Heated phosphoric acid is used for removal of silicon nitrides.
Link to Silicon Nitride Wet Etch, clean, module
Link to Silicon Nitride Wet Etch, flexible, module
Semi-automated wet bench for etching silicon nitride from 3", 4", and 6" Si, SiGe, and quartz substrates using 155C phosphoric acid. The baths can hold up to 25 wafers. Part of the Clean Cleanliness Group.
Resist should have been removed