Anisotropic plasma etching of polymers using a cryo-cooled resist mask

An anisotropic etching process of a perfluorocyclobutene polymer that makes use of a spin-coated photoresist mask instead of a commonly used thin meta l layer is reported. We demonstrate that such masking can be applied to adv antage for anisotropic reactive ion etching of polymers if the wafer is coo led down to T = -50 degrees C. For the fabrication of integrated optical wa veguides, the choice of an appropriate photoresist is very important if the edge roughness needs to be low in order to avoid optical scattering losses . For such applications, the Microresist Technology ma-P 1275 has been foun d to be very suitable. (C) 2000 American Vacuum Society. [S0734-2101(00)065 02-7].