DocumentCode :
2958700
Title :
Gold removal from component terminations via solder dipping
Author :
Hong, Jauwhei ; Chason, Marc
Author_Institution :
Motorola Inc., Fort Lauderdale, FL, USA
fYear :
1989
fDate :
22-24 May 1989
Firstpage :
351
Lastpage :
354
Abstract :
Conversion of gold plating into tin/lead coating on interconnecting pads via solder dipping, i.e., the pretinning process, is investigated with X-ray diffraction and SEM/EDX methods. Under certain conditions, the resultant pads form a gold-tin intermetallic compound layer, AuSn4, at the interface between the substrate and the solder coating. The formation of this intermetallic causes two problems. First, when this compound is exposed at the surface by abrading the solder, it renders the pad surface rough and deviant from the eutective composition. This degrades solderability and ultimately leads to soldering failure. Concern is warranted, since certain production requirements call for a leveling procedure for the solder pads, making intermetallic protrusion possible. The second problem is that long-term solder joint reliability for interconnections made from these pads is compromised, as the AuSn4 layer is always trapped along the joint/substrate interface
Keywords :
X-ray chemical analysis; X-ray diffraction examination of materials; electronic equipment manufacture; reliability; scanning electron microscope examination of materials; soldering; SEM/EDX methods; X-ray diffraction; component terminations; interconnecting pads; intermetallic compound; leveling procedure; long-term solder joint reliability; pad surface; pretinning process; solder dipping; solderability; Coatings; Gold; Intermetallic; Lead; Rendering (computer graphics); Rough surfaces; Soldering; Surface roughness; Tin; X-ray diffraction;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Electronic Components Conference, 1989. Proceedings., 39th
Conference_Location :
Houston, TX
Type :
conf
DOI :
10.1109/ECC.1989.77770
Filename :
77770
Link To Document :
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