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研究Cu/SnBi/Cu焊点在电流密度分别为8×103,1×104和1.2×104A/cm2的作用下通电80h后钎料基体内部金属间化合物(IMC)的形貌演变。结果表明:电流密度为8×103A/cm2时,在焊点的阳极界面出现了大量的形状不规则的IMC,而在阴极界面并未有明显的IMC形成;当电流密度为1×104A/cm2时,阴极界面的IMC层呈扇贝状,有些IMC已经在界面处脱落,而阳极界面的IMC呈层状,而且厚度要比阴极的薄;当电流密度为1.2×104A/cm2时,阳极界面的IMC厚度有所增加,但是阴极界面的IMC已经向钎料基体中进行了扩散迁移,使得界面变得凹凸不平。值得注意的是,随着电流密度的增加,在阳极形成的Bi层的厚度明显增加。
The morphological changes of the intermetallic compound (IMC) in Cu / SnBi / Cu solder joints were investigated after the current density was 8 × 103, 1 × 104 and 1.2 × 104 A / cm2 for 80h respectively. The results show that a large number of irregularly shaped IMCs appear at the anode interface of the solder joint at a current density of 8 × 10 3 A / cm 2, while no obvious IMC is formed at the cathode interface. When the current density is 1 × 10 4 A / cm 2 , The IMC layer of the cathode interface has a scalloped shape, some of the IMCs are already exfoliated at the interface, while the IMC of the anode interface has a lamellar shape and is thinner than the cathode; when the current density is 1.2 × 10 4 A / cm 2, The thickness of the IMC increased, but the IMC at the cathode interface had diffused and migrated into the solder matrix, making the interface rough. It is noteworthy that with the increase of the current density, the thickness of the Bi layer formed at the anode is significantly increased.