Journal of the Microelectronics and Packaging Society (마이크로전자및패키징학회지)

The Korean Microelectronics and Packaging Society (한국마이크로전자및패키징학회)
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Effects of Ar/N2 Two-step Plasma Treatment on the Quantitative Interfacial Adhesion Energy of Low-Temperature Cu-Cu Bonding Interface

Ar/N2 2단계 플라즈마 처리에 따른 저온 Cu-Cu 직접 접합부의 정량적 계면접착에너지 평가 및 분석

  • Choi, Seonghun (School of Materials Science and Engineering, Andong National University) ;
  • Kim, Gahui (School of Materials Science and Engineering, Andong National University) ;
  • Seo, Hankyeol (Graduate School of Nano-IT Design Convergence, Seoul National University of Science and Technology) ;
  • Kim, Sarah Eunkyung (Graduate School of Nano-IT Design Convergence, Seoul National University of Science and Technology) ;
  • Park, Young-Bae (School of Materials Science and Engineering, Andong National University)
  • 최성훈 (안동대학교 신소재공학부 청정에너지소재기술연구센터) ;
  • 김가희 (안동대학교 신소재공학부 청정에너지소재기술연구센터) ;
  • 서한결 (서울과학기술대학교 나노IT디자인융합대학원) ;
  • 김사라은경 (서울과학기술대학교 나노IT디자인융합대학원) ;
  • 박영배 (안동대학교 신소재공학부 청정에너지소재기술연구센터)
  • Received : 2021.04.09
  • Accepted : 2021.05.24
  • Published : 2021.06.30
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Abstract

The effect of Ar/N2 two-step plasma treatment on the quantitative interfacial adhesion energy of low temperature Cu-Cu bonding interface were systematically investigated. X-ray photoelectron spectroscopy analysis showed that Ar/N2 2-step plasma treatment has less copper oxide due to the formation of an effective Cu4N passivation layer. Quantitative measurements of interfacial adhesion energy of Cu-Cu bonding interface with Ar/N2 2-step plasma treatment were performed using a double cantilever beam (DCB) and 4-point bending (4-PB) test, where the measured values were 1.63±0.24 J/m2 and 2.33±0.67 J/m2, respectively. This can be explained by the increased interfacial adhesion energy according phase angle due to the effect of the higher interface roughness of 4-PB test than that of DCB test.

3 차원 패키징을 위한 저온 Cu-Cu직접 접합부의 계면접착에너지를 향상시키기 위해 Cu박막 표면에 대한 Ar/N2 2단계 플라즈마 처리 전, 후 Cu표면 및 접합계면에 대한 화학결합을 X-선 광전자 분광법(X-ray photoelectron spectroscopy)을 통해 정량화한 결과, 2단계 플라즈마 처리로 인해 Cu표면에 Cu4N이 형성되어 Cu산화를 효과적으로 억제하는 것을 확인하였다. 2단계 플라즈마 처리하지 않은 Cu-Cu시편은 표면 산화막의 영향으로 접합이 제대로 되지 않았으나 2단계 플라즈마 처리한 시편은 효과적인 표면 산화방지효과로 인해 양호한 Cu-Cu접합을 형성하였다. Cu-Cu직접접합 계면의 정량적 계면접착에너지를 double cantilever beam 시험방법 및 4점 굽힘(4-point bending, 4-PB) 시험방법을 통해 비교한 결과, 각각 1.63±0.24, 2.33±0.67 J/m2으로 4-PB 시험의 계면접착에너지가 더 크게 측정되었다. 이는 계면파괴역학의 위상각(phase angle)에 따른 계면접착에너지 증가 거동으로 설명할 수 있는데 즉, 4-PB의 계면균열선단 전단응력성분 증가로 인한 계면거칠기의 효과에 기인한 것으로 판단된다.

Keywords

Acknowledgement

본 연구는 산업통상자원부(10067804와 20003524)와 KSRC 지원 사업인 미래반도체소자 원천기술개발사업의 연구결과로 수행되었습니다.

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