A Study of Copper Dissolution During Lead Free PTH Rework Using a Thermally Massive Test Vehicle
Pourquoi ce travail est dans la base
Une base qui oublie comment elle a trouvé un travail ne peut pas être vérifiée. Voici les voies qui ont admis celui-ci.
Notice bibliographique
Résumé
ABSTRACT The process of reworking a lead-free (Pb-free) pin-through-hole (PTH) connector using conventional solder fountain equipment presents a number of new challenges and issues which require resolution. Most importantly, it has been determined that the operating process window for a solder fountain rework, using a Sn-Ag-Cu (SAC) based alloy is substantially smaller when compared to the traditional 63Sn-37Pb (Sn-Pb) process. The maximum allowable cumulative contact time for which a PCB is exposed to molten solder during a SAC405 PTH rework has been reduced by up to 50% when compared to a typical Sn-Pb rework. The reduction in the allowable contact time is primarily due to increased copper (Cu) dissolution rates observed with SAC based Pb-free alloys at elevated process temperatures. The objective of this study was to determine both the Cu dissolution rates as well as to establish an optimized PTH rework process window and operating parameters using a Sn-Ag-Cu alloy to rework a complex PCB, as found in server or storage applications. Further efforts (such as studying alternate Pb-free alloys) were pursued to attempt to increase the allowable process window (or maximum allowable contact time) during PTH rework. This paper includes details of the experiments performed to study the phenomenon of Cu dissolution. Testing was performed using an OEM’s actual product as the test vehicle, which is thermally massive in nature. In Phase 1, a design of experiment (DOE) was performed to identify the significant factors influencing the rate of Cu dissolution occurring during the Pb-free PTH rework process using a Sn-3.8Ag-0.7Cu (SAC405) alloy. The factors included in the DOE were preheat temperature, pot temperature and contact time. In addition to determining the significant factors, average Cu dissolution rates as well as recommended inspection/analysis techniques and visual indicators of Cu dissolution were determined. Furthermore, in Phase 2, a DOE was performed to study and compare the dissolution rates of various Pb-free alloys including, Sn-3.8Ag-0.7Cu (SAC405), Sn-3.0Ag-0.5Cu (SAC305) and Sn-0.7Cu-0.05Ni in order to potentially expand the process window. Each Pb-free alloy was compared to a 63Sn-37Pb (Sn-Pb) control alloy. Lastly, the effects of solder flow rate on Cu dissolution will also be discussed in this paper.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,001 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découle