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Title: Charge neutralization apparatus for ion implantation system

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.

Inventors:
 [1];  [2];  [3];  [4]
  1. Hercules, CA
  2. Berkeley, CA
  3. Danville, CA
  4. Boxford, MA
Issue Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
OSTI Identifier:
868423
Patent Number(s):
5136171
Assignee:
Varian Associates, Inc. (Palo Alto, CA)
Patent Classifications (CPCs):
H - ELECTRICITY H01 - BASIC ELECTRIC ELEMENTS H01J - ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
DOE Contract Number:  
AC03-76SF00098
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
charge; neutralization; apparatus; implantation; methods; workpiece; semiconductor; wafer; beam; positive; applied; electron; source; generating; magnetic; assembly; field; guiding; path; preferably; section; coincident; generates; axial; component; transverse; elbow; region; sections; lanthanum; hexaboride; cathode; extraction; grid; positioned; close; proximity; provides; current; energy; neutralizing; buildup; magnetic assembly; electron source; apparatus provides; semiconductor wafer; close proximity; magnetic field; electron beam; beam path; energy electron; lanthanum hexaboride; source preferably; extraction grid; charge neutral; neutralization apparatus; hexaboride cathode; boride cathode; /250/

Citation Formats

Leung, Ka-Ngo, Kunkel, Wulf B, Williams, Malcom D, and McKenna, Charles M. Charge neutralization apparatus for ion implantation system. United States: N. p., 1992. Web.
Leung, Ka-Ngo, Kunkel, Wulf B, Williams, Malcom D, & McKenna, Charles M. Charge neutralization apparatus for ion implantation system. United States.
Leung, Ka-Ngo, Kunkel, Wulf B, Williams, Malcom D, and McKenna, Charles M. Wed . "Charge neutralization apparatus for ion implantation system". United States. https://www.osti.gov/servlets/purl/868423.
@article{osti_868423,
title = {Charge neutralization apparatus for ion implantation system},
author = {Leung, Ka-Ngo and Kunkel, Wulf B and Williams, Malcom D and McKenna, Charles M},
abstractNote = {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.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1992},
month = {1}
}

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