Faraday dose and uniformity monitor for plasma based ion implantation
US7132672B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 2, 2004 |
| Grant date | Nov 7, 2006 |
| Priority date | — |
| Expiry date | May 5, 2024 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2237/24405
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A Faraday dose and uniformity monitor can include a magnetically suppressed annular Faraday cup surrounding a target wafer. A narrow aperture can reduce discharges within Faraday cup opening. The annular Faraday cup can have a continuous cross section to eliminate discharges due to breaks. A plurality of annular Faraday cups at different radii can independently measure current density to monitor changes in plasma uniformity. The magnetic suppression field can be configured to have a very rapid decrease in field strength with distance to minimize plasma and implant perturbations and can include both radial and azimuthal components, or primarily azimuthal components. The azimuthal field component can be generated by multiple vertically oriented magnets of alternating polarity, or by the use of a magnetic field coil. In addition, dose electronics can provide integration of pulsed current at high voltage, and can convert the integrated charge to a series of light pulses coupled optically to a dose controller.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.