DOI QR코드

DOI QR Code

Effect of the Residual Impurity on the Prepreg Surface on the Wettability of Encapsulant for Chip on Board Package

칩 온 보드 패키지 적용을 위한 프리프레그 표면 잔류 불순물이 봉지재의 젖음성에 미치는 영향

  • Gahui Kim (School of Materials Science and Engineering, Andong National University) ;
  • Doheon Kim (Amkor Technology Korea Inc.) ;
  • Kirak Son (STATS ChipPAC Korea Ltd) ;
  • Young-Bae Park (School of Materials Science and Engineering, Andong National University)
  • 김가희 (국립안동대학교 반도체.신소재공학과) ;
  • 김도헌 ((주)앰코테크놀로지 코리아 기술연구소) ;
  • 손기락 ((유) 스태츠칩팩코리아) ;
  • 박영배 (국립안동대학교 반도체.신소재공학과)
  • Received : 2024.05.17
  • Accepted : 2024.06.20
  • Published : 2024.06.30

Abstract

The effect of the residual impurity on the prepreg surface on the wettability of encapsulant for chip on board package was analyzed with microstructure, compositions and chemical bonds using a scanning electron microscope and X-ray photoelectron spectroscopy. As a result, the contact angle of w/ residual impurity sample was measured to be 28° higher than that of w/o residual impurity sample, and the C-O bond was decreased to be 4% lower than that of w/o residual impurity sample. The surface energy of the prepreg decreased because the impurity ions, Na and F, generated by the manufacturing process and wet etching, reacted chemically with the C on the prepreg surface, forming C-F bonds and breaking the C-O bonds on the prepreg surface. Therefore, the wettability of the encapsulant was degraded because the contact angle between the encapsulant and the prepreg was increased.

칩 온 보드(chip on board) 패키지 적용을 위해 프리프레그(prepreg) 표면에 잔류하는 불순물이 봉지재(encapsulant)의 젖음성에 미치는 영향을 규명하기 위해 전자현미경(scanning electron microscope)과 X-선 광전자 분광기(X-ray photoelectron spectroscopy)를 이용하여 미세구조, 조성 및 화학 결합을 분석하였다. 프리프레그 표면에 잔류 불순물이 존재하는 시편의 경우 잔류 불순물이 존재하지 않는 시편보다 접촉각이 28° 높게 측정되었으며, C-O 결합은 4% 낮게 도출되었다. 이는 공정 중 잔류 불순물인 Na, F이 프리프레그 표면에 존재하는 C와 화학 반응을 하여 C-F 결합 생성으로 인해 프리프레그 표면의 C-O 결합이 끊어지면서 프리프레그 표면에너지가 낮아지게 되고 이로 인해 접촉각이 증가하게 되면서 봉지재의 젖음성이 저하되는 것으로 판단된다.

Keywords

Acknowledgement

이 논문은 안동대학교 기본연구지원사업에 의하여 연구되었음.

