Printed circuit boards are common to receive plasma treatments. These treatments shall clean the exposed surface, place a coating, etching of the surface, or alter the bonding properties, but all of the treatment options do not operate at congruent settings.
Etching the surface of a material for a trench will require a specific frequency and combination of gases, even with the correct balance combination; the treatment method may also affect the end result.
The higher the frequency that is used with the process gases, the faster the plasma will etch the trench. Though the speed of the etching may be important, surfaces that have undergone a reactive ion etching (RIE) treatment will tend to have a more defined finish because of the RIE uses directionally reactive plasma to more accurately spot treat surfaces.
Once the surface has been trenched, the next part of the circuit building process will be the removal of the photoresist. The photoresist is the canvas that is used to mark the locations for the trenches. Circuits are then submitted to plasma ashing to remove the remains of the photoresist. Plasma ashing is a process where the plasma is used to etch away at the photoresist from an etched silicon wafer. There are two methods that only differ by temperature. The higher temperature method is used to quickly as possible remove the photoresist; the other method is to remove the residue photoresist in the trenches.