ULVAC RF and DC Power Generators
ULVAC RF and DC power generators supply controlled power to plasma sources in sputtering, etching, PECVD, and ion beam deposition systems. RF generators operate at 13.56 MHz (ISM band) with automatic matching networks. DC generators supply regulated current or voltage to magnetron sputtering cathodes. This page covers ULVAC MRF and MRF-E series RF generators and associated DC power supplies.
Part Numbers
Operating Principle
RF generators produce 13.56 MHz output and deliver it through an automatic matching network to the plasma electrode. The matching network presents a 50 ohm load regardless of plasma impedance, maximising power transfer and protecting the output stage. DC generators supply regulated power to the sputtering cathode in constant-power, constant-voltage, or constant-current mode.
Installation and Wiring
- Verify mains supply voltage, phase, and current capacity from nameplate before connection
- Minimise coaxial cable length between generator output and matching network
- Use only ULVAC-specified high-power coaxial cable rated for 13.56 MHz at the power level in use — standard RG-type coax is not suitable above 1 kW
- RF earthing: bond generator chassis, matching network, and chamber with short wide braid straps
- Arc protection relay output: wire to process controller or chamber interlock
- Verify all interlock inputs are wired before enabling RF output (vacuum, cooling water, door)
Commissioning Procedure
- Connect a calibrated 50 ohm dummy load to the generator RF output for initial power-up test
- Set to minimum power; enable output; verify forward power matches set point
- Verify reflected power below 5% into 50 ohm load
- Disconnect dummy load; connect to matching network and plasma electrode
- Set process gas pressure to plasma ignition window (typically 0.5 to 5 Pa for argon RF plasma)
- Strike plasma at minimum power; verify matching network converges (reflected power drops below 5%)
- Increase power in steps; verify matching tracks at each level
- Test arc detection by briefly raising pressure to induce an arc; verify generator enters arc-inhibit state
- Record forward power, reflected power, and matching positions at working power on commissioning record
Preventive Maintenance
- Cooling air filter: clean or replace every 3 to 6 months
- Internal cooling fan: clean annually
- RF output connector and coaxial cable connectors: inspect at each PM for looseness, burning, or tracking
- Matching network variable capacitors: inspect for tracking or burning at each PM
- Performance trend: record forward power, reflected power, and arc count at each PM
Fault Diagnosis
| Symptom | Cause | Action |
|---|---|---|
| High reflected power with stable plasma | Matching network not converging; range insufficient | Run auto-match at working pressure; check coax length and quality |
| Generator shuts down on overcurrent | Arc event in chamber | Enable arc suppression mode; reduce power ramp rate |
| Plasma will not strike | Gas pressure outside ignition window | Verify process pressure; check gas flow |
| Forward power unstable | Loose coaxial connector; unstable plasma | Inspect and tighten all RF connectors |
| Generator overtemperature alarm | Cooling fan or filter blocked | Clean or replace air filter; verify fan rotation |
| Interlock fault | Vacuum, cooling water, or door interlock open | Check and satisfy all interlock inputs |
Training
Training covers: RF generator operation, matching network theory and adjustment, plasma diagnostics, arc suppression configuration, and DC power supply modes. Available on-site during commissioning or as a standalone session. Contact mail@ulvacheliot.com — provide: equipment model, site location, number of attendees, topics required.
Service Enquiry
Email mail@ulvacheliot.com — provide: generator model and part number, serial number, fault description including forward power, reflected power, arc count, and alarm codes.