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Hydrogen Diffusion Barrier in Military Microcircuits

IP.com Disclosure Number: IPCOM000103220D
Original Publication Date: 1990-Aug-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 1 page(s) / 34K

Publishing Venue

IBM

Related People

Schuessler, PW: AUTHOR

Abstract

Iron based alloys are commonly used for making hermetically sealed microelectronic devices that must operate in the microwave region, i.e., at a frequency of over 2 gigahertz. However, such alloys are normally annealed in hydrogen to release built-in stresses from processes. As a function of time, the absorbed hydrogen diffuses into the cavity of the device and reduces oxides and/or forms hydrides which eventually destroy the performance of the device.

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Hydrogen Diffusion Barrier in Military Microcircuits

      Iron based alloys are commonly used for making hermetically
sealed microelectronic devices that must operate in the microwave
region, i.e., at a frequency of over 2 gigahertz. However, such
alloys are normally annealed in hydrogen to release built-in stresses
from processes.  As a function of time, the absorbed hydrogen
diffuses into the cavity of the device and reduces oxides and/or
forms hydrides which eventually destroy the performance of the
device.

      Military microcircuits have the added requirements of having
nickel or nickel and gold plating on the alloy to assure
processibility.  Neither of these platings will prevent the diffusion
of hydrogen.

      It has been shown that generating an oxide barrier on the
nickel plating will prevent subsequent diffusion of the hydrogen into
the device cavity and thereby assure long term reliability.  Oxide
formation of the nickel has been done via exposure of the plated base
alloy to air at temperatures of 320oC +10oC for 24 hours.  The
resultant barrier lends itself to subsequent hermetic sealing
operations, and thereby the requirements of the military
specifications are preserved.

      Disclosed anonymously.