Materials Testing of PWB Substrates to Determine Survivability Through Lead Free Assembly
Bibliographic record
Abstract
ABSTRACT As part of High Density Packaging Users Group (HDPUG) Pb-Free Board Materials Reliability Project 3, material testing was performed on both IST test coupons and WIC- 20 test coupons to determine there survivability through Pbfree reflow. The two techniques use similar principles of measuring capacitance change to determine levels of degradation within the B and C stage dielectric materials. The study compared 24 different Pb-free printed wiring board materials in 20 layer constructions, built in a single printed wiring board (PWB) manufacturing facility. Twelve materials are investigated with 2 different glass styles and resin contents, for a total of 24 different builds. The materials in the test included high Tg, filled FR4 materials, high Tg halogen free FR4 materials, and high speed materials. Data is presented showing the impact of each assembly SMT reflow cycle, relative to the location and magnitude of material degradation (delamination). An important aspect of this study compared the performance differences for a via to via spacing of 1mm/0.040” and 0.8mm/0.032”. The results confirmed a major influence from what is considered a relative small design change. The electrical results were compared to traditional microsection analysis to demonstrate the levels of correlation achieved.
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 | 0.000 | 0.002 |
| 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 | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".