A Parametric Approach To Optimizing BGA Design for Reflow Reliability
Bibliographic record
Abstract
ABSTRACT Thermal warpage is a keen reliability concern for BGA (Ball Grid Array) and surface mounted PCBA (Printed Circuit Board Assembly). The authors previously proposed a hybrid method that correlates analytically modeled and directly measured warpage for a real package. While iteratively reaching the high correlation, the accuracy of the input material properties is simultaneously improved. An application of the model to a specific package is basically a model refining and verification process which ensures a high confidence level of the final modeling output such as the stresses/strains along the adhesive interfaces and the package warpage. Given that the output parameters are expressed as functions of temperature, geometric dimension and materials’ properties, the approach enables a quick, quantitative and full scale evaluation of the package’s performance. This paper presents an application example to illustrate how the method is executed in a package performance evaluation and prediction and how the evaluation facilitates the package design and manufacturing for reliability.
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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 | 0.003 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| 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".