銅與銅／鎳／金導體上銲錫遷移性之比較

Comparison of Electrolytic Migration for Solders Coated on Cu and Cu / Ni / Au Conductors

分別在銅與銅／鎳／金兩種導體上電鍍上相同厚度之錫銀、錫鉛合金，施以熱處理（模擬迴銲過程），接著放入去離子水中進行5V偏壓之電解質遷移試驗，藉以比較兩種銲錫在銅與銅／鎳／金基材上之抗遷移行為。結果顯示，抗電解質遷移性最佳的是在銅／鎳／金導體上鍍有錫銀銲料，其次是在銅導體上鍍錫銀銲料，第三為在銅導體上鍍錫鉛銲料，最差的為在銅／鎳／金導體上鍍錫鉛銲料。以XPS對兩電極表面生成物表面分析可促進對上述各系統抗遷移性差異之瞭解，當電解質遷移反應進行時，陽極表面因溶解氧化生成金屬氧化物或氫氧化物覆蓋其表面，這些陽極覆蓋物之成分、性質、反應活度乃主宰此系統遷移反應激烈與否之主要因素。

Specimens were prepared by electroplating Sn-5Ag and Sn-37Pb (5 min thickness) on a couple of electrodes made of Cu (Cu) and Ni/Au deposited Cu (Cu / Ni / Au) conductors. They were heat-treated at 250℃ for 300 s, cooled in the atmosphere, and immersed in the de-ionized water at a dc voltage bias of 5V to examine the electrolytic migration. The behavior of electrolytic migration for the alloys coated on different conductors was compared. The resistance to electrolytic migration for the systems decreases in the order Cu/Ni/Au coated with Sn-5Ag ( Sn-5Ag(a) ) > Cu coated with Sn-5Ag (Sn-5Ag(c) ) > Cu / Ni / Au coated with Sn-37Pb ( Sn-37Pb (a) ) > Cu coated with Sn-37Pb ( Sn-37Pb(c) ). XPS (X-ray photoelectron spectroscopy) analysis on the anode after migration test was helpful in elucidation of electrolytic migration for various systems. Metal hydroxide and oxide were produced and coated on the anode surface of the electrode couple in each system. The solubility product was quite different for the hydroxide and oxide. The hydroxide and oxide with lower solubility product exhibit resistance to electrolytic migration.