LONGYI · WAFER BACK GRINDING · MADE IN TAIWAN
Wafer Grinding Work Chuck100 µm Coarse-Pore Porous Ceramic Chuck Table with 99% Alumina Frame
The vacuum chuck table that holds the wafer through back grinding, thinning and rotary surface grinding. Coarse 100 µm pores keep drawing through grinding water and silicon fines, a 15 mm porous body survives repeated on-machine dressing, and a rigid 99% Al₂O₃ frame holds the chuck taper that becomes your wafer TTV.
A wafer grinding work chuck is a porous ceramic vacuum chuck table used on wafer back-grinding and thinning equipment. LONGYI's version uses a 100 µm coarse-pore suction surface, a 15 mm porous layer for repeated in-situ dressing and a 99% alumina outer frame — for 4″ to 12″ (Ø100–Ø300 mm) wafers, built to drawing or sample.
Grinding Is Wet. Fine Pores Clog — Coarse Pores Keep Breathing.
Grinding is the harshest job a vacuum chuck ever does: constant water, silicon fines, cutting load and repeated dressing. Watch the same wafer on two chucks through a wet grind.
Blinds over in grinding water
Fine pores around 2 µm give a very smooth hold and suit inspection or bonding — but in wet grinding they load up with silicon fines, air flow drops and holding force fades halfway through the run.
Keeps drawing for the whole cycle
An open 100 µm structure has far higher air flow, resists clogging and cleans back with normal vacuum and ultrasonic routines — so vacuum stays stable from the first pass to the last.
One Porous Ceramic, Engineered for Each Station
The grinding chuck is built for flow and dressing life. The rest of the family is tuned for inspection, dicing, general work holding and air bearings.
What Makes a Chuck Survive Grinding
Scroll through the five decisions that separate a grinding chuck from an inspection or dicing chuck.
Pore Grade: 100 µm Coarse
High air flow that survives grinding water and silicon slurry, and cleans back easily. Finer grades are available for polish and stress-relief steps.
Porous Depth: 15 mm
The suction face is a wear surface. A 15 mm porous body can be self-ground and dressed on the machine many times before it is consumed.
Frame: 99% Alumina, Holds Taper
Chuck taper and flatness go straight into wafer TTV. A stiff, wear-resistant alumina frame keeps that geometry under continuous load.
Vacuum Zoning
One continuous zone, or concentric zones so one chuck holds 300, 200 and 150 mm wafers without exposed porous area bleeding vacuum.
Fit & Verification
Built to your grinder from drawing or sample — spindle interface, vacuum port and bolt circle — then flatness and critical dimensions are measured before shipping.
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Standard Grinding-Duty Build
LONGYI's standard build for grinding-duty chuck tables. Every item is adjustable — pore grade, porous thickness, frame material and mounting geometry are specified per application.
| Technical Item | Engineering Capability & Selection Reference |
|---|---|
| Product Type | Porous ceramic vacuum chuck table for wafer grinding, thinning and rotary surface grinding equipment. |
| Suction Surface | Microporous ceramic, coarse-pore grade, standard mean pore size 100 µm. Finer grades (40 µm, 20 µm, 2 µm) available where a smoother, lower-flow hold is preferred. |
| Porous Layer Thickness | Standard 15 mm. The thick porous body is what allows repeated on-machine dressing (self-grinding) of the suction face over the chuck's life. |
| Outer Frame / Body | 99% alumina (Al₂O₃) for rigidity, wear resistance and flatness retention under grinding load. Stainless steel, aluminium alloy and SiC bases available on request. |
| Porosity | 40–45% open porosity, tuned with pore grade to balance holding force against air flow. |
| Wafer Sizes | 4″ / 6″ / 8″ / 12″ (Ø100 / Ø150 / Ø200 / Ø300 mm). Non-standard diameters, square and rectangular formats built to drawing. |
| Flatness | Ground and lapped to typical ≤ 3 µm over the working surface; tighter values and specified chuck taper on request. |
| Vacuum Range | Typical working vacuum -60 to -80 kPa. Coarse pores raise flow demand, so pump capacity should be confirmed against chuck area. |
| Surface Finish | Precision-ground suction face; grit and finish matched to the grinding recipe (coarse for wet grinding, finer for polish and stress-relief steps). |
| ESD / Anti-Static | Anti-static (dissipative) ceramic grades available where charge build-up on thin or compound-semiconductor wafers is a concern. |
| Dressing & Re-Grind | Suction face can be dressed in-situ on the grinder to restore flatness and taper. Once the porous depth is consumed, re-surfacing or replacement can be evaluated. |
| Customisation | Built from drawing or from a sample chuck: diameter, thickness, chuck taper, vacuum port, seal groove, base plate and mounting pattern made to match your machine. |
Material Selection
The porous suction layer and the frame are selected separately. Common combinations for grinding duty:
Supported Wafer & Substrate Materials
Coarse 100 µm pores suit wet grinding of standard silicon; harder and more brittle substrates are usually paired with a finer grade or an anti-static body.
