Dose control for use in an ion implanter
US5760409A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 17, 1997 |
| Grant date | Jun 2, 1998 |
| Priority date | — |
| Expiry date | Jan 17, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2237/31703
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
Electrical charge neutralization effects are known to be factors that affect the dose or concentrations of beam treatment by high current implanters. Raising beam energies to 1 MeV and beyond requires an understanding of the effects of both charge stripping and charge neutralization as well as a numerically efficient model compensating for these effects. Charge stripping generates ions of a higher charge state and may cause the measured electronic current from a Faraday cup to overestimate the true particle current. An analysis is based on the concept of an effective charge state for an ion beam and results in a more general interpretation that covers both the charge stripping effect as well as ion neutralization. Dose control using the techniques requires two adjustable parameters: an apparent cross section of interaction between the beam and particles in the beam path and the ratio of the final steady charge state to the initial charge state.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.