Yield and quality control

If wafer process yield is 95% and wafer test yield is 90%, approximately what is the overall yield obtained by multiplying them?

  1. AAbout 85.5%
  2. BAbout 92.5%
  3. CAbout 185%
Show answer and explanation

Answer: A. About 85.5%

Yields of multiple steps are multiplied to get the overall yield: 0.95 × 0.90 = 0.855, or about 85.5%. The more steps there are, the lower the overall yield, so keeping each step's yield high is important.

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More Yield and quality control questions

  1. What is the system called that tracks each product's manufacturing history, needed to identify products that may have been affected when an abnormality is found?
  2. Which technique rejects chips that are within specification in test but show values far outside the distribution of the same lot?
  3. Which correctly describes the difference between the control limits of a control chart and a product's specification limits?
  4. What is the correct order of the PDCA cycle used in quality control and process improvement?
  5. Which of the seven QC tools is the approach of dividing data into groups, such as by machine, operator or material, and comparing them to find the causes of differences?