Porous Ceramic Vacuum Chuck Tables for Wafer, Glass & Precision Substrates
LONGYI Precision Technology manufactures porous ceramic vacuum chucks in-house — from the porous ceramic itself to the lapped, measured chuck table. Vacuum is drawn evenly through the whole surface, so thin wafers, glass panels and FOPLP substrates are held flat without groove marks.
A porous ceramic vacuum chuck holds thin, fragile or non-magnetic substrates through evenly distributed micro-pore suction instead of grooves or drilled holes — flatness down to 2 μm, with no localized suction marks.
Hold the Whole Surface, Not Just the Grooves
Watch the same thin part go onto two chucks. A grooved or drilled chuck pulls only where there is a hole — and pulls the substrate slightly into each one. A porous ceramic chuck pulls through every micro-pore at once — which is why it is the standard for thin wafers and polished glass.
Suction concentrated at holes and grooves
Cheaper to make and fine for rigid parts. The part lies flat on the surface, but every hole pulls it slightly down into the opening — and only there. On thin or soft substrates those dimples can print through into a ground or polished surface, and one blocked hole loses the hold at that point.
Suction spread across the full contact area
Thousands of interconnected micro-pores carry the vacuum, so the substrate is supported everywhere and there is no open hole for it to be pulled into. The one rule: keep the surface clean, because contamination that fills the pores reduces flow.
The Porous Ceramic Chuck Family
The same porous ceramic, engineered for each step a wafer goes through — grinding, dicing, inspection, general work holding, and even air bearings.
How We Define Your Chuck Table
Scroll through the five decisions our engineers work through with you before any ceramic is cut.
Substrate & Process
What sits on the chuck, how thick it is, how much it bows, and what happens to it — grinding, dicing, laser or inspection. Everything else follows from this.
Pore Size
Fine pores give a smoother surface and less dimple transfer into thin or soft substrates; coarse pores flow more air and tolerate partial coverage. It is a trade-off, not a quality grade.
Material: Standard or Anti-Static
Standard porous ceramic for rigidity and uniform hold; anti-static ceramic with controlled resistivity when charge must bleed away from sensitive devices.
Vacuum Zoning & Flow
Concentric zones for multiple wafer sizes, high-flow ports for warped parts, and a working flow range so you can size the vacuum source correctly.
Flatness & Verification
The surface is ground after the porous ceramic is joined to its base, then every critical dimension is measured before the chuck ships — flatness is always quoted against size.
01 / 05
Two Porous Ceramics, One Decision: Does Charge Matter?
Both are engineered in our own plant for semiconductor, glass, optics and FOPLP work holding. The choice usually comes down to whether your devices are sensitive to electrostatic discharge.
Porous Ceramic
Uniform microporous structure with high rigidity and dimensional stability — the default for inspection, dicing, laser processing and precision measurement.
Anti-Static Ceramic
Controlled surface resistivity dissipates static and reduces particle attraction — for cleanroom automation, wafer transfer and ESD-sensitive devices.
| Material | Key Characteristic | Best Suited For |
|---|---|---|
| Porous Ceramic (PC) | Uniform microporous structure, high rigidity | Wafer inspection, dicing, laser processing, measurement |
| Anti-Static Ceramic (ATC) | Controlled resistivity, 10⁶–10⁹ Ω ESD performance | Cleanroom automation, wafer transfer, ESD-sensitive processes |
Why Choose LONGYI Materials?
Custom Chuck Design Guidelines
Drawing the chuck yourself? Keep to these limits and your model can go straight to engineering review — no redesign loop.
Size & Layer Build-up
How thin the chuck really is — and what each layer does.
Machined Features
Limits for threads, pins and holes in the ceramic body.
Vacuum Port, Flow & Thickness
Where the port goes decides how thick the chuck must be — and how much air it can move.
We size by flow, not vacuum level
Few users seal the surface with film the way semiconductor lines do. Most want one chuck to hold parts of every size, so part of the porous surface is always left open and air leaks in there. The chuck that holds best is the one that moves the most air.
Bigger port = more flow = better hold
With the same vacuum source, a 9 mm port moves far more air than a 1 mm hole. More flow pulls a warped part down fast and keeps small parts held even when most of the surface is uncovered.
