Automatic Vacuum and Deposition Control
The process controller consists of a PC combined with a PLC (Programmable Logic Controller), provided with software for automatic control of pumping cycles, substrate transfer and deposition, with possibility of programming personalized menus by the operator and of manual operation of some critical functions (switching on and off pumping units, opening and closing valves, substrate transfer).
The automatic control of a Multichamber System is designed according to the following logic. A PLC controls all the components provided with Profibus RS485 interface (MFC’s, RF generators, temperature controllers, etc.), with analogue interface (throttle valves, etc.), or components with discrete control (pumps, gate valves, etc.). The robotic transfer arm is controlled via a digital IO board.
The PLC is composed by a CPU, a power supply and by modules either connected to a rack or remoted in the system on Profibus connections. The PLC is the unit that can control a complex system in a reliable way; the PC is interfaced to the PLC and supervises the system by means of a dedicated software.
The process controller allows to perform the following operations:
a) Automatic pumping sequences to startup the system switching on the pumps, opening and closing the valves according to the safety interlocks
b) Vacuum measurements in the various chambers by appropriate gauges and instrumentation
c) Control of the gate valves for substrate transfer and vacuum pumping
d) Substrate transfer sequences in the various chambers of the system by operation of the robotic arm according to the safety interlocks connected to the vacuum level and the gate valve status
e) Display of the substrate position in the system
f) Additional optional substrate movements in the chambers
g) Measurement and control of the temperature in each chamber
h) Control of the gas flows
i) Control of the pressure in each process chamber
j) Control of RF power in each chamber
k) Programming of complete deposition cycles
l) Control of alarms and interlocks