Cathode for sputter coating
View Patent ↗A magnetron sputtering cathode for use in a vacuum deposition process is disclosed wherein the cathode is coated on its sides with an electrically insulating material such as alumina to prevent arcing, and wherein the first end surface of the cathode supports a material to be sputtered. The bottom of the cathode may also be coated with an electrically insulating coating or may be resting upon an insulating platform.
1. A magnetron sputtering apparatus including:
a magnetron cathode having first and second end surfaces and one or more side surfaces, the magnetron cathode having disposed therein a plurality of magnets adjacent to one another, at least one magnet having N-S poles facing first and second end surfaces respectively and at least one magnet having S-N poles facing the first and second end surfaces of the magnetron cathode respectively such that magnetic field lines extend from the N pole of one magnet to the S pole of the other magnet extending through the first end surface of the magnetron cathode, wherein the one or more side surfaces are at least partially covered with an electrically insulating material forming an insulated magnetron cathode to prevent arcing, wherein the first end surface of the insulated magnetron cathode supports a material to be sputtered; and,
an anode defining a vessel having an opening to an electrically conductive inner body and having an outer body, wherein the inner body includes a side wall forming an enclosed, walled portion and also includes an open end and an end wall portion spaced from said open end, the electrically conductive inner body being coupled to a voltage source for providing a voltage difference between the insulated magnetron cathode and the conductive inner body, wherein the anode is physically separated in space from the insulated magnetron cathode and not contacting the insulated magnetron cathode or any parts thereof, wherein the inner body of the anode is positively biased and is connected to a positive side of the voltage source and wherein the cathode is negatively biased and is connected to a negative side of the voltage source, and wherein the anode and cathode form a part of a same electrical circuit.
2. A magnetron sputtering apparatus as defined in claim 1 , wherein one or more surfaces and the second end surface are coated with an electrically insulating material to lessen arcing.
3. A magnetron sputtering apparatus as defined in claim 1 , wherein the second end surface, in operation, is at atmospheric pressure and wherein at least a portion of the side surfaces and the first end surface are in a vacuum.
4. A magnetron sputtering apparatus as defined in claim 1 , further comprising:
a vacuum coating chamber for housing the cathode;
a substrate holding member disposed within the vacuum coating chamber for mounting a substrate on which a film is to be deposited;
a gas control system for supplying a gas to an interior of the vacuum coating chamber; and
a power source system for supplying electrical power to said magnetron cathode; wherein the magnetron cathode is disposed in a predetermined spatial relationship with the substrate and having a target used to deposit the film on a surface of the substrate.
5. A magnetron sputtering apparatus as defined in claim 1 wherein the insulated magnetron cathode is disposed in opposed relation to the substrate.
6. A magnetron sputtering apparatus as defined in claim 1 , wherein the sides of the insulated magnetron cathode are coated with an electrically insulating coating.
7. A magnetron sputtering apparatus as defined in claim 1 , wherein the electrically insulating material is alumina.
8. A magnetron sputtering apparatus as defined in claim 1 , wherein
the electrically insulating coating is at least one of Teflon™, Kaptont™, and alumina.
9. A magnetron sputtering apparatus as defined in claim 1 wherein a Teflon™ plate is disposed adjacent to the second end surface of the magnetron cathode.
10. A magnetron sputtering apparatus as defined in claim 1 wherein the sides of the cathode are electrically insulated with one of, insulating tape, a Teflon™ coating or plate and ceramic plates, a coating of alumina, or combinations thereof.
11. A magnetron sputtering apparatus as defined in claim 8 wherein the second end is electrically insulated with one of a coating of alumina, insulating tape, a Teflon™ coating or plate and ceramic plates, or combinations thereof.
12. A sputtering apparatus anode as defined in claim 1 , wherein the opening is at one end, for communicating with a coating chamber and for allowing charged particles to flow between the electrically conductive inner body and the cathode within the coating chamber.
13. A sputtering apparatus anode as defined in claim 1 , wherein the vessel has an inlet port for receiving an inert gas for igniting plasma in the presence of a sufficient voltage applied between the electrically conductive inner body and the magnetron cathode.
14. A sputtering apparatus anode as defined in claim 1 wherein the anode is adapted to be disposed outside of the coating chamber and physically coupled thereto such that the opening of the vessel is facing and open to the coating chamber.
15. A magnetron sputtering apparatus as defined in claim 1 , wherein the first and second end surfaces and one or more side surfaces are conductive surfaces.
16. A sputtering apparatus as defined in claim 1 wherein said insulated magnetron cathode occupies a space outside of the inner body of the vessel.