Hi, we actually use a STS ICP w/ the Bosch process to etch 100um holes all
the way through wafers. The ER of SF6 in an ICP is inversely proportional to
the dimension of the feature, I would expect your etch to be substantially
slower once you were half way through the wafer with a 50um aperture. None
the less, I think if you have access to a deep reactive ion etch tool you
should be able to etch all the way through the wafer, the STS has a feature
known as parameter ramping which can be used to keep your etch rate uniform
through the etch by ramping the coil/platten power to compensate for depth
affects. If you have access to any type of DRIE there are lots of papers
availble for the etching of deep holes through wafers. A lot of the research
was done for the ink jet printer nozzel which is the same thing.

Let me know if you need any more info.
Leo
Arizona State University


> 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?