Electric Current Effects in Flip Chip Solder Joints

覆晶銲點中之電流效應

王朝弘(Chao-Hong Wang) ； 陳信文(Sinn-Wen Chen)

《Journal of the Chinese Institute of Chemical Engineers》 37卷2期 (2006/03) Pp. 185-191

https://doi.org/10.6967/JCICE.200603.0185

摘要

覆晶技術已成為電子構裝中之主要接合技術之一。隨著電子產品之微小化，銲料凸塊的尺寸越來越小，而銲料凸塊的電流密度也隨之增大。不同的材料在銲點相互接觸，因此在界面處會存在著組成之濃度梯度。當電流通過銲點時，會伴隨產生焦耳熱效應和電遷移效應。焦耳熱效應造成銲點溫度提高。另一方面，擴散和電遷移效應，則造成銲點中的原子移動。本研究探討微結構對電流分佈的影響，包括不同形狀的孔洞及銲料中存在之多相結構，並將計算結果和實驗上所觀察的現象做比較。本研究亦討論在覆晶銲點中之電流聚集效應及其溫度分佈。結果發現在覆晶接點中，障層的消耗速率和電流聚集的位置有密切關聯。在本研究亦發現，覆晶接點的幾何形狀和孔洞對於電流聚集有很大的影響，其效應遠勝於銲料中的多相結構。

並列摘要

Flip chip technology has become one of the major joining technologies in electronic packaging. With the trend toward miniaturization, solder bumps are getting smaller, and the electric current loading of each solder bump is getting higher. At solder joints, different materials are brought into contact, and there are compositional gradients at the interfaces. As an electric current passes through, the Joule heating and electromigration effects occur in the flip chip solder bumps. The joints heat up as a result of the Joule heating effect. Atoms in the solder joints move as a result of both diffusion and electromigration. In this study, current distributions in various microstructures with different shapes of voids and multi-phases of solders were calculated, and the calculated results were compared with experimental observations. The current crowding effect and temperature distributions in flip chip solders are discussed. It is found that the highest consumption rates of barrier layers in certain parts of flip-chip joints are related to the current crowding phenomena. It is also found that the geometry of a flip-chip joint and void formation have stronger effects upon current crowding than the multi-phase nature of solder bumps does.

並列關鍵字

Flip chip ； Electromigration ； Current crowding ； Current density