Enhanced macroparticle filter and cathode arc source

A method of filtering macroparticles from a beam of plasma emitted from a cathode arc source, the method comprising:

• using a magnetic field to steer the beam through a first filter comprising a filter duct having at least one bend;
• and
• steering the beam thereafter through a second filter comprising a baffle and an aperture wherein a magnetic field is provided that is locally enhanced in the region of the second filter so as to steer the beam through the aperture,
• wherein the aperture in the second filter has an opening of less than 33% of the internal sectional area of the filter duct.

A filter for use in a deposition apparatus having a cathode arc source, a filter duct and a deposition chamber, the filter comprising:

• a baffle plate having an aperture therethrough;
• and
• magnetic field generating means for guiding plasma from the cathode arc source through the aperture,
• wherein the aperture in the filter has an opening of less than 33% of the internal sectional area of the filter duct.

An apparatus for generating plasma for deposition upon a substrate, said apparatus comprising:

• a main plasma duct,
• a first cathode arc source,
• a first side duct connected to said main plasma duct,
• a second cathode arc source;
• and
• a second side duct connected to said main plasma duct, wherein plasma output from the first cathode arc source is guided by magnetic field into the main plasma duct via the first side duct and plasma output from the second cathode arc source is guided by magnetic field into the main plasma duct via the second side duct, and wherein the main plasma duct provides a single plasma output from the apparatus.

A method of depositing a coating on a substrate, comprising:

• outputting a first plasma beam from a first cathode arc source;
• guiding said first plasma beam through a first side duct into a main duct;
• outputting a second plasma beam from a second cathode arc source;
• guiding said second plasma beam through a second side duct into the main duct;
• in the main duct, combining said first and second plasma beams to form a combined beam;
• and
• guiding the combined beam onto the substrate.