1. The history and future prospects of Azbil’s MEMS technology
Nobuhiko Zushi, Masayuki Yoneda
For Azbil, in its mission to provide people with safety, comfort, and fulfillment, and to preserve the environment by utilizing measurement and control technology, and following its philosophy of “human-centered automation,” sensors are a key component, and microelectromechanical systems (MEMS) are a very important core technology for realizing high-performance, high-value-added sensors. Azbil noticed this early on, and in the mid-1980s began constructing a cleanroom and developing application technology for MEMS sensors. This paper looks at the history, technology, and features of major MEMS sensors and discusses future prospects.
2. Upgrading a sapphire-based capacitance manometer for reduced size and enhanced anti-deposition characteristics
Takuya Ishihara
We have developed a new vacuum gauge that dramatically improves our previous sapphire capacitance diaphragm gauge model (SPG), which was developed for use in semiconductor manufacturing processes. The sensor chip and the peripheral package structure have been thoroughly reworked for compact size, smaller volume, and high pressure resistance. The specially designed diaphragm structure now
has significantly improved resistance to deposition. Also, by separating the sensor element from the circuit boards we have been able to raise the operating temperature from 200 ºC to 250 ºC, allowing us to meet a great variety of customer needs related to continuously developing
semiconductor manufacturing processes.
3. A differential pressure sensor with ultra-overpressure resistance and an integrated overload protection system utilizing MEMS technology
Tomohisa Tokuda
Utilizing MEMS technology, including grayscale photolithography, wafer-level surface activated bonding (SAB), and a combination Bosch and non-Bosch processing technique, we have developed a differential pressure sensor with a revolutionary structure capable of resisting differential pressures approximately 630 times higher than those used at the sensor chip level. Additionally, this single sensor chip can make high-precision measurements of both differential pressure (DP) and static pressure (SP), and can measure differential pressure and pressure even when pressure exceeding the DP range is applied.
4. Design and application study of an oil-free high-sensitivity pressure sensor
Yuki Seto
The piezoresistive pressure sensor in our pressure and differential-pressure transmitters ensures high stability not only in atmospheric conditions but also in high humidity. Taking advantage of this characteristic, we decided to test whether it could handle the stress placed on a pressure sensor under sanitary specifications. Products for sanitary use must meet a number of requirements, and there are currently no sensors that satisfy the requirement for oil-free operation in particular. We welded a MEMS sensor element of our own design to a metal pressure-receiving diaphragm to directly detect strain. We were able to demonstrate that such a device could provide high-accuracy pressure sensing rivaling that of a liquid-filled sensor even without the use of oil. We also report on the technical verification of this technology with a view to applying it to force sensors for robot arms and hands.
5. Improving mass flow controller usability
Kazutaka Ohnuki
Due to a decrease in the number of skilled workers and stricter quality requirements in the mechanical, electrical, semiconductor, and other markets, automation of control involving mass flow controllers is progressing apace. Since an increasing number of measuring instruments are being managed by a limited number of operators, there is a growing demand for a quick means of ascertaining their status and for easy-to-use operating methods. By redesigning the user interface and providing better adaptability to various operating conditions, we are able to offer a mass flow controller that satisfies market demands and provides optimal control for more applications than existing products.
For the development of MEMS sensors, which is essential measurement and control technology, Azbil possesses both the MEMS sensor chip technology and the sensor packaging technology required. These capabilities enable Azbil to develop superior measurement and control devices not easily emulated by competitors. Sensor packaging must compensate for the characteristics of the MEMS sensor chip that are disadvantageous for commercialization, such as variations in film thickness across the wafer and a thermal expansion coefficient that is different from that of metals, while at the same time fully utilizing the superior characteristics of the MEMS sensor chip materials. In this paper, we report on Azbil’s sensor packaging technology.
7. New cleanroom design concepts for bringing original MEMS sensors to market efficiently
Seishi Nakano, Takashi Kurosawa
As a development base for MEMS sensors, Azbil completed the construction of a new cleanroom at its Fujisawa Technology Center in September 2022. The cleanroom’s purpose is to efficiently develop MEMS sensors and to support their mass production. The cleanroom, along with the young engineers who have grown through their involvement in its construction and equipment installation, is expected to be a long-term foundation for the development of technology for Azbil’s sensing and control business.
