Method and apparatus for coating substrates in a vacuum chamber, with a system for the detection and suppression of undesirable arcing
First Claim
1. Apparatus for coating substrates with an electrically non-conductive coating in a reactive atmosphere, said apparatus comprisinga vacuum chamber having a process gas inlet,a pair of sputtering cathodes located in said vacuum chamber, said cathodes carrying targets consisting of a material to be sputtered,a medium frequency generator connected to said cathodes by a pair of conductors, said generator having a cycle separated by voltage nulls and divided into a plurality of time segments, said generator comprising a programmable storage controller which forms threshold values of voltage and current for detection of arcs,a compensated symmetrical voltage divider connected between said pair of conductors for determining a voltage value,a current converter looped into one of said conductors for determining a current value,an ungrounded meter island which samples said voltage and current values during predetermined said time segments and forms measured value signals based on said sampled voltage and current values,a feedback network for transmitting said measured value signals to said programmable storage controller, and for transmitting said threshold values back to said meter island,means in said meter island for detecting an arc based on measured value signals and said threshold values, and for producing a blocking signal based on at least one said arc, anda connecting line connecting said meter island to said medium frequency generator for blocking said generator for a predetermined time when said blocking signal is received.
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Accused Products
Abstract
In an apparatus for coating substrates, having sputtering cathodes (4, 5) disposed in a vacuum chamber (1), sputtering targets (6, 7), a medium-frequency generator (9) connected to the cathodes (4, 5), and a system (16) for detecting and suppressing undesired arcing, a cycle of the medium-frequency signal of the medium-frequency generator (9) is divided into a plurality of time segments, the electrical values of current and voltage for a predetermined time segment being determined so as to form a measured value signal and being entered into a ground-free meter island (16). The meter island (16) is tied as a remote station into a circular network (9, 16, 17, 18, 19, 11) whose master station is situated in the control unit (11) present in the generator (9). The blocking of the generator (9) when an arc occurs takes place through a line (19) connecting the meter island (16) to the generator (9). The parameters of the arc surveillance and the detection of measured values are preset through the network (17, 18, 19) by means of software.
71 Citations
8 Claims
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1. Apparatus for coating substrates with an electrically non-conductive coating in a reactive atmosphere, said apparatus comprising
a vacuum chamber having a process gas inlet, a pair of sputtering cathodes located in said vacuum chamber, said cathodes carrying targets consisting of a material to be sputtered, a medium frequency generator connected to said cathodes by a pair of conductors, said generator having a cycle separated by voltage nulls and divided into a plurality of time segments, said generator comprising a programmable storage controller which forms threshold values of voltage and current for detection of arcs, a compensated symmetrical voltage divider connected between said pair of conductors for determining a voltage value, a current converter looped into one of said conductors for determining a current value, an ungrounded meter island which samples said voltage and current values during predetermined said time segments and forms measured value signals based on said sampled voltage and current values, a feedback network for transmitting said measured value signals to said programmable storage controller, and for transmitting said threshold values back to said meter island, means in said meter island for detecting an arc based on measured value signals and said threshold values, and for producing a blocking signal based on at least one said arc, and a connecting line connecting said meter island to said medium frequency generator for blocking said generator for a predetermined time when said blocking signal is received.
Specification