Electron cyclotron resonance plasma source and method of operation

Claim 3

The method of claim 1 further comprising the step of selecting the rectilinear array for ensuring uniform surface treatment of specimens with very large and/or curved surface.

Claim 4

An electron cyclotron resonance (ECR) plasma source for use in treating specimens by processes including chemical vapor deposition and etching, comprising a cylindrical chamber which is symmetrical about its longitudinal axis, means for supporting a specimen adjacent one axial end of the cylindrical chamber, means for introducing a gaseous medium into the chamber, two cylindrical magnet assemblies arranged circumferentially about the chamber for generating a circumferentially continuous and symmetrical magnetic field having lines of force forming continuous annular lobes also circumferentially extending about the chamber and continuous resonant interaction regions encircling the longitudinal axis of the chamber adjacent an opposite axial end thereof, means for developing a substantially field free region adjacent the one axial end of the chamber while minimizing extension of magnetic field force lines into the magnetic field free region and toward the specimen, a microwave power applicator arranged between the magnet assemblies and comprising at least one pair of slotted waveguide antennae each formed in an arcuate configuration, the paired antennae each having an injection axis extending radially inwardly toward the longitudinal axis of the chamber for uniformly radiating electromagnetic radiation toward the resonant interaction region about the entire periphery of the chamber so that plasma electrons made energetic by interaction with the electromagnetic radiation are not permitted line-of-sight communication to the specimen along field force lines in the magnetic field free region, and means for maintaining low gas pressure in the chamber, whereby a plasma stream flows through the magnetic field free region toward the specimen with characteristics of high plasma density, uniformity over transverse dimensions larger than the specimen, low plasma temperature and absence of energetic particles resulting from plasma instabilities even with operating gas pressures as low as 10 -5 Torr.

Claim 5

An electron cyclotron resonance (ECR) plasma source for use in treating specimens by processes including chemical vapor deposition and etching, comprising a cylindrical chamber which is symmetrical about its longitudinal axis, means for supporting a specimen adjacent one axial end of the cylindrical chamber, means for introducing a gaseous medium into the chamber, two cylindrical magnet assemblies arranged circumferentially about the chamber for generating a circumferentially continuous and symmetrical magnetic field having lines of force forming continuous annular lobes also circumferentially extending about the chamber and continuous resonant interaction regions encircling the longitudinal axis of the chamber adjacent an opposite axial end thereof, means for developing a substantially field free region adjacent the one axial end of the chamber while minimizing extension of magnetic field force lines into the magnetic field free region and toward the specimen, a microwave power applicator arranged between the magnet assemblies and comprising at least one pair of slotted waveguide antennae each formed in an arcuate configuration, the paired antennae each having an injection axis extending radially inwardly toward the longitudinal axis of the chamber for uniformly radiating electromagnetic radiation toward the resonant interaction region about the entire periphery of the chamber so that plasma electrons made energetic by interaction with the electromagnetic radiation are not permitted line-of-sight communication to the specimen along field force lines in the magnetic field free region, and means for maintaining low gas pressure in the chamber, whereby a plasma stream flows through the magnetic field free region toward the specimen with characteristics of high plasma density, uniformity over transverse dimensions larger than the specimen, low plasma temperature and absence of energetic particles resulting from plasma instabilities even with operating gas pressures as low as 10 -5 Torr.

Claim 6

The ECR plasma source of claim 1 further comprising a hybrid coupler for supplying microwave power to the paired antennae while providing a stable match to variable impedance of the plasma.

Claim 7

The ECR plasma source of claim 1 further comprising a fused quartz liner defining walls of the chamber for minimizing introduction of impurities into the chamber from interaction of electrons with the chamber walls.

Claim 8

The ECR plasma source of claim 5 further comprising means associated with the permanent magnets for final adjustment of the magnetic field configuration.

Claim 9

The ECR plasma source of claim 6 wherein the final adjustment means comprise annular magnetic bands movably positioned respectively adjacent the two cylindrical magnet assemblies.

Claim 10

The ECR plasma source of claim 1 further comprising means associated with the permanent magnets for final adjustment of the magnetic field configuration.

Claim 11

The ECR plasma source of claim 8 wherein the final adjustment means comprise annular magnetic bands movably positioned respectively adjacent the two cylindrical magnet assemblies.

Claim 12

The ECR plasma source of claim 1 wherein the chamber has all-metallic surfaces.

