無鉛銲料錫銀鉍銦與銅電極之電遷移研究

Study of Electromigration on lead-free tinsilver-Bismuth-indium Solder with cu Electrodes

江昱彥(Yu-Yen Chiang) ； 孫國浩(Kuo-Hao Sun) ； 吳子嘉(Albert T. Wu)

《興大工程學刊》 21卷2期 (2010/07) Pp. 65-71

https://doi.org/10.6287/JENCHU.2010.2102.02

摘要

本實驗在Si晶片上製作一U型溝槽，於溝槽中製作出銅―錫―銅的導線結構並研究其電遷移的行爲。首先，兩端的銅電極利用電鍍的方式填滿，再將自行調配的84Sn-3Ag-3Bi-10In無鉛銲料，迴銲於電極中完成導線的製作。將製作完成的導線在不同的溫度及電流密度下進行電遷移的實驗，並與未添加銦的Sn-Ag-Bi無鉛銲料相比較。由於使用的銲料含錫量高，將與銅電極產生介金屬化合物Cu6(Sn, In)5，化合物有助於銲錫與印刷電路板的金屬墊層的接合，銲料中還出現ζ-phase的化合物，ζ-phase爲Ag4Sn與Ag3In的固熔相。本實驗將估計其自由能及銲料的微結構在電遷移中的變化。

關鍵字

電遷移 ； 無鉛銲料 ； 錫銀鉍銦

並列摘要

Pb-free SnAgBiIn solder strips were prepared in Si(001) U-grooves to investigate the behaviors under electromigration. Cu electrodes were electroplated in the grooves and the solders were consequently reflowed between the electrodes. The samples were tested under various temperatures and current densities. The addition of indium and bismuth decreases the melting point to 203℃. Average failure time was compared for 84Sn3Ag3Bi10In and 89Sn3Ag3Bi at the same homologous temperature. The results show longer life time of 84Sn3Ag3Bi10In than 89Sn3Ag3Bi, and the mechanism under the influence of current will be discussed in this paper.
The formation of the intermetallic compounds in the solder were either Cu 6(Sn, In) 5 or ζ-phase, while ζ-phase is the solid solution of Ag4Sn and Ag3In. The composition of compounds was analyzed by EPMA; the formation Gibbs free energy was calculated to discuss the electromigration effect on microstructure evolution. The results suggested that the existence of ζ-phase plays an important role to prolong the lifetime of SnAgBiIn solders under electromigration.

並列關鍵字

electromigration ； lead-free solder ； SnAgBiIn