Two High-Precision Proximity Capacitance CMOS Image Sensors with Large Format and High Resolution

Yuki Sugama; Yoshiaki Watanabe; Rihito Kuroda; Masahiro Yamamoto; Tetsuya Goto; Toshiro Yasuda; Hiroshi Hamori; Naoya Kuriyama; Shigetoshi Sugawa

doi:10.3390/s22072770

Two High-Precision Proximity Capacitance CMOS Image Sensors with Large Format and High Resolution

Sensors (Basel). 2022 Apr 4;22(7):2770. doi: 10.3390/s22072770.

Authors

Yuki Sugama¹, Yoshiaki Watanabe¹, Rihito Kuroda^{1

2}, Masahiro Yamamoto¹, Tetsuya Goto², Toshiro Yasuda³, Hiroshi Hamori³, Naoya Kuriyama⁴, Shigetoshi Sugawa²

Affiliations

¹ Graduate School of Engineering, Tohoku University, 6-6-11-811, Aza-Aoba, Aramaki, Aoba-ku, Sendai 980-8579, Miyagi, Japan.
² New Industry Creation Hatchery Center, Tohoku University, 6-6-10, Aza-Aoba, Aramaki, Aoba-ku, Sendai 980-8579, Miyagi, Japan.
³ OHT Inc., 1118-1, Nishinakajo, Kannabe-cho, Fukuyama 720-2103, Hiroshima, Japan.
⁴ LAPIS Semiconductor Co., Ltd., 2-4-8, Shin-Yokohama, Kohoku-ku, Yokohama 222-8575, Kanagawa, Japan.

Abstract

This paper presents newly developed two high-precision CMOS proximity capacitance image sensors: Chip A with 12 μm pitch pixels with a large detection area of 1.68 cm²; Chip B with 2.8 μm pitch 1.8 M pixels for a higher resolution. Both fabricated chips achieved a capacitance detection precision of less than 100 zF (10^-19 F) at an input voltage of 20 V and less than 10 zF (10^-20 F) at 300 V due to the noise cancelling technique. Furthermore, by using multiple input pulse amplitudes, a capacitance detection dynamic range of up to 123 dB was achieved. The spatial resolution improvement was confirmed by the experimentally obtained modulation transfer function for Chip B with various line and space pattens. The examples of capacitance imaging using the fabricated chips were also demonstrated.

Keywords: CMOS; high precision; high resolution; image sensor; large format; proximity capacitance.