Comprehensive particle and fiber testing for cleanroom wipers

A microscopy-based measurement technique has been developed for accurately quantifying the total number of particles and fibers in all size ranges released from a cleanroom wiper during conditions of simulated use. The method uses both optical and scanning electron microscopy in conjunction with computerized image analysis for counting particles and fibers. The technique uses a single sample preparation for the extraction of both particles and fibers from the wiper. Seven cleanroom wiping products were examined using this measurement technique. The results are shown for the various size groupings of particles and fibers. A composite measure of contamination is presented. This work reveals that a cleanroom wiper may appear very clean in certain size categories and appear extremely dirty in others. The results of this study show that all size ranges of particles and fibers need to be examined when determining the total contamination risk posed by any cleanroom wiper.