Journal of the Korean Society for Nondestructive Testing (비파괴검사학회지)

The Korean Society for Nondestructive Testing (한국비파괴검사학회)
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Development of capacitive Micromachined Ultrasonic Transducer (II) - Analysis of Microfabrication Process

미세가공 정전용량형 초음파 탐촉자 개발(II) - 미세공정기술 분석

  • Kim, Ki-Bok (Center for Environment & Safety Measurement, Korea Research Institute of Standards and Science) ;
  • Ahn, Bong-Young (Center for Environment & Safety Measurement, Korea Research Institute of Standards and Science) ;
  • Park, Hae-Won (Center for Environment & Safety Measurement, Korea Research Institute of Standards and Science) ;
  • Kim, Young-Joo (Center for Environment & Safety Measurement, Korea Research Institute of Standards and Science) ;
  • Kim, Kuk-Jin (Center for Environment & Safety Measurement, Korea Research Institute of Standards and Science) ;
  • Lee, Seung-Seok (Center for Environment & Safety Measurement, Korea Research Institute of Standards and Science)
  • 김기복 (한국표준과학연구원 환경안전계측센터) ;
  • 안봉영 (한국표준과학연구원 환경안전계측센터) ;
  • 박해원 (한국표준과학연구원 환경안전계측센터) ;
  • 김영주 (한국표준과학연구원 환경안전계측센터) ;
  • 김국진 (한국표준과학연구원 환경안전계측센터) ;
  • 이승석 (한국표준과학연구원 환경안전계측센터)
  • Published : 2004.12.30
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Abstract

The main goal of this study was to develop a micro-fabrication process for the capacitive micromachined ultrasonic transducer (cMUT). In order to achieve this goal, the former research results of the micro-electro-mechanical system (MEMS) process for the cMUT were analyzed. The membrane deposition, sacrificial layer deposition and etching were found to be a main process of fabricating the cMUT. The optimal conditions for those microfabrication were determined by the experiment. The thickness, uniformity, and residual stress of the $Si_3N_3$ deposition which forms the membrane of the cMUT were characterized after growing the $Si_3N_3$ on Si-wafer under various process conditions. As a sacrificial layer, the growth rate of the $SiO_2$ deposition was analyzed under several process conditions. The optimal etching conditions of the sacrificial layer were analyzed. The microfabrication process developed in this study will be used to fabricate the cMUT.

본 연구는 cMUT 제작을 위한 미세공정기술을 개발하기 위하여 수행되었다. 이를 위하여 외국의 관련 제조공정 연구결과들을 분석하였다. cMUT 제작의 주요 공정인 미소 진동 박막 형성, 희생층 형성, 식각 공정에 대한 실험을 수행하여 적절한 공정조건을 찾고자 하였다. 각 제작 공정조건들을 변화시켜 가면서 증착된 실리콘 질화막의 두께, 균일도, 잔류응력을 측정하였다. 희생층으로서 실리콘 산화막의 공정조건을 변화시켜 가면서 산화막의 성장률을 분석하였다. 마지막으로 희생층 식각을 위한 최적 식각공정을 얻기 위한 실험을 수행하였다. 본 연구에서 얻어진 주요 미세공정 조건은 추후 cMUT 제작에 적용될 예정이다.

Keywords

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