In:
ECS Meeting Abstracts, The Electrochemical Society, Vol. MA2020-01, No. 15 ( 2020-05-01), p. 1039-1039
Abstract:
The Minimal Fab concept was proposed in 2008 to produce low-volume customized devices with a low investment cost [1]. The different points of Minimal Fab compared with those of the conventional Mega Fab are as follows. (a) Wafer size is half-inch (12.5 mm), (b) the transferring and processing of the wafer are performed with a cleanliness level identical to that of a super clean room, and (c) the machine used compact dimensions of 144 cm height, 30 cm width, and 45 cm depth. Since the proposal of the Minimal Fab concept, many Minimal Fab machines and Minimal Fab processes have been developed actively for the fabrication of CMOS integrated circuits [2, 3] . However, the Minimal Fab process for MEMS sensor fabrications has not been developed sufficiently. In this work, we develop the CMOS-MEMS cointegrated process using the Minimal Fab deep-RIE and mask aligner. By using the developed process, we also fabricate and characterize the digital type CMOS-MEMS pressure sensor. The pressure sensing element in the CMOS-MEMS pressure sensor is the CMOS ring oscillator with the longitudinal PMOSFETs located at the edge areas of a thin circular diaphragm. In the device fabrication, we used (100) oriented half-inch SOI wafers, and the source-drain (SD) regions of the MOSFETs were patterned along with the 〈 110 〉 direction to effectively utilize mechanical stress induced drain current variations. As the gate material, we used a 30-nm-thick PVD-TiN layer to obtain a suitable logic gate threshold voltage of the CMOS invertors. The circular diaphragm was fabricated using Minimal Fab mask aligner and deep-RIE. It was confirmed that the oscillation frequency changes from 360 to 400 kHz by changing pressures from -40 to +40 kPa in the fabricated CMOS-MEMS cointegrated pressure sensor chip. The developed CMOS-MEMS pressure sensor is suitable for the application to the battery drive IoT sensor systems owing to its low power consumption. [1] S. Hara et al., J. Jpn. Precis. Eng., vol. 77, no. 3, p. 249, 2011. [2] Y. X. Liu et al., Jpn. J. Appl. Phys. 56, p. 06GG01-1. [3] Y. X. Liu et al., J. Appl. Phys. 57, p. 06HD03-1.
Type of Medium:
Online Resource
ISSN:
2151-2043
DOI:
10.1149/MA2020-01151039mtgabs
Language:
Unknown
Publisher:
The Electrochemical Society
Publication Date:
2020
detail.hit.zdb_id:
2438749-6
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