Magnetron sputtering process
To control reactive magnetron sputtering process using a reactive gas or reactive gases the process overall pressure is regulated by means of the flow of the reactive gas or the reactive gases, respectively. Oscillations of the flow of the reactive gas or the reactive gases, respectively are determined and used as feedback to determine the process overall pressure.
1. A method of controlling a reactive magnetron sputtering process, wherein said magnetron sputtering process uses a reactive gas or reactive gases, characterized by regulating a process overall pressure by a flow of the reactive gas or the reactive gases by determining oscillations in the flow of said reactive gas or reactive gases and using said oscillations as feedback to regulate said process overall pressure, wherein a reactive gas flow rate q i is measured and the process overall pressure is regulated by calculating a mean deviation from last N measured values of reactive gas flow d wherein:
d
_
=
1
N
∑
i
=
1
N
q
i
-
q
_
,
and N in a range from 2 to 50, and further wherein:
q i is a particular measured gas flow rate value;
N is a selected number of last measured values of reactive gas flow;
q is an average of N values of q i ; and,
d is an average deviation of measured reactive gas flow values.
2. The method according to claim 1 , characterized in that the regulation of the process overall pressure using the flow of the reactive gas or the reactive gases, respectively, is controlled with a PID regulator.
3. The method according to claim 1 , characterized in that N is selected in the range of 8 to 12 for an initial rough, fast search.
4. The method according to claim 1 , characterized in that N is selected in the range of 25 to 35 for slow fine tuning.
5. The method according to claim 1 , characterized in that the reactive gas used is nitrogen, oxygen or a mixture of nitrogen and oxygen.