Why Comprehensive Testing Matters for Cleanroom Wipers

When it comes to cleanroom operations, even the smallest contaminant can cause big problems. While many facilities routinely test for particles in the submicron range, the truth is that contamination isn’t limited to tiny particles alone—fibers and larger particles can be equally damaging.

A comprehensive study on cleanroom wipers highlights the importance of looking at the full spectrum of contamination.

Beyond Small Particles: The Hidden Risk of Fibers

Traditional testing methods often rely on laser-based particle counters. These tools are excellent for detecting particles in a narrow size range but fall short when it comes to very small or very large contaminants. That’s a problem because:

• Fibers and large particles can cause scratches or damage across wide areas in microelectronics or data storage processes.

• Edges of wipers, especially unsealed or poorly sealed ones, are often the biggest source of these large contaminants.

In other words, a wiper might look “clean” when tested for submicron particles but still shed harmful fibers that threaten critical environments.

A More Complete Approach to Testing

To solve this challenge, researchers developed a microscopy-based method that uses both optical and scanning electron microscopes (SEM) along with computerized image analysis.

This method:

• Uses a single sample preparation to capture all contamination—both particles and fibers.

• Classifies contaminants into three groups:

• Small particles (0.5–5 µm)

• Large particles (5–100 µm)

• Fibers and particles (≥100 µm)

• Provides direct, precise measurements across the entire size spectrum.

The result is a more reliable way to measure how clean—or dirty—a wiper really is under simulated use conditions.

What the Testing Revealed

Seven different polyester wipers were tested, and the findings were eye-opening:

• Some wipers appeared very clean in one size category but extremely dirty in others.

• Edge sealing mattered. The only unsealed wiper released significantly more fibers than the sealed-edge versions.

• Not all “clean” is equal. One wiper (identified as Wiper G) was consistently the cleanest across all particle sizes, while others varied widely in performance.

The researchers also developed a “total contamination index” by comparing each wiper’s results to the cleanest one. This made it clear which products posed the highest contamination risks.

Why This Matters for Cleanroom Managers

The key takeaway is simple: don’t rely on a single test or particle size range when choosing cleanroom wipers.

• A wiper that performs well in one test might still release fibers or large particles that jeopardize sensitive operations.

• Comprehensive testing ensures you’re getting a product that minimizes contamination risks across the board.

In industries like semiconductors, pharmaceuticals, and data storage, this can mean the difference between smooth production and costly contamination events.

Conclusion

Cleanroom managers face constant pressure to reduce contamination risks. This research shows that a holistic testing approach is critical. By evaluating wipers across all particle and fiber sizes, facilities can make better-informed decisions and maintain tighter contamination control.

To dive deeper into the full methodology and results, click here to read the full technical note.