Microcontroller Based System for Cathodic Arc Evaporator's Control

This twin channel microprocessor system for non-planar cathodic arc evaporator's control includes controller, based on singlechip mixed signal processor, high power MOSFET switches, mounted on water cooled sink, opto-isolated MOSFET drivers, 18V DC power supply of the drivers and opto-isolated transistor switches of the arc igniters. The arc current magnitude, which is possible to commutate, is 120 A. By using of the system is possible to automate the process of thin film deposition by cathodic arc evaporation from non-planar arc evaporators in the case of long-time deposition, which prevents electro-mechanical igniter to cathode welding. Used method of control permits single strike of the arc and subsequently keeping the arc discharge arbitrary long time by permanent changing the arc spot motion's direction. It decreases the probability for burning out the rectifier because of over-voltage every time, when arc current magnitude decreases rapidly. If the arc disappears accidentally, the controller ignite it again for less than 50 ms. It is provided the possibility of remote "Start" and "Stop" of the process and output for remote start of other devices like a system for evaporator's motion control. The controller's firmware provides full diagnostics of the system's work, including good working order of the power supply and high power MOSFET switches. It is provided LED indication of detected failure even in working regime. Both channels works simultaneously and independently each other.

The controller for cathodic arc evaporation control is mounted in plastics case with overall dimensions 90 x 90 x 180 mm acc. to DIN 43 700. The supply voltage is 230 V, 50 Hz and power consumption is 6 VA. There are situated on the front panel "Start" and "Stop" buttons and two LEDs, which indicate the arc evaporator's proper operation or the type of the detected system fault. There is mounted on the rear panel terminal connector for controller's linking to the other system components, mentioned above. The class of protection is IP 54 of the front panel and IP 20 of the rear panel.

This microcontroller based system for non-planar cathodic arc evaporator's control is used for control of the thin film deposition process by using arc evaporators in high vacuum plant HVP 4200 T/AE. This plant, production of the firm, produces mirror and semi-transparent reflective architectural glass. The use of this system decreased drastically electro-mechanical igniter to cathode welding probability and thus allowed longer time running the deposition process. This is necessary to receive thin films with different colours (blue, green, yellow, grey-brown, etc.). It decreased drastically the cases of untimely stops of deposition process and thus the waste losses.

In recent days we develop new system firmware, which will provide non-simultaneous work of both independent channels, to be able apply the system for automation of deposition of Me1/Me2 multi-layers like a W/Mo or reactive deposited multi-layers like a AlN/TiN.

↑ Back to top