Values shown are typical for the standard grinding-duty build and are provided for selection reference. Final specifications are confirmed on the approved drawing before production.
Pick the Pore Grade for the Step, Not the Catalogue
Pore size is the single most important choice in a porous chuck, and grinding pulls it in the opposite direction from inspection or bonding. Coarse pores trade a little surface smoothness for flow, clog resistance and easy cleaning.
| Comparison Item | 100 µm (Coarse) | 20–40 µm (Medium) | 2 µm (Fine) |
|---|---|---|---|
| Mean pore size | 100 µm | 20–40 µm | 2 µm |
| Air flow | Highest | Medium | Low |
| Clogging in wet grinding | Very low | Moderate | High |
| Cleaning / recovery | Easy | Moderate | Difficult |
| Partial coverage holding | Needs masking | Partial OK | Yes, no masking |
| Pump capacity required | High | Medium | Low |
| Best suited step | Back grinding | Fine grinding | Inspection / bonding |
Comparison is a selection guide for typical builds; actual performance depends on chuck area, wafer thickness, vacuum system capacity and grinding recipe.
Wet Back Grinding & Thinning
The standard grinding-duty grade — runs under grinding water with continuous silicon fines and holds vacuum stably for the whole cycle.
Fine Grinding & Dry Polish
A middle ground for stress-relief, dry polishing and final thinning steps where a smoother suction face matters more than maximum flow.
Inspection, Bonding & Small Parts
Holds small or partially covering workpieces without masking and leaves no pore marks — for metrology and bonding chucks, not grinding.
Anti-Static Requirement
Where thin or compound-semiconductor wafers are charge-sensitive, the same geometry can be built in a dissipative anti-static ceramic grade.
One Zone or Concentric Zones
A 99% alumina ring frame carries a recessed coarse-pore porous insert, machined as one continuous zone or as concentric vacuum zones. The bolt circle on the outer flange is made to your grinder's spindle interface.
3-ZONE VACUUMØ300 / 200 / 150 mm
12″ work chuck with three concentric porous zones. One chuck covers 300, 200 and 150 mm wafers — no tooling change between sizes.
3-ZONE VACUUMØ200 / 150 / 100 mm
8″ multi-zone build for lines running mixed small-diameter and compound-semiconductor wafers on the same grinder.
SINGLE ZONEØ200 mm (8″)
Single continuous porous face for one fixed wafer size — maximum uniform holding area and the simplest vacuum circuit.
Why Multi-Zone Vacuum Matters
Equipment Compatibility & Custom Builds
Images show representative LONGYI builds. Zone count, zone diameters, land width, porous depth, flange thickness and bolt pattern are defined per drawing. Equipment names are trademarks of their respective owners and indicate compatibility only; LONGYI is not affiliated with these manufacturers.
Filmed on Real Equipment
A LONGYI chuck table running on a wafer grinder, plus the principle behind it.
Chuck Table in Processing on a Wafer Grinder
The wafer is cut while it is held, so the chuck surface is the reference the cut is taken against — a chuck that has lost its form cannot be compensated by dressing the wheel.
What a Correctly Specified Grinding Chuck Changes on the Line
As a Taiwan-based advanced ceramics manufacturer, LONGYI produces the porous body, machines the frame and finishes the suction surface in-house — so pore grade, flatness and mounting geometry are tuned to your process rather than taken off a shelf.
