The size of the holes should be large enough to let the etchant in. And the
density influences the total releasing time since the sacrificial layer is
etched laterally.

2008/11/27 Yan Xin 

> 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?
>
>
--
Best regards,
Yours sincerely
Fei Wang