Impact of Higher Melting Lead-Free Solders on the Reliability of Printed Wiring Assemblies
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
ABSTRACT The move toward lead-free electronics has become a rapidly emerging issue for concern and evaluation. The movement has been triggered by the European Union's (EU) proposal for a Directive on Waste from Electrical and Electronic Equipment (WEEE) and by the Japanese focus on environmental marketing. The candidate solder alloys that have been identified as substitutes require high soldering temperatures since these alloys have typical melting temperatures between 198°C and 227°C. Concern has been raised that the higher processing temperatures required for wave and reflow soldering with these alloys will create increased drop out due to printed wiring board (PWB) warpage and component failures, since most components are not qualified in terms of reliability for these higher processing temperatures. In this paper, we present evidence for an additional reliability concern for lead-free soldered electronic product. Conductive anodic filament (CAF) formation is a failure mode associated with boards, which either operate or are stored in a humid environment. This paper compares the number of CAF formed on boards reflowed at 201°C vs. 241°C after aging under 100V bias at 85°C/85% RH for 28 days. The incidence of CAF under the higher reflow conditions was typically 1-2 orders of magnitude greater than at the lower reflow conditions. The data provide additional reliability concerns for lead-free soldering.
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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 | 0.002 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.002 | 0.000 |
| Research integrity | 0.001 | 0.003 |
| 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