How to choose
Frame Material: Alumina, Not Aluminium
Recommended whenever flatness is critical.
Lightweighting Pockets
Draw the pockets you want directly in your model.
For how we place pockets without losing stiffness, see Lightweighting under Design Options.
Our engineering team recommends the porous ceramic solution from your substrate material, vacuum system, flatness requirement and production process.
Design Options When a Flat Porous Surface Isn't Enough
Each of these exists because a real part on a real machine would not behave otherwise.
TWO-STAGE CLAMPINGDrilled holes + porous ceramic for badly warped parts
A porous surface cannot pull down a part that starts far off the surface — the open gap simply leaks, and raising vacuum makes no difference: the chuck runs out of flow, not pressure. So we drill through-holes in the porous layer, like a conventional vacuum chuck, and feed them from a separate high-flow line.
Stage one uses the large holes to draw the warped part down. Once it is seated, the supply switches to the porous ceramic, which holds it flat with suction spread across the whole contact area — instead of pulling the material slightly into each hole the way a hole-only chuck does.
▶ Watch how two-stage clamping works
RELIEVED UNDERSIDELess contact area underneath — easier to grind flat
A chuck that seats on its whole underside is at the mercy of every particle on the machine table: one piece of swarf under a large flat face tilts the whole assembly, and the error goes straight into the working surface above it.
So the underside is relieved and only a defined contact land touches the table. Less area to grind means that land comes out flatter and more consistent than a full face, there are fewer places for a particle to sit, and the chuck seats the same way every time it goes back on the grinder.
LIGHTWEIGHTINGPockets machined into the base frame
Base frames get heavy quickly as the footprint grows, and mass matters wherever the chuck moves, sits on a load-limited table, or is lifted by hand during changeover.
Material is removed from the low-stress zones of the frame while the section depth stays intact. Bending stiffness comes mostly from that depth, so the pockets cut weight without letting the chuck sag under vacuum load. Pocket layout is worked out per part, not copied between sizes.
Large holes pull the part down. Porous ceramic holds it flat.
One chuck, two separate vacuum circuits. Drilled through-holes run to their own high-flow line (A); the porous ceramic sits over its own vacuum chamber on a second line (B). Each does the job the other cannot.
- 1A badly warped part is placedIts edges sit far above the surface. Air leaks in through the gap, so the pores alone cannot build enough pull — raising vacuum doesn't help, the chuck runs out of flow.
- 2Stage 1 · Line A pulls it downThe large drilled holes on the high-flow line move a lot of air fast and drag the raised areas down onto the ceramic surface.
- 3Stage 2 · Line B holds it flatOnce the part is seated, vacuum switches to the porous ceramic. Suction spread across the whole contact area holds it flat — without pulling the material into each hole the way a hole-only chuck does.
None of these are catalogue options. Which ones a chuck needs depends on the substrate's starting bow, what the table will carry, and how clean the environment really is. Send us the substrate, the machine and the problem you are having — we will tell you which apply before quoting.
Customized Porous Ceramic Chucks We Have Made
Chuck tables, heating chucks, cleaning tables and porous nozzles — each built to a customer's drawing or sample.
CLICK ANY PHOTO TO ENLARGE →
Equipment brand names are trademarks of their respective owners and indicate compatibility only.
Filmed on Real Equipment
Including one clip where the customer — not us — does the measuring.
How a Porous Ceramic Vacuum Chuck Works
The same surface does two opposite jobs. Draw air in and the workpiece is held down; push air out and it lifts clear on a film of air. Filmed on copper sheet and battery film.
Porous Ceramic Chuck Table FAQ
The questions dicing, grinding, laser and inspection engineers ask most often when specifying a new or replacement chuck table.
01What is a porous ceramic chuck table?
It is the vacuum work-holding surface a wafer, glass panel or thin substrate sits on during dicing, grinding, lapping and inspection — a single piece of open-pore ceramic instead of a metal plate with drilled holes or machined grooves, so vacuum is drawn evenly through the whole surface.
Because suction is distributed rather than concentrated, the part stays flat enough for thin wafer grinding and clean enough for dicing, where a single groove imprint can shift the kerf.
02Is a chuck table the same as a porous ceramic vacuum chuck?
