Dear MEMS experts, I'm looking for details about the selectivity factor between the SiO2 and Pyrex when they are chemically etched. Could you give me any references? Thanks a lot ********************************************** Dr. Paolo Bondavalli R&D Engineer LABCOM - Laboratoire Interconnexions Optiques et MEMS THALES (ex THOMSON-CSF) CORPORATE RESEARCH CENTER Domaine de Corbeville, Route Departementale 128 F91404 ORSAY (FRANCE) Tel : 01 69 33 08 63 Fax : 01 69 33 08 62 Email : Paolo.Bondavalli@thalesgroup.com **********************************************