Ion implant dose control
US6297510A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 19, 1999 |
| Grant date | Oct 2, 2001 |
| Priority date | — |
| Expiry date | Apr 19, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2237/31703
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The true beam current corrected for neutrals in the beam impinging on the wafer during processing, is calculated by taking repeated measurements of the beam current during periods when the beam is clear of the wafer during a process. During such periods of multiple beam current measurements, the residual gas pressure declines in accordance with a pump down constant which is also determined. A quadratic expression relating measured beam current and time can then be solved for a factor giving a value for the corrected beam current. A corrected beam current is used to control the dosimetry of the apparatus to ensure the correct dose is uniformly applied to the surface of a wafer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.