Journal of the Microelectronics and Packaging Society (마이크로전자및패키징학회지)

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

DOI QR Code

Fabrication of Cu Flakes by Ball Milling of Sub-micrometer Spherical Cu Particles

서브 마이크론급 구형 동분말의 볼 밀링을 통한 플레이크 동분말의 제조

  • Kim, Ji Hwan (Department of Materials Science & Engineering, Seoul National University of Science & Technology) ;
  • Lee, Jong-Hyun (Department of Materials Science & Engineering, Seoul National University of Science & Technology)
  • 김지환 (서울과학기술대학교 신소재공학과) ;
  • 이종현 (서울과학기술대학교 신소재공학과)
  • Received : 2014.12.19
  • Accepted : 2014.12.29
  • Published : 2014.12.30
Download PDF
⟨ Previous Next ⟩

Abstract

As a preceding process for preparing several micrometer sized Ag-coated Cu flakes, ball milling of submicrometer-sized Cu particles synthesized through a wet chemical method was performed in order to convert the particles into flakes. To suppress oxidation and aggregation of the particles during ball milling, ethylene glycol and ethyl acetate were used as a medium and a surface modifying agent, respectively. Results obtained with different rotation speeds of a jar indicated that the rotation speed changes a rotating mode, and strikingly alters the final shapes and shape uniformity of Cu particles after milling. The diameter of zirconia ball was also confirmed. Although there was aggregates in the initial submicrometer-sized Cu particles, therefore, well-dispersed Cu flakes with a size of several micrometers were successfully prepared by ball milling through optimization of rotation speed, amount of ethyl acetate, and diameter of zirconia ball.

직경 수 마이크론급의 Ag 코팅 Cu 플레이크를 제조하기 위한 선행공정으로 습식 화학적 합성법으로 제조된 서브마이크론급의 Cu 입자를 볼 밀링 공정을 통해 프레이크화 하였다. 입자들의 산화 및 응집을 막기 위해 볼 밀링 유체로는 에틸렌글리콜을 사용하였고, 에틸아세테이트 표면개질제도 첨가하였다. 용기의 회전수에 따른 실험 결과를 통해 회전수에 따른 회전 모드의 변화가 밀링 후 Cu 입자들의 평균적인 형상과 형상 균일도를 크게 변화시킴을 확인할 수 있었다. 또한 첨가한 지르코니아 볼의 직경 역시 Cu 입자들의 플레이크화 균일도를 결정하는 대표 공정변수임을 확인할 수 있었다. 그 결과 다소간의 응집체를 포함한 서브마이크론급의 Cu 입자를 사용했음에도 불구하고, 회전수, 표면개질제 첨가량, 그리고 지르코니아 볼의 직경 등의 대표 공정변수들을 최적화한 볼 밀링 공정을 통해 분산성이 우수한 수 마이크론급의 Cu 플레이크를 성공적으로 제조할 수 있었다.

Keywords

References

  1. M. Nakamoto, M. Yamamoto, Y. Kashiwagi, H. Kakiuchi, T. Tsujimoto and Y. Yoshida, "A Variety of Silver Nanoparticle Pastes for Fine Electronic Circuit Pattern Formation", Proc. 6th International Conference on Polymers and Adhesives in Microelectronics and Photonics (Polytronic 2007), Tokyo, 105, IEEE (2007).
  2. D.-H. Kim, S. Yoo, C.-W. Lee and T.-Y. Lee, "Temperature Measurement and Contact Resistance of Au Stud Bump Bonding and Ag Paste Bonding with Thermal Heater Device", J. Microelectron. Packag. Soc., 17(2), 55 (2010).
  3. H. T. Hai, J. G. Ahn, D. J. Kim, J. R. Lee, H. S. Chung and C. O. Kim, "Developing Process for Coating Copper Particles with Silver by Electroless Plating Method", Suf. Coat. Technol., 201, 3788 (2006). https://doi.org/10.1016/j.surfcoat.2006.03.025
  4. M. Tsuji, S. Hikino, Y. Sano and M. Horigome, "Preparation of Cu@Ag Core-Shell Nanoparticles Using a Two-step Polyol Process under Bubbling of $N_2$ Gas", Chem. Lett., 38, 518 (2009). https://doi.org/10.1246/cl.2009.518
  5. Y. Peng, C. Yang, K. Chen, S. R. Popuri, C. Lee and B. Tang, "Study on Synthesis of Ultrafine Cu-Ag Core-Shell Powders with High Electrical Conductivity", Applied Surface Science, 263, 38 (2012). https://doi.org/10.1016/j.apsusc.2012.08.066
  6. A. Muzikansky, P. Nanikashvili, J. Grinblat and D. Zitoun, "Ag Dewetting in Cu@Ag Monodisperse Core-Shell Nanoparticles", J. Phys. Chem. C, 117, 3093 (2013).
  7. H. T. Hai, H. Takamura and J. Koike, "Oxidation Behavior of Cu-Ag Core-Shell Particles for Solar Cell Applications", Journal of Alloys and Compounds, 564, 71 (2013). https://doi.org/10.1016/j.jallcom.2013.02.048
  8. S.-S. Chee and J.-H. Lee, "Preparation and Oxidation Behavior of Ag-Coated Cu Nanoparticles Less Than 20 nm in Size", J. Mater. Chem. C, 2, 5372 (2014). https://doi.org/10.1039/c4tc00509k
  9. J. H. Kim and J.-H. Lee, "Effects of Pretreatment and Ag Coating Processes Conditions on the Properties of Ag-Coated Cu Flakes", Kor. J. Mater. Res., 24(11), 617 (2014). https://doi.org/10.3740/MRSK.2014.24.11.617
  10. R. Zhang, W. Lin, K. Lawrence and C. P. Wong, "Highly Reliable, Low Cost, Isotropically Conductive Adhesives Filled with Ag-coated Cu Flakes for Electronic Packaging Applications", Int. J. Adhes. Adhes., 30(6), 403 (2010). https://doi.org/10.1016/j.ijadhadh.2010.01.004
  11. S.-S. Chee and J.-H. Lee, "Effects of Process Parameters in Synthesizing Sn Nanoparticles via Chemical Reduction", Electron. Matter. Lett., 8(1), 53 (2012). https://doi.org/10.1007/s13391-011-0510-3
  12. L. Froyen, L. Delaey, X. P. Niu, P. LeBrun and C. Peytour, "Synthesizing Aluminum Alloys by Double Mechanical Alloying", JOM, 47(3), 16 (1995).
  13. X. P. Niu, L. Froyen, L. Delaey and C. Peytour, "Hydride Formation in Mechanically Alloyed Al-Zr and Al-Fe-Zr", Scripta Metall. Mater., 30(1), 13 (1994). https://doi.org/10.1016/0956-716X(94)90350-6
  14. L. Lu, M. O. Lai and C. W. Ng, "Enhanced Mechanical Properties of an Al Based Metal Matrix Composite Prepared Using Mechanical Alloying", J. Mater. Sci. Eng. A, 252(2), 203 (1998). https://doi.org/10.1016/S0921-5093(98)00676-5
  15. S.-H. Hong and B.-K. Kim, "Effects of Lifter Bars on the Ball Motion and Aluminum Foil Milling in Tumbler Ball Mill", Mater. Lett., 57(2), 275 (2002). https://doi.org/10.1016/S0167-577X(02)00778-4

Cited by

  1. Graphene Oxide 첨가에 따른 Sn-3.0Ag-0.5Cu 무연솔더 접합부의 Electromigration 특성 분석 vol.26, pp.3, 2019, https://doi.org/10.6117/kmeps.2019.26.3.081