Charge neutralization apparatus for ion implantation system
US5136171A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 25, 1991 |
| Grant date | Aug 4, 1992 |
| Priority date | — |
| Expiry date | Jan 25, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J37/026
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
Methods and apparatus for neutralization of a workpiece such as a semiconductor wafer in a system wherein a beam of positive ions is applied to the workpiece. The apparatus includes an electron source for generating an electron beam and a magnetic assembly for generating a magnetic field for guiding the electron beam to the workpiece. The electron beam path preferably includes a first section between the electron source and the ion beam and a second section which is coincident with the ion beam. The magnetic assembly generates an axial component of magnetic field along the electron beam path. The magnetic assembly also generates a transverse component of the magnetic field in an elbow region between the first and second sections of the electron beam path. The electron source preferably includes a large area lanthanum hexaboride cathode and an extraction grid positioned in close proximity to the cathode. The apparatus provides a high current, low energy electron beam for neutralizing charge buildup on the workpiece.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.