Method of producing flat ECR layer in microwave plasma device and apparatus therefor
US5198725A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 12, 1991 |
| Grant date | Mar 30, 1993 |
| Priority date | — |
| Expiry date | Jul 12, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J37/32678
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A microwave plasma generating device including a plasma chamber for generating plasma, a reaction chamber having a specimen stage on which a specimen is treated with the plasma, a gas supply for supplying gas to the plasma generating chamber, a microwave generator for generating a microwave electric field in the plasma and reaction chambers and a plurality of axially spaced apart and concentric electromagnet coils for generating a magnetic field in the plasma and reaction chambers. The microwave electric field and the magnetic field have perpendicularly crossing components and the magnetic field has a strength which decreases in the axial direction from the plasma chamber towards the reaction chamber with constant strength magnetic flux density lines lying in planes which are substantially parallel to each other and perpendicular to the axial direction. The magnetic field produces a flat ECR condition wherein the ECR layer extends perpendicularly to the axial direction over at least 50% of the width of the plasma chamber. In a method of using this device, upper and lower electromagnets produce magnetic fields such that the magnetic field produced by the lower electromagnet is weake…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.