An ECR plasma device provided with the above ECR plasma source and a sample moving mechanism for moving a large sample.

The ECR plasma cavity serves as a source of electrons from which the beam will be extracted.

The at least two linear plasma discharge openings (7, 8, 23, 24, 34, 35) are arranged with regard to one another in such a manner that, together, they form at least one plasma discharge opening (9, 27, 28, 30) of the ECR plasma source.

A polymer (31) is mounted on the substrate (30) that is located in the etching chamber (12) of a plasma etching arrangement (1) such as an ECR plasma etching arrangement or an ICP plasma etching arrangement for instance.

The present invention describes a technique to control the radial profile of microwave power in an ECR plasma discharge.