The depolymerization reaction is immediately apparent when SU-8 samples that have been treated with dimethylamine are immersed in sulfuric acid (Fig. ). In our tests with SU-8 thicknesses ranging from 1 µm to 5 µm, a 1 min immersion suffices to completely remove SU-8 in all cases and no etching has been observed for any of the other materials in our samples, including Ag, Pt, Ti, Si, and GaAs. A wide range of metals and dielectrics can withstand a short immersion in concentrated sulfuric acid (aluminum and chromium being notable exceptions). We find that the sulfuric acid immersion time required for SU-8 removal increases with the UV exposure time and the post exposure bake time (Table ).