Simply put, if you will run an RF power supply simultaneously
with a DC magnetron power supply, you need one of these.
This filter is required to be installed on the output of the
Ion™ series power supplies when 13.56 MHz RF power is present in
the sputtering environment ( including substrate bias and
heaters in addition to RF power to one or more sputtering
sources). Its use results in keeping the RF energy inside the
“process” instead of leaking out and radiating. Radiation of RF
energy may cause coupling to adjacent system cabling and
interference with the connected hardware.
The filter allows low-frequency (DC) < 1 MHz to pass from the DC
power supply to the sputtering source while at the same time
preventing RF power from interfering with or damaging DC or AC
power supplies. The filter uses a “Pi” topology and ferrite
cores. This is a somewhat more expensive, but much more
reliable design compared to “L” topology without a ferrite
core. Ferrite cores improve the stability, sensitivity and
reliability of the filtering function. Plainly stated – the
filter is more effective.
Note that the orientation of the filter is important. The
capacitor must always be on the power supply side (“output”) to
ensure process stability. Input and output are defined as
Output: Toward Plasma Load
Input: Toward DC or AC Power Supply