The data below relate to failures of terminations in a sample of 20 semiconductor devices. Each failure results from breaking of either the wire (W) or the bond (B), whichever is the weaker. The specification requirement is that fewer than 1% of terminations shall have strengths of less than 500 mg.
a. Estimate Weibull parameters for
(i) termination strength;
(ii) wire strength;
(iii) bond strength.
Comment on the results.
b. If using Weibull++ select rank regression on X (RRX) and run 'Distribution Wizard' for this data.
Choose the best fitting statistical distribution for those results and re-evaluate the strength termination requirement.
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Failure load (mg)
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or
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Failure load (mg)
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or
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550
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1250
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750
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1350
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950
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1450
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950
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1450
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1150
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1450
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1150
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1550
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1150
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1550
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1150
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1550
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1150
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1850
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1250
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2050
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