IMPROVED GUIDANCE OF IONS FROM A PLASMA TO A SUBSTRATE TO BE COATED

Abstract

The invention relates to a substrate holder (1) comprising a first contact (3) for the supply of a potential U.sub.s to the substrate (2), a charging region (12) on the surface (11) of the substrate holder (1) being designed such that it can be charged (13) with ions (101, 102) from the ion source (104) of a coating facility (100), and/or a second contact (4) is provided by means of which a freely selectable potential U.sub.H different from the potential U.sub.s can be applied to an electrode region (14) on the surface (11) of the substrate holder (1). The invention also relates to a coating facility (100) comprising at least one ion source (104) and a first voltage source (106) that can be connected to the substrate to be coated (2) such that gas ions (101) and/or ions (102) of a coating material (103) can be accelerated in the direction of the substrate (2) from the ion source (104) by means of an electric potential U.sub.s applied to the substrate (2) from the first voltage source (106), at least one secondary surface (11, 105), towards which ions (101, 102) missing the substrate (2) move, being designed (13, 113) such that it can be charged with arriving ions (101, 102), and/or at least one second voltage source (107) being provided, which can be connected to the secondary surface (11, 105) such that a freely selectable potential U.sub.s different from the potential U.sub.s can be applied to said secondary surface (11, 105). The invention further relates to an operating method and to a computer program product.

Claims

1. A substrate holder (1) for mounting a substrate (2) in a coating system (100), in such a way that a surface (11) of the substrate holder (1) faces toward an ion source (104) of the coating system (100), the substrate holder comprising: a first contact (3) for delivering a potential US to the substrate (2), a charging region (12) on the surface (11) of the substrate holder (1) configured (13) to be chargeable by ions (101, 102) incident from the ion source (104) of the coating system (100).

2. A coating system (100) having at least one ion source (104), a first voltage source (106), which can be connected to a substrate (2) to be coated so that ions can be accelerated in the direction of the substrate (2) by an electrical potential US applied to the substrate (2) by the first voltage source (106), and at least one secondary surface (11, 105), toward which ions (101, 102) that miss the substrate (2) move, configured (13, 113) to be chargeable by incident ions (101, 102).

3. The coating system (100) as claimed in claim 13, further comprising a controller (108) for the second voltage source (107) is provided, which is configured in order to track the potential UH to a change in the potential US, in such a way that the potential US is at a lower energy than the potential UH as seen by the ions (101, 102).

4. The coating system (100) as claimed in claim 13, further comprising a controller (108) for the second voltage source (107), which is configured to track the potential UH to (a) a change in properties of the ion reservoir (104), (b) to a change in the potential US, or both (a) and (b) in such a way that the potential UH is repulsive as seen by the ions (101, 102).

5. The coating system (100) as claimed in claim 2, further comprising a substrate holder (1) connected into the electrical connection between the first voltage source (106) and the substrate (2).

6. A method for operating a coating system (100), the method comprising: accelerating ions in the direction of the substrate (2) by applying an electrical potential US to a substrate (2), and applying a potential UH different to the potential US to at least one secondary surface (11, 105), toward which ions (101, 102) that miss the substrate (2) move.

7. The method as claimed in claim 6, wherein a potential UH is selected which has a repulsive effect on the ions (101, 102).

8. The method as claimed in claim 7, wherein a combination of potentials US and UH is selected, which deviates ions (101, 102) travelling in the direction of the secondary surface (11, 105) onto the substrate (2).

9. The method as claimed in claim 8, wherein the potential UH is varied in order to modify the position (21) at which the deviated ions (101, 102) strike the substrate (2).

10. (canceled)

11. A non-transitory computer-readable medium containing machine-readable instructions which, when they are executed on a computer with a coating system (100) connected thereto, cause the coating system to accelerate ions in the direction of the substrate (2) by applying an electrical potential US to a substrate (2), and apply a potential UH different to the potential US to at least one secondary surface (11, 105), toward which ions (101, 102) that miss the substrate (2) move.

12. A substrate holder (1) as claimed in claim 1, the substrate holder further comprising a second contact (4), by means of which a freely selectable potential UH different to the potential US is applied to an electrode region (14) on the surface (11) of the substrate holder (1).

13. The coating system (100) as claimed in claim 2, further comprising at least one second voltage source (107), which can be connected to the secondary surface (11, 105) so that a freely selectable potential UH different to the potential US can be applied to the secondary surface (11, 105)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0036] FIG. 1 shows an exemplary embodiment of a coating system 100 according to the invention;

[0037] FIG. 2 shows an exemplary embodiment of a substrate holder 1 according to the invention;

[0038] FIGS. 3a and 3b show perturbing effects in the prior art, which the invention counteracts.

