Reliability

What is the common name for the phenomenon in which, at gold wire to aluminum pad bonds, intermetallic compounds and voids grow during long storage at high temperature, weakening the bond?

  1. APurple plague
  2. BWhisker
  3. CPopcorn effect
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Answer: A. Purple plague

At gold-aluminum bonds, intermetallic compounds grow at high temperature, and differences in atomic diffusion rates during this process create voids, weakening the bond and raising resistance. Because one of the compounds looks purple, it is called purple plague.

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