Why “Clean” Chambers Still Shed Particles After PM
PAMS inevitably redeposits metal/oxide/nitride on shields, shutters, and walls; the brittle build-up later cracks and falls. During PM, legacy materials can make things worse:
- Polyester knit wipers shed microfibers that can fuse to hot surfaces and re-emit.
- Household abrasive pads (e.g., Scotch-Brite) introduce alumina/polymer fragments and scratching.
- DI-only wipe-downs can leave ionic residues that destabilize first-plasma ignition.
Result: elevated adders, extra conditioning runs, and schedule slip.
Foamtec System: Accurate Product Roles
1) MiraWIPE® — Woven Microfiber Cleanroom Wipers for PM on Wafer-Processing Tools
What it is: A woven cleanroom microfiber wiper engineered to enhance absorbency and foreign-particle removal versus traditional polyester wipers, while reducing abrasion-generated particles during wiping. Variants (e.g., MiraWIPE 256, SN, SM) support ISO 1–8 usage and fab PQ needs.
Why does it help in PAMS PMs?
- The woven microfiber structure improves particle pickup and fluid handling on walls, shutters, clamps, and doors, minimizing re-deposition during restart.
- Fabric and wash process tuned for cleanroom use; datasheets specify enhanced contamination removal vs. polyester.
Best uses: final wipe after wet scrubbing; moisture and residue removal; precision cleaning of accessible faces before pump-down.
2) UltraSOLV® ScrubPADS — Patented Coated Abrasive Pads for Vacuum-Chamber Film Removal
What they are: Patented wet-/dry coated abrasives designed specifically to remove deposition by-products, residue, and rust from process tools in wafer fabs and related industries; available media include diamond, silicon carbide, and aluminum oxide. Compatible with ErgoSCRUB® handles and ScrubDISK® for reach and coverage. Cleanroom-validated for chamber PM.
Why do they help in PAMS PMs?
- Deliver controlled mechanical removal of thick metal/oxide/nitride build-up on shields/doors/fixtures—with engineered, washed abrasives intended for vacuum tools, unlike general-purpose pads.
- System accessories (ErgoSCRUB/ScrubDISK) focus the abrasive only where needed to limit over-scrub and collateral wear.
Best uses: heavy build-up on shields, doors, and fixture plates; followed by solvent/DI rinse and MiraWIPE final clean.
Field-Observed Benefits After Converting the PM Stack
When fabs switch from polyester + household pads to MiraWIPE + UltraSOLV ScrubPADS:
- Fewer adders after restart; less flaking from shield surfaces cleaned with coated abrasives designed for vacuum tools.
- Faster first-plasma stabilization after a final microfiber wipe that limits abrasion-generated particles.
- Longer intervals between major cleans due to more complete film removal and cleaner wipe-downs.
(Quantified outcomes vary by tool/material set; benchmark with your witness wafers and defect maps.)
Recommended BKM Flow (PAMS)
- Wet scrub heavy film on shields/doors/fixtures using UltraSOLV ScrubPADS (select diamond/SiC/AlOx grade per deposit), with DI or neutral detergent (e.g., Citranox/Alconox).
- Rinse and wipe all accessible surfaces with MiraWIPE to remove residues and moisture before closing up.
- Clean viewports/clamps/recesses with appropriate tools; pump down, dry N₂ purge as needed, then short Ar pre-sputter to condition.
Bottom Line
Using a cleanroom-designed coated abrasive (UltraSOLV ScrubPADs) for gross removal and a woven microfiber cleanroom wiper (MiraWIPE) for final contamination control directly targets the two dominant post-PM particle sources in PAMS: brittle film flakes and wipe-induced residues. The result is cleaner starts, shorter conditioning, and more predictable yield.