Method and apparatus for controlling the rate of emission of electrons used for charge neutralization in ion implantation
US5126576A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 13, 1990 |
| Grant date | Jun 30, 1992 |
| Priority date | — |
| Expiry date | Dec 13, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2237/304
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
Method and apparatus for the control of the rate of emission of electrons added to an ion implantation beam to neutralize charging effects on semiconductor wafers being processed. A net charging current, or equivalent voltage, is sensed continuously, but is sampled only when a selected wafer, or multiple selected wafers, are positioned to receive the entire cross section of the ion beam. The sampled charging current is used to control the addition of charge-neutralizing electrons to the ion beam, thereby eliminating problems that ensue from the use of an averaged charging current that is sensed without regard to the relative beam position or the number of wafers being processed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.