Dear all,

I've tried to etch 2 micron thickness of Si3N4 using hot H3PO4. The
concentration of H3PO4 is 85w%. I heat the H3PO4 at 150 degree celcius for 1
hour. Unfortunately, this experiment didn't work as expected. None of the
nitride is etch away.

Can anybody share with me your experience on nitride etch using H3PO4.

Thank you.

Hafizah