时效对Sn-Cu-Ni-<i>x</i>Pr/Cu焊点组织与性能的影响

时效对Sn-Cu-Ni-xPr/Cu焊点组织与性能的影响

摘要: 采用Sn-Cu-Ni-xPr无铅钎料对片式电阻进行钎焊试验,并且利用加速老化试验模拟片式电阻中焊点的服役环境,研究了时效过程中Sn-Cu-Ni-xPr焊点界面化合物层的厚度以及焊点抗剪强度的变化.结果表明,随着时效的进行,片式电阻Sn-Cu-Ni-xPr焊点的厚度不断增加,抗剪强度不断下降.与此同时,添加微量稀土元素Pr可有效提高Sn-Cu-Ni-xPr焊点的力学性能,当Pr元素含量为0.05%时,焊点力学性能优良,且在长时间的时效条件下仍然优于其它焊点.

Abstract: Chip resistors were joined with Sn-0.7Cu-0.05Ni-xPr solder. To guarantee the reliability of the Sn-0.7Cu-0.05Ni-xPr/Cu joints in service requirement,the growth rate of intermetallic compounds of Cu side was evaluated and the effects of the intermetallic compound layer on the electrical and mechanical properties have been investigated under various aging time. The shear strength of Sn-0.7Cu-0.05Ni-xPr/Cu joint gradually decreased during thermal aging. Meanwhile,under the same condition, the Sn-0.7Cu-0.05Ni-xPr/Cu joint achieved good mechanical properties when the addition of Pr was about 0.05%.