Plasma booster for plasma treatment installation

1. A vacuum treatment installation for plasma treatment, in particular for the plasma coating of workpieces, comprising at least one arrangement for boosting and/or igniting a glow discharge plasma for the treatment of said workpieces, said arrangement comprising at least one hollow body of an electrically conductive material, the hollow body comprising a hollow space and at least one opening at an entrance to the hollow space through which charge carriers can flow off into environs of the arrangement in order to make here possible ignition and operation of a plasma or to boost a plasma existing here, the hollow body comprising at least two cathode annuli having a hollow space and at least one lateral surface, which comprises at least a part of said lateral surface being a surface of a grid and of at least a part of said lateral surface being realized by mutually distant rods, wherein the hollow space of the hollow body is formed such that when an electric signal is applied to the hollow body, at least in a certain pressure and voltage range, geometric conditions for the ignition of a discharge in the interior of the hollow body are satisfied and wherein said hollow body is not a workpiece carrier.

2. The vacuum treatment installation as claimed in claim 1 , comprising a vacuum chamber comprising a chamber bottom and a chamber cover, wherein said at least one arrangement is mounted to one of said chamber bottom and of said chamber cover.

3. The vacuum treatment installation as claimed in claim 1 , wherein the geometric conditions are satisfied for a pressure range between 1×10 −3 and 5×10 −2 mbar.

4. The vacuum treatment installation as claimed in claim 1 , wherein the geometric conditions are satisfied for a pressure range between 4×10 −3 and 2×10 −2 mbar.

5. The vacuum treatment installation as claimed in claim 1 , wherein the electric signal is a DC voltage or an AC voltage.

6. The vacuum treatment installation as claimed in claim 1 , wherein the electric signal is a bipolar or unipolar pulsed AC voltage signal in the medium frequency range.

7. The vacuum treatment installation as claimed in claim 1 , wherein the geometric conditions for an electric signal are satisfied with a voltage range between 200 and 2000 V.

8. The vacuum treatment installation as claimed in claim 1 , wherein the geometric conditions for an electric signal are satisfied with a voltage range between 400 and 1200 V.

9. The vacuum treatment installation as claimed in claim 1 , wherein the hollow body has at least one of a top-opening and of a bottom opening, said at least one opening being covered with a grid.

10. The vacuum treatment installation as claimed in claim 1 , said hollow space being within a lateral surface having a plurality of through openings.

11. The vacuum treatment installation as claimed in claim 10 , wherein said through-openings comprises at least one of at least a part of said surface being a surface of a grid and of at least a part of said surface being realized by mutually distant rods.

12. The vacuum treatment installation as claimed in claim 9 , wherein the distance d′ is less or equal to the twofold, however greater or equal to the simple cathode drop distance in a certain pressure and voltage range.

13. The vacuum treatment installation as claimed in claim 1 , the hollow body having a hollow space with a cross-sectional distance decisive for said conditions d′ and having the form of a circle, an ellipse or a polygon or a form composed of different of these geometries, wherein said distance d′ is one of between 20 to 200 mm and of between 60 and 100 mm.

14. The vacuum treatment installation as claimed in claim 1 , wherein the hollow body comprises several circular, elliptical or polygonal annuli or annuli of combined geometries, disposed one above the other, wherein the annuli are disposed at a mutual distance a, which is sufficiently small to avoid the ignition of a discharge between the annuli.

15. The vacuum treatment installation as claimed in claim 14 , wherein the distance a is smaller than the cathode drop distance in said certain pressure and voltage range.

16. The vacuum treatment installation as claimed in claim 15 , wherein the distance a is one of between 1 and 60 mm and of between 5 and 25 mm.