Bibliographic record
Abstract
ABSTRACT The reliability of solder joints between a ball grid array (BGA) package and a printed circuit board (PCB) is commonly improved by bonding the BGA to the PCB using an underfill epoxy. Experimental fracture measurements were made using specimens prepared from a commercial multi-layer PCB assembled with thin profile fine-pitch ball grid array (TFBGA) packages. Two types of thermally cured capillary underfills were tested: underfill A was an unfilled epoxy, while underfill B contained 38 wt% silica particles. Fracture experiments were performed in a bending configuration under quasistatic loading conditions. In all specimens, the crack initiated within the underfill fillet, indicating the importance of cohesive fracture properties in controlling damage initiation. Finite element modeling showed that this crack initiation occurred under mode I conditions, with subsequent crack growth being mixed-mode in the PCB or at the interface between the PCB and the solder mask. The load corresponding to crack initiation in the underfill fillet for silica-filled underfill was significantly higher than unfilled underfill, indicating the toughening effect of the silica particles on the epoxy.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 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".