Maintenance and cleaning of process tools are indispensable. Opening the process chamber to the cleanroom air and the mechanical and chemical treatment of the process chamber surfaces release a number of chemicals that are not included in the list of chemicals. This usually increases the level of contamination in cleanrooms and poses major challenges for cleanroom operators. Customized solutions, consisting of Filter Fan Units (FFU), HEPA filters and molecular filters, remove the contamination through highly efficient air filtration of the cleanroom air.