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Method for Detecting Electrical Conductor Defects Using Constant Sine Current

IP.com Disclosure Number: IPCOM000101937D
Original Publication Date: 1990-Sep-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 1 page(s) / 34K

Publishing Venue

IBM

Related People

Meier, HE: AUTHOR [+2]

Abstract

Cross-section area defects in conductors are detected by subjecting the conductor to sinusoidal current and observing the third harmonic voltage with commercially available equipment.

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Method for Detecting Electrical Conductor Defects Using Constant Sine Current

       Cross-section area defects in conductors are detected by
subjecting the conductor to sinusoidal current and observing the
third harmonic voltage with commercially available equipment.

      Conductors subjected to sinusoidal current experience
sinusoidal heating.  The waveform of the voltage drop across the
conductor is sinusoidal, having a fundamental frequency equal to the
frequency of the input sinusoidal current and having odd harmonics of
fundamental frequency.

      A Fourier transform shows that the third harmonic is directly
proportional to the current cubed and the length of the conductor and
is inversely proportional to the width cubed and thickness squared of
the conductor.  An extensive distributed parameter simulation study
on MC (metalized ceramic) conductor defects shows that this
proportionality is valid for defect lengths as small as .0001 inches
and input current frequencies as high as 10KC.

      The buckling beam tester permits probes to make contact with
the C-4 (controlled collapse chip connection) pads on the substrate
so that sinusoidal current can be sent through each conductor on the
substrate along its full length.  The tester is programmed to
selectively go-no- go test each substrate conductor, first for shorts
and opens, and then for cross-section area defects.  The method
therefore readily lends itself to automated inspection of conducto...