References

  1. S. E. Kim, "Heterogeneous Device Packaging Technology for the Internet of Things Applications(in Kor.)", J. Microelectron. Packag. Soc., 23(3), 1 (2016).
  2. Y. -J. Park, G. -J. Jeong, and K. -S. Kim, "Research Trends in Thermal Interface Materials for Flexible and Stretchable Electronic Device (in Kor.)", J. Microelectron. Packag. Soc., 31(1), 7 (2024).
  3. M. J. Kim, J. A. Heo, J. H. Hyun, and S. -Y. Lee, "Reliability of Cu Interconnect under Compressive Fatigue Deformation Varying Interfacial Adhesion Treatment (in Kor.)", J. Microelectron. Packag. Soc., 30(4), 105 (2023).
  4. K. Son, G. Kim, and Y. B. Park, "Effects of Dielectric Curing Temperature and T/H Treatment on the Interfacial Adhesion Energies of Ti/PBO for Cu RDL Applications of FOWLP (in Kor.)", J. Microelectron. Packag. Soc., 30(2), 52 (2023).
  5. J. -K. Kim, K. Son, and Y. -B. Park, "Interfacial Adhesion and Reliability between Epoxy Resin and Polyimide for Flexible Printed Circuit Board(in Kor.)", J. Microelectron. Packag. Soc., 24(1), 75 (2017).
  6. B. J. Shim, Y. Choi, and J. S. Yi, "Improvement of COF Bending-induced Lead Broken Failure in LCD Module(in Kor.)", J. KIEEME 21, 265 (2008).
  7. B. -J. Kim, M. H. Jeong, S. H. Hwang, H. Y. Lee, S. W. Lee, K. D. Chun, Y. -B. Park, and Y. C. Joo, "Relationship between Tensile Characteristics and Failure by Folding or Bending in Cu Foil on Flexible Substrate(in Kor.)", J. Microelectron. Packag. Soc., 18(1), 55 (2011).
  8. J. -Y. Kim, "Development of an Automatic Test System for Chip on Boards(in Kor.)", J. Industrial Technology Institute, 18, 237 (2003).
  9. H. J. Kim, K. H. Ahn, S. J. Oh, D. H. Kim, J. S. Kim, E. S. Kim, and T. -S. Kim, "Measurement of EMC/PCB Interfacial Adhesion Energy of Chip Package Considering Warpage(in Kor.)", J. Microelectron. Packag. Soc., 26(4), 101 (2019).
  10. F. Steiner, K. Rendl, and V. Wirth, "Correlation Analysis of Wettability Intermetallic Compound Formation and PCB Contamination", Circuit World, 41(2), 70 (2015).
  11. K. J. Min, S. C. Park, K. W. Lee, J. D. Kim, D. G. Kim, G. H. Lee, and Y. -B. Park, "Effect of Ion-beam Pre-treatment of the Interfacial Adhesion of Sputter-deposited Cu film on FR-4 Substrate(in Kor.)", J. Inst. Met. & Mater., 47(1), 26 (2009).
  12. O. -W. Kweon and Y. Jee, "The Development of a Multichip COB Memory Package", Proc. 6th International Conference on Consumer Electronics (ICCE), Korea, 419, IEIE (1994).
  13. B. Wunderle, K. Becker, R. Sinning, O. Wittler, R. Schacht, H. Walter, R. Schneider, K. Halser, N. Simper, B. Michel, and H. Reichl, "Thermo-Mechanical Reliability during Technology Development of Power Chip-on-board Assemblies with Encapsulation", J. Microsyst. Technol., 15, 1467 (2009).
  14. J. J. Kim, H. Y. Kim, B. Y. Bae, S. H. Jung, and S. R. Jung, "Manufacturing Method of Prepreg (in Kor.)", (2012). Patent No. 10-2010-0140765. Seoul : Kor. Hyosung.
  15. M. S. Seo, "Package and Test to increase Semiconductor added Value", 212-216, Hanol, Seoul (2020).
  16. B. I. Noh, C. S. Seok, W. C. Moon, and S. B. Jung, "Effect of Plasma Treatment on Adhesion Characteristics at Interfaces between Underfill and Substrate", Int. J. Adhes. Adhes., 27(3), 200 (2007).
  17. Y. X. Liu, E. T. Kang, K. G. Neoh, J. F. Zhang, C. Q. Cui, and T. B. Lim, "Surface Graft Copolymerization Enhanced Adhesion of an Epoxy-based Printed Circuit Board Substrate (FR-4) to Copper", IEEE Trans. Adv. Packag., 22(2), 214 (1999).
  18. K. J. Min and Y. -B. Park, "Effect of Desmear Treatment on the Interfacial Bonding Mechanism of Electroless-Plated Cu film on FR-4 Substrate(in Kor.)", J. Mater. Res., 19(11), 625 (2009).
  19. K. K. C. Ho, A. F. Lee, and A. Bismarck, "Fluorination of Carbon fibres in Atmospheric Plasma", Carbon, 45, 775 (2007).
  20. H. Jiang, F. M. Plathe, and A. Z. Panagiotopoulos, "Contact angles from Young's equation in Molecular Dynamics Simulations", J. Chem. Phys., 147(8), 084708 (2017).
  21. S. W. Park and D. Lee, "Adhesive Joint Strength of Glass/Epoxy Composites Surface treated with Nano-size Carbon Black", Proc. 17th International Conference on Composite Materials (ICCM), United Kingdom, IEEE (2009).
  22. C. J. Van Oss, M. K. Chaudhury, and R. J. Good, "Monopolar Surfaces", J. Colloid Interf. Sci., 28, 35 (1987).
  23. M. H. Kim, K. Y. Rhee, and Y. N. Paik, "Plasma Treatment of Carbon/Epoxy Prepreg and its Effect on the Durability of Carbon/Epoxy Laminated Composites", J. Kor. Phys. Soc., 54(3), 1325 (2008).
  24. K. K. C. Ho, S. Lamoriniere, G. Kalinka, E. Shulz, and A. Bismarck, "Interfacial behavior between Atmospheric Plasma Fluorinated Carbon Fibers and Poly (vinylidene fluoride)", J. Colloid Interf. Sci., 313, 476 (2007).