Kamikoriyama Yoichi, Imamura Hiroshi, Muramatsu Atsushi, Kanie Kiyoshi
Tohoku University, Institute of Multidisciplinary Research for Advanced Materials, Sendai, 980-8577, Japan.
Mitsui Mining & Smelting Co., Ltd., Corporate Engineered Materials Sector R&D Center, Ageo, 362-0021, Japan.
Sci Rep. 2019 Jan 29;9(1):899. doi: 10.1038/s41598-018-38422-5.
Copper nanoparticles (NPs) with an average particle diameter of 50-60 nm were successfully obtained by reducing an aqueous solution of a copper(II)-nitrilotriacetic acid complex with an aqueous hydrazine solution at room temperature under an air atmosphere. Copper NP-based nanopastes were printed onto a glass substrate using a metal screen mask and pressureless sintered under a nitrogen atmosphere at 200 °C for 30 min. The electrical resistivity of the resulting copper electrode was 16 μΩ · cm. For a metal-to-metal bonding test, copper nanopaste was printed on an oxygen-free copper plate, another oxygen-free copper plate was placed on top, and the bonding strength between the copper plates when pressureless sintered under a nitrogen atmosphere at 200 °C for 30 min was 39 MPa. TEM observations confirmed that highly crystalline metal bonding occurred between the copper NPs and the copper plate to introduce the ultrahigh strength. The developed copper NPs could provide promising advances as nanopastes for sustainable fabrication of copper electrodes and die attachment materials for the production of next-generation power semiconductors.
在空气气氛下，于室温通过用肼水溶液还原铜（II）-次氮基三乙酸配合物的水溶液，成功获得了平均粒径为50 - 60纳米的铜纳米颗粒（NPs）。使用金属丝网掩膜将基于铜纳米颗粒的纳米浆料印刷到玻璃基板上，并在氮气气氛下于200℃无压烧结30分钟。所得铜电极的电阻率为16μΩ·cm。对于金属-金属键合测试，将铜纳米浆料印刷在无氧铜板上，在其上方放置另一块无氧铜板，在氮气气氛下于200℃无压烧结30分钟时，铜板之间的键合强度为39MPa。透射电子显微镜（TEM）观察证实，铜纳米颗粒与铜板之间发生了高度结晶的金属键合，从而引入了超高强度。所开发的铜纳米颗粒作为用于可持续制造铜电极的纳米浆料以及用于生产下一代功率半导体的芯片附着材料，有望取得进展。
