickness measured in tens of microns while holding tolerances on thickness, flatness and surface finish. It is used for sensors, MEMS devices, optics and microelectronics where package height matters.
How thin can Valley Design polish a wafer?
Fused silica, fused quartz and optical glass can be polished to 10–15 µm, silicon and aluminum nitride to 15–20 µm, and 96% and 99.6% alumina to 20 µm. Sapphire minimums depend on orientation: 25 µm for A-plane, 50 µm for R-plane and 75 µm for C-plane. Results depend on material, size and condition, so ask us about your part.
What is total thickness variation (TTV)?
TTV is the difference between the maximum and minimum thickness measured across a wafer, expressed in micrometers. A lower TTV means a more uniform wafer. Valley Design’s ultra-thin capability includes TTV below 1 µm, depending on material and geometry.
Is surface roughness the same as flatness?
No. Surface roughness (Ra) describes fine-scale texture and is measured in angstroms or nanometers. Flatness describes how far the whole surface departs from a perfect plane and is specified in fractions of a wavelength of light. Our ultra-thin polishing can reach <5 Å Ra surface roughness on fused silica, glass and sapphire, and 1/4 wave flatness, depending on the part.
Can ultra-thin wafers be handled without a carrier?
At the standard thicknesses listed above, wafers remain relatively easy to handle with normal care. Thinner parts can be produced, but they must be adhered to a supportive backing plate, and you would dismount and clean the wafer at your facility.
Can you thin and polish wafers I supply?
Yes. We routinely thin and polish customer-supplied wafers and die, including finished devices that need backside thinning. Valley Design does not manufacture the raw wafers or crystals; we finish them.
Which materials can be polished ultra-thin?
Fused silica and fused quartz, optical glass (AF45, Borofloat, B270, D263, Eagle, BK7), silicon, aluminum nitride, 96% and 99.6% alumina, and sapphire.
What standard ultra-thin wafer sizes are available?
From stock we offer 10 mm wafers at 10–15 µm, 1″ at 25 µm, 50.8 mm at 50 µm, 75.6 mm at 60 µm, 100 mm at 75 µm, 125 mm at 85 µm, 150 mm at 100 µm, 200 mm at 125 µm and 300 mm at 150 µm, depending on material. Custom sizes and thicknesses are routine.
Related ultra-thin resources
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Please note: Our ability to achieve these specifications is entirely dependent on the material type, dimensions, surface finish, manufacturer, condition and other factors. Contact our team at info@valleydesign.com or via the Contact Us form below to discuss your project requirements.