Reliability

Which failures are mainly evaluated by temperature cycling tests?

  1. ASoft errors caused by cosmic rays
  2. BCracks in solder joints and packages due to differences in materials' coefficients of thermal expansion
  3. CDRAM refresh failures
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Answer: B. Cracks in solder joints and packages due to differences in materials' coefficients of thermal expansion

Temperature cycling tests repeatedly apply high and low temperatures. Because the chip, substrate, mold resin and solder have different coefficients of thermal expansion, each temperature change creates strain, causing fatigue fracture of solder joints, package cracks, delamination and similar failures. The test evaluates resistance to these.

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More Reliability questions

  1. What is provided at an LSI's I/O pins as a countermeasure against ESD (electrostatic discharge)?
  2. Which degradation phenomenon causes the absolute value of a pMOS transistor's threshold voltage to gradually increase under sustained negative gate voltage and high temperature?
  3. Which correctly describes latch-up in CMOS circuits?
  4. Which phenomenon degrades transistor characteristics when carriers accelerated by the high electric field near the drain are injected into the gate dielectric?
  5. Which failures are mainly evaluated by temperature-humidity-bias tests (THB and HAST)?