Photomask Descum

Photoresist is used in wafer fabrication to transfer a circuit pattern onto the wafer. Once the photoresist pattern is applied, remaining photoresist must be removed from the photomask before it is used again.
 Plasma stripping with dry chemistry is an environmentally friendly way of removing photoresist.

Wet chemistry may be used, but the danger and expense associated with handling wet chemicals are significant, and wet process leaves residues (scum) that can interfere with the next use. If wet process is used, plasma cleaning is the preferred method to remove wet residue.