一种基于正面对准的CMUT制备工艺  

CMUT Preparation Process Based on Top Side Alignment

作　　者：刘书睿 秦祚敏 王靖文 曾祥铖 赵晨雅 王智豪 王任鑫[1] 杨玉华[1] Liu Shurui;Qin Zuomin;Wang Jingwen;Zeng Xiangcheng;Zhao Chenya;Wang Zhihao;Wang Renxin;Yang Yuhua(State Key Laboratory of Dynamic Measurement Technology,North University of China,Taiyuan 030051,China)

机构地区：[1]中北大学省部共建动态测试技术国家重点实验室,太原030051

出　　处：《微纳电子技术》2024年第9期168-176,共9页Micronanoelectronic Technology

基　　金：国家自然科学基金(61927807,52275578);国家重点研究发展计划(2020YFC0122102);山西省基金委研究计划(20210302123027,20210302124203)。

摘　　要：基于晶圆键合的电容式微机械超声换能器(CMUT)制备工艺凭借其对膜厚控制度高、制备过程简单且良品率高等优势,是当前CMUT的主要制备工艺之一。分析了上电极位置准确性对CMUT发射声压的影响,结合薄膜透光率和光刻机正面对准精度高的特点,提出了一种基于正面对准的CMUT制备工艺并完成了CMUT阵列的制备。制备过程中通过两种开窗工艺获得正面对准标记,通过正面对准的方式实现上电极金属图形化,提高了上电极金属制备的可重复性和准确性。挑选制备好的CMUT阵列进行了一致性测试,经测试其接收灵敏度在-207.30~-208.01 dB以内,表明基于此工艺制备的CMUT阵列具有很好的一致性,为后续大规模批量制备用于无损检测和超声医疗成像的CMUT器件奠定了基础。Capacitive micromechanical ultrasonic transducer(CMUT)based on wafer bonding is one of the main preparation processes for CMUT because of its advantages of high film thickness control,simple preparation process and high yield.The influences of the accuracy of the upper electrode position on the emission acoustic pressure were analyzed.Combining with the film transmittance and the high accuracy of photolithography top side alignment,a CMUT preparation process based on top side alignment was proposed and the preparation of CMUT arrays were completed.Top side aligned marks were obtained by two windowing processes during the preparation process,and the upper electrode metal patterning was realized through top side alignment,which improving the reproducibility and accuracy of the upper electrode metal preparation.The prepared CMUT arrays were selected for consistency test.The receiving sensitivity of the tested CMUT arrays is within-207.30--208.01 dB,indicating that the CMUT arrays prepared based on the process has a good consistency.It lays a foundation for the subsequent large-scale batch preparation of CMUT devices for non-destructive testing and ultrasonic medical imaging.

关 键 词：电容式微机械超声换能器(CMUT) 晶圆键合 正面对准 一致性 金属图形化 

分 类 号：TB552[理学—物理]