ETRI Journal

Electronics and Telecommunications Research Institute (한국전자통신연구원)
권호 표지
DOI QR코드

DOI QR Code

Process window of simultaneous transfer and bonding materials using laser-assisted bonding for mini- and micro-LED display panel packaging

  • Yong-Sung Eom (Creative & Basic Technology Research Division, Electronics and Telecommunications research Institute) ;
  • Gwang-Mun Choi (Creative & Basic Technology Research Division, Electronics and Telecommunications research Institute) ;
  • Ki-Seok Jang (Creative & Basic Technology Research Division, Electronics and Telecommunications research Institute) ;
  • Jiho Joo (Creative & Basic Technology Research Division, Electronics and Telecommunications research Institute) ;
  • Chan-mi Lee (Creative & Basic Technology Research Division, Electronics and Telecommunications research Institute) ;
  • Jin-Hyuk Oh (Creative & Basic Technology Research Division, Electronics and Telecommunications research Institute) ;
  • Seok-Hwan Moon (Creative & Basic Technology Research Division, Electronics and Telecommunications research Institute) ;
  • Kwang-Seong Choi (Creative & Basic Technology Research Division, Electronics and Telecommunications research Institute)
  • Received : 2022.12.23
  • Accepted : 2023.02.27
  • Published : 2024.04.20
Download PDF
⟨ Previous Next ⟩

Abstract

A simultaneous transfer and bonding (SITRAB) process using areal laser irradiation is introduced for high-yield and cost-effective production of mini- or micro-light-emitting diode (LED) display panels. SITRAB materials are special epoxy-based solvent-free pastes. Three types of pot life are studied to obtain a convenient SITRAB process: Room temperature pot life (RPL), stage pot life (SPL), and laser pot life (LPL). In this study, the RPL was found to be 1.2 times the starting viscosity at 25℃, and the SPL was defined as the time the solder can be wetted by the SITRAB paste at given stage temperatures of 80℃, 90℃, and 100℃. The LPL, on the other hand, was referred to as the number of areal laser irradiations for the tiling process for red, green, and blue LEDs at the given stage temperatures. The process windows of SPL and LPL were identified based on their critical time and conversion requirements for good solder wetting. The measured RPL and SPL at the stage temperature of 80℃ were 6 days and 8 h, respectively, and the LPL was more than six at these stage temperatures.

Keywords

Acknowledgement

The authors would like to thank InSeok Gae and YoonHwan Moon for their support in sample preparation and measurements.

References

  1. Y. Wu, J. Ma, P. Su, L. Zhang, and B. Xia, Full-color realization of micro-LED displays, Nanomaterials 10 (2020), 2482. 
  2. Y. Huang, E. L. Hsiang, M. Y. Deng, and S. T. Wu, Mini-LED, micro-LED and OLED displays: present status and future perspectives, Light Sci. Appl. 9 (2020), 105. 
  3. E. H. Virey, Micro LED display technology trends and intellectual property landscape, PCIM Europe 2010SID 2020 Digest, 30-4. 
  4. J. Li, G. Yan, B. Luo, and Z. Liu, Study of micro-LED transfer-printing technologies, In International Conference on Display Technology, Vol. 52, SID, 2020, 625-627. 
  5. Y. Yin, L. Gao, J. Fan, L. Zhang, M. Liu, Y. Sun, S. J. Chen, X. Zhang, and H. Meng, A novel Sn paste free approach for manufacturing mini-LED display, In International Conference on Display Technology, Vol. 52, SID, 2020, 402-404. 
  6. K. Choi, Simultaneous transfer and bonding (SITRAB) process for mini-LED display, SID Digest 30-4 (2021), 436-439. 
  7. J. Joo, Simultaneous transfer and bonding (SITRAB) process for mini-LED display, SID Digest 74-4 (2022), 1005-1008.  https://doi.org/10.1002/sdtp.15667
  8. Y.-S. Eom, J. H. Son, K. S. Jang, H. S. Lee, H. C. Bae, K. S. Choi, and H. S. Choi, Characterization of fluxing and hybrid underfills with micro-encapsulated catalyst for long pot life, ETRI J. 36 (2014), no. 3, 343-351.  https://doi.org/10.4218/etrij.14.0113.0570
  9. Y.-S. Eom, K. S. Jang, J. T. Moon, and J. D. Nam, Electrical interconnection with a smart ACA composed of fluxing polymer and solder powder, ETRI J. 32 (2010), no. 3, 414-421.  https://doi.org/10.4218/etrij.10.0109.0400
  10. Y.-S. Eom, J. W. Baek, J. T. Moon, J. D. Nam, and J. M. Kim, Characterization of polymer matrix and low melting point solder for anisotropic conductive film, Microelectron. Eng. 85 (2008), 327-331.  https://doi.org/10.1016/j.mee.2007.07.005
  11. Y. S. Eom, K. Jang, J. T. Moon, J. D. Nam, and J. M. Kim, Electrical and mechanical characterization of an anisotropic conductive adhesive with a low melting point solder, Microelectron. Eng. 85 (2008), no. 11, 2202-2206.  https://doi.org/10.1016/j.mee.2008.05.038
  12. J.-W. Baek, K. S. Jang, Y. S. Eom, J. T. Moon, J. M. Kim, and J. D. Nam, Process window of simultaneous transfer and bonding materials using laser-assisted bonding for mini- and micro-LED display panel packaging, Microelectron. Eng. 87 (2010), 1968-1972.  https://doi.org/10.1016/j.mee.2009.12.020
  13. Y.-S. Eom, K. S. Choi, S. H. Moon, J. H. Park, J. H. Lee, and J. T. Moon, Characterization of a hybrid Cu paste as an isotropic conductive adhesive, ETRI J. 33 (2011), no. 6, 864-870.  https://doi.org/10.4218/etrij.11.0110.0520
  14. Y.-S. Eom, L. Boogh, V. Michaud, P. Sunderland, and J. A. Manson, Time-cure-temperature superposition for the prediction of instantaneous viscoelastic properties during cure, Polym. Eng. Sci. 40 (2000), no. 6, 1281-1292.  https://doi.org/10.1002/pen.11256
  15. A. Hale, C. W. Macosko, and H. E. Bair, Glass transition temperature as a function of conversion in thermosetting polymers, Macromolecules 24 (1991), 2610-2621.  https://doi.org/10.1021/ma00009a072
  16. J. S. Hwang, Solder technologies for electronic packaging and assembly, In Electronic materials and processes handbook, McGraw Hill, 2004.