MICROWAVE PLASMA DEVICE

Abstract

A microwave plasma device includes a treatment space and a number of two or more microwave semiconductors. The microwave semiconductors are attached to the treatment space in such a way that the microwaves of a microwave semiconductor only interfere with the microwaves of other microwave semiconductors when in the treatment space.

Claims

1-10. (canceled)

11. A microwave plasma device, comprising a treatment space (2) configured as a resonator structure and a number of two or more microwave semiconductors (1), wherein the microwave semiconductors (1) are attached to the treatment space (2) in such a way that the microwaves of each one of the microwave semiconductors only interfere with the microwaves of other microwave semiconductors (1) when in the treatment space, and in that output coupling of the microwaves from the microwave semiconductors (1) is effected via, in each case, an antenna (4), and in that the microwave plasma device is configured in such a way that the microwaves are fed from the antennas (4) into the treatment space (2) via, in each case, a further coupling element (7) and a further antenna arrangement comprising antennas (8).

12. A microwave plasma device according to claim 11, wherein the microwaves are coupled out from at least one microwave semiconductor via a rod antenna, wherein a rod antenna is preferably configured as an extension of the inner conductor of the, in particular coaxial, output-coupling means coupling out from the microwave semiconductor.

13. A microwave plasma device according to claim 11, wherein the microwave plasma device comprises rectangular, oval or round waveguides and/or couplers as further coupling elements (7) into which the microwaves are initially coupled, and in that the antennas (8) of the further antenna arrangement, from which the microwaves are coupled into the treatment space, are preferably slot antennas, rod antennas or hole couplers.

14. A microwave plasma device according to claim 11, wherein the treatment space (2) is divided into two regions, in particular by means of a dielectric wall element (6) which is a wall or a window, wherein said treatment space is configured as a cylindrical, rectangular, spherical, ellipsoidal, coaxial resonator, or as a combination thereof

15. A microwave plasma device according to claim 11, wherein microwave input-coupling points in the treatment space lie in at least one plane.

16. A microwave plasma device according to claim 11, wherein a group of the microwave semiconductors is frequency-coupled, wherein preferably all microwave semiconductors are frequency-coupled to one another, and wherein individual microwave semiconductors or further groups of microwave semiconductors frequency-coupled to one another are present which emit microwaves having other frequencies than the aforementioned group.

17. A microwave plasma device according to claim 11, wherein a microwave semiconductor is configured to be excited in a pulsed manner, wherein preferably a group of the microwave semiconductors is pulse-coupled, and wherein all microwave semiconductors of the microwave plasma device are pulse-coupled to one another, or individual microwave semiconductors or further groups of microwave semiconductors pulse-coupled to one another are present which emit microwaves with other pulses than the aforementioned group.

18. A microwave plasma device according to claim 11, wherein a group of microwave semiconductors is power-coupled, wherein the power coupled in is preferably variable over time, and wherein preferably all microwave semiconductors of the microwave plasma device are in this group, or individual microwave semiconductors or further groups of microwave semiconductors power-coupled to one another are present which emit microwaves having a different power than the aforementioned group.

19. A microwave plasma device according to claim 11, wherein the microwave semiconductors are configured to emit microwaves having linear or circular polarization, wherein preferably a group of the microwave semiconductors is configured such that these microwave semiconductors emit microwaves of the same polarization.

20. A method for operating a microwave plasma device according to claim 11, wherein the microwaves of each one of the microwave semiconductors are coupled into the treatment space in such a way that they only interfere with the microwaves of other microwave semiconductors when in the treatment space.

Description

[0034] Examples of preferred embodiments of the microwave plasma device according to the invention are schematically illustrated in the figures.

[0035] FIG. 1 shows a top view of a preferred embodiment.

[0036] FIG. 2 shows a sectional image of the embodiment according to FIG. 1 in a side view.

[0037] FIG. 3 shows a top view of another preferred embodiment.

[0038] FIG. 4 shows a sectional image of the embodiment according to FIG. 3 in a side view.

[0039] All components of the device according to the invention can also be present more than once. Only those components which are necessary or helpful for understanding the invention are illustrated. Thus, for example, further components which are known to the person skilled in the art, and their embodiments, are not shown in the Figures; such components are, for example, gas inlet and gas outlet, pump, pressure control unit, control, material locks, or corresponding components.

[0040] FIG. 1 shows an illustration of a preferred embodiment of the microwave plasma device from above. A treatment space 2, which is designed as a cylinder made of metal (for example brass, copper or aluminium) with a base and a cover and can serve as a resonator, is shown in the centre. Although this embodiment of the treatment space 2 in the form of a cylinder resonator is particularly preferred, spherical resonators, ellipsoidal resonators, rectangular resonators or mixed forms thereof can also offer advantages, depending on the application.

[0041] Four microwave semiconductors 1 are arranged equidistantly around the treatment space 2. If required, the number of microwave semiconductors 1 can be both increased and lowered. A bias electrode 3 can be seen in the centre of the treatment space 2. The treatment space 2 and two microwave semiconductors 1 are traversed centrally by the section plane A-A.

