Extreme ultraviolet (XUV) radiation is highly efficient for functionalization of solid materials by means of pronounced radical formation. To prevent collective effects, and study single photon effects, a low-fluence XUV source with 200 μJ/cm² was used to irradiate polymers such as poly-methyl methacrylate (PMMA) and poly-tetrafluoroethylene (PTFE). The unexposed and XUV-exposed sample domains were analyzed with time-of-flight secondary ion mass spectrometry (TOF-SIMS), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). The findings show that XUV photons drive photochemical modification of the surface, fragmentation, and ionization of the desorbed products. Besides a theoretical analysis, the XUV-induced surface modification of PTFE is discussed a new application for surface functionalization.