Sn-9Zn-(0~4)Ag迴銲於化金基板後在水中之電化學遷移行為

Electrochemical Migration of Sn-9Zn-(0 ~ 4)Ag Reflowed on Cu/Ni/Au Substrate in Pure Water

Sn-9Zn-(0 ~ 4)Ag迴銲於Cu/Ni/Au基板上，完全浸泡於去純水中做為陰陽兩極，兩極間施以3 V ~ 5 V直流偏壓，研究其電化學遷移現象。結果顯示：此銲料系統中銀含量由0增高至4wt%時，其抗電化學遷移能力下降。兩銲球間之電化學遷移後之析出物經X-光光電子光譜儀（X-ray photoelectron spectrometer, XPS）分析結果顯示：其主要成分為ZnO、Zn、SnO、Sn，其中所含的鋅/錫比值會隨遷移時間增加而比而減少；由能量散佈光譜（Energy Dispersive Spectrometer, EDS）分析顯示：在遷移1800秒、3600秒後兩極間樹狀析出物的錫含量亦隨時間增加而增加。電化學動態極化法（potentiodynamic polarization）在Sn、Zn、Ag等單一金屬、AgZn3介金屬及Sn-9Zn-(0 ~ 4)Ag三元銲料系統的探討有助於電化學遷移機理之解析。

The resistance of electrochemical migration of Sn-9Zn-(0 ~ 4)Ag solders, having been reflowed on Cu/Ni/Au, in water at 3 ~ 5 V DC was found to decrease with increasing their silver content from 0 to 4 wt%. Analysis of XPS and EDX on the dendritc precipitate formed between two electrodes displays that the main components of the precipitate are ZnO, Zn, SnO, Sn .The ratio of Zn/Sn in the precipitate increases with the elapse of migration time. EDS analysis shows that the concentration of tin in the dendrite increases with increasing migration time from 1800s to 3600s. Exploration in anodic potentiodynamic polarization curves for Sn , Zn , Ag , AgZn3 and Sn-3Ag-XCu(X=0.0 ~ 0.9) benefits discussion of the electrochemical migration mechanism for the Sn-9Zn-(0 ~ 4)Ag soldering systems.