Method and device for generating a plasma excited by a microwave energy in the electron cyclotron resonance (ECR) domain, in order to carry out a surface treatment or produce a coating around a filiform element

1. A process to generate a plasma excited by microwave energy in a field of electron cyclotron resonance (ECR), to execute a surface treatment or coating around a filiform component, comprising:

arranging at least two annular magnets constituting magnetic dipoles at atmospheric pressure opposite each other and mounted concentrically around a tube constituting a treatment chamber, to produce axisymmetric magnetic field lines parallel to the filiform component,

continuously linearly moving the filiform component through the at least two annular magnets and the tube constituting a treatment chamber,

introducing the microwave energy to the tube, between the at least two annular magnets via a microwave applicator mounted between the at least two annular magnets, and

thereby generating a linear axisymmetrical plasma confined around the filiform component in the treatment chamber.

2. The process according to claim 1 , wherein the surface treatment comprises a cleaning, a pickling, a functionalisation, or a grafting.

3. The process according to claim 1 , wherein the coating is obtained by PECVD (plasma-enhanced chemical vapour deposition).

4. A device to generate a microwave excited plasma by electron cyclotron resonance (ECR), around a continuously linearly driven filiform component, comprising:

at least one module composed of two annular magnets constituting magnetic dipoles arranged at atmospheric pressure opposite each other and mounted concentrically around a tube constituting a treatment chamber, and producing axisymmetric magnetic field lines parallel to the filiform component wherein

the filiform component to be treated is linearly moved through the two annular magnets and through the tube constituting the treatment chamber, and

wherein the device further includes a microwave applicator connected to the tube, between the two annular magnets to introduce microwave energy between the two annular magnets,

thus generating a linear axisymmetrical plasma confined around the filiform component in the treatment chamber.

5. The device according to claim 4 , wherein the annular magnets comprise permanent magnets.

6. The device according to claim 4 , wherein the annular magnets comprise electromagnet coils.

7. The device according to claim 4 , wherein the microwave applicator is arranged perpendicularly to a central axis of the tube.

8. The device according to claim 4 , wherein the tube constitutes a Tee having a median branch and two other branches on either side of said median branch, the median branch receives the microwave applicator and the other two branches receive the annular magnets.

9. The device according to claim 4 , wherein the device comprises several modules mounted in series and in linear alignment and connected together by a sealing ring.

10. The device according to claim 9 , wherein each sealing ring acts as a pumping zone being connected to a gas pumping collector.

11. The device according to claim 9 , wherein the sealing ring acts alternatively as a gas pumping zone and as a gas injection zone.

12. The device according to claim 4 , wherein the filiform component is electrically polarised to allow an ion bombardment of the plasma.