DETAILED DESCRIPTION

[0039] FIG. 1 shows an exemplary embodiment of a coating system 100 in plan view. The coating system 100 comprises a vacuum container 110, at the center of which a plasma with a plasma boundary layer 104a is arranged as an ion source 104. The substrates 2a-2f to be coated are electrically connected to one another by means of a ring line 111, and a potential U.sub.S is applied to them by the first voltage source 106. This potential U.sub.S has an attractive effect on the ions 101, 102 from the ion source 104.

[0040] In order to clean the substrates 2a-2f, the ion source is adjusted in such a way that it only emits argon ions. The argon ions 101 ablate impurities from the substrates 2a-2f. Subsequently, the ion source 104 is adjusted in such a way that it also emits ions 102 of the actual coating material 103. The coating material 103 is deposited on the substrates 2a-2f. The substrates 2a-2f are held by the substrate holder 1 in the vacuum container 110. The substrate holders 1 are covered by the substrates 2a-2f in the perspective selected in FIG. 1, and are therefore not indicated.

[0041] The inner wall of the vacuum container 110 forms a secondary surface 105, toward which ions 101, 102 that miss the substrates 2a-2f move. This secondary surface 105 is provided with an insulating covering 113, the thickness of which is shown greatly exaggerated in FIG. 1. Furthermore, a potential U.sub.H is applied to the secondary surface 105 by means of the second voltage source 107. This potential U.sub.H is then continuously tracked by the controller 118 in such a way that, on the one hand the potential U.sub.S is always lower than the potential U.sub.H as seen by the ions 101, 102, and on the other hand the potential U.sub.H is always repulsive as seen by the ions 101, 102.

[0042] The insulating covering 113 and the potential U.sub.H together have the effect that the ions 101, 102 that miss the substrates 2a-2f are at least partially deviated in the direction of the substrates 2a-2f. The trajectory that the deviated ions 101, 102 would follow without the deviation is indicated by dashes.

[0043] During the cleaning of the substrates 2a-2f, the deviation on the one hand has the effect that less material is ablated from the secondary surface 105 and deposited on the substrates 2a-2f. On the other hand, the entire surface of the substrate 2a-2f is respectively reached, and not only the subregions which lie in direct line of sight with the ion source 104.

[0044] During the actual coating, the deviation correspondingly has the effect that the coating material 103 is respectively deposited on the entire surface of the substrate 2a-2f, and no subregions remain uncoated. Such defects could, for example in wear protection layers, lead to increased wear occurring and the component failing prematurely.

[0045] FIG. 2 shows an exemplary embodiment of a substrate holder 1 according to the invention. The substrate holder 1 has a first contact 3, by means of which a potential U.sub.S can be applied to the substrate 1. In addition, its electrically conductive surface 11 has a charging region 12, which is provided with an insulating covering 13. The entire surface 11 of the substrate holder 1 can furthermore have the potential U.sub.H applied to it by means of a second contact 4, and to this extent also serves as an electrode region 14. In order to illustrate the effect, FIG. 2 indicates the ion source with the plasma boundary layer 104a as well as the trajectories of the ions 101, 102, including their deviation in the direction of the substrate 2. The substrate 2 is insulated from the substrate holder 1 by means of an insulating intermediate piece 15 on the substrate holder 1, so that the potential U.sub.S is not short-circuited to the potential U.sub.H.

[0046] FIG. 3 illustrates the perturbing effects in the prior art, which the invention counteracts.

[0047] FIG. 3a shows the previous situation during the cleaning of the substrate 2. From the ion source 1, gas ions 101 are accelerated in the direction of the substrate 2, which is at the potential U.sub.S. Since the substrate 2 is electrically conductively connected to the substrate holder 1, the substrate holder 1 is also at the potential U.sub.S and attracts the gas ions 101 as strongly as the substrate 2 does. As a result, the gas ions 101 may remove extraneous atoms 16 from the substrate holder 1, which are deposited as impurities 21 on the substrate 2. Furthermore, the side of the substrate 2 facing away from the ion source 104 is not detected by the gas ions 101. Impurities 22 already present there are thus not removed by the cleaning of substrate 2 and may interfere with the application of the coating material 103.

[0048] FIG. 3b shows the previous situation during production of the coating from the coating material 103 on the substrate 2. The ions of the coating material 103 can reach only about half of the surface of the substrate 2. In order to coat the substrate 2 fully, it must for example be rotated.