在金價持續上漲的影響下，電子封裝產業逐漸以銅基與銀基導線作為替代金導線的材料。銅線由於容易氧化與抗腐蝕性較差，並且因硬度較高容易造成接合基板的破壞，降低打線接合可靠度。本研究將Ag-4Pd合金導線(A4P導線)表面電鍍一層厚度約65 nm的金層，製成電鍍金層Ag-4Pd合金導線(ACA4P導線)以有效強化銀線的抗腐蝕性，並藉由氯化、硫化以及通電循環試驗，探討線材在實際應用中的可靠度問題，並分析其劣化機制。
氯化試驗方面，A4P導線在機械性質和電性方面的劣化程度明顯較ACA4P導線高，並且在長時間氯化後可觀察到A4P線材表面由於氯離子侵蝕晶界而造成的裂紋，最終導致線材沿著晶界發生脆性破裂。在銲點部份，第一銲點在較短的氯化時間便會從接合面處剝離，由橫截面分析可以觀察到第一銲點外緣的鋁基板遭侵蝕掏空導致銲點的脫落；第二銲點則由於下壓力較大，接合較第一銲點緊密，僅有在接合邊緣位置可見鋁墊受氯離子侵蝕產生細小裂縫。
硫化試驗方面，隨著硫化時間增加，A4P導線表面生成硫化銀的速率明顯高於ACA4P導線，且在電性方面由於A4P導線孔洞的生成，電流有效通道減少造成電阻大幅上升。第一與第二銲點部份，從拉伸破斷的結果可以發現破斷位置皆位於熱影響區內，ACA4P第一銲點因頸部金原子仍分佈於表面，呈現延性破斷；A4P第一銲點則已呈現脆性破斷。第二銲點部份，ACA4P線材端由於表層有鍍金層保護，拉伸破斷位置位於銲點部份；A4P則在線材端受硫化侵蝕的情形較為嚴重，導致長時間處於的富硫環境下會優先從線材端發生破壞。
通電循環試驗部份，ACA4P導線與A4P導線具有相近的電性與疲勞壽命，因此針對ACA4P導線進行探討。在不同測試電流情況下，ACA4P導線在50%熔斷電流 (Fusing Current, FC)流通時，金原子依然分佈於線材表層，並未擴散至導線內部；提升至70%FC時，可見表面金原子沿著晶界擴散進入線材內部；當電流達90%FC時，金原子已均勻分佈於導線內。不同循環次數下，導線晶粒受通電所誘發之焦耳熱伴隨著循環次數增加而逐漸上升，線徑也逐漸縮小。當晶粒成長至線徑大小時，由於該位置強度較低，在通電循環所引發的循環熱應力下產生熔斷而導致線材斷裂並失效。綜合而論，ACA4P導線能確實提高線材的抗氯化與抗硫化能力，並針對線材與銲點部分解析其氯化與硫化後的劣化機制；通電循環部份則解析不同循環次數下，微觀組織的演變與熔斷機制，並了解表面鍍金層在高密度電流下的擴散路徑，以提供封裝產業應用參考。

In this study, 65 nm gold layer was electroplated on the surface of Ag-4Pd alloy wire (A4P wire) as Au-coated Ag-4Pd alloy wire (ACA4P wire) to improve the corrosion resistance. Chlorination, sulfidation and power cycling tests were introduced to discuss problems might arise in practical applications as well as investigated their deterioration mechanism.
In chlorination test, the deterioration rate of A4P wire on mechanical properties were higher than those of ACA4P wire due to chloride ions corrode along grain boundaries on the surface of A4P wire and caused brittle fracture. In bonding reliability, chloride ions corroded Al pad and caused first bond peeling off on the bonding interface.
In sulfidation test, lower sulfide signal was detected on the surface of ACA4P wire than A4P wire. According to microstructure on cross-section, larger voids formed on A4P wire and caused deterioration on mechanical and electrical properties. In first bonding reliability, both ACA4P and A4P wire fractured on heat affected zone. Besides, ACA4P remained ductile fracture due to presence of gold on neck region but A4P showed brittle fracture. In second bonding reliability, ACA4P fractured on tail part, however, A4P fractured on wire part due to more severe corrosion on wire.
In power cycling test, as the testing current increased, gold atoms remained on wire surface under 50% of fusing current (FC); then, gold atoms diffused through grain boundaries under 70%FC; at last, gold atoms would uniformly distribute throughout the wire under 90%FC. As power cycles increased, grain growth due to Joule’s heat induced by high current density, and Poisson’s effect made diameter of wire decrease. Finally, fatigue would occur on the place where grain growth dramatically.

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