@article{24a2fff1b73249989cad532bfa0d5f60,
title = "3-axis fully-integrated capacitive tactile sensor with flip-bonded CMOS on LTCC interposer",
abstract = "This paper reports a 3-axis fully integrated differential capacitive tactile sensor surface-mountable on a bus line. The sensor integrates a flip-bonded complementary metal-oxide semiconductor (CMOS) with capacitive sensing circuits on a low temperature cofired ceramic (LTCC) interposer with Au through vias by Au-Au thermo-compression bonding. The CMOS circuit and bonding pads on the sensor backside were electrically connected through Au bumps and the LTCC interposer, and the differential capacitive gap was formed by an Au sealing frame. A diaphragm for sensing 3-axis force was formed in the CMOS substrate. The dimensions of the completed sensor are 2.5 mm in width, 2.5 mm in length, and 0.66 mm in thickness. The fabricated sensor output coded 3-axis capacitive sensing data according to applied 3-axis force by three-dimensional (3D)-printed pins. The measured sensitivity was as high as over 34 Count/mN for normal force and 14 to 15 Count/mN for shear force with small noise, which corresponds to less than 1 mN. The hysteresis and the average cross-sensitivity were also found to be less than 2% full scale and 11%, respectively.",
keywords = "3-axis tactile sensor, Au-Au thermo-compression bonding, Capacitive sensor, Low temperature cofired ceramic, MEMS-CMOS integration",
author = "Sho Asano and Masanori Muroyama and Takahiro Nakayama and Yoshiyuki Hata and Yutaka Nonomura and Shuji Tanaka",
note = "Funding Information: Acknowledgments: This study was performed in R & D Center of Excellence for Integrated Microsystems, Tohoku University under the program “Formation of Innovation Center for Fusion of Advanced Technologies” supported by Special Coordination Funds for Promoting Science and Technology. This work was supported by VLSI Design and Education Center (VDEC), the University of Tokyo in collaboration with Synopsys, Inc., Cadence Design Systems, Inc. and Mentor Graphics, Inc. This work was partially supported by Grant-in-Aid for JSPS Research Fellow (Grant number 16J01558). The authors would like to thank Hitachi Chemical Co., Ltd. for providing ACF. The authors would also like to thank Travis Bartley who previously belonged to Tohoku University for developing measurement system software. Funding Information: Acknowledgments: This study was performed in R & D Center of Excellence for Integrated Microsystems, Tohoku University under the program “Formation of Innovation Center for Fusion of Advanced Technologies” supported by Special Coordination Funds for Promoting Science and Technology. This work was supported by VLSI Design and Education Center (VDEC), the University of Tokyo in collaboration with Synopsys, Inc., Cadence Design Systems, Inc. and Mentor Graphics, Inc. This work was partially supported by Grant-in-Aid for JSPS Research Fellow (Grant number 16J01558). The authors would like to thank Hitachi Chemical Co., Ltd. for Publisher Copyright: {\textcopyright} 2017 by the authors. Licensee MDPI, Basel, Switzerland.",
year = "2017",
month = nov,
doi = "10.3390/s17112451",
language = "English",
volume = "17",
journal = "Sensors",
issn = "1424-3210",
publisher = "Multidisciplinary Digital Publishing Institute (MDPI)",
number = "11",
}