無鉛銲料錫銀銦與銅基板的界面反應

隨著時代的變遷，環境保護的觀念越來越重要，在封裝製程中常用的錫鉛銲料，由於鉛具有毒性，因此已經全面改用無鉛銲料。無鉛銲料的種類眾多，但能夠取代錫鉛銲料較少，取代錫鉛銲料必須有相似或更佳的機械性質、濕潤性、熔點、可靠度等等性質。許多銲料的機械性質較佳，但熔點過高將導致生產成本增加。為了降低熔點並維持機械性質，在本實驗中利用SnAg銲料添加In，以降低熔點。本實驗利用Sn-Ag銲料混合In，調配出94Sn-3Ag-3In及80Sn-3Ag-17In兩種成分的銲料，其熔點分別為214.7℃及193.3℃，與銅基板進行液相/固相界面反應及固相/固相界面反應。實驗中形成的介金屬化合物為Cu3(Sn,In)及Cu6(Sn,In)5。利用影像軟體計算IMC生成的厚度與時間的關係，求得時間對數n近似於1/3，表示反應為熟化機制所控制，以Arrhenius equation計算出兩種銲料與銅基板生成Cu6Sn5所需的視活化能，94Sn-3Ag-3In及80Sn-3Ag-17In分別為23及24.5 KJ/mol，與文獻中的Sn-Ag-Bi-In相較之下活化能少了一半，主要的原因為添加Bi將導致Cu於銲料的溶解度增加，進而減少析出形成IMC的機會。除了界面處以外，銲料內部也有Cu6Sn5及大量的細微顆粒的存在，經過EPMA分析，散布於銲錫中的IMC主要成分以Sn、Ag及In三種原子以不固定比例組成之ζ相，在94Sn-3Ag-3In中，In含量較低，因此研判為ζ相，而80Sn-3Ag-17In由於含In量極高，Ag：In的比例接近2：1，因此研判IMC為Ag2In+ζ相。在固相/固相反應中，94Sn-3Ag-3In的活化能為64.92，80Sn-3Ag-17In由於實驗溫度過於接近反應起始點，無法求得準確之活化能。94Sn-3Ag-3In中，ζ相經過時效處理後，轉為Ag3Sn+ζ，而80Sn-3Ag-17In則維持Ag2In+ζ的相。

關鍵字

界面反應；錫銀銦；無鉛銲料

並列摘要

This thesis investigated the interfacial reaction between Sn-Ag-In lead-free solder and Cu substrates. Two composition of solder, 94Sn-3Ag-3In and 80Sn-3Ag-17In, were employed. the addition of indium decreases the melting point of 94Sn-3Ag-3In and 80Sn-3Ag-17In to 214.7 and 193.3℃, respectivily. When increaseing the amount of indium, the pasty range increases. due to partial melting of solder. The amount of Sn affects the undercooling despite the amount of external additives. The interfacial intermetallic compound are Cu6(Sn,In)5 in Sn-Ag-In system solder and Cu6Sn5 in SnAgBi and SnAgBiIn solder. Because the addition of Bi increase the solubility of In in Sn. The activation energy were 23 and 24.5 KJ/mol in 94Sn-3Ag-3In and 80Sn-3Ag-17In, respectivily. The value is half of that in SnAgBiIn. The Bi could enhance the dissolution of Cu in solder. The white particals that formed inside the bulk solder of 94Sn-3Ag-3In are ζ phase, a solid solution of Ag4Sn and Ag3In, and the particles in 80Sn-3Ag-17In should be Ag2In+ζ phase. In solid state reaction. The activation energy are 64.92 and 219.8 KJ/mol in 94Sn-3Ag-3In and 80Sn-3Ag-17In, respectivily. The white particals inside bulk solder should be Ag3Sn+ζ phase and Ag2In+ζ phase in 94Sn-3Ag-3In and 80Sn-3Ag-17In, respectivily.

並列關鍵字

Pb-free solder ； Sn-Ag-In ； Interfacial Reaction

參考文獻

4. H. J. Fecht, M. X. Zhang, Y. A. Chang and J. H. Perepezko, “Metastable Phase Equilibria in the Lead-Tin Alloy System, Part II: Thermodynamic Modelling”, Met. Trans. A, vol. 20, no. 5, 1989, pp.795-803.

5. A. J. Sunwoo, J. W. Morris and G. K. Lucey, “The growth of Cu-Sn intermetallics at a pretinned copper/solder interface”, Metall Trans. A, vol. 23 no. 4, 1992, pp. 1323-1332

6. D. Grivas, D. Frear, L. Quan, J. Morris, “The formation of Cu3Sn intermetallic on the reaction of copper with 95Pb5Sn solder”, J. Electron. Mater, vol. 15 ,no. 6, 1986, pp. 355-359

7. H. K. Kim, H. K. Liou, K. N. Tu, “Three-dimensional morphology of a very rough interface formed in the soldering reaction between eutectic SnPb and Cu”, Appl. Phys. Lett., vol. 66, no. 18, 1995, pp. 2337-2339

8. H. K. Kim, K. N.Tu, “Kinetic analysis of the soldering reaction between eutectic SnPb alloy and Cu accompanied by ripening”, Phy. Rev. B., vol. 53, no. 23, 1996, pp. 16027-16034

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無鉛銲料錫銀銦與銅基板的界面反應

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