Mr Yan,

    From my understanding, undercut refers to the difference betweeen oxide and
silicon. That is, if the silicon hole size is 10um, then the oxide hole size
will be 10+2*2=14 um. Just my guessing.

    If you want to use the SOIMUMPs process, you can contact the company for
further information.

                                                  Matthew King

> Hi everyone,
>
> For the inertial sensors, we usually need to perforate the
> suspended
> structure to release the structure with wet etching
> process.
> -But how to know if the holes are big or dense enough to
> release the structure
> completely?
>
> For example, in the SOIMUMPs process, the oxide layer is 1
> microm, the
> structure layer is about 25 micron, undercut is 1.8 micron
> per side by  HF
> vapor etching,
> -Does this mean that  the distance between edges of  two
> adjacent etched
> holes must be less the 1.8*2 micron if i need  to release
> the structure
> completely?