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Magnetically Coupled Vacuum Shutter Window

IP.com Disclosure Number: IPCOM000121224D
Original Publication Date: 1991-Aug-01
Included in the Prior Art Database: 2005-Apr-03
Document File: 3 page(s) / 95K

Publishing Venue

IBM

Related People

Brady, MJ: AUTHOR [+3]

Abstract

Observation of deposition sources, such as electron beam, sputter guns, ion guns, etc., in high vacuum systems is crucial, in order to avoid damage to the sources and the system. The prior art teaches techniques that allow this monitoring by way of glass plates, slides, mirrors and mechanical shutters. In high deposition rate systems, the plates and mirrors quickly become opaque, due to material coating, thus eliminating observation. For low or normal deposition rate systems, the plates or mirrors have to be continuously replaced. Utilization of mechanical shutters requires transfer of mechanical motion into the vacuum system and is usually facilitated by subassemblies known as feedthroughs, which are usually flange mounted to the vacuum chamber.

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Magnetically Coupled Vacuum Shutter Window

      Observation of deposition sources, such as electron beam,
sputter guns, ion guns, etc., in high vacuum systems is crucial, in
order to avoid damage to the sources and the system.  The prior art
teaches techniques that allow this monitoring by way of glass plates,
slides, mirrors and mechanical shutters.  In high deposition rate
systems, the plates and mirrors quickly become opaque, due to
material coating, thus eliminating observation.  For low or normal
deposition rate systems, the plates or mirrors have to be
continuously replaced.  Utilization of mechanical shutters requires
transfer of mechanical motion into the vacuum system and is usually
facilitated by subassemblies known as feedthroughs, which are usually
flange mounted to the vacuum chamber.  These feedthroughs generally
require shafts, O-rings and elastomer seals, are subject to
outgassing, and often cause pressure bursts when activated.  An
additional problem exists in Ultra High Vacuum (UHV) systems which
utilize high temperature bake-out procedures and would cause
deterioration of the elastomer seals.  The herein described mechanism
avoids the above disadvantages and uses a method of inducing motion
of a shutter in a vacuum by magnetic coupl ing through the glass wall
of a vacuum viewport.  The technique uses a magnet external to the
system which allows manipulation of a magnetic metal shutter on the
interior of the vacuum chamber.  One implementation of the mechanism
is shown in Fig. 1.  A vacuum viewing port 1, typically a thick pyrex
disc, is shown.   The viewing port to vacuum chamber seal is not
shown.  A sacrificial window 3, typically a thin glass disc, is shown
mounted flush against the vacuum side of the viewing port.  Supported
by the vacuum chamber, the support-pivot bracket 5 provides a fixed
center of rotation for the shutter 4 with viewing opening 6 and
magnet receiver 2.  A bar magnet is shown in the shutter magnet
receiver 2 and a...