METHOD AND APPARATUS FOR COATING A SUBSTRATE

The invention relates to an apparatus (1) for coating a surface (21) of a substrate (20). The apparatus comprises a processing chamber (2) with a particle source (3) for producing coating particles (19), which are also deposited on the inner wall (5) of the processing chamber (2) and on shielding apparatuses (4') arranged therein during operation, in addition to the desired coating of the substrate surface. As the operating time increases, the layer thickness of these deposits (6) grows until the latter undergo spalling, which can lead to contamination of the substrate surfaces to be coated. In order to prevent this, shielding screens (10, 10') are arranged on the inner wall (5) of the processing chamber (2) and/or on the shielding apparatuses (4') and prevent deposits (6, 7) which undergo spalling from passing into the interior (17) of the processing chamber (2). The shielding screens (10, 10') consist preferably of an expanded metal. The invention also relates to a process for coating a surface (21) of a substrate (20), including receiving the substrate (20) in a processing chamber (2) during the coating process, producing coating particles (19) using a particle source (3), allowing coating particles (19) to penetrate into a region between a shielding screen (10, 10'), which is arranged between the particle source (3) and a surface (5, 5') facing toward the interior (17), detaining deposits (6), which have spalled from the surfaces (5, 5'), in the region between the shielding screen (10, 10') and the surface (5, 5') by means of the shielding screen (10, 10').