The plasma process is often used in the fabrication of semiconductor wafers. However, due to the lack of real-time etching control, this may result in some unacceptable process performances and thus leads to significant waste and lower wafer yield. In order to maximize the product wafer yield, a timely and accurately process fault or abnormal detection in a plasma reactor is needed. Optical emission spectroscopy (OES) is one of the most frequently used metrologies in in-situ process monitoring. Even though OES has the advantage of non-invasiveness, it is required to provide a huge amount of information. As a result, the data analysis of OES becomes a big challenge. To accomplish real-time detection, this work employed the sigma matching method technique, which is the time series of OES full spectrum intensity. First, the response model of a healthy plasma spectrum was developed. Then, we defined a matching rate as an indictor for comparing the difference between the tested wafers response and the health sigma model. The experimental results showed that this proposal method can detect process faults in real-time, even in plasma etching tools.

Recently, saving the cooling power in servers by controlling the fan speed has attracted considerable attention because of the increasing demand for high-density servers. This paper presents an optimal self-tuning proportional-integral-derivative (PID) controller, combining a PID neural network (PIDNN) with fan-power-based optimization in the transient-state temperature response in the time domain, for a server fan cooling system. Because the thermal model of the cooling system is nonlinear and complex, a server mockup system simulating a 1U rack server was constructed and a fan power model was created using a third-order nonlinear curve fit to determine the cooling power consumption by the fan speed control. PIDNN with a time domain criterion is used to tune all online and optimized PID gains. The proposed controller was validated through experiments of step response when the server operated from the low to high power state. The results show that up to 14% of a server’s fan cooling power can be saved if the fan control permits a slight temperature response overshoot in the electronic components, which may provide a time-saving strategy for tuning the PID controller to control the server fan speed during low fan power consumption.

Infrared dedicated short‐range communication (IR‐DSRC) has been used in single‐lane vehicle‐to‐roadside applications, and is challenged for its application in multi‐lane‐free‐flow vehicle‐to‐vehicle (V2V) conditions. However, based on IR positioning technology, the IR‐DSRC is expected to be useful and valuable under V2V conditions for several intelligent‐transportation‐system applications. In the previous studies, a three‐dimensional IR positioning system was developed to position a preceding vehicle. However, the positioning performance degrades as the longitudinal or the lateral distance between vehicles increases because the resolution of the received signal is deteriorated for weak signals. In this study, onboard units (OBUs) with wide radiation‐pattern designs and automatic radiation‐strength control are realised to provide stable signal strength for positioning, and the non‐ideality of the IR positioning system is compensated by the calibrating procedures as well. A two‐vehicle trial is performed, in which the positioning OBU is installed on the most front of the following vehicle to reduce the scattering effect of the vehicle body. The experimental result demonstrates that the positioning performance is greatly improved after aforementioned improvements.

The vertical comb electrodes capacitive sensor (VCECS) has been widely used in inertia sensors, resonant sensors, and pressure sensors, etc. In this paper, we present an improved microspring, called a W-form spring, that provides a large stiffness ratio in an out-of-plane direction while retaining a long sensing range for a VCECS. The stiffness ratio, defined as the ratio of the stiffness in the lateral direction to the out-of-plane direction, is an important parameter for determining the stability of the VCECS. To realize the properties of the W-form spring, such as the spring constant and stiffness ratio, theoretical analysis and numerical simulations are performed. In addition, VCECSs with W-form and other springs have been fabricated using microelectromechanical systems (MEMS) micromachining technology. The spring constants of the sensor have been calculated from simulations and measured results. The characteristics among different suspension springs are compared. According to the numerical simulations and experiment results, the working range and stability of the device are both improved for the VCECS by using the W-form suspension spring.