Factors affecting activation energy for pd-coated cu ball bond resistance degradation on Al bond pads in high temperature storage
Bibliographic record
Abstract
Copper wire bonds have become a mainstay in many electronics areas, including automotive, where more data is needed regarding the reliability of Cu wire bonds on Al pads in high temperature conditions. Arrhenius models are frequently used to estimate product lifetimes, with the activation energy being the main parameter. Activation energies from 0.46 eV to 1.34 eV have been reported in the literature for similar materials and aging conditions. This apparent inconsistency between the results of different studies indicates one or more failure mechanisms that are not active in all cases, with causes that have not been clearly identified. To obtain uniformly high reliability, it is important to identify and eliminate the causes of rapid degradation observed by some authors. This work investigates the effects of Al pad metallization thickness and the choice of failure criterion on the bond resistance and activation energy for Pd-coated Cu (PCC) ball bonds with epoxy encapsulation. By testing samples at 175 °C, 200 °C, and 225 °C, with pad thicknesses of 800 nm and 3000 nm, we found that at least two mechanisms contributed to resistance changes. The first mechanism has an activation energy of about 0.7 eV, calculated using the times required for a 1 % increase in resistance. The second, calculated from the times until a 10 % resistance increase, has an activation energy of about 0.4 eV. Pad thickness did not have a significant effect on activation energy, but thicker pads did lead to slower increases in resistance at the beginning of aging.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".