Sn—5Ag鍍層在去離子水中對銅遷移之影響

Effect of Sn-5Ag coating on the migration of copper conductors in de-ionized water

10.6376/JCCE.200309.0201

林景崎(J. C. Lin)；陳俊宇(C. Y. Chen)；陳威宇(W. Y. Chen)；巫芳青(F. C .Wu)

無鉛銲錫 ； 電解質遷移 ； 陽極極化 ； 熱處理 ； lead-free solder ； electrolytic migration ； anodic polarization ； heat treatment

防蝕工程

17卷3期（2003 / 09 / 01）

201 - 210

繁體中文

本文主要在探討銅導線鍍上Sn-5Ag鍍層後對銅遷移的影響。銅導線鍍上0.67～2μm厚的Sn-5Ag鍍層，在去離子水中5V偏壓的情況下，可抑制銅導線的電解質遷移，且隨著鍍層厚度的增加，抑制效果愈佳。若經過熱處理（250℃／5分鐘）之後，試片的抗遷移能力亦會大幅提升。 藉由在0.01M NaOH水溶液中進行動態陽極極化掃瞄，將有助於了解抑制遷移的機制。在Sn-5Ag鍍層的極化曲線中發現兩個電流峰，其分別對應於SnO及SnO2的生成反應，這兩種氧化物皆提供了保護，防止銅導線中銅元素及Sn-5Ag鍍層中銀元素的溶解。因此，在銅導線上鍍上Sn-5Ag鍍層可以有效的抑制遷移。此外，在同樣2μm的鍍層厚度下，Sn-5Ag鍍層比Sn-10Pb鍍層具有較佳的抗遷移能力。

The effect of Sn-5Ag coating on the electrolytic migration of Cu-conductors has been studied. The Sn-5Ag coating layer with a thickness of 0.67～2μm tends to inhibit the migration of the copper conductor in de-ionized water at a bias of 5V.The inhibition becomes more efficient with increasing the thickness of the coating. Heat treatment(250℃ for 5minutes)of the coated specimens pronouncedly increases their resistance to electrolytic migration. The investigation of potentiodynamic polarization in 0.01M NaOH is useful in delineation of the migration inhibition mechanism for the Sn-5Ag coated specimens. For Sn-5Ag coated specimen, two passive peaks corresponding to the formation of SnO and SnO2 are observed. Bothoxides on the coating provide a protective layer, which prevents copper dissolution from the substrate and silver dissolution from the Sn-5Ag coating. Thus tin oxides resulting from the Sn-5Ag coating effectively inhibit copper migration of the copper conductors. Furthermore, comparing the coatings with the thickness of 2μm,Sn-5Ag is superior to Sn-10Pb in the inhibition of copper electrolytic migration.