05Wafer handling
Cassettes, carriers, baskets, boxes and tweezers from 100 to 300 mm. Low-value items that decide whether a good wafer arrives good — so we buy virgin resin, measure the slot geometry, and ask for extractables data per lot.
01What we source
The interface matters more than the item. A cassette that fits your wet bench but not your load port is scrap with a part number — so we start from the tool, then choose the carrier.
Table 1 · Carrier types and typical configuration
| Item | Resin | Sizes | Slots | Interface | Used for |
|---|---|---|---|---|---|
| Open cassette H-bar | PFA | 100–200 mm | 25 13 / 50 on request | Manual, wet bench | Acid and DI rinse, transport inside the fab |
| Closed cassette C-bar | PFA | 150–300 mm | 25 | Robot end-effector | Automated handling, lower particle pick-up |
| Cleaning basket | PFA / PTFE | 100–200 mm | custom | Wet bench carrier | Batch immersion, megasonic, drying |
| Single-wafer box | PP / PFA | 100–300 mm | 1 | Shipping | Shipping and hand-carry of a finished wafer |
| Multi-wafer shipper | PP / PFA | 100–150 mm | 25 | Shipping | Export packing, double-bagged |
| FOUP 300 mm | PP / PC | 300 mm | 25 | FOUP load port | Fab-standard front opening transport |
| Tweezers | PFA / ceramic | — | — | Manual | Edge handling only, never face contact |
Scroll the table sideways for all columns →
Interface first. We confirm the exact SEMI revision and the load-port model before quoting a 200 mm or 300 mm carrier. Cassette standards have been revised several times and the differences show up as mis-picks, not as a drawing error.
02Materials
Fluoropolymers are not interchangeable, and the price gap between virgin PFA and regrind is large enough that substitution is common. These are the properties that actually decide the choice.
Table 2 · Resin comparison, typical values for virgin unfilled grades
| Property | PFA | PTFE | PP | PEEK |
|---|---|---|---|---|
| Continuous service °C | 260 | 260 | 100 | 250 |
| Melting point °C | 305 | 327 | 165 | 343 |
| Extractable metals | very low | low, but porous | moderate | low |
| Optical clarity | transparent | opaque white | translucent | opaque tan |
| Machining | fair | poor | good | excellent |
| Autoclave | yes | yes | no | yes |
| Typical part | Cassettes, baskets | Liners, seals, gaskets | Shippers, trays | Tweezers, chucks |
Scroll the table sideways for all columns →
Why PFA wins for carriers. It is melt-processable, so it can be injection moulded with a smooth, non-porous surface — PTFE cannot be, which is why PTFE carriers are machined and why their surfaces trap more residue. PFA also welds cleanly, so a basket has fewer crevices than an assembled PTFE part.
03Written into the order
Cost engineering on a moulded cassette happens in three places. Each of them is invisible on a quotation, and each of them shows up later as particles on your wafer.
Virgin pellet, named supplier, named grade. Regrind is legitimate in industrial moulding and unacceptable here — the difference is molecular weight and it comes out as shedding.
Pitch drift and a sharp slot radius are the two causes of the scratch you cannot explain. Both are measurable in ten minutes with the right gauge.
A carrier moulded in a general workshop and bagged afterwards is a carrier with workshop on it. The room class is part of the specification.
04Qualification
Cheap carriers are not a quality problem you can inspect your way out of at the end — the resin and the mould are decided long before. So the checks happen at the factory, on the machine.
We ask to see the resin bag the machine is actually running, and match the grade on it to the grade on the CoC. This one check removes most of the regrind risk.
FTIR for the polymer family — it catches PVDF sold as PFA — and DSC for the melting peak, which separates virgin from heavily reground material.
CMM or optical scan across the full slot stack, not three points. We report pitch, cumulative drift and the slot root radius on the first article.
ICP-MS on a leachate from the actual lot, with the elements listed. "Semiconductor grade" is not a measurement, and it is not accepted as one.
Class 1 moulding, verified by the room's own particle log rather than a certificate on the wall. Downgraded rooms are common and are usually visible in the log.
One carrier goes onto your tool or your wet bench before the balance is released. Fit is binary and it is cheap to test early — and expensive to discover in a full lot.
05Where it goes wrong
Regrind is easy to hide in a transparent part and easy to find with a DSC melting peak that has drifted or broadened. Left alone, it sheds and the particles end up on your wafer, not on the certificate.
Both are fluoropolymers, both are white or clear, and the temperature rating differs by more than 100 °C. Only an FTIR scan settles it — a datasheet copied from a resin supplier settles nothing.
A worn mould produces carriers that pass a visual check and mis-load at slot 19. Cumulative pitch drift is the failure mode; three-point inspection is how it gets through.
Other categories
Silicon, SiC and sapphire with flatness and particle data attached.
View category 02 · CrystalsPlates and finished elements with orientation measured on the part.
View category All fivePrecision optics and quartz glass, plus machined technical ceramics.
Back to overviewSend the load port, the wet bench or the drawing. We will come back with the resin, the slot configuration, the extractables data we can get before the order — and the price with the factory invoice attached.