Journal of the Microelectronics and Packaging Society (마이크로전자및패키징학회지)

The Korean Microelectronics and Packaging Society (한국마이크로전자및패키징학회)
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Recent Advances in Fine Pitch Cu Pillar Bumps for Advanced Semiconductor Packaging

첨단 반도체 패키징을 위한 미세 피치 Cu Pillar Bump 연구 동향

  • Eun-Chae Noh (Department of Advanced Materials Engineering, Chungbuk National University) ;
  • Hyo-Won Lee (Department of Advanced Materials Engineering, Chungbuk National University) ;
  • Jeong-Won Yoon (Department of Advanced Materials Engineering, Chungbuk National University)
  • 노은채 (충북대학교 신소재공학과) ;
  • 이효원 (충북대학교 신소재공학과) ;
  • 윤정원 (충북대학교 신소재공학과)
  • Received : 2023.08.18
  • Accepted : 2023.09.11
  • Published : 2023.09.30
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Abstract

Recently, as the demand for high-performance computers and mobile products increases, semiconductor packages are becoming high-integration and high-density. Therefore, in order to transmit a large amount of data at once, micro bumps such as flip-chip and Cu pillar that can reduce bump size and pitch and increase I/O density are used. However, when the size of the bumps is smaller than 70 ㎛, the brittleness increases and electrical properties decrease due to the rapid increase of the IMC volume fraction in the solder joint, which deteriorates the reliability of the solder joint. Therefore, in order to improve these issues, a layer that serves to prevent diffusion is inserted between the UBM (Under Bump Metallization) or pillar and the solder cap. In this review paper, various studies to improve bonding properties by suppressing excessive IMC growth of micro-bumps through additional layer insertion were compared and analyzed.

최근, 고사양 컴퓨터, 모바일 제품의 수요가 증가하면서 반도체 패키지의 고집적화, 고밀도화가 요구된다. 따라서 많은 양의 데이터를 한 번에 전송하기 위해 범프 크기 및 피치 (Pitch)를 줄이고 I/O 밀도를 증가시킬 수 있는 플립 칩 (flip-chip), 구리 필러 (Cu pillar)와 같은 마이크로 범프 (Micro-bump)가 사용된다. 하지만 범프의 직경이 70 ㎛ 이하일 경우 솔더 (Solder) 내 금속간화합물 (Intermetallic compound, IMC)이 차지하는 부피 분율의 급격한 증가로 인해 취성이 증가하고, 전기적 특성이 감소하여 접합부 신뢰성을 악화시킨다. 따라서 이러한 점을 개선하기 위해 UBM (Under Bump Metallization) 또는 Cu pillar와 솔더 캡 사이에 diffusion barrier 역할을 하는 층을 삽입시키기도 한다. 본 review 논문에서는 추가적인 층 삽입을 통해 마이크로 범프의 과도한 IMC의 성장을 억제하여 접합부 특성을 향상시키기 위한 다양한 연구를 비교 분석하였다.

Keywords

Acknowledgement

이 논문은 2023년도 정부(과학기술정보통신부)의 재원으로 한국연구재단의 지원(No. 2021R1A2C1009714, No. RS-2023-00247545)과 2023년도 정부(산업통상자원부)의 재원으로 한국산업기술진흥원의 지원(P0008458, 산업혁신인재성장지원사업)을 받아 수행된 연구임

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