Instability of the Wetting Tip in Lead-Free Solder Reactions

点击翻译按钮获取中文摘要

9320769 Tu This program provides a systematic research effort on tin-bismuth- antimony-based solders. Their wetting behavior on copper and silica/chromium/copper/gold surfaces is measured and compared to lead-tin solders. The science of instability at the wetting tip due to dynamic interfacial reaction between the liquid solder and the solid copper is emphasized in this study. For this purpose cross-sectional transmission electron microscopy of the reaction at the wetting tip using thin film samples is employed. Also solder wetting on single crystal surfaces of copper is examined. This wetting behavior is the most important processing parameter in the selection of lead-free solder for electronic packaging. Both low melting point (about 180C) and high melting point (about 300C) lead-free solders will be studied. %%% The lead-based solder used in microelectronic devices is an environment issue. For environmental conscious manufacturing lead replacement and reliable lead-free solders are urgent issues. ***