Nanoindentation measurements on Cu-Sn and Ag-Sn intermetallics formed in Pb-free solder joints
Nanoindentation measurements on Cu-Sn and Ag-Sn intermetallics formed in Pb-free solder joints
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DOI：
10.1557/jmr.2003.0314
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发表时间：
2003-09-01
影响因子：
2.7
通讯作者：
Notis, MR
中科院分区：
文献类型：
--
作者：
Chromik, RR;Vinci, RP;Notis, MR
纳米压痕测试已被用于测量Ag 3Sn，Cu 6Sn 5和Cu 3Sn金属间化合物，以及Sn-Ag-Cu焊料和纯Sn和Cu的硬度和弹性模量。金属间化合物是通过固态退火从基板（铜或银）和焊料材料（锡或Sn-Ag-Cu焊料）制备的扩散偶。提供尽可能接近真实的焊点的几何形状和长度尺度。金属间化合物的纳米压痕结果，代表20-220 nm的穿透深度和0.7至9.5 mN的载荷，揭示了弹性/塑性变形而没有断裂的证据。Cu、Sn（6.5 +/- 0.3 GPa）和Cu 3Sn（6.2 +/- 0.4 GPa）的测量硬度值表明脆性行为的可能性，而Ag 3Sn（2.9 +/- 0.2 GPa）看起来更软和更有延展性。使用块状Cu 6Sn 5样品，维氏硬度测试揭示了该化合物的压痕尺寸效应，在9.8 N的载荷下测量的硬度为4.3 GPa。一个能量平衡模型被用来解释硬度与负载或深度的依赖关系，其中观察到的增加量的断裂与施加的负载被确定为主要机制。这一结果解释了纳米压痕和维氏结果之间的差异以前报道。
Nanoindentation testing has been used to measure the hardness and elastic modulus of Ag3Sn, Cu6Sn5, and Cu3Sn intermetallics, as well as Sn-Ag-Cu solder and pure Sn and Cu. The intermetallics were fabricated by solid-state annealing of diffusion couples prepared from a substrate (Cu or Ag) and a solder material (Sn or Sn-Ag-Cu solder). providing geometries and length scales as close as possible to a real solder joint. Nanoindentation results for the intermetallics, representing penetration depths of 20-220 nm and loads from 0.7 to 9.5 mN, reveal elastic/plastic deformation without evidence of fracture. Measured hardness values of Cu,Sn, (6.5 +/- 0.3 GPa) and Cu3Sn (6.2 +/- 0.4 GPa) indicate a potential for brittle behavior, while Ag3Sn (2.9 +/- 0.2 GPa) appears much softer and ductile. Using a bulk Cu6Sn5 sample, Vickers hardness testing revealed an indentation size effect for this compound, with a hardness of 4.3 GPa measured at a load of 9.8 N. An energy balance model is used to explain the dependence of hardness with load or depth, where the observation of an increasing amount of fracture with applied load is identified as the primary mechanism. This result explains discrepancies between nanoindentation and Vickers results previously reported.