Yield and quality control

What is the purpose of evaluating manufacturing variation separately by factor, such as lot-to-lot, wafer-to-wafer and within-wafer?

  1. ATo find which level of variation is largest and narrow down the responsible process or equipment
  2. BTo set product selling prices
  3. CTo make wafer colors uniform
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Answer: A. To find which level of variation is largest and narrow down the responsible process or equipment

If lot-to-lot variation is large, changes in materials or equipment condition are suspected; if within-wafer variation is large, equipment uniformity is suspected. The causes to suspect differ by level of variation. Separating variation by factor with analysis of variance and similar methods leads to effective countermeasures.

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More Yield and quality control questions

  1. Which correctly describes the idea behind the quality management activity called 'Six Sigma'?
  2. On the same wafer, why does making chip area smaller greatly increase the number of good chips per wafer?
  3. Which control chart is used to control the fraction defective?
  4. What is the purpose of inspecting for defects after each step and extracting only the defects newly added since the previous step?
  5. Which concept expresses, from particle size and wiring layout, the area in which a falling particle could cause a failure?