Matsuda Tomoki, Kawabata Rei, Okamoto Takuya, Hirose Akio
Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, Suita 565-0871, Japan.
Nanomaterials (Basel). 2023 Aug 9;13(16):2292. doi: 10.3390/nano13162292.
This paper demonstrates the in situ sinter bonding of Ag microparticle pastes to a Si substrate via the temporal formation and decomposition of Ag carboxylate on the surface of Ag microparticles. This was proposed via the investigation of Ag sinter bonding using the redox reaction between AgO and ethylene glycol, which achieved a bonding strength above 30 MPa even for the bonding temperature at 220 °C. Thermal analysis was used to identify the product of the redox reaction between AgO and ethylene glycol and determine the bonding temperature because the final reaction facilitates the interfacial sinter bonding with the substrate. Fourier-transform infrared spectroscopy and nuclear magnetic resonance results indicated the in situ formation of Ag salts of carboxylic acids, such as Ag oxalate on the surface of Ag microparticles. Therefore, the sinter bonding process enabled by the in situ formation and subsequent decomposition of these Ag salts was investigated using Ag microparticles and oxalic acid. Observations of the surface and interfacial morphology of the Ag particles after heating revealed the formation of Ag nanoparticles on the surfaces of the microparticles and the formation of sintering necks between the particles. The bonding experiments demonstrated a significant increase in strength with the addition of oxalic acid to the Ag paste due to the enhanced interfacial sinter bonding with the substrate. The in situ formation and decomposition of Ag salts are promising strategies for improving sintered bonds in electronic devices because they can provide enhanced localized sinter bonding using stable insert materials.
本文通过银微粒表面羧酸银的瞬时形成和分解，展示了银微粒浆料与硅衬底的原位烧结键合。这是通过研究氧化银与乙二醇之间的氧化还原反应进行银烧结键合而提出的，即使在220℃的键合温度下，该反应也能实现高于30MPa的键合强度。由于最终反应促进了与衬底的界面烧结键合，因此采用热分析来确定氧化银与乙二醇之间氧化还原反应的产物并确定键合温度。傅里叶变换红外光谱和核磁共振结果表明，在银微粒表面原位形成了羧酸银盐，如草酸银。因此，使用银微粒和草酸研究了由这些银盐的原位形成和随后分解实现的烧结键合过程。加热后对银颗粒表面和界面形态的观察揭示了微粒表面形成了银纳米颗粒以及颗粒之间形成了烧结颈。键合实验表明，由于与衬底的界面烧结键合增强，向银浆料中添加草酸后强度显著提高。银盐的原位形成和分解是改善电子器件烧结键合的有前景的策略，因为它们可以使用稳定的插入材料提供增强的局部烧结键合。
