Hi Guys

Currently i am using 0.2 micron size filter for my
H3PO4 wet etch bath. I have an abnormal situation
where my filter is plug after 2 weeks it has been
installed. I understand that silica is formed when
etching silicon nitride, do anyone have any idea what
form is this silica in and how can it plug the filter
?
If i would reduce the chemical life time, would it
able to help to prevent the chocking or extend the
filter life time ?

Many thanks

Andrew Choong