Claim 13

An electron cyclotron resonance (ECR) plasma source for use in treating specimens by processes including chemical vapor deposition and etching, comprising a cylindrical chamber which is symmetrical about its longitudinal axis, means for supporting one of the specimens adjacent one axial end of the cylindrical chamber, means for introducing a gaseous medium into the chamber, two cylindrical magnet assemblies arranged circumferentially about the chamber for generating a circumferentially continuous and symmetrical magnetic field having lines of force forming continuous annular lobes also circumferentially extending about the chamber and continuous resonant interaction regions encircling the longitudinal axis of the chamber adjacent an opposite axial end thereof, means for developing a substantially field free region adjacent the one axial end of the chamber while minimizing extension of magnetic field force lines into the magnetic field free region and toward the specimen, a microwave power applicator arranged between the magnet assemblies and having multiple injection axes extending radially inwardly toward the longitudinal axis of the chamber and thereby radiating electromagnetic radiation toward the resonant interaction region about the entire periphery of the chamber, means for maintaining low gas pressure in the chamber, and means associated with the permanent magnets for final adjustment of the magnetic field configuration, whereby a plasma stream flows through the magnetic field free region toward the specimen with characteristics of high plasma density, uniformity over transverse dimensions larger than the specimen, low plasma temperature and absence of energetic particles resulting from plasma instabilities even with operating gas pressures as low as 10 -5 Torr.

Claim 14

An electron cyclotron resonance (ECR) plasma source for use in treating specimens by processes including chemical vapor deposition and etching, comprising a cylindrical chamber which is symmetrical about its longitudinal axis, means for supporting one of the specimens adjacent one axial end of the cylindrical chamber, means for introducing a gaseous medium into the chamber, two cylindrical magnet assemblies arranged circumferentially about the chamber for generating a circumferentially continuous and symmetrical magnetic field having lines of force forming continuous annular lobes also circumferentially extending about the chamber and continuous resonant interaction regions encircling the longitudinal axis of the chamber adjacent an opposite axial end thereof, means for developing a substantially field free region adjacent the one axial end of the chamber while minimizing extension of magnetic field force lines into the magnetic field free region and toward the specimen, a microwave power applicator arranged between the magnet assemblies and having multiple injection axes extending radially inwardly toward the longitudinal axis of the chamber and thereby radiating electromagnetic radiation toward the resonant interaction region about the entire periphery of the chamber, means for maintaining low gas pressure in the chamber, and means associated with the permanent magnets for final adjustment of the magnetic field configuration, whereby a plasma stream flows through the magnetic field free region toward the specimen with characteristics of high plasma density, uniformity over transverse dimensions larger than the specimen, low plasma temperature and absence of energetic particles resulting from plasma instabilities even with operating gas pressures as low as 10 -5 Torr.

Claim 15

The ECR plasma source of claim 11 wherein the final adjustment means comprises further comprising annular magnetic bands movably positioned respectively adjacent the two cylindrical magnet assemblies.

Claim 16

An electron cyclotron resonance (ECR) plasma source for use in treating specimens by processes including surface treatment, comprising a cylindrical chamber including means for introducing a gaseous medium into the chamber and means for maintaining low gas pressure in the chamber, means for supporting a specimen in the chamber, and a rectilinear array of interleaved linear magnets and at least one pair of microwave power injector segments having multiple injection axes extending into the chamber and toward the specimen, the rectilinear array being effective for developing a plasma stream flow toward the specimen with characteristics of high plasma density, uniformity over transverse dimensions larger than the specimen, low plasma temperature and absence of energetic particles resulting from plasma instabilities even with operating gas pressures as low as 10 -5 Torr.

Claim 17

An electron cyclotron resonance (ECR) plasma source for use in treating specimens by processes including surface treatment, comprising a cylindrical chamber including means for introducing a gaseous medium into the chamber and means for maintaining low gas pressure in the chamber, means for supporting a specimen in the chamber, and a rectilinear array of interleaved linear magnets and at least one pair of microwave power injector segments having multiple injection axes extending into the chamber and toward the specimen, the rectilinear array being effective for developing a plasma stream flow toward the specimen with characteristics of high plasma density, uniformity over transverse dimensions larger than the specimen, low plasma temperature and absence of energetic particles resulting from plasma instabilities even with operating gas pressures as low as 10 -5 Torr.

Claim 18

The ECR plasma source of claim 13 wherein the injector segments are linear slotted waveguide antennae.

Claim 19

The ECR plasma source of claim 14 further comprising a magnetic shell for mounting the rectilinear array.

Claim 20

The ECR plasma source of claim 15 wherein the magnetic shell is formed from milled steel.

Claim 21

The ECR plasma source of claim 13 further comprising a magnetic shell for mounting the rectilinear array.