Hello Nathan, Im not sure about your design, but if you have to etch silicon by wet chemistry there is definitely no alternative to HF-containing solutions. You can save yourself any search. If its possible to use DRIE, you can define a process without side wall passivation which etches nearly isotropic. Best regards/Mit freundlichem Gruß André Bödecker Institut für Mikrosensoren, -aktoren und -systeme Universität Bremen Fachbereich 1 Otto-Hahn-Allee1 28359 Bremen Tel: 0421 218 62596 _______________________________________________ Hosted by the MEMS and Nanotechnology Exchange, the country's leading provider of MEMS and Nanotechnology design and fabrication services. Visit us at http://www.mems-exchange.org Want to advertise to this community? See http://www.memsnet.org To unsubscribe: http://mail.mems-exchange.org/mailman/listinfo/mems-talk