Patent ID: 8992742
Filing Date: 2015-03-31
Classification: C23C

Abstract:
1. A method for applying a coating to a substrate in a vacuum chamber having a tubular magnetron, wherein a target voltage is applied to a rotating tubular target of the magnetron, and wherein a substrate is guided past the magnetron in a substrate transport direction and is coated in a coating process by a material detached from the rotating tubular target of the magnetron, comprising: regulating an operating point of the coating process by applying a periodic change in a second process parameter, the second process parameter comprising the target voltage, the periodic change in the target voltage having a frequency synchronized to frequency of rotation of the rotating tubular target, and a level determined to correct a periodic change in a first process parameter caused by rotation of the target, and wherein the first process parameter comprises at least one of intensity of an emission spectral line of a coating component in an optical emission spectrogram of the coating, a partial pressure of a reactive gas situated in the vacuum chamber, and an intensity ratio of two emission spectral lines of coating components in the optical emission spectrogram, and wherein the periodic change in the target voltage as the second process parameter comprises a positive change and a negative change of equal value wherein an absolute value of the change in target voltage is less than an absolute value of the target voltage, and wherein amplitude and phase of the periodic change in the target voltage are continuously adapted to present states by determining amplitude of the periodic change in the first process parameter.