FORM 04
Ceramic Plates
Flat plates and substrates where flatness, insulation and wear resistance decide the part.
View ceramic platesDUTY 05
Ceramic parts for vacuum, plasma and high-voltage equipment
In a vacuum chamber, a part has to be dimensionally exact, electrically insulating, and clean enough not to become the contamination source.
Vacuum and plasma hardware punishes materials in ways that are invisible from outside: a porous part outgasses, an organic binder leaves a residue on the wafer, a sharp edge concentrates a field, and a chip becomes a particle. The mechanical requirements are modest; the cleanliness and consistency requirements are not.
That changes what "good part" means. Dimensional repeatability between lots matters more than the absolute tolerance on one drawing, surface finish has to be specified where it faces the plasma rather than everywhere, and the cleaning route has to be agreed before the first part is made — because a part that is correct but contaminated is still a reject.
Why ceramic
What changes when the part is ceramic
No outgassing in vacuum
Dense ceramic does not release volatiles the way polymer and some composites do, so it does not become the chamber's contamination source.
Insulation and dimensional stability together
An alumina plate holds its flatness and its dielectric behaviour through thermal cycling in a chamber.
Edge definition that survives cleaning
A fired and finished ceramic edge does not burr or shed the way a machined polymer or coated metal edge can.
Material fit
Which system suits this duty
Ratings follow the comparison published for the four systems. The grade is confirmed against the duty at quotation.
| Material | Choose it when |
|---|---|
| Alumina | Insulating plates, spacers and chamber hardware; the default where cleanliness and flatness matter. |
| Silicon nitride | Parts that are structural as well as insulating, and see thermal cycling. |
| Silicon carbide | Erosion-dominated duty such as a nozzle or an orifice plate in an abrasive or high-velocity stream. |
| Zirconia | Wear-resistant locating and contact parts inside the tool. |
Part forms
Forms supplied for this duty
Each form page carries the dimensional call-outs and ordering route for that shape.
FORM 05
Ceramic Rings
Ground rings and sealing elements for assemblies that must hold a bore or a face at temperature.
View ceramic ringsFORM 06
Ceramic Nozzles
Nozzles and orifice parts where an abrasive or corrosive stream must keep its shape.
View ceramic nozzlesFORM 07
Ceramic Insulators
Insulating bodies, spacers and supports for equipment that runs hot and live at the same time.
View ceramic insulatorsFORM 11
Ceramic Discs
Machined discs with concentric features for seats, wear faces and rotating duty.
View ceramic discsOn the drawing
What this duty needs pinned down
- The chamber environment: base pressure, process gas, plasma power, and the temperature at the part.
- Which faces are in the plasma and which are shielded, since finish and cleanliness are only needed where they act.
- Flatness and parallelism as separate call-outs — one without the other is usually not enough for a plate.
- The cleaning and handling requirement: baked, solvent-cleaned, or packed for cleanroom entry.
Inspection
What gets checked
- Flatness across the full face, measured the way the fixture will load it.
- Hole position and edge quality on gas passages, where a burr or chip becomes a particle source.
- Surface finish and visual condition on the process-facing side, recorded per lot rather than per drawing.
Inspection points are agreed at quotation and recorded, so the first article and the tenth are judged the same way.
Questions
Asked about this duty
Can you supply parts that meet a cleanroom packing requirement?
Cleaning and packing are agreed as part of the order, not assumed. The route — solvent clean, bake, double-bag, particle count on request — is written into the specification before production so that the first lot and the tenth lot are comparable.
Why is lot-to-lot consistency emphasised over tight tolerance?
A tool is qualified against one set of parts. If the next lot shifts within tolerance, the process drifts with it. Repeatability between lots is usually worth more than a marginally tighter number on a single drawing.
Is alumina acceptable for plasma-facing parts?
It is widely used for insulating hardware in plasma tools. Whether it suits a given position depends on the gas chemistry, the power and whether the surface is eroded or coated over time — those three decide the grade and the finish.
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Other pages in this catalogue
The same catalogue, filed by material and by shape.