Testing and inspection

What is the basic method for judging whether a chip is good in logic circuit testing?

  1. AJust looking at the chip under a microscope
  2. BMeasuring only the chip temperature
  3. CApplying test patterns to the inputs and comparing the outputs with the expected values from a correct circuit
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Answer: C. Applying test patterns to the inputs and comparing the outputs with the expected values from a correct circuit

In logic testing, the tester applies test patterns (sequences of input signals) to the chip and compares the outputs with the expected values a correct circuit would produce. Any single mismatch marks the chip as defective.

  • A. Visual inspection cannot reveal internal electrical defects.
  • B. Temperature alone cannot judge functional correctness.
  • C. Correct. Outputs are compared with expected values.
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More Testing and inspection questions

  1. In testing, what is the set of sequences of 0 and 1 signals applied to a chip's inputs, together with the expected responses, called?
  2. What are the dedicated patterns called, placed between chips on the wafer (in scribe lines) and elsewhere, used to measure characteristics of transistors, resistors and the like to evaluate the process?
  3. What is the inspection called that measures TEG parameters such as threshold voltage and sheet resistance on wafers that have completed front-end processing, to confirm the process met specifications?
  4. In test fixtures connecting the tester and IC, which component uses thin spring-loaded pins to make reliable contact with terminals?
  5. What is the printed circuit board called that attaches to the tester's test head, carries the IC socket and peripheral components and routes signals to the IC for each product?