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Ion Beam Milling With Gettering

IP.com Disclosure Number: IPCOM000101659D
Original Publication Date: 1990-Aug-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 2 page(s) / 66K

Publishing Venue

IBM

Related People

Bauer, HJ: AUTHOR [+3]

Abstract

Residual moisture is reduced in an ion milling chamber to prevent dissociation of water and reaction with polyimide insulating films. The technique employed for this purpose is based on the principle of sputter gettering. The argon ion beam is first directed onto a material with a high water vapor affinity. Then, the beam is directed onto the workpieces for ion milling. The insulating property of polyimide is maintained by the described technique during the ion milling of the contact areas.

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Ion Beam Milling With Gettering

       Residual moisture is reduced in an ion milling chamber to
prevent dissociation of water and reaction with polyimide insulating
films.  The technique employed for this purpose is based on the
principle of sputter gettering.  The argon ion beam is first directed
onto a material with a high water vapor affinity.  Then, the beam is
directed onto the workpieces for ion milling.  The insulating
property of polyimide is maintained by the described technique during
the ion milling of the contact areas.

      Little or no gettering of residual water vapor is provided by
ion beam milling, since the beam is locally confined and no gettering
material is sputtered.  This is a disadvantage when materials, such
as aluminum, are ion milled which reoxidize easily even at low
moisture levels. Another disadvantage is the dissociation of water
molecules by the ion beam and the reaction with organic insulating
thin films.  Polyimide, for example, becomes partially conductive
during ion beam milling when the partial pressure of water vapor is
high.  This article describes an apparatus and a method, based on the
principle of gettering, for avoiding reoxidation of metal surfaces
and the occurrence of electrical leakage of polyimide.

      Fig. 1 is a schematic of the ion beam apparatus with a shutter
A made of a material, such as aluminum or titanium, having a high
water vapor and oxygen affinity.  The shutter can be rotated in the
path...