Hi

We have a pre-clean chamber with parallel plate electrodes where 13.56MHz power
supply is connected to substrate table. We are trying to etch SiO2 wafer in this
chamber before taking the wafer to PVD/Sputtering chamber for deposition.

Problem: The plasma extinguishes after few runs, and we can not ignite the
plasma. To ignite the plasma, we have to vent the chamber and pump it down. It
runs OK up to few runs and then plasma drops again and does not ignite until we
vent the chamber and pump it down. By venting and pumping down the chamber, what
exactly is getting changed inside the chamber?

I really appreciate your expert opinion.

With regards,

Pramod Gupta