Key Engineering Materials Vols. 645-646

Abstract: The article brings out a digital silicon gyroscopes closed-loop driving system using the phase relationship of the input driving signal and the signal of the forced motion of the mass block in sensor structure based on analyzing the working principle and phase characters of digital silicon gyroscopes. We make a low-cost, simple and high precision measurement technique for resonant frequency of silicon micro-machinery gyroscopes by the whole digital locked loop system designed with MicroBlaze method. Dichotomy and Fourier transform spectrometry method constitute the algorithm of the system and the solution precision can be determined by the number of the times of approximation. Under the control of the MicroBlaze softcore, the system realizes the realization of the digital signal, the high speed frequency transformation, the acquisition of mass block response signal and the calculation of phase difference. Lastly, each module of the system and the whole system are simulated, the whole system is approved on the test broad.

Abstract: A micro biochemical sensor based on a SOI optical waveguide sensing platform is reported in this article. The sensing platform utilizes a Mach-Zehnder Interferometer (MZI) configuration. In order to satisfy the single-mode transmission condition of the waveguide and match the coupling size of standard single-mode fiber, a ridge waveguide structure is adopted to construct the MZI configuration. The key parameters of the waveguide are optimized by FDTD method. A process composed of contact exposure photolithography and Inductively Coupled Plasma (ICP) etching technology has been worked out for the fabrication of the optical waveguide sensing platform on SOI wafer. In the process, only one photolithographic mask is used. The mask is designed to have several patterns including an array of MZI configurations for multiple species sensing, a group of ridge waveguides with different key parameters as test references, and a group of geometric compensation schemes to test the methods of modifying the deviation which may arise during the ICP etching step. Process simulations are conducted to predict the exposure and etching results, which give strong support to the fabrication process control. Lithography problems including photoresist desquamation and line narrowing are solved to achieve the special structure.

Abstract: In this paper, we focus on the electroplating technology used for RF micro inductor coil. The technological parameters in DC electroplating are determined by SEM, linear sweep voltammetry and so on. It turns out that a high quality of plating layer is obtained when the PH value of electrochemical solution is 9, temperature is 45°C,current density is 1 A/dm², additive is added and stirred slowly. Then the research on pulse electroplating is conducted on the basis of DC electroplating, and the result indicates that the pulse plating layer is of better quality compared with DC plating layer. Afterwards, surface structure and resistance of the copper layer are analyzed, demonstrating the obtained coating layer is good enough to be the main structure of micro inductor coil. In the end, this electroplating technology is applied to micro inductor coil. The simulation, fabrication, package and test of micro inductor coil are introduced briefly.

Abstract: Inductance detection methods of metal particle in hydraulic oil are generally based on the inductance change detection. With this method, when particles pass through the microchannel, ferromagnetic and non-ferromagnetic metal particle can be distinguished by monitoring inductance. In this study, it was found that not only inductance pulse but also resistance pulse was produced when detecting particle by inductance detection method. The theory of inductance or resistance change caused by particle is presented from the perspective of electromagnetism in this paper. To verify this phenomenon, the oil sample mixed with different metal particles was forced through the detection coil of microfluidic by constant flow rate. Then several sizes of iron and copper particles were measured. Experimental results showed that the resistance pulses caused by iron particles and copper particles were positive. And for copper particle, SNR (Signal Noise Ratio) of copper particles detected in improved effectively by detecting the resistance pulse.

Abstract: This paper describes the stability research of MEMS spring used in fuze. The micro-spring in thickness dimension is thin, while the size of axial direction is larger, during compression the micro-spring is prone to suffering buckling and become unstable. In order to consider the extreme environments in launch, this paper aims to carry out buckling simulation in high or low temperature, by using FEM analysis. The effect of temperature load on the micro-spring buckling can be obtained. These researches can provide theory reference for the design applications and reliability analysis of micro-spring, and also lay the foundation for the response characteristics of the micro-scale elastic components under compressive force.

Abstract: In this paper, we demonstrate the design ‚ optimization and simulation of an electric field microsensor based on PZT piezoelectric interdigitated cantilevers driven. The working principle is introduced, and the induced charge ability of the sensitive cantilever structure is simulated and analyzed using finite element analysis (FEA) method. A multilayer compound cantilever structure (Al/Si₃N₄/Pt/PZT/Pt/Ti/SiO₂/Si) have been designed as the sensing element and PbZr_xTi_(1-x)O₃ (PZT) thin film is used as the piezoelectric material to drive the cantilevers vibrating. This microsensor is fabricated based on the simulation results. The electric field microsensor is tested under the direct current electric field with the field intensity from 0 to 45000 v/m, and the output voltage signal of the microsensor showed a good linear response to the intensity of applied electric field.

Abstract: A novel digitally-programmable delay-time microchip is introduced in this paper, which is based on detonating system. In order to make the detonating system more safety and reliability, C-MBUS is proposed in this paper. The programmable delay-time detonator can get power and data from Logger simultaneously. As a conclusion, the programmable delay time of this microchip ranges from 1 millisecond to 10000 milliseconds using the dedicated programming device, and the time programmable increment step can reach 1 millisecond. With its safety and reliability, its accuracy in delay time and its easy use, it will be extensively applicable to complicated blasting engineering of high quality.

Abstract: Micro-structure dimension metrology is a grand challenge to current metrological methods and tools. In this paper, a retraceable metrological scanning electron microscopy (M-SEM) system with precision stage and laser interferometer is presented in detail. The double stages structure is used to realize both sample positioning in 50mm×50mm range and accuracy imaging in several tens of micron scale. In order to acquiring metrological scanning image, the control system based on digital signal processing (DSP) is constructed. Furthermore, this paper focuses on demonstrating a metrological SEM image edge detection algorithm which is the essential part of the metrological SEM system to realize the traceable metrology of line width.

Abstract: Atomic force microscope (AFM) is widely used to measure nanoforce in the analysis of nanomechanical and biomechanical properties. As the critical factor in the nanoforce measurement, the stiffness of the AFM cantilever must be determined properly. In this paper, an accurate and SI-traceable calibration method is presented to obtain the stiffness of the AFM cantilever in the normal direction. The calibration system consists of a homemade AFM head and an ultra-precision electromagnetic balance. The calibration is based on the Hooke's law i.e. the stiffness is equal to the force divided by the deflection of the cantilever. With this system, three kinds of cantilevers were calibrated. The relative standard deviation is better than 1%. The results of these experiments showed good accuracy and repeatability.

Abstract: The capacitance among the structure of the accelerometer is rather small, usually at sub-pF level. Detection of the capacitance among the sensor’s tiny structure and analysis of the variation of these capacitances are necessary to improve the sensor’s performance. In this paper, one capacitance detect circuit for minimal capacitance is designed. Simulation and experiment results indicate a good linearity when the circuit is applied to detect capacitance range from 0.5pF to 5pF.