Journal of the Microelectronics and Packaging Society (마이크로전자및패키징학회지)

The Korean Microelectronics and Packaging Society (한국마이크로전자및패키징학회)
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Elastic Properties Evaluation of Thin Films on Flexible Substrates with Consideration of Contact Morphology in Nanoindentation

나노압입시험에서의 접촉형상 보정을 통한 유연소자 박막의 탄성특성 평가

  • Kim, Won Jun (School of Materials Science & Engineering, Research Center for Energy and Clean Technology, Andong National University) ;
  • Hwang, Gyeong-Seok (Department of Materials Science and Engineering, UNIST(Ulsan National Institute of Science and Technology)) ;
  • Kim, Ju-Young (Department of Materials Science and Engineering, UNIST(Ulsan National Institute of Science and Technology)) ;
  • Kim, Young-Cheon (School of Materials Science & Engineering, Research Center for Energy and Clean Technology, Andong National University)
  • 김원준 (안동대학교 신소재공학부 청정에너지소재기술연구센터) ;
  • 황경석 (울산과학기술원 신소재공학과) ;
  • 김주영 (울산과학기술원 신소재공학과) ;
  • 김영천 (안동대학교 신소재공학부 청정에너지소재기술연구센터)
  • Received : 2020.09.09
  • Accepted : 2020.09.29
  • Published : 2020.09.30
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Abstract

The evolution of smartphones has led to numerous researches in the mechanical behavior of flexible devices. Due to the nano-size of the thin flexible film, nanoindentation is widely used to evaluate its mechanical behaviors, such as elastic modulus, and hardness. However, the commonly used Oliver-Pharr method is not suited for analyzing the indentation force-depth curves of hard films on soft substrates, as the effects of soft substrate is not considered theoretically. In this study, the elastic modulus of the thin film was evaluated with references to other reported models which include the substrate effect, and with calibration of the indentation depth for the pile-ups between the indenter and test surface. We fabricated test samples by deposition of amorphous metal film on polyimide and silicon wafers for verification of modified models.

최근 스마트폰 산업의 발전으로 인하여 실사용 환경에서 유연소자의 기계적 거동에 대한 연구가 많이 이루어지고 있다. 유연소자 박막은 두께가 나노 단위이고, 기존의 시험법으로 측정하기 어려워 주로 나노압입시험을 이용하여 경도, 탄성계수 등의 특성을 구하고 있다. 그러나 현재 널리 쓰이고 있는 분석법(Oliver-Pharr Method)은 기판의 영향이 이론적으로 고려되지 않아 단순히 적용하기에는 무리가 있다. 따라서 본 연구에서는 기판 영향을 고려한 타 연구자들의 모델에 대한 적용성을 확인하고, 압입자와 시편 표면에서 발생하는 소성쌓임 현상(pile-up)에 대해 압입깊이의 보정을 실시하였다. 유연소자 박막의 탄성계수를 평가하고 검증하기 위하여 폴리이미드 및 실리콘 웨이퍼 기판 위에 금속, 비정질 박막을 증착하여 실제 실험을 수행하여 비교하였다.

Keywords

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