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研究了215℃时效过程中Sn3.8Ag0.7Cu无铅钎料焊点内部及与Cu基板界面处显微组织的演化规律。结果表明:试样在时效过程中的放置方式对显微组织的变化会产生重要影响。当钎料焊点处于Cu基板的上方时,215℃时效后显微组织的变化与以往170℃时效后显微组织的变化相似,即界面处金属间化合物层的厚度会随着时效时间的延长而逐渐增加。然而,当钎料焊点处于Cu基板的下方时,215℃时效后钎料焊点内部及界面处的显微组织发生了显著的变化,伴随着Cu基板的溶解在钎料焊点表面形成了大量的体积较大的金属间化合物Cu6Sn5。
The evolution of the microstructure at the interface between Sn3.8Ag0.7Cu lead-free solder and the interface with Cu substrate during 215 ℃ aging was studied. The results show that the way of placing the sample in the aging process will have a significant effect on the microstructure. When the brazing filler metal solder is above the Cu substrate, the microstructure change after aging at 215 ℃ is similar to the change of the microstructure after 170 ℃ aging, that is, the thickness of intermetallic compound layer at the interface increases with the aging time And gradually increased. However, when the brazing material solder joint is located under the Cu substrate, the microstructure at and after the solder joint aging at 215 ℃ has a significant change. Along with the dissolution of the Cu substrate, the solder joint surface is formed A large number of larger intermetallic compounds Cu6Sn5.