[0042] The components indicated by dashed lines in the drawing are not designated in detail here for reasons of a better overview. They are explained in more detail in the context of FIG. 2.

[0043] FIG. 2 shows the sectional plane A-A of the embodiment according to FIG. 1 in a side view. It can be seen here that input coupling of the microwaves from a microwave semiconductor 1 is in each case achieved via a rod antenna 4, which is configured, for example, as an extension of the inner conductor of the coaxial output-coupling means coupling out from the microwave semiconductor 1 into the treatment space 2.

[0044] A dielectric wall element 6, for example a quartz glass cylinder, divides the treatment space 2 in such a way that, depending on the application, a corresponding gas atmosphere having a desired gas composition and pressure can be adjusted in the region located in the interior of the dielectric wall element 6. The dielectric wall element 6 can be configured as a complete partition wall or else as a window in an otherwise non-dielectric wall.

[0045] A sample receiving unit 5 is located under the bias electrode 3, wherein the bias electrode 3 and the sample receiving unit 5 can be designed to be displaceable along the cylinder axis of the treatment space 2, that is to say upwards and downwards in the Figure. A bias voltage can be applied between the bias electrode 3 and the sample receiving unit 5 in order to direct plasma species (e.g. ions or electrons) onto the sample receiving unit 5.

[0046] FIG. 3 shows an illustration of a further preferred embodiment of the microwave plasma device from above. As in FIG. 1, four microwave semiconductors 1 are again arranged equidistantly around a treatment space 2. The bias electrode 3 can also be seen again in the centre of the treatment space 2. In contrast to FIG. 1, coupling elements 7 are shown in this Figure, each at the position of a microwave semiconductor 1. The treatment space 2 and two microwave semiconductors 1 are traversed centrally by the sectional plane B-B.

[0047] FIG. 4 shows the sectional plane B-B of the embodiment according to FIG. 3 in side view. As in the preceding example, input coupling of the microwaves from a microwave semiconductor 1 is achieved via, in each case, a rod antenna 4. In contrast to FIG. 2, the microwaves are coupled in from the microwave semiconductor 1 via the rod antenna 4, into a coupling element 7. Here, the coupling element 7 is configured as a rectangular waveguide element and converts the coaxial microwave feed into a rectangular waveguide wave. The latter is coupled into the treatment space 2 by means of coupling slots 8. In modification of this embodiment, there may be more or fewer microwave feeds composed of microwave semiconductor 1, rod antenna 4, coupling element 7 and coupling slots 8.

[0048] In the Figure, the coupling points 7 for coupling the microwaves into the treatment space or the microwave feeds lie in a plane. An arrangement of the coupling points or microwave feeds in a plurality of planes is also possible. In this way, higher powers or better homogeneity levels, for example for a plasma, of the irradiated microwave radiation can be obtained.

[0049] For example, the preferred embodiments of FIGS. 1 and 2 or 3 and 4 represent a microwave plasma device for generating a plasma. As already mentioned above, the dielectric wall element 6 can be a quartz glass recipient which partitions off an internal plasma chamber, said internal plasma chamber serving as a volume for carrying out a plasma treatment. The desired process conditions, such as, for example, gas composition, gas pressure or microwave power, can be set in the plasma chamber.

[0050] FIGS. 1 and 2 show a preferred way of coupling microwaves into the treatment space 2, i.e. direct input-coupling from the coaxial outlet. The inner conductor of the microwave semiconductor 1 couples-in the case shown, in the form of a rod antenna 4-into the treatment space 2.

[0051] FIGS. 3 and 4 show a further preferred way of coupling microwaves into the treatment space 2, i.e. the indirect input-coupling from the coaxial outlet.

[0052] Here, microwaves are converted into waveguide waves of any type via coupling elements 7, for example rectangular waveguides or circular waveguides, and then fed to the treatment space via the coupling slots 8. The way in which power is coupled in can thus be adapted to the structure of the treatment space 2.

[0053] Input coupling of the microwaves via the various microwave semiconductors 1 preferably takes place at the same frequency and phase but can also be adapted to that of the microwave plasma device if required.

[0054] An advantage of the embodiment according to the invention is that circulators and tuning elements in the feed of the microwaves to the treatment space can, but need not, be dispensed with.

[0055] The microwaves can be coupled in in a pulsed or unpulsed manner, as required. The power can vary between different power levels, i.e. it does not have to vary between 0 and 100%, but can be pulsed, for example, between 20% and 80%.

[0056] The polarization of the microwaves (e.g. linear, circular or elliptical) of the individual microwave semiconductors or microwave feeds can be implemented so as to be identical. Depending on the application, the polarization of different microwave semiconductors can also be selected so as to be different, or else so as to change over time.

[0057] The various input coupling options (pulsed, polarized, phase or frequency ratio) can also be combined as required.

LIST OF REFERENCE NUMERALS

[0058] 1 Microwave semiconductor [0059] 2 Treatment space [0060] 3 Bias electrode [0061] 4 Rod antenna [0062] 5 Sample-receiving unit [0063] 6 Dielectric wall element [0064] 7 Coupling element [0065] 8 Coupling slots