The process chamber is pumped by an Alcatel ATH1300MT Maglev turbomolecular pump via
an Automatic Pressure Controller. The turbomolecular pump is backed via a heated isolation
valve by an Alcatel ADP122P dry pump.
The process chamber process pressure is measured by a heated 100-mTorr Capacitance
Manometer gauge. Note that the CM gauge output does not stabilise until it has been
switched on and under vacuum for 15 minutes.
Base pressure is measured by an active Penninggauge, which is disabled at pressures above
10 mTorr.
A Vacuum Switch monitors the chamber pressure. When the pressure falls below 600 mbar, its
contacts close to enable the 24V process line and allow the process gases and the RF to
operate.
The automatic load lock is pumped by an Alcatel ACP28G dry pump. Pressure is measured by a
Pirani gauge.
For details of the vacuum pumps and gauges, refer to the manufacturer’s literature in Volume
3 of this manual.