In high-cleanliness environments such as semiconductor manufacturing, biopharmaceuticals, and aerospace, cleanroom wipes are critical consumables for maintaining cleanroom classification and process stability. The IEST (Institute of Environmental Sciences and Technology) released the IEST-RP-CC004.4 standard, providing a scientific and systematic testing framework for quality control of cleanroom wipes. This article analyzes the key test items and their purposes based on the standard, revealing its technical value in cleanroom applications.

1. Particle Release Characterization

• Liquid Particle Counting (LPC, 0.5–20 μm):
  Using a liquid particle counter combined with orbital shaking to simulate mechanical friction on wet wipes, quantifying released particles between 0.5 and 20 microns to prevent contamination of precision instruments and interference with optical surfaces.

• Fiber Analysis (>100 μm):
  Optical microscopy is used to detect large residual fibers or particles after orbital shaking, preventing clogging of microporous structures or mechanical failures caused by macroscopic particles.

• Airborne Particle Counting (APC, 0.3–10 μm):
  Helmke drum simulates dry state wipe motion, and airborne particle counters monitor particle release between 0.3 and 10 microns to assess particulate risk during dynamic cleanroom operations.

2. Chemical Contaminant Analysis

• Ion Content Test (IC):
  After extraction with deionized water, ion chromatography detects anions (F⁻, Cl⁻, NO₃⁻, etc.) and cations (Na⁺, K⁺, Ca²⁺, etc.) to prevent ion residues from corroding electronic components or interfering with chemical processes, especially crucial in semiconductor wafer manufacturing.

• Non-Volatile Residue (NVR) Test:
  Short-term extraction with deionized water and isopropanol followed by evaporation and weighing quantifies transferable oils and polymers, preventing deposition on sensitive surfaces.

• Fourier Transform Infrared Spectroscopy (FTIR):
  After hexane extraction, FTIR detects organic compounds such as silicone oils, amides, and phthalates (DOP), identifying potential contamination sources to protect optical components and ensure biocompatibility.

3. Physical Performance and Functional Evaluation

• Liquid Absorption Capacity and Rate:
  Measures maximum liquid uptake per unit area and absorption speed, ensuring wiping efficiency and avoiding contamination from insufficient liquid absorption leading to repeated wiping.

• Surface Static Charge Test:
  Measures surface resistivity to control static accumulation risk and prevent electrostatic discharge (ESD) damage to electronic components.

4. Biological Contamination Control

• Bioburden Test:
  Microbial culture methods quantify aerobic bacteria and fungi counts on wipe surfaces, ensuring wipes do not introduce microbial contamination in pharmaceutical or biological lab environments.

5. Technical Significance of the Standard
IEST-RP-CC004.4 comprehensively covers physical, chemical, and biological performance indicators of cleanroom wipes through multi-dimensional testing. It offers graded particle control from submicron to macroscopic fibers, compatible with ISO Class 1 to 5 cleanrooms, tightly controls ions and organic contaminants for semiconductor and optical industries, and verifies absorption efficiency and antistatic performance to guarantee operational reliability. This standard provides a scientific basis for wipe selection, acceptance, and quality management and is a core technical specification to maintain clean environments in high-value industries.

Conclusion:
By rigorously following the IEST-RP-CC004.4 standard, users can precisely select high-quality cleanroom wipes tailored to specific cleanroom scenarios, effectively reducing contamination risks, extending equipment lifetime, improving process yield, and enhancing product reliability, thereby supporting sustained growth in high-cleanliness industries.