Journal of the Microelectronics and Packaging Society (마이크로전자및패키징학회지)

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

DOI QR Code

Development of Epoxy Based Stretchable Conductive Adhesive

신축 가능한 에폭시 베이스 전도성 접착제 개발

  • Nam, Hyun Jin (ICT device packaging Research Center, Korea Electronics Technology Institute (KETI)) ;
  • Lim, Ji Yeon (ICT device packaging Research Center, Korea Electronics Technology Institute (KETI)) ;
  • Lee, Chang Hoon (ICT device packaging Research Center, Korea Electronics Technology Institute (KETI)) ;
  • Park, Se-Hoon (ICT device packaging Research Center, Korea Electronics Technology Institute (KETI))
  • 남현진 (전자부품연구원 ICT디바이스패키징연구센터) ;
  • 임지연 (전자부품연구원 ICT디바이스패키징연구센터) ;
  • 이창훈 (전자부품연구원 ICT디바이스패키징연구센터) ;
  • 박세훈 (전자부품연구원 ICT디바이스패키징연구센터)
  • Received : 2020.07.21
  • Accepted : 2020.09.18
  • Published : 2020.09.30
Download PDF
⟨ Previous Next ⟩

Abstract

To attach a stretchable/flexible electrode to something or something to on electrode, conductive adhesives must be stretchable/flexible to suit the properties of the electrode. In particular, conductive adhesive require durability and heat resistance, and unlike conventional adhesives, they should also have conductivity. To this end, Epoxy, which has good strength and adhesion, was selected as an adhesive, and a plasticizer and a reinforcement were mixed instead of a two-liquid material consisting of a conventional theme and a hardener, and a four-liquid material was used to give stretchability/flexibility to high molecules. The conductive filler was selected as silver, a material with low resistance, and for high conductivity, three shapes of Ag particles were used to increase packing density. Conductivity was compared with these developed conductive adhesives and two epoxy-based conductive adhesives being sold in practice, and about 10 times better conductivity results were obtained than products being actually sold. In addition, conductivity, mechanical properties, adhesion and strength were evaluated according to the presence of plasticizers and reinforcement agent. There was also no problem with 60% tensile after 5 minutes of curing at 120℃, and pencil hardness was excellently measured at 6H. As a result of checking the adhesion of electrodes through 3M tape test, all of them showed excellent results regardless of the mixing ratio of binders. After attaching the Cu sheet on top of the electrode through conductive adhesive, the contact resistance was checked and showed excellent performance with 0.3 Ω.

신축/유연한 전극을 무언가에 접착하거나 전극에 무언가를 접착하기 위해서는 전극의 특성에 맞는 전도성 접착제가 필요하다. 전도성 접착제는 접착성과 전도성이 필수적으로 요구된다. 특히 접착성 부분은 내구성과 내열성이 요구되며 기존 접착제와 다르게 전도성까지 보유해야한다. 그러기 위해서는 강도와 접착성이 좋은 에폭시를 접착제로 선정하였고 여기에 기존 주제와 경화제로 이루어진 2액형 소재가 아닌 가소제와 보강제까지 혼합하여 4액형 소재를 사용하여 신축/유연성을 고분자에 부여하였다. 전도성 필러는 비저항이 낮은 재료인 은으로 선정하였고 높은 전도성을 위해 3가지 모양의 Ag 입자를 사용해 패킹성을 높였다. 이렇게 개발된 전도성 접착제와 실제 판매되고 있는 에폭시 기반 전도성 접착제 2개와 전도성을 비교하였고 실제 판매되고 있는 제품보다 약 10배정도의 우수한 전도성 결과가 도출되었다. 그리고 가소제와 보강제 여부에 따른 전도성, 기계적 특성, 접착력, 강도를 평가하였다. 또한 120℃에서 5분 경화 후에 60%의 인장에도 문제가 없었으며 연필경도는 6H로 우수하게 측정되었다. 3M tape test를 통해 전극의 접착력을 확인한 결과 바인더의 배합 비율에 관계없이 모두 우수한 결과를 보였다. 전극 위에 Cu sheet를 전도성 접착제를 통해 부착시킨 후 접촉저항을 확인한 결과 0.3 Ω으로 우수한 성능을 보였다.

