Sensitized Excited Free-Radical Processes as Read-Write Tools: Impact on Non-Linear Lithographic Processes

A prefluorescent radical probe in which a 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO) unit is sensitized with visible light via energy transfer from a tethered coumarin dye has been synthesized. The excited TEMPO moiety undergoes hydrogen abstraction from a polymer with concomitant functionalization of the polymeric matrix; this writing process can be reversed thermally. The fluorescent probes can be bleached under high intensity illumination, making these new materials suitable for dual-tone lithography with potential applications in sub-diffraction lithographic imaging.