Guides / Sourcing
Specifying Machined PEEK for Semiconductor Equipment
September 20, 2026
Sources: manufacturer datasheets and published standards. See editorial standards.
Fab equipment is where PEEK earns its price most easily. The parts are small, the tools are expensive to stop and a plastic part that sheds particles or holds a charge next to a wafer costs far more than it saved.
What gets machined from PEEK
- Wafer handling combs, forks and end effectors
- CMP retaining rings
- Test socket bodies, probe card hardware and insulators
- Chuck insulators, isolators and thermal breaks
- Gas and chemical delivery fittings, fluid path parts
- Alignment fixtures, jigs and inspection tooling
- Vacuum feedthrough insulation and hardware
Above PEEK in the material stack sit PI and PAI for the hottest or most dimensionally critical parts. Below it sit PTFE and PVDF for chemical lines with no load. PEEK covers the wide middle where a part needs strength, stability, chemical resistance and cleanliness at once.
Why CF30 dominates
Most wafer handling and fixture work is carbon filled, and not for strength. Three properties arrive together:
Static dissipation. Carbon filled PEEK bleeds charge instead of holding it. Near a wafer that is the difference between a handled product and a damaged one.
Dimensional stability. About 15 µm/m·K against roughly 47 for unfilled. On a 200 mm comb cycling between ambient and process temperature, that is what keeps the fingers where the machine expects them.
Heat transfer. Roughly 0.9 W/m·K against 0.25. Heat leaves the part instead of soaking into it, which also helps the shop hold tighter tolerances.
Where a part must insulate electrically, carbon is wrong and unfilled or glass filled is right. That decision is set out in CF30 vs GF30.
The requirements that never make it onto the drawing
Most semiconductor PEEK drawings arrive with geometry and a grade, and nothing about the things that actually get parts rejected:
Virgin resin, no regrind. Say it. It is normal for this market and not universal in plastics machining.
Lot traceability. Ask for the stock supplier lot certificate with the parts. If a tool later contaminates a batch of wafers, this is the only way back to the cause.
Metallic contamination in handling. Steel brushes, steel deburring tools and dirty fixtures leave traces. Shops that serve fabs use dedicated non metallic deburring and clean fixtures.
Cleaning method. Ultrasonic in deionised water is the usual expectation, with a stated final rinse. Say whether solvent cleaning is acceptable, because some solvents plus residual stress equals crazing.
Packing. Double bagged as a minimum, cleanroom packing where the tool demands it. It costs a little and it is the step most often left out of a cheap quote.
Outgassing and extractables. If the part goes into vacuum or into a wet process, ask for data on the grade. Generic figures are a starting point, not evidence.
Tolerances that hold in a tool
A fixture that locates a wafer is usually the tightest PEEK work a shop sees. Practical expectations:
- ±0.025 mm on small annealed features in CF30 is achievable
- ±0.05 mm is the sensible default for everything else
- Slot widths and finger pitch matter more than outside profile, so tolerance those and leave the rest open
- State the temperature at which a critical dimension applies
The reasoning behind those numbers is in PEEK machining tolerances, and the stress relief step that makes thin fingers hold is in annealing PEEK parts.
Questions for a shop quoting fab parts
- Do you machine PEEK weekly, and which grades?
- Do you keep tooling for filled grades separate from unfilled work?
- How do you extract carbon dust, and where is that machine in the shop?
- What is your deburring and cleaning process for plastics?
- Can you pass through the stock lot certificate?
- What packing options do you offer, and have you shipped into a fab before?
A shop that answers these in one email has done it before. A shop that treats a wafer comb as a small milled part will deliver something that measures correctly and still gets rejected at incoming inspection.
PEEK against the other fab plastics
PEEK is one of four materials that cover most non metallic parts in a tool, and knowing why the others get specified helps you defend your choice at design review.
| Material | Where it beats PEEK | Where PEEK wins |
|---|---|---|
| PI (polyimide) | Higher continuous temperature, better in hot vacuum zones | Cost, machinability, toughness, moisture stability |
| PAI (Torlon) | Higher strength and stiffness at temperature | Cost, and no moisture conditioning needed |
| PTFE and PFA | Chemical resistance at the extremes, lowest friction | Strength, creep resistance, dimensional stability |
| PEI (Ultem) | Lower cost, transparent grades available | Steam and solvent resistance, temperature limit |
The pattern: PI and PAI sit above PEEK on temperature and price, PTFE sits beside it on chemistry but cannot carry load, and PEI sits below it on both temperature and chemical resistance. A part that needs strength, stability and cleanliness at once usually lands on PEEK, and a part that needs one of those at the extreme usually does not.
Send the drawing with the grade, the cleanliness requirement and the packing you need, and we match you with shops that already work that way.
Frequently asked questions
Why is carbon filled PEEK used for wafer handling?
Three reasons in one material: it is static dissipative so charge does not build up near the wafer, it expands about a third as much as unfilled PEEK so parts stay located, and it conducts heat out of the part.
Does PEEK outgas in vacuum?
Less than most plastics, and it is used in vacuum tools, but it is not metal. For high vacuum and hot zones, ask for outgassing data for the specific grade and lot rather than assuming the generic figure.
What should a semiconductor PEEK drawing ask for?
Grade, virgin resin, lot traceability, no metallic contamination in handling, deburring and cleaning method, then double bagged or cleanroom packing. All of it at RFQ time, not after the parts are cut.
Need a quote for this part?
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