Instability of the Wetting Tip in Lead-Free Solder Reactions

9320769 Tu该项目对锡-铋-锑基焊料进行了系统的研究。测量了它们在铜和二氧化硅/铬/铜/金表面的润湿行为，并与铅锡焊料进行了比较。本文着重研究了液态焊料与固体铜之间的动态界面反应对润湿尖端不稳定性的影响。为此，利用薄膜样品对润湿尖端的反应进行了横截面透射电子显微镜观察。此外，还研究了铜单晶表面的润湿问题。在选择电子封装用无铅焊料时，这种润湿行为是最重要的工艺参数。低熔点(约180℃)和高熔点(约300℃)的无铅焊料都将被研究。微电子设备中使用的铅基焊料是一个环境问题。对于具有环保意识的制造业来说，铅替代和可靠的无铅焊料是迫切需要解决的问题。***

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. ***