Underfill delamination to chip sidewall in advanced flip chip packages
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
A number of failure mechanisms related to the underfill material in flip chip plastic ball grid array packages are well documented in the literature (underfill-to-chip passivation delamination, underfill-to-substrate soldermask delamination, chip cracking, interconnect fatigue, etc.). This paper discusses the delamination of the underfill from the chip sidewalls, another failure mechanism which has become more prevalent with component material changes, increases in die dimensions, finer C4 pitches and substrates with larger coefficient of thermal expansion. A detailed study is presented for the initiation of underfill-to-sidewall delamination, based on experimental data as well as finite element modeling. It is shown generally that both stress at the chip-underfill interface near the chip corner, and poor adhesion of the underfill to the chip sidewalls contribute to the initiation of underfill delaminations. Various parameters influencing stress (package design, underfill material thermo-mechanical properties) and adhesion (underfill base chemistry and additives, filler treatment, chip sidewall cleanliness) are discussed.
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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 it