Method and apparatus for improved ion dose accuracy
US4680474A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 22, 1985 |
| Grant date | Jul 14, 1987 |
| Priority date | — |
| Expiry date | May 22, 2005 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S414/139
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The implant chamber pressure during ion implantation is controlled within a specified intermediate pressure range higher than the baseline pressure. Implanted dose errors resulting from neutralizing collisions of the beam with residual gas molecules are held constant and can be compensated. The pressure is maintained within the specified intermediate pressure range by a control system including a controllable vacuum valve associated with a vacuum pump, a chamber pressure sensor and a valve controller responsive to the pressure sensor. The valve controller opens and closes the valve to maintain the chamber pressure within the specified range after introduction of a wafer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.