Using single-crystal sapphire as the sensor material, we have developed the Sapphire Capacitance Diaphragm Gauge, which is high-precision, highly-reliable, and intended to be used mainly in semiconductor manufacturing processes. Single-crystal sapphire possesses extremely high corrosion resistance and heat resistance, and also possesses excellent mechanical characteristics. The gauge provides high precision even in harsh environments such as corrosive atmospheres or high temperatures, allowing us to succeed in realizing a long-term stable vacuum measurement. We have also developed high-precision measurement with high linearity and high tolerance for temperature changes, by means of signal processing using microprocessor based control.
Commissioning of Taiwan Photon Source (TPS), a 3-GeV synchrotron light source, began in 2014 summer, observed the first light on 2014 December 31, and achieved in three months the primary goals of low emittance ∼1.6 nm rad at beam current 100 mA with lifetime 6 h and top-up operation. The dynamic pressure 1.2×10−9 Pa mA−1 at accumulated beam dose 33 A h after beam cleaning and a measured broadband impedance about 0.12 Ω reflects the satisfactory vacuum performance of this electron-storage ring. The implementation of ultrahigh-vacuum systems (aluminium, length 14 m) constructed for the 24 arc-cells of TPS involved numerically controlled precise machining free of oil in an ethanol environment, cleaning with ozonized water, automatic TIG welding of aluminium chambers (large, 4 m), assembly of vacuum systems (aluminium, full length 14 m) in the clean room, baking to ultrahigh vacuum ex situ before installation, and rapid loading of the 14-m vacuum cells into the TPS tunnel with hangers for carriage and transport; associated with the engineering developments are key technologies to achieve the high quality of the ultrahigh-vacuum systems for the electron-storage ring of this accelerator light source.
We monitor the change in thickness of films deposited on the inner chamber wall of mass-production plasma etching equipment by using previously developed load impedance monitoring system. The film composed of etching reaction products causes generation of flaked particles and is a factor that decreases production yield and overall equipment effectiveness (OEE) in the mass production of LSI. The method that can monitor the change in film thickness and contribute to decreasing flaked particles is highly required. The results of this study indicate that mainly the imaginary part of load impedance changes when a film is deposited on the inner wall, and demonstrate that the system can detect changes in the film thickness without remodeling of the equipment. This real-time and noninvasive monitoring method is expected to improve the production yield and OEE, and it could be used to develop a predictive maintenance regime in future.