US 6,645,343 B1Granted

Plasma reactor

AssigneeFraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V.

InventorsChristof Wild, Peter Koidl

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Abstract

A plasma reactor (1) especially for diamond-CVD (chemical vapor deposition) or, for example, plasma surface treatment or plasma etching is provided. The plasma reactor (1) includes a reactor housing (2) designed as resonator, to which is attached a high-frequency coaxial line (5) connected with a high-frequency generator (6) for irradiation of microwaves. Located in the reactor housing is a substrate holder (3) for a substrate to be coated. A vacuum-tight window (12) of microwave-permeable material is positioned in a transition area from the coaxial line (5) to the reactor housing (2) and the reactor housing includes connections (10, 11) for supplying and removing process gas. The microwave window (12) is essentially ring-shaped. As a result, the coupling is distributed over a large surface so that high microwave power levels can be coupled without high electric field intensities developing at the microwave window and thus without the danger of window discharge.

Claims10

Dependent claims

A plasma reactor comprising:

a reactor housing (2) designed as a resonator in which a substrate holder (3) for a substrate to be coated is located, the reactor housing (2) including connections (10, 11) for supplying and removing a process gas, and having a ring-shaped, vacuum-tight window (12) of microwave-permeable material with a ring surface that extends about a circumference of the reactor housing;
a high-frequency coaxial line (5) arranged coaxially with a longitudinal axis of the housing and being connected with a high-frequency generator (6) for irradiation of microwaves and having a delivery end at a transition area from the high-frequency coaxial line to the housing that is directed at the microwave-permeable window;
the high-frequency coaxial line (5) is funnel-shaped as it extends through the transition area to the delivery end outside the reactor housing (2) and is essentially rotationally symmetric and is directed at a periphery of the reactor housing (2) toward the microwave window (12) for a coupling that is symmetrically distributed over the entire ring surface of the microwave window.

Dependencies are inferred from the claim text.