Journal of the Microelectronics and Packaging Society (마이크로전자및패키징학회지)

The Korean Microelectronics and Packaging Society (한국마이크로전자및패키징학회)
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Effects of Post-annealing and Temperature/Humidity Conditions on the Interfacial Adhesion Energies of ALD RuAlO Diffusion Barrier Layer for Cu Interconnects

후속열처리 및 고온고습 조건에 따른 Cu 배선 확산 방지층 적용을 위한 ALD RuAlO 박막의 계면접착에너지에 관한 연구

  • Lee, Hyeonchul (School of Materials Science and Engineering, Andong National University) ;
  • Jeong, Minsu (Amkor Technology Korea Inc.) ;
  • Bae, Byung-Hyun (VITZROTECH Co., Ltd.) ;
  • Cheon, Taehun (School of Materials Science and Engineering, Yeungnam University) ;
  • Kim, Soo-Hyun (School of Materials Science and Engineering, Yeungnam University) ;
  • Park, Young-Bae (School of Materials Science and Engineering, Andong National University)
  • 이현철 (안동대학교 신소재공학부 청정에너지소재기술연구센터) ;
  • 정민수 (앰코테크놀로지 코리아) ;
  • 배병현 ((주)비츠로테크) ;
  • 천태훈 (영남대학교 신소재공학부) ;
  • 김수현 (영남대학교 신소재공학부) ;
  • 박영배 (안동대학교 신소재공학부 청정에너지소재기술연구센터)
  • Received : 2016.05.16
  • Accepted : 2016.05.25
  • Published : 2016.06.30
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Abstract

The effects of post-annealing and temperature/humidity conditions on the interfacial adhesion energies of atomic layer deposited RuAlO diffusion barrier layer for Cu interconnects were systematically investigated. The initial interfacial adhesion energy measured by four-point bending test was $7.60J/m^2$. The interfacial adhesion energy decreased to $5.65J/m^2$ after 500 hrs at $85^{\circ}C$/85% T/H condition, while it increased to $24.05J/m^2$ after annealing at $200^{\circ}C$ for 500 hrs. The X-ray photoemission spectroscopy (XPS) analysis showed that delaminated interface was RuAlO/$SiO_2$ for as-bonded and T/H conditions, while it was Cu/RuAlO for post-annealing condition. XPS O1s peak separation results revealed that the effective generation of strong Al-O-Si bonds between $AlO_x$ and $SiO_2$ interface at optimum post-annealing conditions is responsible for enhanced interfacial adhesion energies between RuAlO/$SiO_2$ interface, which would lead to good electrical and mechanical reliabilities of atomic layer deposited RuAlO diffusion barrier for advanced Cu interconnects.

차세대 반도체의 초미세 Cu 배선 확산방지층 적용을 위해 원자층증착법(atomic layer deposition, ALD) 공정을 이용하여 증착한 RuAlO 확산방지층과 Cu 박막 계면의 계면접착에너지를 정량적으로 측정하였고, 환경 신뢰성 평가를 수행하였다. 접합 직후 4점굽힘시험으로 평가된 계면접착에너지는 약 $7.60J/m^2$으로 측정되었다. $85^{\circ}C$/85% 상대습도의 고온고습조건에서 500시간이 지난 후 측정된 계면접착에너지는 $5.65J/m^2$로 감소하였으나, $200^{\circ}C$에서 500시간 동안 후속 열처리한 후에는 $24.05J/m^2$으로 계면접착에너지가 크게 증가한 것으로 평가되었다. 4점굽힘시험 후 박리된 계면은 접합 직후와 고온고습조건의 시편의 경우 RuAlO/$SiO_2$ 계면이었고, 500시간 후속 열처리 조건에서는 Cu/RuAlO 계면인 것으로 확인되었다. X-선 광전자 분광법 분석 결과, 고온고습조건에서는 흡습으로 인하여 강한 Al-O-Si 계면 결합이 부분적으로 분리되어 계면접착에너지가 약간 낮아진 반면, 적절한 후속 열처리 조건에서는 효과적인 산소의 계면 유입으로 인하여 강한 Al-O-Si 결합이 크게 증가하여 계면접착에너지도 크게 증가한 것으로 판단된다. 따라서, ALD Ru 확산방지층에 비해 ALD RuAlO 확산방지층은 동시에 Cu 씨앗층 역할을 하면서도 전기적 및 기계적 신뢰성이 우수할 것으로 판단된다.

Keywords

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