An easy and versatile photochemical procedure for immobilizing polymer films on silicon wafers has been developed by the authors. An organic azide, covalently linked to the wafer surface. serves as the precursor of a reactive nitrene that inserts into C-H bonds in the polymer. Due to the photochemical nature of the process, patterns of different polymers can be created by use of opaque masks. The Figure shows an AFM image of a polystyrene/poly(2-ethyl-2-oxazoline) array on silicon wafer.