Reliability

Which failures are mainly evaluated by temperature-humidity-bias tests (THB and HAST)?

  1. ASoft errors caused by cosmic rays
  2. BClock delay
  3. CElectrode corrosion and increased leakage current due to moisture ingress
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Answer: C. Electrode corrosion and increased leakage current due to moisture ingress

When voltage is applied in a hot, humid environment, moisture that has entered the package causes corrosion of aluminum pads and ion migration, leading to increased leakage current and open circuits. HAST applies high pressure to accelerate moisture ingress, evaluating moisture resistance in a short time.

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More Reliability questions

  1. Which distribution, often used in reliability data analysis, can represent early-failure, random-failure and wear-out types depending on its shape parameter?
  2. Which phenomenon creates voids as metal atoms move due to internal stress in wiring, even without current flowing?
  3. What is the phenomenon called in which needle-like metal crystals grow from the surface of tin plating and short to an adjacent terminal?
  4. Which typical reliability test evaluates lifetime and failure rate by operating products at high temperature for a long time?
  5. For a failure mechanism with an activation energy of 0.7 eV, approximately what is the Arrhenius acceleration factor of 125 °C relative to 55 °C? (Boltzmann constant 8.6×10⁻⁵ eV/K)