Realization of Three-Dimensionally MEMS Stacked Comb Structures for Microactuators Using Low-Temperature Multi-Wafer Bonding with Self-Alignment Techniques in CMOS-Compatible Processes

Abstract

A high-aspect-ratio three-dimensionally (3D) stacked comb structure for micromirror application is demonstrated by wafer bonding technology in CMOS-compatible processes in this work. A vertically stacked comb structure is designed to circumvent any misalignment issues that could arise from multiple wafer bonding. These out-of-plane comb drives are used for the bias actuation to achieve a larger tilt angle for micromirrors. The high-aspect-ratio mechanical structure is realized by the deep reactive ion etching of silicon, and the notching effect in silicon-on-insulator (SOI) wafers is minimized. The low-temperature bonding of two patterned wafers is achieved with fusion bonding, and a high bond strength up to 2.5 J/m2 is obtained, which sustains subsequent processing steps. Furthermore, the dependency of resonant frequency on device dimensions is studied systematically, which provides useful guidelines for future design and application. A finalized device fabricated here was also tested to have a resonant frequency of 17.57 kHz and a tilt angle of 70° under an AC bias voltage of 2 V.

Design and Measurement of Microelectromechanical Three-Axis Magnetic Field Sensors Based on the CMOS Technique

“…Various micro components [ 29 , 30 , 31 , 32 , 33 ] and devices [ 34 , 35 , 36 , 37 , 38 ] are manufactured employing the CMOS process. Micro MFSs developed by this process have many benefits [ 27 , 28 ].…”

Fabrication and Characterization of Photovoltaic Microgenerators Using the Complementary Metal Oxide Semiconductor Process

“…Various microsensors [19][20][21][22][23], actuators [24][25][26][27][28][29], and devices [30][31][32][33][34] have been fabricated using the CMOS-MEMS technique. Photovoltaic microgenerators created through this technique offer improved efficiency, compactness, versatility, and cost-effectiveness, making them well-suited for a wide range of applications [35][36][37][38][39], including self-powered sensors, wearable devices, and internet of things (IoT).…”