Han Seong-Ju, Lee Seungyeon, Jang Keon-Soo
Department of Polymer Engineering, School of Chemical and Materials Engineering, The University of Suwon, Hwaseong 18323, Gyeonggi-do, Republic of Korea.
Polymers (Basel). 2024 Jan 31;16(3):398. doi: 10.3390/polym16030398.
The investigation of interconnection technologies is crucial for advancing semiconductor packaging technology. This study delved into the various methods of achieving electrical interconnections, focusing on the sintering process and composition of the epoxy. Although silver (Ag) has traditionally been utilized in the sintering process, its high cost often precludes widespread commercial applications. Copper (Cu) is a promising alternative that offers advantages, such as cost-effectiveness and high thermal and electrical conductivities. However, the mechanical robustness of the oxide layers formed on Cu surfaces results in several challenges. This research addresses these challenges by integrating epoxy, which has advantages such as adhesive capabilities, chemical resistance, and robust mechanical properties. The chemical reactivity of the epoxy was harnessed to both fortify adhesion and inhibit oxide layer formation. However, the optimal sintering performance required considering both the composite composition (20 wt% epoxy) and the specific sintering conditions (pre-heating at 200 °C and sintering at 250 °C). The experimental findings reveal a balance in the incorporation of epoxy (20 wt%) for the desired electrical and mechanical properties. In particular, the bisphenol A epoxy (Da)-containing sintered Cu chip exhibited the highest lab shear strength (35.9 MPa), whereas the sintered Cu chip without epoxy represented the lowest lab shear strength of 2.7 MPa. Additionally, the introduction of epoxy effectively curtailed the onset of oxidation in the sintered Cu chips, further enhancing their durability. For instance, 30 days after sintering, the percentage of oxygen atoms in the Da-containing sintered Cu chip (4.5%) was significantly lower than that in the sintered Cu chip without epoxy (37.6%), emphasizing the role of epoxy in improving Cu oxidation resistance. Similarly, the samples sintered with bisphenol-based epoxy binders exhibited the highest electrical and thermal conductivities after 1 month. This study provides insights into interactions between epoxy, carboxylic acid, solvents, and Cu during sintering and offers a foundation for refining the sintering conditions.
互连技术的研究对于推动半导体封装技术至关重要。本研究深入探讨了实现电气互连的各种方法，重点关注烧结工艺和环氧树脂的组成。尽管传统上银（Ag）已用于烧结工艺，但其高成本常常阻碍其广泛的商业应用。铜（Cu）是一种很有前景的替代材料，具有成本效益高、热导率和电导率高等优点。然而，在铜表面形成的氧化层的机械强度导致了一些挑战。本研究通过引入具有粘合能力、耐化学性和强大机械性能等优点的环氧树脂来应对这些挑战。利用环氧树脂的化学反应性来增强附着力并抑制氧化层的形成。然而，最佳烧结性能需要同时考虑复合材料组成（20 wt%环氧树脂）和特定烧结条件（200°C预热和250°C烧结）。实验结果表明，加入20 wt%的环氧树脂可实现所需的电气和机械性能的平衡。特别是，含双酚A环氧树脂（Da）的烧结铜芯片表现出最高的实验室剪切强度（35.9 MPa），而不含环氧树脂的烧结铜芯片的实验室剪切强度最低，为2.7 MPa。此外，环氧树脂的引入有效地抑制了烧结铜芯片中的氧化现象，进一步提高了它们的耐久性。例如，烧结30天后，含Da的烧结铜芯片中的氧原子百分比（4.5%）明显低于不含环氧树脂的烧结铜芯片（37.6%），这突出了环氧树脂在提高铜抗氧化性方面的作用。同样，用双酚基环氧树脂粘合剂烧结的样品在1个月后表现出最高的电导率和热导率。本研究深入了解了烧结过程中环氧树脂、羧酸、溶剂和铜之间的相互作用，并为优化烧结条件提供了基础。
