Dear Huabin 1) One at a time is good enough. 2) I'd like the opposite walls to be metallized. Thanks Leo On 10/14/06, Huaibin Zhangwrote: > Wow, it is a challenging task. Good thing is that 1mm x 1mm is not too hard to handle. I have few questions want to know: (1) how many cavities do you need to make? > (2) What is the relative position of the two side walls? Do they have to be in the opposite side? > > Huaibin