Hi Sukanta, it depends what kind of ething you have in mind. 1. wet chemical etching can be done by alcalic solution with slow etch rate for <111> planes, such as hot KOH, Tetra Methyl Ammonium Hydroxide, NaOH (CsOH, RbOH), EDP, DPW and hydrazine. 2. wet chemical etching without preference by HF with oxidant, such as HNO3 (and typically also CH3COOH) called HNA 3. wet electromemical etching in F+ environment such as HF of NH4F solution. 4. dry plasma etching by fluorine or chlorine based plasma, such as SF6, NH3, CF4 (except for CHF3) 5. dry vapor etching without preference by XeF2 We can do for you the last one as we normally do for our customers and partners. Pavel Neuzil CTO SiMEMS Pte Ltd Singapore __________________________________ Do you Yahoo!? SBC Yahoo! DSL - Now only $29.95 per month! http://sbc.yahoo.com