Journal of the Microelectronics and Packaging Society (마이크로전자및패키징학회지)

The Korean Microelectronics and Packaging Society (한국마이크로전자및패키징학회)
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Wet Etching Characteristics of Cu Surface for Cu-Cu Pattern Direct Bonds

Cu-Cu 패턴 직접접합을 위한 습식 용액에 따른 Cu 표면 식각 특성 평가

  • Park, Jong-Myeong (School of Materials Science and Engineering, Andong National University) ;
  • Kim, Yeong-Rae (Mechanical design and automation engineering, Seoul National University of Science and Technology & Seoul Technopark) ;
  • Kim, Sung-Dong (Mechanical design and automation engineering, Seoul National University of Science and Technology & Seoul Technopark) ;
  • Kim, Jae-Won (Department of Nano-Mechanics, Korea Institute of Machinery & Materials) ;
  • Park, Young-Bae (School of Materials Science and Engineering, Andong National University)
  • 박종명 (안동대학교 신소재공학부 청정에너지소재기술연구센터) ;
  • 김영래 (서울과학기술대학교 기계설계자동화공학부 및 서울테크노파크) ;
  • 김성동 (서울과학기술대학교 기계설계자동화공학부 및 서울테크노파크) ;
  • 김재원 (한국기계연구원 나노융합기계연구본부) ;
  • 박영배 (안동대학교 신소재공학부 청정에너지소재기술연구센터)
  • Received : 2011.12.12
  • Accepted : 2012.02.24
  • Published : 2012.03.31
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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. In this work, BOE and HF wet etching of Cu line surfaces after CMP were conducted for Cu-Cu pattern direct bonding. Step height of Cu and $SiO_2$ as well as Cu dishing after Cu CMP were analyzed by the 3D-Profiler. Step height increased and Cu dishing decreased with increasing BOE and HF wet etching times. XPS analysis of Cu surface revealed that Cu surface oxide layer was partially removed by BOE and HF wet etching treatment. BOE treatment showed not only the effective $SiO_2$ etching but also reduced dishing and Cu surface oxide rather than HF treatment, which can be used as an meaningful process data for reliable Cu-Cu pattern bonding characteristics.

Cu-Cu 패턴의 직접접합 공정을 위하여 Buffered Oxide Etch(BOE) 및 Hydrofluoric acid(HF)의 습식 조건에 따른 Cu와 $SiO_2$의 식각 특성에 대한 평가를 수행하였다. 접촉식 3차원측정기(3D-Profiler)를 이용하여 Cu와 $SiO_2$의 단차 및 Chemical Mechanical Polishing(CMP)에 의한 Cu의 dishing된 정도를 분석 하였다. 실험 결과 BOE 및 HF 습식 식각 시간이 증가함에 따라 단차가 증가 하였고, BOE가 HF보다 더 식각 속도가 빠른 것을 확인하였다. BOE 및 HF 습식 식각 후 Cu의 dishing도 식각시간 증가에 따라 감소하였다. 식각 후 산화막 유무를 알아보기 위해 Cu표면을 X-선 광전자 분광법(X-ray Photoelectron Spectroscopy, XPS)를 이용하여 분석 한 결과 HF습식 식각 후 BOE습식 식각보다 Cu표면산화막이 상대적으로 더 얇아 진 것을 확인하였다.

Keywords

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