覆晶銲錫接點鎳墊層/錫銀銲錫/SOP製程銅銲墊結構的電遷移破壞模式之研究

隨著電子產業的發展，高效能、小體積已經成為未來的潮流，在此發展趨勢影響之下，銲錫接點所承載的電流密度將大幅上升，電遷移的可靠度已經成為一個重要的問題。本實驗利用錫銀無鉛銲錫，搭配厚鎳UBM層及銲錫預墊層製程 (solder-on-pad)的銅銲墊，對其破壞模式加以研究。在1.3 A的施加電流下，當溫度高於120 ℃時，鎳層消耗反應為介金屬化合物造成銲錫回填以及陰極SOP銅墊層端的孔洞生成為破壞模式。當溫度下降至100 ℃時，破壞模式轉變為介金屬化合物與銲錫之間的孔洞生成，且電子流流向晶片端的基板銲墊此時也出現大範圍孔洞生成。此外，對於電流所引發的熱遷移效應加以研究，在本銲錫接點結構於150 ℃溫度下，通入1.3 A以上的電流值時，熱遷移對銅原子所造成的影響將超過電遷移，造成銅原子向冷端移動，當電流低於1.3 A時，電遷移將主導銅原子的遷移行為。

關鍵字

電遷移；破壞模式；銲錫預墊層

並列摘要

As the current density carried by solder joints becomes higher and higher, electromigration has became an critical reliability issue. In this thesis, the electromigration failure mode of SnAg solder joints with thick nickel UBM and solder-on-pad (SOP) copper pad is studied. Under the different stressing temperatures of 1.3 A, the failure mode was due to the Ni dissolution in the chip side at temperature higher than 120 ⁰C. It was also found that voids form in the substrate side. The Cu-Sn intermetallic compounds was found to move to low current density region at high stressing current. It was proposed that the thermomigration dominates the Cu atom diffusion at high stressing current. The Cu atoms migrate to the cold end under the applied current above 1.3 A. When the current is lower than 1.3 A, the electron wind force will dominates the migration of Cu atoms.

並列關鍵字

Electromigration ； Failure mode ； solder on pad

參考文獻

[18] T. L. Shao, S. W. Liang, T. C. Lin, Chih Chen, J. Appl. Phys. 98,

[2] V.B. Fiks, Soviet Physics – Solid State, Vol. 1, pp. 14-28, 1959.

[4] K.N. Tu, K. Zeng, Electronic Components and Technology Conference, 2002. Proceedings. 52nd.

[5] European Union Waste in Electrical and Electronic Equipment (WEEE) Directive, 3rd Draft, May 2000.

[6] Japanese Ministry of Health and Welfare Waste Regulation on Un-Reusable Pb, June 1998.

國際替代計量

覆晶銲錫接點鎳墊層/錫銀銲錫/SOP製程銅銲墊結構的電遷移破壞模式之研究

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