|Pfeiffer, F.; Neuber, C.; Schmidt, H.-W.: All-dry photoresist systems: Physical vapor depositions of molecular glasses, Proceedings of SPIE 69231, 69231F/1-69231F/8 (2008) -- DOI: 10.1117/12.771101
The aim of the paper is the development of an all-dry photolithographic process in which the film preparation step as well as the development step is performed without the use of solvent. To implement an all-dry photoresist system we focused on coumarin derivatives, as this class can be photodimerized in the solid state and features sufficient high thermal stability. The dimerized product exhibits sufficiently different physical properties. The monomer can be evaporated at elevated temperatures whereas the dimerized product remains non-volatile under these conditions. With a tailored glass forming coumarin derivative we demonstrated the capability to develop clear patterns. A combinatorial approach, i.e. producing a compositional library in combination with the variation of exposure dose was utilized to efficiently optimize the all-dry photoresist system.