探討錫鉍與銅反應於低溫接合應用

Investigation of SnBi Reacting with Cu for Low Temperature Bonding Applications

梁華兌(Hua-Tui Liang)

指導教授 ： 王儀雯

淡江大學/工學院/化學工程與材料工程學系碩士班/碩士(2022年)

https://doi.org/10.6846/TKU.2022.00543

摘要

近期諸多需求使得封裝領域不斷進步，而製程中對於銲料的研究也更趨重要，通常這關係到介金屬化合物的生長種類與生長情形並對於產品的可靠度與良率至關重要。而由於RoHS條令而使錫鉛銲料走向無鉛銲料的時代，其中低溫無鉛銲料具有更低能耗比，可降低熱損害(Thermal Damage)，且對於3D IC整合以及傳感器的應用非常關鍵。SnBi銲料除上述優點外還具有成本低與可降低錫鬚長度等特點，不過Bi析出於界面後可能使機械性質降低，因此我們將研究並討論Bi析出後的各種性質。
本實驗將Sn58Bi與Cu基板在160 ℃進行接合，並觀察長時間的固態熱處理後的介金屬型態變化與機械性質測試，探討介金屬其生長機制並求出活化能等性質。實驗結果發現熱處理溫度120 ℃及130 ℃下，經反應1000 h後發現部分區域有Bi偏析在OFHC的Cu基板上的現象，並伴隨著孔洞發生，此外Cu3Sn厚度改變且較不均勻，於是我們圍繞有無Bi偏析區域進行分析與比較。
另一部分，我們進行Sn58Bi/ENEPIG的實驗，在160 ℃下迴焊，並進行固態熱處理，觀察改變銲料體積以及基板種類對界面微觀結構之影響。

關鍵字

無鉛銲料 ； 低溫銲料 ； 錫鉍銲料 ； Bi偏析

並列摘要

With the demand of heterogeneous integration, the development of electronic packaging becomes more and more important. The microstructure of intermetallic compounds is the critical factor that influences the reliability and product yield. The RoSH regulations move towards replacement of Sn-Pb solder by lead-free solder. In this situation, low-temperature lead-free solder has been widely discussed because of its low melting point. A great benefit includes low energy consumption and thermal damage. In addition, low-temperature solder can be applied to 3D integration, SnBi solder is one of the potential candidates for low-temperature solder. This is because the low melting point and low cost. Besides, SnBi can reduce the length of tin whiskers. However, the mechanical properties may be reduced after Bi segregation at the interface. The mechanism of Bi segregation would be discussed in the results and discussion.
In this study, Sn58Bi and Cu substrate were reflowed at 160 °C and then aged at 80 oC to 130 oC for different reaction time. The experimental results show that there was Bi segregation on the OFHC Cu substrate in particular areas. Bi segregation accompanied by the occurrence of voids. In addition, the uneven Cu3Sn formation at the interface. We also investigate the reactions between Sn58Bi and ENEPIG after reflow at 160 oC and then aged at 80 oC or 130 oC for different reaction time to investigate the effects of different substrates on interfacial reactions.
The objectives of this study are to analyze the phase transformations, activate energies and mechanical properties of intermetallic compounds. Bi segregation and substrates effects were also investigated in this study.

並列關鍵字

Lead-Free Solder ； Low-Temperature Solder ； SnBi Solder ； Bi Segregation

參考文獻

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