Challenges in the assessment of the cleanroom suitability of equipment and materials

In the field of manufacturing engineering, cleanroom technology has become a key technology for a number of reasons. Without it, trends such as enhanced performance and miniaturization or the adherence to legal requirements would be impossible to maintain. The main task of cleanroom technology is to reduce the amount of airborne contamination in manufacturing environments to an acceptable level. As the aim to control contamination in clean production facilities cannot be achieved by implementing cleanroom technology alone, a number of other measures need to be taken which also affect cleanliness levels. These measures are grouped together under the term “cleanliness technology” and include influencing factors such as personnel, logistics processes and manufacturing equipment, which together contribute significantly towards the contamination of a clean manufacturing environment. As today's trend towards increased automation continues, the subsystem of manufacturing equipment - including the materials used in its construction - has become the most important factor affecting cleanliness. In the meantime, the semiconductor industry calculates this to account for 40% of the total contamination. Bearing this in mind, it is especially important to focus on equipment design, as this allows to consider and optimize cleanliness suitability early in the conception phase, e.g. by choosing appropriate materials or arranging components. Depending on the purpose of the equipment or the process to be carried out, the relevance of cleanliness factors such as particulate emission, cleanability, outgassing behavior, chemical resistance and microbiological properties need to be individually determined. In order to be able to use such information in the design and optimization of cleanliness-suitable equipment, international standardization work is currently being carried out (e.g. the amendment of the ISO 14644 series “Cleanrooms and associated controlled environments”) to determine the cleanliness- and cleanroom-suitability of equipment and materials realistically and comparably according to international practiced methods. The results gained from the standardized tests can be utilized effectively in equipment design if the information is made available via databases; these are practical tools which enable specific search queries regarding cleanliness-suitable materials and equipment to be made