Journal of the Microelectronics and Packaging Society (마이크로전자및패키징학회지)

The Korean Microelectronics and Packaging Society (한국마이크로전자및패키징학회)
권호 표지
DOI QR코드

DOI QR Code

Effect of Ag Nanolayer in Low Temperature Cu/Ag-Ag/Cu Bonding

저온 Cu/Ag-Ag/Cu 본딩에서의 Ag 나노막 효과

  • Kim, Yoonho (Department of Protection and Safety Engineering, Seoul National University of Science and Technology) ;
  • Park, Seungmin (Department of Protection and Safety Engineering, Seoul National University of Science and Technology) ;
  • Kim, Sarah Eunkyung (Department of Nano-IT Convergence Engineering, Seoul National University of Science and Technology)
  • 김윤호 (서울과학기술대학교 국방방호공학과) ;
  • 박승민 (서울과학기술대학교 국방방호공학과) ;
  • 김사라은경 (서울과학기술대학교 나노IT융합공학과)
  • Received : 2021.05.05
  • Accepted : 2021.05.17
  • Published : 2021.06.30
Download PDF
⟨ Previous Next ⟩

Abstract

System-in-package (SIP) technology using heterogeneous integration is becoming the key of next-generation semiconductor packaging technology, and the development of low temperature Cu bonding is very important for high-performance and fine-pitch SIP interconnects. In this study the low temperature Cu bonding and the anti-oxidation effect of copper using porous Ag nanolayer were investigated. It has been found that Cu diffuses into Ag faster than Ag diffuses into Cu at the temperatures from 100℃ to 200℃, indicating that solid state diffusion bonding of copper is possible at low temperatures. Cu bonding using Ag nanolayer was carried out at 200℃, and the shear strength after bonding was measured to be 23.27 MPa.

차세대 반도체 기술은 이종소자 집적화(heterogeneous integration)를 이용한 시스템-인-패키징(system-inpackage, SIP) 기술로 발전하고 있고, 저온 Cu 본딩은 SIP 구조의 성능 향상과 미세 피치 배선을 위해서 매우 중요한 기술이라 하겠다. 본 연구에서는 porous한 Ag 나노막을 이용하여 Cu 표면의 산화 방지 효과와 저온 Cu 본딩의 가능성을 조사하였다. 100℃에서 200℃의 저온 영역에서 Ag가 Cu로 확산되는 것보다 Cu가 Ag로 확산되는 것이 빠르게 관찰되었고, 이는 저온에서 Ag를 이용한 Cu간의 고상 확산 본딩이 가능함을 나타내었다. 따라서 Ag 나노막을 이용한 Cu 본딩을 200℃에서 진행하였고, 본딩 계면의 전단 강도는 23.27 MPa로 측정되었다.

Keywords

Acknowledgement

This research was supported by the Basic Science Research Program through the National Research Foundation of Korea funded by the Ministry of Science and ICT (NRF-2018R1A2B6003921) and also was partially supported by the Ministry of Trade, Industry & Energy (#20003524)

