Case Study (Semiconductor): Particle Fail After Transit

Situation

A batch of semiconductor-adjacent machined components met dimensional requirements and looked visually clean at the supplier. After delivery, the customer performed particle extraction and reported failures.

Key complexity:

• The failures occurred after transit, not immediately after machining.

Hypothesis (mechanism-driven, not guesswork)

We considered three dominant particle pathways:

1. Burr latency: micro-burrs and fragile asperities fractured during shipping vibration.
2. Packaging micro-motion: tiny repeated contact caused fretting debris generation.
3. Handling fibers: wipes, gloves, or packaging introduced non-metallic contamination.

Investigation design (built like a study)

Step 1 — establish baseline

Perform extraction at ship-ready state:

• same handling steps as actual shipping
• baseline filter/microscopy classification

Step 2 — simulate transit hazard

Use a vibration/handling simulation aligned to distribution hazard logic:

• packaged parts exposed to controlled vibration cycles
• then extracted again

Step 3 — classify debris

Microscopy and basic classification:

• metallic particles vs polymer vs fiber
• morphology that indicates fracture vs rubbing vs external lint

Step 4 — map particle sources

Create a “particle risk map” of geometry:

• edge exits, cross holes, threads, thin webs
• verify edge breaks and burr presence under magnification

Root cause

The dominant contributors were:

• latent micro-burr fracture at specific exit regions
• packaging-induced micro-motion causing fretting particles

Visual cleanliness was not predictive because the particle release occurred later under vibration.

Corrective actions (control the mechanism)

Machining and deburr controls

• Modify exit strategies to minimize burr formation
• Add tool-life gating for burr-critical operations
• Define edge-break acceptance criteria (not subjective)

Cleaning and handling controls

• Controlled clean handling steps and time-to-pack limits
• Standardized wipe/glove materials for particle-sensitive programs

Packaging redesign

• No-contact separators on critical surfaces
• Immobilize parts to eliminate rubbing and micro-motion
• Low-shedding packaging materials and clean labeling discipline

Validation evidence

• Before/after extraction results on representative geometry
• Post-vibration extraction improvement confirmation
• Updated control plan and packaging spec with revision control

Buyer takeaways

• Visual inspection is insufficient for particle-sensitive programs.
• Packaging design can be a primary source of particles.
• Burr control is a contamination control process, not only a cosmetic requirement.

FAQ for buyers

1. Can particles be generated after shipping even if parts were clean at inspection?
2. What packaging features prevent fretting particles?
3. How do you verify particle control without excessive cost?