Surface-mountable capacitive tactile sensors with flipped CMOS-diaphragm on a flexible and stretchable bus line

Sho Asano, Masanori Muroyama, Travis Bartley, Takahiro Kojima, Takahiro Nakayama, Ui Yamaguchi, Hitoshi Yamada, Yutaka Nonomura, Yoshiyuki Hata, Hirofumi Funabashi, Shuji Tanaka

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)


This paper describes a MEMS-CMOS integrated tactile sensor for surface mounting on a flexible and stretchable bus line. The sensor is featured by the following configurations; (1) A sensing diaphragm is formed on a CMOS substrate by backside etching, and (2) the CMOS substrate is flip-bonded to a special low temperature cofired ceramic (LTCC) substrate with Au through vias. The flipped CMOS substrate and the LTCC substrate were electrically and mechanically connected using Au-Au bonding, which also formed differential capacitive gaps. The structure and fabrication process are simple compared with the existing surface-mountable MEMS-CMOS integrated sensors. Bendable and stretchable bus lines were fabricated by etching metal, which is deposited on a polyimide substrate and the outer shape is then determined by laser cutting. The bus line with a silicone protection coat is capable of stretching up to 50%. The sensors covered with silicone worked even under 10% stretching of the bus line. The tactile sensors mounted on the surface of the flexible bus line were characterized in terms of force sensitivity. Also, smart functions such as threshold and adaptation operations and the configuration of sensor parameters were demonstrated.

Original languageEnglish
Pages (from-to)167-176
Number of pages10
JournalSensors and Actuators A: Physical
Publication statusPublished - 2016 Apr 1


  • Au-Au bonding
  • Human-inspired system
  • MEMS-CMOS integration
  • Parameter configuration
  • Stretchable interconnection
  • Surface mounting
  • Tactile sensor
  • Wafer-level packaging


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