Yes. "Chuck table" is the term in equipment part lists and service manuals; "porous ceramic vacuum chuck" is the term used by component suppliers. Engineers also say porous chuck, vacuum chuck or wafer chuck — all the same open-pore ceramic work-holding surface, and LONGYI manufactures all of them.
03When is a porous ceramic vacuum chuck the best choice?
When you need to hold a thin, fragile or highly flat substrate without suction marks — wafer inspection, dicing, laser processing, thin-glass handling and precision metrology. Because vacuum is spread evenly through thousands of micro-pores, the whole surface is supported and can be held flat from about 2 μm — which grooved or single-hole chucks cannot match.
04What pore size should I specify?
We supply 2 to 100 μm at 40–45% porosity. Fine pores give a smoother surface and less dimple transfer but flow less air; coarse pores flow more and tolerate partial coverage but can print into thin films.
Starting point: fine pore for thin wafer grinding, polished glass and film-coated substrates; coarse pore for dicing frames, saw-cut parts and tables the workpiece does not fully cover. Tell us the substrate, thickness and coverage and we will propose a structure.
05How flat can a porous ceramic chuck table be made?
Flatness from 2 μm and parallelism from 3 μm — always quoted against size, because a large table cannot hold the same absolute value as a small one. The surface is ground after the porous ceramic is joined to its base. Asking for one number across every size is the most common specification mistake we see. Maximum assembly size is 1200 × 800 mm — send the dimensions and the flatness your process is measured against, and we will confirm what is achievable before quoting.
06How do you handle a warped or bowed substrate?
The key is airflow, not peak vacuum. A larger open-pore area and higher flow pull the bowed material down; raising vacuum on a low-flow chuck often just leaks at the gap. We select pore size and porosity to give enough flow for your substrate, and for severe bow we add drilled high-flow holes for two-stage clamping. Tell us the material, thickness and how much bow you start with.
07What suction flow rate does the chuck need?
Typically 40 to 100 L/min, depending on chuck size, pore grade and how much surface is exposed. Larger chucks and coarser pores need more flow. We specify the working range for your configuration so you can size the vacuum source correctly, rather than discovering it on the machine.
08How do we choose the right vacuum source?
Match the pump to both vacuum level and flow. Fine-pore chucks reach high vacuum at modest flow; coarse-pore and large chucks need sustained higher flow. A vacuum pump suits continuous holding; a venturi or ejector is convenient where compressed air is already available. Tell us your substrate and cycle and we will recommend a suitable source.
09Do you make ESD or anti-static porous chuck tables?
Yes — anti-static ceramic with a controlled surface resistivity of 10⁶–10⁹ Ω, so charge bleeds away instead of accumulating under the substrate. Specify the resistivity window your fab works to rather than just "anti-static" — the term covers several orders of magnitude.
10How does it compare with a grooved or drilled vacuum chuck?
A grooved or drilled chuck applies vacuum only at its holes and grooves — cheaper and fine for rigid parts, but thin substrates are pulled slightly into each opening and the pattern can print through. A porous chuck spreads vacuum across the full contact area; the trade-off is that the surface must be kept clean.
11Can you build a chuck table from my drawing, or copy an existing one?
Both. We manufacture to a 2D or 3D drawing, and we can reproduce a chuck table from an existing part when no drawing survives — measuring diameter, thickness, mounting interface, vacuum port and porous area, then confirming the reconstruction with you before cutting material. A worn or damaged table is replaced with a newly manufactured one built to the measured original.
Porous Ceramic Vacuum Chuck Catalog
The whole chuck family in one 8-page catalog — specifications, standard models and selection guidance for engineering teams.
Also Known As
Depending on the industry, equipment manufacturer or production process, the same porous ceramic workholding technology — used for precision vacuum holding and air-floating applications — goes by several names:
Custom Ceramic Wafer End Effectors
The wafers your porous ceramic chuck holds still have to be transferred across the tool. LONGYI machines ceramic wafer end effectors to your drawing in Alumina (Al₂O₃), Silicon Carbide (SiC) and anti-static ceramic — with the rigidity, low outgassing and static dissipation metal end effectors struggle to hold. One precision-ceramic partner for both holding and handling.
Have a Drawing or a Worn Chuck to Replace?
Send it to our engineers — we review the substrate and the machine, recommend pore size and material, and quote. A worn chuck with no drawing is fine: we can measure and rebuild it.