The photo-activated, acid catalyzed decomposition of polycarbonate was investigated in this study. The impact of the chemical and physical properties of the photoacid generators (PAG) and the ambient atmosphere effect on polycarbonate decomposition were discussed. The photo-patterns resulted from the photoacid catalyzed decomposition of a polycarbonate can be used as a sacrificial placeholder for fabrication of microelectromechanical and microfluidic devices. The effects of acid strength, vapor pressure of the acid, PAG activation process, and ambient conditions (temperature, moisture, and oxygen concentrations) on polymer film decomposition were studied. Several superacids (e.g. triflic and nonaflic based PAGs) were not suitable for decomposition of the polycarbonate because of their high vapor pressures resulting in the high volatility properties. From the decomposition experiments it was found that the nonfluorinated sulfonic acid based PAGs do not posses the superacidity needed for decomposition. Perfluorinated methide and a tetrakis (pentafluoropheyl)borate PAG were effective in the decomposition of polycarbonate films. The combination of two PAGs, one which generates high vapor pressure acid (thus, highly volatile) and the other with a lower vapor pressure acid (thus, less volatile) showed very low residue levels. This is because of the volatility of the generated high vapor pressure acid (usually remaining acid in the film was the cause of the residue left behind) and the remaining nonvolatile low vapor pressure acid was sufficient to decompose the polycarbonate that was not decomposed by the generated high volatile acid.

There is a growing need to reduce processing temperatures used in the manufacturing of microelectomechanical systems (MEMS). Polycarbonates, which can be used as sacrificial layers in the fabrication of MEMS devices [1,2], typically decompose at 200-300 'C. Adding a photoacid generator (PAG) to a polycarbonate makes it photosensitive and reduces its processing temperature to 100-180 'C. A study has been conducted to examine how various weight percentages (1-5%) of the photoacid generator, diphenyliodonium tetrakis-(pentafluorophenyl) borate (DPI FABA PAG), added to a solution of the polycarbonate, polypropylene carbonate (PPC) and gamma butyroacetone (GBL), effects the temperature and time of development of the photosensitive solution after exposure to UV radiation through a chrome mask and subsequent heating for a specific amount of time. Data from the experiment is used to model this process using neural networks. The inputs to the neural networks are initial solution thickness, PAG weight composition, and development time. The output of one of the networks is average residual remaining, and the output of the second network is development rate. To validate the neural network models, the root-mean-square (RMS) error is used as a performance metric. RMS errors on the order of 12% are achieved when comparing the outputs of the neural network models with test data.