Polymer foils with thicknesses 150 nm to around 1 mu m were manufactured using the process of spincoating. Varying the concentration of the polymer solution was found to be the most efficient way to control resulting foil thickness. Both interferometric microscopy and energy loss of alpha particles were used for characterization and found to yield agreeing results. For an experiment on laser-driven ion acceleration, these films were used as targets and as substrates for cryogenic hydrogen targets.