Keywords

References

  1. T. S. Han, D. K. Kim, O. Y. Kwon, and S. H. Choa, "Study of Standardization and Test Certification for Wearable Smart Devices", J. Microelectron. Packag. Soc., 23(4), 11 (2016). https://doi.org/10.6117/kmeps.2016.23.4.011
  2. H. A. Oh, D. Park, K. S. Han, and T. S. Oh, "Elastic Modulus of Locally Stiffness-variant Polydimethylsiloxane Substrates for Stretchable Electronic Packaging Applications", J. Microelectron. Packag. Soc., 22(4), 91 (2015). https://doi.org/10.6117/kmeps.2015.22.4.091
  3. S. Lee, S. Shin, S. Lee, J. Seo, J. Lee, S. Son, H. J. Cho, H. Algadi, S. Al?Sayari, D. E. Kim, and T. Lee, "Ag Nanowire Reinforced Highly Stretchable Conductive Fibers for Wearable Electronics. Advanced Functional Materials", Adv. Funct. Mater., 25(21), 3114 (2015). https://doi.org/10.1002/adfm.201500628
  4. A. Shankar, E. Salcedo, A. Berndt, D. Choi, and J. E. Ryu, "SPulsed light sintering of silver nanoparticles for large deformation of printed stretchable electronics", Adv. Compos. Hybrd. Mater., 1(1), 193 (2017).
  5. N. Matsuhisa, M. Kaltenbrunner, T. Yokota, H. Jinno, K. Kuribara, T. Sekitani, and T. Someya, "Printable elastic conductors with a high conductivity for electronic textile applications", Nat. Commun., 6(1), 7461 (2015). https://doi.org/10.1038/ncomms8461
  6. Y. Hanaoka, K. Hinode, K. Takeda, and D. Kodama, "Increase in Electrical Resistivity of Copper and Aluminum Fine Lines", Mater. Trans., 43(7), 1621 (2002). https://doi.org/10.2320/matertrans.43.1621
  7. Y. Lin, X. Dong, S. Liu, S. Chen, Y. Wei, and L. Liu, "Graphene-elastomer composites with segregated nanostructured network for liquid and strain sensing application Graphene-elastomer composites with segregated nanostructured network for liquid and strain sensing application", ACS Appl. Mater. Interfaces., 8(36), 24143 (2016). https://doi.org/10.1021/acsami.6b08587
  8. L. V. Kayser and D. J. Lipomi, "Stretchable Conductive Polymers and Composites Based on PEDOT and PEDOT : PSS", Adv. Mater., 31(10), 1806133 (2019). https://doi.org/10.1002/adma.201806133
  9. W. Kim and W. Kim, "3V omni-directionally stretchable onebody supercapacitors based on a single ion-gel matrix and carbon nanotubes", Nanotechnology, 27(22), 225402 (2016). https://doi.org/10.1088/0957-4484/27/22/225402
  10. J. Fu, C. Zhang, T. Liu, and J. Liu, "Room temperature liquid metal: its melting point, dominating mechanism and applications", Front. Energy, 14(1), (2019).
  11. R. Nagata, "A glucose sensor fabricated by the screen printing technique", Biosensors and Bioelectronics, 10(3-4), 261 (1995). https://doi.org/10.1016/0956-5663(95)96845-P
  12. L. Huang, Y. Huang, J. Liang, X. Wan, and Y. Chen, "Graphene-based conducting inks for direct inkjet printing of flexible conductive patterns and their applications in electric circuits and chemical sensors", Nano Res., 4(7), 675 (2011). https://doi.org/10.1007/s12274-011-0123-z
  13. M. Gonzalez, F. Axisa, M. V. Bulcke, D. Brosteaux, B. Vandevelde, and J. Vanfleteren, "Design of metal interconnects for stretchable electronic circuits", Microelectron. Reliab., 48(6), 825 (2008). https://doi.org/10.1016/j.microrel.2008.03.025
  14. A. Hartono, M. Djamal, S. Satira, Herman, and Ramli, "Preparation of PVDF film using deep coating method for biosensor transducer applied", Proc. 3rd International Conference on Instrumentation, Communications, Information Technology, and Biomedical Engineering (ICICI-BME), Bandung, 408, IEEE (2013).
  15. F. Xu and Y. Zhu, "Highly Conductive and Stretchable Silver Nanowire Conductors", Adv. Mater., 24(37), 5117 (2012). https://doi.org/10.1002/adma.201201886
  16. I. Kim, K. Woo, Z. Zhong, P. Ko, Y. Jang, M. Jung, J. Jo, S. Kwon, S. H. Lee, S. Lee, H. Youn, and J. Moon, "A photonic sintering derived Ag flake/nanoparticle-based highly sensitive stretchable strain sensor for human motion monitoring", Nanoscale, 10(17), 7890 (2018). https://doi.org/10.1039/C7NR09421C
  17. S. N. Ibrahim, F. A. Rahman, and S. Rosli, "Characterization of Screen Printed Ag-PDMS Flexible Electrode for Electrical Muscle Stimulation (EMS)", Indones. J. Electr. Eng. Inform., 5(4), 295 (2017).