Reliability Testing of PWB Plated Through Holes Using Interconnect Stress Testing Thermal Cycling before and after PB-Free Reflow Preconditioning
Bibliographic record
Abstract
ABSTRACT The High Density Packaging Users Group Consortium completed their 3 rd phase investigation into plated through hole reliability of printed wiring board test vehicles constructed with 24 different Pb-free capable printed wiring board materials. The study contained a total of 24 different constructions built by a single high-end Asia based PWB manufacturer. The materials were tested using Interconnect Stress Testing (IST) methodology. The test vehicle combined both via reliability and materials analysis testing capabilities, using two specially designed IST coupons with via to via spacing of both 0.040” (1mm) and 0.032” (0.8mm), All products were constructed with 20 layers, laminated to an average thickness of 0.115” (2.92mm), and drilled with 0.010” (0.254mm) vias, producing an aspect ratio of 11.5 to 1. Twelve materials were investigated with two different glass styles and resin contents. The materials were IST tested on the two coupon types, both as built and after 6X Pb-free (260°C) reflow. Materials in the test included four high Tg, filled FR4 materials, twelve high Tg halogen-free FR4 materials, and eight high speed materials. In addition, some materials were submitted into testing with the prior knowledge that material damage was present following the 6 cycles of assembly. Failure analysis was completed after IST thermal cycling testing and compared to the materials relative performance.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| 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) | 0.001 | 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 source (direct Gemma or distilled Codex), 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".