PLasma Cleaning SIlicones

[hoegs]

Q:I need to increase the adhesion of fresh silicone applied to cured
silicone and want to know the concerns for plasma cleaning the cured
silicone first. Will it increase the adhesion? Will there be any
redeposit of silicone onto hybrids cleaned in the chamber at a later
time?
A：The answer to your first question is yes. Plasma cleaned cured
Silicone will improve adhesion to fresh silicone through surface
modification or though surface activation. It can render the surface
more attractive to some functional groups depending on the process gas
used. Therefore, with appropriate chemistry, adhesion of pure silicone
to cured silicone can be increased.
The answer to question # 2 is that some sputtering effect will result.
How much? The amount is probably negligible. Because the sputtered
material will be deposited on the chamber walls, re-deposition on to
the hybrid can happen, but it will be more difficult because ion
bombardment is less aggressive at the chamber walls than at the powered
electrode.
For a production tool, sputtering effect is a valid concern for chamber
usage over a long period of time without cleaning; the sputtered
material deposited on the walls of the chamber can flake off and
deposit on to the cleaned hybrids. However, that can be minimized by
running an O2 cleaning recipe prior to processing samples if you
suspect that the chamber is contaminated.