Process for producing thin layers by means of reactive cathode sputtering and apparatus for implementing the process

A process for controllably producing a thin film by reactive cathodic sputtering which comprises the steps of:

• (a) feeding a process gas as a gas mixture into a process chamber having a gas inlet and a gas outlet to reach plasma surrounding a target formed as a cathode;
• (b) sputtering material from the target to form plasma which is then deposited on a substrate while holding the pressure of the process gas constant;
• (c) disposing at least one voltage probe in the plasma so that charged atoms in the process gas are detected;
• and
• (d) regulating the voltage value of the probe to be constant by regulation of the process gas mixing ratio in order to achieve a desired homogeneity of deposition of the target material on the substrate.

An apparatus for producing thin films deposited on a substrate which comprises:

• (a) a chamber for reactive cathodic sputtering having a gas inlet and a gas outlet for control of a process gas provided as a gas mixture;
• (b) at least one target provided as a cathode within said chamber;
• (c) a means for mounting a substrate;
• (d) a gas feeding means which introduces the process gas into the chamber from the gas inlet until it reaches the plasma volume surrounding the target during the cathodic sputtering;
• (e) a measuring device for in situ spectroscopic measurement of the intensity of the cross sectional profile of one or more emission lines of one or more components provided in the plasma, and which is so arranged that said measuring device detects in a cross sectional area of a spatial region of the plasma parallel to the target surface;
• and
• (f) means for controlling the process gas mixing ratio that is responsive to changes in the intensity of the cross sectional profile of said emission lines.

An apparatus for producing thin films deposited on a substrate which comprises:

• (a) a chamber for reactive cathodic sputtering having a gas inlet and a gas outlet for control of a process gas provided as a gas mixture;
• (b) at least one target provided as a cathode within said chamber;
• (c) a means for mounting a substrate;
• (d) a gas feeding means for introducing the process gas into the chamber from the gas inlet until it reaches the plasma volume surrounding the target during the cathodic sputtering;
• (e) at least one voltage probe as a detector of charged atoms of the process gas, said probe arranged in the vicinity of the plasma;
• and
• (f) a control system which in dependence upon the desired homogeneity of the film deposited on the substrate, maintains the voltage value of the probe at a constant value by regulation of the process gas mixing ratio.