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Fatigue Test for Conductors in Interconnection Structures

IP.com Disclosure Number: IPCOM000101242D
Original Publication Date: 1990-Jul-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 1 page(s) / 51K

Publishing Venue

IBM

Related People

Chance, DA: AUTHOR [+4]

Abstract

A method whereby signal lines in an interconnection module or other structures may be tested at acceleration level and frequencies far beyond the usual mechanical acceleration methods is disclosed. Defects, such as intermittent electrical contacts or weak connections which can be displaced, are detected by breaking the line or causing an increase in resistance.

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Fatigue Test for Conductors in Interconnection Structures

       A method whereby signal lines in an interconnection
module or other structures may be tested at acceleration level and
frequencies far beyond the usual mechanical acceleration methods is
disclosed.  Defects, such as intermittent electrical contacts or weak
connections which can be displaced, are detected by breaking the line
or causing an increase in resistance.

      The lines are tested using alternating currents of the order of
10 to 1000 ma in perpendicular magnetic fields of the order of 1 t 10
teslas.  Under these testing conditions, the resulting force on the
lines is perpendicular to both the current and magnetic field.  The
maximum vibrationally applied strain depends on the geometry of the
defective line and may be applied for thousands of cycles in a short
time (< 1 sec.).  The test dislodges intermittent contacts and breaks
line geometries for which the endurance stress limits for fatigue are
exceeded.  By use of an alternating current and a DC magnetic field,
the force on the line is reversed periodically, and by using a
triang- ular waveform, the force is applied gradually.  High
frequency currents are most effective in moving the line from one
side of a cavity to the other repeatedly with the highest shear
strain concentration.

      The Lorentz force on a current carrying line in a magnetic
field is given by

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