Hi Judith, Have you tried a RCA cleaning? The first step, SC1, removes organic contaminants. Other options are using a "piranha" etch or an oxygen plasma. Best regards, Jorge Ramiro Unidad Micro y Nano FabricaciĆ³n/Mikro eta Nanofabrikazio Unitatea/Micro and Nano Manufacture Unit Tekniker-IK4 -----Mensaje original----- De: Judith Linacero Blanco [mailto:yuyunoemi@gmail.com] Enviado el: lunes, 07 de noviembre de 2011 15:50 Para: mems-talk@memsnet.org Asunto: [mems-talk] cleaning e-beam litography sample Hello everyone, I made a lithography by e-beam with lines of 200nm separated 200nm with 300nm of PMMA on silicon. Once I etch the silicon with RIE, and then I try to clean the sampleacetone, sonicated. The problem is that I still have traces of PMMA in the sample, and I can't clean at all the sample. Can anyone help? How I can clean the whole sample of e-beam lithography?