Journal of the Microelectronics and Packaging Society (마이크로전자및패키징학회지)

The Korean Microelectronics and Packaging Society (한국마이크로전자및패키징학회)
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Study on Behavior Characteristics of Embedded PCB for FCCSP Using Numerical Analysis

수치해석을 이용한 FCCSP용 Embedded PCB의 Cavity 구조에 따른 거동특성 연구

  • Cho, Seunghyun (Department of Mechanical Engineering, Dongyang Mirae University) ;
  • Lee, Sangsoo (Department of Mechanical Engineering, Dongyang Mirae University)
  • 조승현 (동양미래대학교 기계공학과) ;
  • 이상수 (동양미래대학교 기계공학과)
  • Received : 2020.02.21
  • Accepted : 2020.03.25
  • Published : 2020.03.30
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Abstract

In this paper, we used FEM technique to perform warpage and von Mises stress analysis on PCB according to the cavity structures of embedded PCB for FCCSP and the types of prepreg material. One-half substrate model and static analysis are applied to the FEM. According to the analysis results of the warpage, as the gap between the cavity and the chip increased, warpage increased and warpage increased when prepreg material with higher modularity and thermal expansion coefficient was applied. The analysis results of the von Mises stress show that the effect of the gap between the cavity and the chip varies depending on prepreg material. In other words, when material whose coefficient of thermal expansion is significantly higher than that of core material, the stress increased as the gap between the cavity and the chip increased. When the prepreg with the coefficient of thermal expansion lower than the core material is applied, the result of stress is opposite. These results indicate that from a reliability perspective, there is a correlation between the structure of the cavity where embedded chips are loaded and prepreg material.

본 논문에서는 FEM(유한요소) 기법을 사용하여 FCCSP용 임베디드 PCB의 캐비티 구조와 프리프레그 재료의 종류에 따라 PCB에서 발생한 warpage와 von Mises 응력 해석을 수행하였다. 유한요소 해석에는 1/2 substrate 모델과 정적해석이 적용되었다. warpage 해석 결과에 의하면 칩이 실장되는 캐비티와 칩의 간격이 증가할수록 warpage가 증가하였고, 탄성계수와 열팽창계수가 높은 프리프레그 재료를 적용했을 때 warpage가 증가하였다. 응력의 해석결과에 따르면 칩이 실장되는 캐비티와 칩의 간격의 영향은 프리프레그 재료에 따라 다르게 나타났다. 즉 열팽창계수가 코어재료보다 월등히 높은 재료를 적용했을 때 칩이 실장되는 캐비티와 칩의 간격이 증가할수록 응력이 증가하였고, 열팽창계수가 코어재료보다 낮은 프리프레그를 적용하면 응력이 감소하였다. 이와 같은 결과는 신뢰성 관점에서 실장된 칩이 실장되는 캐비티의 구조와 프리프레그 재료간 상관관계가 있음을 시사하고 있다.

Keywords

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