Application of Ion Mobility Spectrometry to Semiconductor Technology: Outgassings of Advanced Polymers under Thermal Stress

Due to the continuing trend toward higher integration scales and smaller structural dimensions in semiconductor technology, a new class of detrimental contaminants arises: volatile organics. Recently it has been shown that, among others, they cause severe problems in epitaxial growth, in oxidation kinetics, and in all wet chemical treatments of the wafer. In order to select appropriate polymeric materials for future boxes, minienvironments, or other equipment, we investigated the outgassing characteristics of polypropylene (PP: natural, antistatic, and blue, respectively), polycarbonate (PC), periluoroalkoxy polymer (PFA), polyvinylidenefluoride (PVDF), acrylonitrile butadiene styrene copolymer (ABS), and polytetrafluoroethylene (PTFE). All samples were taken from commercial products for semiconductor technology. Each polymer was heated up from 60 to 20°C below its softening temperature with continuous monitoring of the amount of outgassing. Additionally, the outgassing components were identified separately. PTFE and PFA showed the lowest amounts of outgassings over the entire temperature range. If only selected temperature ranges are of interest, other polymers like PVDF or PC are almost as good. From the knowledge about particular outgassings and the understanding of the chemistry of the polymer, measures can be derived on how to improve certain polymers.