Methodology for Analyzing Strain States During In Situ Thermomechanical Cycling in Individual Lead-Free Solder Joints Using Synchrotron Radiation
Methodology for Analyzing Strain States During In Situ Thermomechanical Cycling in Individual Lead-Free Solder Joints Using Synchrotron Radiation
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DOI：
10.1007/s11664-009-0919-8
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发表时间：
2009-08
影响因子：
2.1
通讯作者：
T. Bieler;Tae-Kyu Lee;K. Liu
中科院分区：
文献类型：
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作者：
T. Bieler;Tae-Kyu Lee;K. Liu
为了研究无铅焊点在热循环环境中如何变形，必须了解弹性和塑性应力和应变行为。描述了在热循环过程中识别内部应变（应力）状态演变的方法。将包含单行焊点的封装的切片从0°C热循环至100°C，时间为约1小时，同时使用同步加速器辐射获取透射劳厄图案。这些结果表明，大多数关节是单晶，与一些多晶不超过几个锡晶粒取向。劳厄图案进行了分析，以估计在不同的温度在不同的晶体方向在热循环过程中的局部应变。虽然垂直于各个晶面的应变都以类似的方式变化，但应变的大小不同。随后对样品进行数百次额外的热循环，并再次测量以评估晶体取向的变化。这些结果表明，在热循环过程中，晶体取向发生适度的变化。
To examine how a lead-free solder joint deforms in a thermal cycling environment, both the elastic and plastic stress and strain behavior must be understood. Methods to identify evolution of the internal strain (stress) state during thermal cycling are described. A slice of a package containing a single row of solder joints was thermally cycled from 0°C to 100°C with a period of about 1 h with concurrent acquisition of transmission Laue patterns using synchrotron radiation. These results indicated that most joints are single crystals, with some being multicrystals with no more than a few Sn grain orientations. Laue patterns were analyzed to estimate local strains in different crystal directions at different temperatures during a thermal cycle. While the strains perpendicular to various crystal planes all vary in a similar way, the magnitude of strain varies. The specimens were subsequently given several hundred additional thermal cycles and measured again to assess changes in the crystal orientations. These results show that modest changes in crystal orientations occur during thermal cycling.