Him This is very easy to do using ICP etching if this hole is the first step of your process. Aspect ratio might be achieved up to 1:20 but 1:10 is already a reasonnable challenge. Laser machining silicon does give smooth sidewalls as compared to ICP. Florian Quoting Jeff chen: > Hi, > > I am working on a project which needs to etch a hole through the > silicon wafer (525 micron thick). The hole diameter is around 50 > micron. > Does anyone have experience to do that? > Is there any way to do that? Etching? Laser excimer? or grounding > technology?