Pressureless sinter-joining of micron-Ag flake pastes at 160 °C enabled by solvent and interface engineering
Pressureless sinter-joining of micron-Ag flake pastes at 160 °C enabled by solvent and interface engineering
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DOI：
10.1016/j.jmatprotec.2023.118207
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发表时间：
2023-10
影响因子：
6.3
通讯作者：
Wanli Li;Yitian Li;Yujian Wang;Yuncan Liu;Chuantong Chen;Jie Zhang;Haidong Yan
中科院分区：
文献类型：
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作者：
Wanli Li;Yitian Li;Yujian Wang;Yuncan Liu;Chuantong Chen;Jie Zhang;Haidong Yan
由于表面活性差和振实密度低，在低于 200°C 的温度下无压烧结连接具有成本效益的微米级银片浆料带来了重大挑战。在此，我们提出了一种新颖的溶剂和界面工程方法，以增强相邻微米银薄片之间以及薄片与基材之间的接触。提出了溶剂增强烧结工艺，并详细研究了其对烧结银图案和接头电阻率和剪切强度的影响。结果表明，对银薄片和基材具有高润湿能力的溶剂有助于在烧结银图案和接头中实现低电阻率和高剪切强度。特别是，当溶剂具有高表面张力时，它们会在银片和基材之间产生很强的毛细管粘附力。这减少了银片和基底之间的间隙，从而通过最小化原子扩散的距离来促进银片之间的结合。最后，50% α-萜品醇和 50% 二丙二醇甲醚乙酸酯的混合溶剂由于润湿性和表面张力之间的平衡而表现出协同效应，使得烧结接头即使在 160 °C 的超低温下也能实现 27 MPa 的优异剪切强度。这一成就代表了最先进的银浆无压烧结连接技术，并在电力电子封装应用中具有广阔的实际应用潜力。
Pressureless sinter-joining of cost-effective micron-Ag flake pastes at temperatures below 200 °C poses significant challenges due to their poor surface activity and low tapped density. Herein, we propose a novel solvent and interface engineering approach to enhance the contact among adjacent micron-Ag flakes and between the flakes and substrates. The solvent-enhanced sintering process is proposed, and its effect on the resistivity and shear strength of sintered Ag patterns and joints is studied in detail. Results show that the solvents with high wetting abilities on the Ag flakes and substrates are instrumental in achieving low resistivity and high shear strength in the sintered Ag patterns and joints. In particular, when the solvents possess high surface tension, they generate strong capillary adhesion among Ag flakes and substrates. This reduces the gap between Ag flakes and substrates, thereby promoting bonding among the Ag flakes by minimizing the distance of atom diffusion. Finally, mixed solvents of 50 % α-Terpineol and 50 % dipropyleneglycol methyl ether acetate show a synergistic effect due to the balance between wettability and surface tension, which enables the sintered joints to achieve an exceptional shear strength of 27 MPa even at an ultralow temperature of 160 °C. This achievement represents the state-of-the-art pressureless sinter-joining of Ag pastes and holds promising potential for practical use in power electronic packaging applications.