Applied Chemistry for Engineering (공업화학)

The Korean Society of Industrial and Engineering Chemistry (한국공업화학회)
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Analysis of Adhesion Force and Adhesive Energy of Ag Thin Films under Pressure Conditions Using Nanoscratch Test

나노스크래치 테스트를 활용한 가압 조건에 따른 Ag 박막의 접합력 및 접합에너지 분석

  • YeonKyeong Park (School of Materials Science and Engineering, University of Ulsan) ;
  • Jun-Hyuk Choi (Nano-lithography & Manufacturing Research Center, Korea Institute of Machinery & Materials) ;
  • Dae-Geun Choi (Nano-lithography & Manufacturing Research Center, Korea Institute of Machinery & Materials) ;
  • Joo-Yun Jung (Nano-lithography & Manufacturing Research Center, Korea Institute of Machinery & Materials) ;
  • Eun-chae Jeon (School of Materials Science and Engineering, University of Ulsan)
  • 박연경 (울산대학교 첨단소재공학부) ;
  • 최준혁 (한국기계연구원 나노리소그래피연구센터) ;
  • 최대근 (한국기계연구원 나노리소그래피연구센터) ;
  • 정주연 (한국기계연구원 나노리소그래피연구센터) ;
  • 전은채 (울산대학교 첨단소재공학부)
  • Received : 2024.11.02
  • Accepted : 2024.11.18
  • Published : 2024.12.10
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Abstract

The demand for ultra-high-resolution organic light-emitting diodes (OLED) continues to rise, thereby driving extensive research into transfer processes aimed at overcoming the physical limitations of conventional deposition methods. As a process that transfers target materials from a transfer mold to a substrate, the transfer process requires the adhesion between the target material and the substrate to exceed the adhesion of the transfer mold for effective bonding. To achieve this, pressure is often applied during transfer; however, excessive pressure can potentially damage the device, making it essential to thoroughly analyze the adhesion between the target material and substrate under varying applied pressure. In this study, nanoscratch testing, capable of detailed quantitative nanoscale analysis, was employed to evaluate the adhesion and adhesion energy between the target material and substrate in OLED devices subjected to different pressures. As a result, the adhesion significantly increased under an applied pressure of 5 bar compared to conditions without applied pressure or with 1 bar of pressure, with no delamination occurring until the Si substrate fractured. The fracture loads varied among specimens without delamination, enabling a quantitative comparison of adhesion. These findings confirm that applying appropriate pressure during the transfer process can produce devices with superior adhesion compared to deposition methods.

초고해상도 organic light-emitting diode (OLED)의 수요가 꾸준히 증가하면서 기존 증착 공정의 물리적인 한계를 극복하기 위해 전사 공정을 활용한 연구들이 활발히 진행되고 있다. 전사 공정은 전사 몰드 위의 타깃 물질을 기판으로 옮기는 공정이므로 전사 기판과 타깃 물질 간의 접합력이 전사 몰드의 접합력보다 높아야 한다. 이를 위해 전사 시 압력을 인가하는 경우가 많은데, 너무 높은 압력은 소자에 손상을 줄 수 있으므로 인가 압력에 따른 타깃 물질과 기판간 접합력 분석이 필요하다. 이에 본 연구에서는 나노스케일에 대한 정량적인 분석이 가능한 나노스크래치 테스트를 활용하여 OLED용 소자에 인가 압력에 따른 타깃 물질과 기판 간의 접합력 및 접합에너지를 분석하였다. 그 결과, 압력을 인가하지 않거나 1 bar의 압력을 인가하였을 때보다 5 bar의 압력을 인가하였을 때 접합력이 월등히 증가하여 Si 기판이 파괴될 때까지 박리가 발생하지 않았다. 이때, 박리가 발생하지 않은 시편들의 기판 파괴 하중이 서로 달랐으며 이 차이를 사용하여 접합력을 정량적으로 비교하였다. 이를 통해 전사 공정 시 적절하게 압력을 인가하면 증착 공정보다 더 우수한 접합력을 갖는 소자를 제작할 수 있음을 확인하였다.

Keywords

Acknowledgement

본 연구는 2024년도 산업통상자원부 및 산업기술평가관리원(KEIT) 연구비 지원에 의한 연구임. (과제번호: 20019400, 과제명: 초고해상도 구현을 위한 OLED 디스플레이용 메타 표면 구조 설계제조 기술개발)

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