Journal of Welding and Joining

The Korean Welding and Joining Society (대한용접접합학회)
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Effect of BOE Wet Etching on Interfacial Characteristics of Cu-Cu Pattern Direct Bonds for 3D-IC Integrations

3차원 소자 적층을 위한 BOE 습식 식각에 따른 Cu-Cu 패턴 접합 특성 평가

  • Park, Jong-Myeong (School of Materials Science and Engineering, Andong National University) ;
  • Kim, Su-Hyeong (MSP Center, Seoul Technopark) ;
  • Kim, Sarah Eun-Kyung (Graduate School of NID Fusion Technology, Seoul National University of Science and Technology) ;
  • Park, Young-Bae (School of Materials Science and Engineering, Andong National University)
  • 박종명 (안동대학교 신소재공학부 청정에너지소재기술연구센터) ;
  • 김수형 (서울테크노파크 MSP 기술지원센터) ;
  • 김사라은경 (서울과학기술대학교 NID융합기술대학원) ;
  • 박영배 (안동대학교 신소재공학부 청정에너지소재기술연구센터)
  • Published : 2012.06.30
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Abstract

Three-dimensional integrated circuit (3D IC) technology has become increasingly important due to the demand for high system performance and functionality. We have evaluated the effect of Buffered oxide etch (BOE) on the interfacial bonding strength of Cu-Cu pattern direct bonding. X-ray photoelectron spectroscopy (XPS) analysis of Cu surface revealed that Cu surface oxide layer was partially removed by BOE 2min. Two 8-inch Cu pattern wafers were bonded at $400^{\circ}C$ via the thermo-compression method. The interfacial adhesion energy of Cu-Cu bonding was quantitatively measured by the four-point bending method. After BOE 2min wet etching, the measured interfacial adhesion energies of pattern density for 0.06, 0.09, and 0.23 were $4.52J/m^2$, $5.06J/m^2$ and $3.42J/m^2$, respectively, which were lower than $5J/m^2$. Therefore, the effective removal of Cu surface oxide is critical to have reliable bonding quality of Cu pattern direct bonds.

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References

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