Characterization of particle contamination for optical application

For high-tech industries, such as semiconductor or optical ones, controls must be done not only on airborne particle contaminants in cleanroom and associated controlled environments but also on surface particle contamination. Optical components are leading technologies for particle contamination control with atomic scale resolution over large areas. The aim is to enhance production reliability on miniaturized systems. Finding a correlation between such airborne and surface particle contaminations is the challenge we have to meet. This paper presents a methodology in order to answer this specific question. For, the latter depends on the cleanroom activity, operating personnel, cleanroom lay-out and equipment for example. Theoretically, we can calculate the surface particle contamination based on deposition velocities and deposition rates of airborne particle contamination defined in ISO 14644-1 for very simple cases. The reality is much more complex and the whole methodology presented here is based on experimental complementary measurements. The characterization of particle surface contamination is done mainly by light microscopy measurements and by optical particle counters...Complementary chemical data are obtained thanks to electronic microscopy with X-ray spectroscopy.