Why Semiconductor Manufacturing Requires High-Purity Seals: Our Approach to Contamination Control
Content prepared by sunyihan
Dalian Yida Precision Rubber Products Co., Ltd.
On a seal drawing, dimensions and tolerances are usually straightforward to specify. The words “high purity” leave more to settle. They give the supplier no particle limit, extraction method or packaging instruction.
For an ultrapure water line, the concern includes substances released into the water. A chamber seal exposed to plasma needs assessment of its damaged surface and any particles left behind. The same cleanliness report may not answer both questions.
Yida offers TOC testing, cleaning and double-layer packaging. Before these services become part of an order, the customer and supplier need a common specification: which part is tested, how it is prepared and what result is acceptable.
Start with the seal location
In August 2026, SEMI announced work on revising F51, highlighting chemical compatibility, thermal cycling, particles, outgassing and handling. The feedback covers several process environments, including wet chemicals, plasma chambers and ultrapure water systems.
As checked on November 3, 2026, the SEMI catalog still lists F51-0917 as current. It guides material selection, performance evaluation, cleanliness, packaging and handling. The revision activity should not be written into a purchase order as a newly published requirement.
That range of applications matters when requesting a quotation. Name the fluid or gas, temperature, pressure and exposure sequence. For a plasma process, show where the seal sits relative to the exposed area. A supplier can then assess the proposed compound against the conditions it will actually see.
Specify the contamination being measured
A room classification describes the environment around a part. It does not tell you what the rubber will release into process water, or how its surface will behave after plasma exposure.
| Risk | Where to focus | Evidence to request |
|---|---|---|
| Particle generation | Exposed surfaces, plasma erosion and moving contact | Particle count and size distribution under defined collection or exposure conditions |
| Outgassing | Vacuum and heated locations | Release data with temperature, pressure, time and sample preparation stated |
| Metallic or ionic contamination | Contact with sensitive chemicals or high purity liquids | Analysis of specified elements or ions using an agreed extraction method |
| Organic extractables | Liquid-contact applications | TOC results and, where needed, identification of specific extracted compounds |
Buying FFKM does not settle the particle question. Qnity describes a mechanism in which plasma removes the polymer around a resistant filler, leaving particles behind. Its discussion also links differences in outgassing to the curing system. The report for the selected FFKM grade is therefore more useful than a general family description.
Our high purity elastomer overview covers material families. During procurement, record the exact grade with the drawing so an alternative compound can be reviewed before it is supplied.
What is behind the TOC number?
A TOC result needs a sample description beside it. Was the finished seal extracted in water, or was the laboratory given a rinse sample? Had the part already been cleaned and packed? Those details establish what the test can tell the buyer.
TOC testing measures total organic carbon in the analyzed sample. For a seal extract, the result relates to material collected under that extraction procedure. It gives neither a list of individual organic compounds nor a measurement of metal ions.
Shimadzu's cleaning-validation guidance describes rinse sampling, aqueous extraction of swabs and direct carbon measurement for pharmaceutical equipment. It is a useful illustration of why the sampling route must be stated. Semiconductor acceptance limits still have to come from the customer's application requirements.
| On the report | What the buyer needs to know |
|---|---|
| Part and batch | Which grade and lot were sampled, and whether the sample was a finished seal or a material specimen |
| Sample preparation | Cleaning condition, extraction liquid, time, temperature and liquid volume relative to the sample |
| Measurement | Method, units, blank treatment, detection limit and quantification limit |
| Decision | The agreed limit for that method, sampling stage and testing frequency |
Changing the amount of extraction water can change the reported concentration. Before comparing suppliers' numbers, put their preparation methods side by side. Keep a result below the reporting limit in that form; rewriting it as “zero” removes information.
Yida can support TOC testing for agreed requirements. The quotation should identify the method, laboratory and reporting scope, including whether testing is performed internally or externally. Assess particle generation, ionic contamination and sealing performance separately.
When an ultrapure water gasket cracked
A Garlock field case describes pinhole leaks and cracking in two-piece PTFE/EPDM envelope gaskets at a semiconductor producer. The ultrapure water system ran at ambient temperature and 50 psi, using PVDF flanges and stainless steel hardware.
The supplier replaced the gaskets with a one-piece PTFE design and reports 18 months without leakage or adverse effects on water purity. The account concerns that water system and is not an elastomer plasma test. For procurement, it adds a construction question to the purity review: will the finished component remain intact in the installed joint?
Cleaning and packaging have to follow the same specification
Ask where the controlled handling route begins. The process plan should cover compound identification, mold cleanliness, permitted release agents, trimming and inspection. Remove loose flash and reject unacceptable surface damage before final cleaning.
When a supplier quotes a cleanroom class, request the classification report and check which area it covers. ISO 14644-1:2015 classifies airborne particle concentration. Testing organic residues on a seal, or measuring its outgassing, requires separate evidence.
The cleanroom packaging specification should name the bag material and the area used for packing. It should also say where each bag is opened. The outer bag can be removed at the designated transfer point while the inner bag protects the part until the next controlled step.
Yida offers cleaning and double-layer packaging. For a particular order, record the cleaning method, drying conditions and packaging specification with the approved grade. Additional cleaning, baking or post-curing should be reviewed before use because it may affect the material or dimensions.
Keep the batch identity with the package. If a delivery is split or repacked, the receiving team still needs to connect each part to the relevant production and test records.
Check the seal after exposure
Sample approval should include the condition in which the seal will be delivered and the conditions it will encounter in service:
Define the duty. Identify the seal location, chemistry, concentration, temperature, pressure or vacuum, motion and maintenance interval.
Examine production-representative parts. Confirm grade, batch, dimensions and surface condition after the intended cleaning and packaging route.
Measure the relevant contamination. Apply the agreed TOC, particle, extractables or outgassing method, with sampling conditions and limits fixed beforehand.
Test in representative hardware. Check leakage through the agreed exposure and operating cycles, then inspect for erosion, cracking, swelling or wear.
For a vacuum test, agree how the reading will be interpreted. Gas can pass through an elastomer as well as escape through an imperfect sealing interface; the part may also release volatile material. Greene Tweed's leakage study examines how gas, material and geometry affect measurements.
Once a sample is approved, retain its specification with the order. A later change to compound, manufacturing site, cleaning or packaging needs review against that approval.
Preparing an enquiry for Yida
At Yida, the enquiry can cover the molded part, TOC testing, cleaning and double-layer packaging together. Our company profile describes our tooling, compounding and molding background, cleanroom investment and CNAS-accredited laboratory. The scope of any requested test still needs confirmation for the project.
Send the drawing, process conditions, required cleanliness limits, sample quantity and expected annual demand. Include the report format and cleanroom packaging requirements. For vacuum service, attach the thermal and vacuum test conditions too.
Send your requirements to Yida so the proposed material, available evidence and remaining validation work can be reviewed together.
