Ulvac RFS-13100F, Инструкция по эксплуатации, Страница: 56 / 74

RF Power Supply and Matching Box 5. Operation
48
5-3. Matching adjustment
5-3-1. Matching fundamentals
The matching box is composed of variable capacitors (C1, C2) and a coil (L) as shown in "Figure 5-5
Basic matching circuit". The TUNE variable capacitor serves to terminate at 50
Ω
and the MATCH
variable capacitor serves for phase correction. The load impedance is matched to the RF power
supply's output impedance by these variable capacitors, thereby becoming able to efficiently supply
power to the load.
Warning
High voltage is present in the matching box. Never put your hand into the matching box
when energized. Even if not energized, the coil and variable capacitors in the matching box
may retain a charge. You may get an electric shock or die by contact with high voltages, so
when touching the coil or variable capacitors inside the matching box, discharge the
electricity to ground with a grounding rod before touching them.
5-3-2. Matching adjustment
Turn on RF and increase Pf until 70% to 80% of the maximum reflected power.
When not discharging:
Turn off RF and change the gas pressure and the number of short circuits for the coil inside the
matching box so that discharging can begin.
2. When set up for a weak amount of discharge, turn the TUNE or MATCH variable capacitors to
intensify the discharge (so that Pr decreases). Generally, moving a variable capacitor to increase
VPP voltage makes discharging easier.
Because of the tendency for Pr to decrease, see "Table 5-2 Relationship between the tendency for
Pr to decrease and coil short circuits" and increase or decrease the number of coil short circuits or
add a fixed capacitor.
Reference
The air core coil and variable capacitors will oxidize if touched with bare hands. Wear gloves
when you must touch them.
TUNE
C1
MATCH
C2
RF IN
RF OUT
L
Figure 5-5 Basic matching circuit