MEMS压电超声换能器二维阵列的制备方法

Fabrication Method of 2-Dimensional Piezoelectric Micromachined Ultrasonic Transducer Arrays

针对超声换能器阵列中阵元密度难以提升和工艺重复性差等问题,提出了一种基于硅-硅键合技术的MEMS压电超声换能器二维阵列的制备方法,并采用该方法制备了阵元间距小至150μm的密排二维换能器阵列。阵列中每个声学单元均为由上电极、压电材料(PZT)层、下电极和支撑层组成的多层膜结构,并通过其弯曲振动模式实现超声波的发射和接收。制备样品的测试结果表明,采用该方法制作MEMS压电超声换能器阵列,具有阵元间距小、工艺流程可靠、成品率高、一致性好、工作频率(2.45MHz)与设计值(2.5MHz)的吻合度高等优点,适用于医学成像等高频超声成像系统。

A fabrication method of 2D piezoelectric micromachined ultrasonic transducer（pMUT） arrays based on the silicon-silicon bonding was presented to solve the problems that the array element density was hard to improve,the process repeatability was poor,etc.The compact 2D transducer array with the element pitch down to 150 μm was fabricated by this method.Each sound-radiating element in the array consists of the top electrode,PZT layer,bottom electrode and supporting layer,which forms the multilayer film structure.And the ultrasonic transmission and reception were achieved through the bending vibration model.The test result of the sample indicates that the MEMS piezoelectric ultrasonic transducer array fabricated with the method is of small array element spacing,reliable process flow,high yield,good uniformity,excellent consistency between the operational frequency（2.45 MHz） and the designed value（2.5 MHz） and other advantages.Thus,it is suitable for the high frequency ultrasound imaging system,such as the medical imaging.