The Faraday Cup

The Faraday Cup is arranged in the process chamber and beam line, corresponding to an ion beam shooting position. For each positive ion that enters the faraday, an electron is drawn from ground through the current meter to neutralize the positive charge of the ion. The magnetic field stops outside secondary electrons from entering and secondary electrons produced inside from exiting.

The Faraday Assembly The Faraday Cup

 
 
 Introduction
The Ion Implanter
The Vacuum system 
The Ion Source 
The Ion Beam
 Glossary
The Faraday 
Matching Network
The Magnet 
Boron Trifluoride
Charge Neutralization
 References
 
 

The Dose Control Systems for an ion implantation system of the type in which the wafers to be implanted are mounted around the periphery of a disk which rotates and also moves in a radial direction relative to an ion beam to expose successive sections of each wafer to the radiation. The control system senses beam current which passes through one or more apertures in the disk and is collected by a Faraday cup. This current is integrated to obtain a measure of charge which is compared with a calculated value based upon the desired ion dosage and other parameters. The resultant controls the number of incremental steps the rotating disk moves radially to expose the adjacent sections of each wafer. This process is continued usually with two or more traverses until the entire surface of each wafer has been implanted with the proper ion dosage. United States Patent # 4,517,465
 
 

Electrons spiral

 
 
 Top of PageTop of Page Top of Page
 
 
 

A faraday cup detector


 

 Introduction
The Ion Implanter
The Vacuum system 
The Ion Source 
The Ion Beam
 Glossary
The Faraday 
Matching Network
The Magnet 
Boron Trifluoride
Charge Neutralization
 References
  

 Top of PageTop of Page Top of Page

This page is sponsored by Case Technology Inc. since 5/1/98.

Updated 6/6/99.