If I remember correctly, low concentration usually gives a faster etching rate, but it comes with poor surface quality. hope this helps. --- On Thu, 10/29/09, Jing Xiaowrote: From: Jing Xiao Subject: [mems-talk] silicon etching with KOH solution 10% To: mems-talk@memsnet.org Date: Thursday, October 29, 2009, 12:02 AM Have you guys ever tried to etch silicon with KOH solution (10%)? I just found 20% and higher concentration are often used . I want to know if 10% will have a faster etching rate than 20% and if so, how much. Thanks.