2024

Vol.31 No.2

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  • Journal of the Microelectronics and Packaging Society
  • Volume 31(2); 2024
  • Article

Review

Journal of the Microelectronics and Packaging Society 2024;31(2):9-15. Published online: Jul, 25, 2024

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DOI : doi.org/10.6117/kmeps.2024.31.2.009

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

  • Gahui Kim1 , Doheon Kim2 , Kirak Son3 , and Young-Bae Park1,†
    1 School of Materials Science and Engineering, Andong National University, 1375, Gyeongdong-ro, Andong-si, Gyeongsangbuk-do 36729, Korea, 2 Amkor Technology Korea Inc., 150, Songdomirae-ro, Yeonsu-gu, Incheon 21991, Korea, 3 STATS ChipPAC Korea Ltd, 191, Jayumuyeok-ro, Jung-gu, Incheon 22379, Korea
Corresponding author E-mail: ybpark@anu.ac.kr
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.

Keywords Prepreg, Encapsulant, Surface energy, Wettability, Contact angle

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