Kim, Hae Youn Kang, Dong-Hyun Lee, Byung Chul Khuri-Yakub, Butrus T. Kim, Jinsik 2024-01-19T09:09:35Z 2024-01-19T09:09:35Z 2022-02-26 2020-09 1948-5719 https://pubs.kist.re.kr/handle/201004/113593 A capacitive micromachined ultrasonic transducer (CMUT) with substrate-embedded springs has been demonstrated high transmit efficiency with non-flexural parallel-plate piston movement. In this paper, we introduce whole wafer-scale uniform nanometer silicon posts with a fabrication technique of combination between DRIE and RIE. In order to maintain our fabrication cost-effective, a photomask with a minimum feature size of 2.0 mu m was used for whole wafer-scale photolithography, and a size-reduced RIE process followed by DRIE was conducted for achieving the sub-micron or nanometer post area. Furthermore, In-situ nanomechanical tests of the fabricated silicon posts were conducted using a pico-indenter (PI 85L Pico-Indenter, Bruker) monitored under a scanning electron microscopy. The length and the diameter of the silicon post after size-reduction by RIE are measured as 5.6 mu m and 0.74 mu m, respectively. The uniformity across the whole 4-inch wafer is less than 5%. The loading-unloading graph by In-situ nanomechanical experiments confirmed that the silicon posts could consistently achieve above 6% elastic strain. We are currently applying this nanometer springs to the CMUTs with substrate-embedded springs. English IEEE Wafer-scale Fabrication of Nanometer Silicon Posts for Capacitive Micromachined Ultrasonic Transducers with Substrate-Embedded Springs Conference 1 IEEE International Ultrasonics Symposium (IEEE IUS) IEEE International Ultrasonics Symposium (IEEE IUS) US Las Vegas, NV 2020-09-07 PROCEEDINGS OF THE 2020 IEEE INTERNATIONAL ULTRASONICS SYMPOSIUM (IUS) 000635688900225 2-s2.0-85097875439