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Browse Prior Art Database

Simple RF Current Monitor

IP.com Disclosure Number: IPCOM000105522D
Original Publication Date: 1993-Aug-01
Included in the Prior Art Database: 2005-Mar-20
Document File: 2 page(s) / 55K

Publishing Venue

IBM

Related People

Hopwood, JA: AUTHOR

Abstract

A simple device for monitoring the rf current present in the inductive coupling element of a rf inductively coupled plasma source is described. The monitor is simple, inexpensive, insensitive to electrostatic interference, and has provedn useful for diagnosing and controlling the properties of the inductive plasma processing tool.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 70% of the total text.

Simple RF Current Monitor

      A simple device for monitoring the rf current present in the
inductive coupling element of a rf inductively coupled plasma source
is described.  The monitor is simple, inexpensive, insensitive to
electrostatic interference, and has provedn useful for diagnosing and
controlling the properties of the inductive plasma processing tool.

      The Figure shows a schematic diagram of the rf current monitor
which is implemented on a rf induction plasma source [*].  The
monitor consists of a cylindrically symmetric piece through which rf
current in the inductive coupling element is conducted.  A small loop
antenna (area A = 6 mm sup 2) constructed at the end of a 0.086 in.
diam 50 ohm coazial transmission line is placed at r = 8.5 mm from
the central axis of the conducting piece.  The loop is oriented such
that the normal vector to the surface defined within the loop is
pointing in the azimuthal direction with respect to the cylindrical
current-conducting piece.  The monitor is positioned at the
electrically grounded end of the inductive coupling element (coil) to
eliminate electrostatic coupling between the coil and the loop.
Since rf magnetic fields generated by the coil do not intersect the
loop, only rf magnetic fields generated by the current-conducting
piece intersect the loop.  These fields induce a voltage (V) in the
loop which is measured by an oscilloscope or spectrum analyzer.  The
current in the current-conducting piece is...