Charge density detector for beam implantation
US4675530A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 11, 1985 |
| Grant date | Jun 23, 1987 |
| Priority date | — |
| Expiry date | Jul 11, 2005 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J37/3171
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
Apparatus for accurately measuring the charge distribution, and hence the voltage, on a non-conducting workpiece during ion bombardment. The invention is based on the principal that the charge on the surface of the workpiece induces equal and opposite charge on the surface of an isolated proof plane conductor placed in front of it. A workpiece is moved at a known speed in front of the proof plane, whose dimensions are small compared to the workpiece. The measurement of the time distribution of the induced charge on the proof plane is a measure of the spatial distribution of the charge on the bombarded workpiece. The proof plane surface is isolated from currents which might flow directly to its surface. The invention has utility for several purposes important to the semiconductor industry: monitoring the surface voltage distribution on a given workpiece during ion bombardment; certification to the device user that the workpiece was implanted under specified values or limits of surface voltage distribution; control of the surface charge distribution on the workpiece through the feedback of the charge-measurement signal to a device which compensates the charge on the workpiece.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.