Stable holding through the whole grind
Coarse pores keep air flow up as fines accumulate, so vacuum does not fade halfway through a wet grinding run.
Fewer cracks and edge chips
Uniform full-surface suction avoids the local stress concentrations that groove-type and large-hole chucks impose on thin wafers.
Better TTV control
A rigid 99% alumina frame holds taper and flatness, and the surface is dressed on-machine to correct drift instead of being scrapped.
Longer tool life
15 mm of porous depth means many dressing cycles before the body is consumed, which lowers cost per wafer.
Faster recovery after clogging
An open coarse structure cleans back with standard vacuum and ultrasonic cleaning routines rather than needing replacement.
Repeatable results across chucks
In-house porous body production and precision measurement keep chuck-to-chuck variation controlled on repeat orders.
Grinder model, wafer size, target flatness and taper — our engineers confirm pore grade, porous thickness, frame material and mounting geometry.
Wafer Grinding Work Chuck FAQ
Common engineering questions about pore size, porous thickness, frame material and chuck life in wafer grinding.
01What is a wafer grinding work chuck?
It is the porous ceramic vacuum chuck table that holds the wafer on back-grinding and thinning equipment. LONGYI builds it with a 100 µm coarse-pore suction surface, a 15 mm porous layer for repeated in-situ dressing and a 99% alumina outer frame, for 4″ to 12″ (Ø100–Ø300 mm) wafers, made to drawing or sample.
02Why does a grinding chuck use 100 µm pores instead of fine pores?
Because a grinding chuck has to keep breathing through grinding water and silicon fines. Fine pores (around 2 µm) give a very smooth hold for inspection or bonding, but they blind over quickly in wet grinding and holding force drops mid-run. A 100 µm coarse-pore structure has far higher air flow, resists clogging and cleans back with normal maintenance.
03Why is the porous layer 15 mm thick?
Because the suction face is a wear surface. Grinding chucks are dressed on the machine to restore flatness and chuck taper, and every dressing removes material. A 15 mm porous body provides the depth to absorb many dressing cycles, so the chuck stays in service far longer than a thin porous plate bonded to a base.
04What does the 99% alumina outer frame do?
It provides rigidity and dimensional stability. Under continuous grinding load the chuck must not deflect or wear at the rim, because chuck taper and flatness are transferred straight into wafer TTV. A 99% alumina (Al₂O₃) frame is stiff, wear resistant and chemically stable in grinding water.
05Can LONGYI make a chuck to fit my existing grinder?
Yes. Chucks are built from your 2D/3D drawing or from a sample chuck that we reverse-measure — diameter, thickness, chuck taper, vacuum port, seal groove, base plate and mounting pattern are reproduced so the part fits the machine as-is, including legacy equipment.
06What flatness can be held, and how is it maintained?
Typical delivered flatness is within about 3 µm over the working surface, with tighter values or a specified taper on request. In service, flatness is maintained by dressing the suction face on the grinder itself; the thick porous body makes that possible repeatedly.
07My chuck has lost suction. Is it clogged or worn out?
Both are possible and the remedies differ. Clogging shows up as gradually weakening hold that partially recovers after cleaning — a coarse-pore body usually recovers well. Wear or loss of flatness shows up as unstable holding, wafer slip or rising TTV that cleaning does not fix. Send the chuck or its drawing for evaluation.
08Which wafer sizes and materials are supported?
Standard builds cover 4″, 6″, 8″ and 12″ (Ø100–Ø300 mm), with non-standard diameters and square or rectangular formats made to drawing. Supported substrates include silicon, SiC, GaAs, GaN, sapphire, glass and quartz, as well as thin, bonded and taped wafers.
Porous Ceramic Vacuum Chuck Catalog
Standard sizes, PC / ATC material options, vacuum zoning and selection guide for the whole chuck family.
↓ Download Catalog (PDF)Also Known As
Depending on the equipment maker, the process step and the region, this component is also called:
Ready to Specify Your Wafer Grinding Work Chuck?
Send us your grinder model and either a drawing or a sample chuck. Our engineers confirm pore grade, porous thickness, frame material and mounting geometry, and come back with a build proposal.