“Clean for semiconductor use” is not a measurable purchase requirement. One supplier may interpret it as wiping visible oil from the part; another may use controlled washing, glove handling, protected transfer and sealed bagging. Without a specification, both can claim compliance.
This guide gives OEM buyers a practical structure for writing a semiconductor sheet metal cleaning and packaging specification. It is intentionally risk-based: process-adjacent stainless parts should not be controlled the same way as an external painted service panel.
Specification rule - Define part cleanliness zones, prohibited residues, the last dirty operation, approved cleaning chemistry, drying and handling controls, bagging level, acceptance method and required records. Use an approved first article or limit sample when visual language alone cannot define the result.
Start with part risk zones
Classify parts by where they operate and what a contamination event would affect.
| Zone | Typical parts | Control level |
|---|---|---|
| A: Process-adjacent | Wafer-area brackets, shields, trays | Highest residue and particle control |
| B: Clean interior | Internal panels, gas-box covers, supports | Controlled cleaning and sealed protection |
| C: Cleanroom exterior | Equipment skins, doors and HMIs | Cosmetic and abrasion control |
| D: Non-clean support | Frames below covers, shipping fixtures | Standard industrial cleaning |
This zoning should appear on the drawing, bill of materials or controlled cleanliness document. It prevents both underprocessing critical parts and overspending on hidden structural components.
For a broader workflow, see cleanroom sheet metal packaging and inspection. This page focuses on the specification itself.
Define the incoming surface condition
The supplier needs to know what condition must exist before final cleaning. State requirements for:
- Burrs and loose metal particles.
- Weld spatter, heat tint and grinding residue.
- Cutting oil, coolant and fingerprints.
- Adhesive and protective-film residue.
- Polishing compound in corners or hardware.
- Carbon-steel cross-contamination on stainless parts.
- Dust trapped in hems, threads and blind features.
Passivation, pickling and electropolishing are not interchangeable with final cleaning. If stainless corrosion performance is important, define the surface-treatment standard separately from particle and residue controls.
Identify the last dirty operation
Final cleaning should occur after operations that generate particles or residue, including:
- Cutting and deburring.
- Bending with shop tooling.
- Welding and weld dressing.
- Hardware insertion.
- Machining or tapping.
- Surface finishing and coating touch-up.
- Dimensional rework.
After final cleaning, the part should not return to a grinding bench, unprotected rack or mixed-material inspection table. If rework is needed, define whether the full clean-and-pack cycle must be repeated.
Cleaning-process requirements
Avoid prescribing chemistry the buyer has not validated. Instead, define the result and any prohibited substances, then require the supplier to document the approved process.
A specification may include:
- Aqueous or approved solvent cleaning compatible with the material and finish.
- Defined rinse-water quality where residue sensitivity justifies it.
- Complete drying before bagging.
- No silicone, chloride-bearing cleaner or other prohibited residue, as applicable.
- Separate tools and wipes for critical stainless surfaces.
- Cleaning of threads, blind holes and narrow channels.
- Process change notification after first-article approval.
If ionic contamination, nonvolatile residue or particle count is a real functional risk, state the test method and acceptance value. Do not add laboratory limits that the product does not need.
Design features that complicate cleaning
Review these features during DFM:
- Closed hems and lock seams.
- Blind cavities and overlapping plates.
- Rough or intermittent welds.
- PEM hardware with inaccessible undersides.
- Dense louver patterns.
- Adhesive-backed labels in critical zones.
- Deep channels with no drain orientation.
When the feature cannot be removed, add access, drainage or a specific inspection method. Our semiconductor equipment sheet metal guide covers design choices that reduce particle traps.
Handling after cleaning
Define the clean-handling boundary. Typical requirements include:
- Powder-free gloves for final handling.
- Covered carts or clean trays between inspection and bagging.
- No direct carbon-steel contact with cleaned stainless.
- Protected tools and work surfaces.
- Separation of accepted and rejected material.
- Bag replacement after reinspection.
The objective is not a ceremonial clean area. It is a repeatable chain that prevents the supplier from undoing the final cleaning step.
Bagging and export packaging
Specify packaging by risk zone:
| Requirement | When to use it |
|---|---|
| Individual clean bag | Critical parts or protected cosmetic faces |
| Double bag | Transfer into controlled assembly environments |
| Interleaf/formed tray | Parts that scratch or nest during shipment |
| Desiccant/barrier bag | Moisture-sensitive bare metal or long storage |
| Lot label outside bag | Traceability without reopening |
| Packaging photographs | First article or high-risk export programs |
Define bag material, closure method, quantity per bag and whether labels may contact the part. Packaging must survive freight without abrasion, puncture or particle generation.
Inspection and acceptance
Possible acceptance methods include:
- Visual inspection under defined lighting.
- White-wipe or approved swab check.
- UV inspection for selected residues.
- Water-break or surface test where appropriate.
- Particle or nonvolatile-residue testing for validated critical applications.
- Packaging seal and label inspection.
State the sampling plan and whether acceptance occurs before or after bagging. Use an approved reference sample for cosmetic discoloration, brushing variation or permissible weld appearance.
Required records
For traceable programs, request only records that support an actual control:
- Material certificate and heat/lot link.
- Drawing and process revision.
- Cleaning batch or traveler record.
- Inspection result and operator/date.
- Nonconformance and re-clean history.
- Packaging lot and shipment identity.
- Certificate of conformance where required.
Our material traceability guide explains how to connect these records without creating unnecessary paperwork.
Copy-ready RFQ template
CLEANLINESS ZONE: [A/B/C/D] PER OEM SPEC [NUMBER/REV].
COMPLETE ALL CUTTING, DEBURRING, WELDING, HARDWARE AND REWORK BEFORE FINAL CLEAN.
REMOVE VISIBLE OIL, PARTICLES, METAL CHIPS, ADHESIVE AND POLISHING RESIDUE.
PROHIBITED MATERIALS/RESIDUES: [LIST OR N/A].
FINAL HANDLE WITH CLEAN POWDER-FREE GLOVES ON PROTECTED SURFACES.
PACKAGE: [INDIVIDUAL/SINGLE BAG/DOUBLE BAG], [QTY] PARTS PER BAG.
LABEL BAG WITH PART NUMBER, REVISION, PO AND LOT; DO NOT APPLY LABEL TO PART.
ACCEPTANCE METHOD: [VISUAL/WIPE/TEST METHOD] PER [SAMPLING PLAN].
REWORK AFTER FINAL CLEAN REQUIRES RE-CLEANING AND REINSPECTION.Replace bracketed fields with project-specific requirements. Compliance-sensitive programs should have the template reviewed by the OEM’s contamination-control team.
Supplier qualification questions
- Where does final clean handling begin?
- How are critical parts separated from carbon-steel work?
- What happens after a bag is opened?
- Which processes are subcontracted?
- Can lot identity survive cleaning and bagging?
- How are process changes approved?
- Can the supplier demonstrate the workflow on a first article?
Related customer project: Semiconductor Parts Kits: Particle and Clean-Packing Control. Related resources: semiconductor sheet metal parts · equipment enclosures · send your cleanliness specification.
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