References

  1. J. Lu and K. Rose, "3D Integration: Why, What, Who, When?", Future Fab International, 23, 25-27 (2007).
  2. A. K. Panigrahi and K. N. Chen, "Low Temperature Cu-Cu Bonding Technology in 3D Integration: An Extensive Review.", J. Electron. Packag., 140(1), 010801 (2017). https://doi.org/10.1115/1.4038392
  3. "Chapter 21 SiP and module system integration" and "Chapter 22 interconnects for 3D and 3D architectures", Heterogeneous Integration Roadmap (2020) from http://eps.ieee.org/hir
  4. C. S. Tan, R. J. Gutmann, and L. R. Reif, "Overview of Wafer Level 3D ICs, in Wafer Level 3-D ICs Process Technology", 1-11, Springer, New York (2008).
  5. P. Ramm, J. J. Lu, and M. M.V. Taklo, "Cu/SiO2 hybrid bonding.", John Wiley & Son, Handbook of Wafer Bonding, 237-259 (2012).
  6. S. Choa, B. H. Ko, and H. Lee, "Recent Trends of MEMS Packaging and Bonding Technology." J. Microelectron. Packag. Soc., 24.4, 9-17 (2017). https://doi.org/10.6117/KMEPS.2017.24.4.009
  7. H. Seo, H. Park, and S. E. Kim, "Cu-SiO2 Hybrid Bonding", J. Microelectron. Packag. Soc., 27(1), 17-24 (2020).
  8. C. S. Tan, D. F. Lim, X. F. Ang, J. Wei, and K. C. Leong, "Low temperature Cu-Cu thermo-compression bonding with temporary passivation of self-assembled monolayer and its bond strength enhancement.", Microelectron. Reliab., 52.2, 321-324 (2012). https://doi.org/10.1016/j.microrel.2011.04.003
  9. S. L. Chua, J. M. Chan, S. C. K. Goh, and C. S. Tan, "Cu-Cu bonding in ambient environment by Ar/N2 plasma surface activation and its characterization", IEEE Trans. Comp. Packag. Manufact. Technol., 9(3), 596-605 (2018). https://doi.org/10.1109/tcpmt.2018.2875460
  10. H. Park and S. E. Kim, "Two-Step Plasma Treatment on Copper Surface for Low-Temperature Cu Thermo-Compression Bonding", IEEE Trans. Comp. Packag. Manufact. Technol., 10(2), 332-338 (2018). https://doi.org/10.1109/tcpmt.2019.2928323
  11. H. Park, H. Seo, Y. Kim, S. Park, and S. E. Kim, "Low Temperature (260℃) Solderless Cu-Cu Bonding for Fine Pitch 3D Packaging and Heterogeneous Integration", IEEE Trans. Comp. Packag. Manufact. Technol., 11(4), 565 - 572 (2021). https://doi.org/10.1109/TCPMT.2021.3065531
  12. Y. Huang, Y. Chien, R. Tzeng, M. Shy, T. Lin, K. Chen, C. Chiu, and J. Chiou. "Novel Cu-to-Cu Bonding with Ti Passivation at 180℃ in 3-D Integration", IEEE Electron Dev. Lett., 34(12), 1551-1553 (2013). https://doi.org/10.1109/LED.2013.2285702
  13. S. Bonam, A. K. Panigrahi, C. H. Kumar, and S. R. K. Vanjari, "Interface and Reliability Analysis of Au-Passivated Cu-Cu Fine-Pitch Thermocompression Bonding for 3-D IC Applications", IEEE Trans. Comp. Packag. Manufact. Technol., 9(7), 1227-1234 (2019). https://doi.org/10.1109/tcpmt.2019.2912891
  14. Z. Liu, J. Cai, Q. Wang, Z. Wang, L. Liu, and G. Zou, "Thermal-stable void-free interface morphology and bonding mechanism of low-temperature Cu-Cu bonding using Ag nanostructure as intermediate", J. Alloys and Compounds, 767, 575-582 (2018). https://doi.org/10.1016/j.jallcom.2018.07.060
  15. M.X. Chen, X. H. Song, Z. Y. Fan, and S. Liu, "Low temperature thermo compression bonding between aligned carbon nanotubes and metallized substrate", Nanotechnology, 22, 345704 (2011). https://doi.org/10.1088/0957-4484/22/34/345704
  16. M. Kim and H. Nishikawa, "Silver nanoporpus sheet for solid-state die attach in power device packaging", Scripta Mater., 92, 43-46 (2014). https://doi.org/10.1016/j.scriptamat.2014.08.010
  17. Z. Y. Liu, J. Cai, Q. Wang, L. Tan, and Y. Hu, "Low temperature Cu-Cu bonding using Ag nanostructure for 3D integration", ECS Solid State Lett., 4, 75-76 (2015).
  18. T. Chou, S. Huang, P. Chen, H. Hu, D. Liu, C. Chang, T. Ni, C. Chen, Y. Lin, T. Chang, and K. Chen, "Electrical and Reliability Investigation of Cu-to-Cu Bonding with Silver Passivation Layer in 3D Integration", IEEE Trans. Comp. Packag. Manufact. Technol., 11(1), 36-42 (2020).