Journal of the Microelectronics and Packaging Society (마이크로전자및패키징학회지)

The Korean Microelectronics and Packaging Society (한국마이크로전자및패키징학회)
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Micro-LED Mass Transfer using a Vacuum Chuck

진공 척을 이용한 마이크로 LED 대량 전사 공정 개발

  • Kim, Injoo (Dept. of Mechanical Design and Robot Engineering, Seoul National University of Science and Technology) ;
  • Kim, Yonghwa (Dept. of Mechanical System Design Eng. Seoul National University of Science and Technology) ;
  • Cho, Younghak (Dept. of Mechanical System Design Eng. Seoul National University of Science and Technology) ;
  • Kim, Sungdong (Dept. of Mechanical System Design Eng. Seoul National University of Science and Technology)
  • 김인주 (서울과학기술대학교 일반대학원 기계설계로봇공학과) ;
  • 김용화 (서울과학기술대학교 기계시스템디자인공학과) ;
  • 조영학 (서울과학기술대학교 기계시스템디자인공학과) ;
  • 김성동 (서울과학기술대학교 기계시스템디자인공학과)
  • Received : 2022.06.20
  • Accepted : 2022.06.30
  • Published : 2022.06.30
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Abstract

Micro-LED is a light-emitting diode smaller than 100 ㎛ in size. It attracts much attention due to its superior performance, such as resolution, brightness, etc., and is considered for various applications like flexible display and VR/AR. Micro-LED display requires a mass transfer process to move micro-LED chips from a LED wafer to a target substrate. In this study, we proposed a vacuum chuck method as a mass transfer technique. The vacuum chuck was fabricated with MEMS technology and PDMS micro-mold process. The spin-coating approach using a dam structure successfully controlled the PDMS mold's thickness. The vacuum test using solder balls instead of micro-LED confirmed the vacuum chuck method as a mass transfer technique.

마이크로 LED는 크기가 100 ㎛ 이하인 LED 소자로 기존 LED에 비해 해상도, 밝기 등 여러 면에서 우수한 성능을 보일 뿐 아니라 유연 디스플레이, VR/AR 등 다양한 분야에 적용이 가능하다. 마이크로 LED 디스플레이를 제작하기 위해선 LED 웨이퍼로부터 최종기판으로 마이크로 LED를 옮기는 전사 공정이 필수적이며, 본 연구에서는 진공 척을 이용하여 마이크로 LED를 고속 대량 전사하는 방식을 제안하고 이를 검증하였다. MEMS 기술을 이용한 PDMS 마이크로 몰딩 공정을 통해 진공 척을 제작하였으며, PDMS 몰딩 공정을 제어하기 위해 댐 구조를 이용한 스핀 코팅 공정을 성공적으로 적용하였다. 솔더볼을 이용한 진공 척 구동 실험을 통해 진공 척을 이용한 마이크로 LED의 대량 전사 가능성을 확인하였다.

Keywords

Acknowledgement

논문은 2022년도 정부(산업통상자원부)의 재원으로 한국산업기술진흥원의 지원을 받아 수행된 연구임(P0012744, 2022년 산업혁신인재성장지원사업).

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