From the Code 562 Archives

Long Bond Wires Resonating in Vibration Environment

In 1997 intermittent signals were encountered by the Hubble Space Telescope project in multichip modules containing memory stacks used in the solid state recorder.  Destructive Physical Analyses (DPA) showed that the bond wires were very long compared to those we normally see in microelectronic packaging.  Analysis and testing performed by Dr. Henning Leidecker and Scott Hull showed that, given weak bonds (caused by bonding problems at a subcontractor), the spectrum of the qualification level vibration conditions included the first resonant mode of the long wire bond.  When this frequency was encountered during the test, the wire would oscillate, further weakening the bond and leading to intermittent signals or failure.  A paper was written by Leidecker and Hull on their work and was presented at the 1998 International Conference and Exhibition on Multichip Modules and High Density Packaging (MCM'98, IEEE Catelog number 98EX154).  Here is a copy of that Paper.