Papers by Keyword: Surface Micromachining

Abstract: The monolithic integrated technology of MEMS was discussed. First discussed the advantages and difficulties faced by the MEMS monolithic integration technology. Second the features and the process of the mainstream MEMS monolithic integration technology was introduced. And finally put forward a SOI MEMS monolithic integration technology, the technology with no high-temperature process, Post-CMOS integrated solution, compatible with the CMOS process. This technology can achieve high aspect ratio, high-performance micro-inertial devices..

Abstract: This paper describes the use of HuaJing Company Pspice Transistor Division developed a miniature accelerometer parameters and signal processing integrated circuits. This system can be on the surface micromachining process for the production of the sensor signal processing, to achieve monolithic integration, but also the fabrication of bulk silicon sensors for signal processing, and hybrid integration.

Abstract: Current MEMS design methods do not fulfill the needs of emerging complex MEMS devices. In this paper, a systematic direct solid modeling approach for surface micromachined MEMS design is proposed. In this approach, practical model of a surface micromachined MEMS device, designed in a traditional CAD environment, is simplified firstly; after simplification, masks and process sequences are generated through solid-based mask synthesis; then local variation is used to refining the 3D layer model; finally masks and process sequences are verified in rough simulation and accurate simulation. The approach aims at enabling designers to focus on creative design activity in an intuitive mode.

Abstract: A method for generating fabricating information of micro device from a feature-based design model is presented. With cooperative design mode, the process model derivation and optimization are accomplished simultaneously. This work provides designer a more intuitive way to design product by means of process verification to improve manufacturability. The key enabling technologies are introduced briefly.

Abstract: With the gradual complication of micro devices, the poor manufacturability of product becomes a bottleneck. In this paper, we discuss the optimal design method that involves the model restriction, model revising and cooperative design management. Firstly, the design rules checking for the original model is introduced, which constrains the 3D models into an appropriate form to satisfy the manufacturing requirements. Then, the informational description of micro device involves two levels. The device level modeling focuses on geometric information, while the process level modeling works at manufacturability. Based on the two level models, the model revising procedure is performed in cooperative design environment. Furthermore, a polysilicon electro-thermal actuator is used to illustrate the cooperative optimal design approach.

Abstract: This paper concentrates on how to generate manufacturing flow from the feature model of surface micromachined device. Firstly, the feature-based designing framework is presented, in which the manufacturing flow generation method plays an important role for feature mapping. Then, the graph-based approach makes benefit for the logical organizing and real-time adjusting of design features. The features combination approach is further presented to obtain layered model, which in turn corresponds to an optional manufacturing flow. In the meantime, some optimal operations are performed for better manufacturability. Finally, a polysilicon micro motor is used to illustrate the approach. In addition, the results are discussed to indicate the future work on scheme evaluation.

Abstract: A planar micro triggered spark gap switch with three electrodes was designed and fabricated based on non-silicon surface micromachining technology. It consists of two main electrodes, the shape of which is semicircle, and a triggering electrode which is a thin strip. The gap distance between two main electrodes is 800μm. Benefitting from MEMS technology, the switch is integratable and its cost has the potential to be reduced. The designed switch has been optimized and tested. It gives out a pulse current with peak of 5165.21A and 129.6ns rise time. The test data has an agreement with the simulation results.

Abstract: A monolithic MEMS accelerometer process was established. This process successfully combines our standard BiCMOS technology and MEMS surface micromachining technique. The acceleration sensing element is a kind of comb-finger structure which is built by polysilicon surface micromachining technique. The polysilicon structure is designed to form two capacitors for acceleration sensing. The external acceleration will cause the value of two capacitors to vary in different direction. That means one reduces if the other increases. It was integrated with the signal conditioning circuit. In a single die, the active devices including vertical NPN, lateral PNP, PMOS and passive devices such as capacitors, resistors were fabricated which was followed by the steps to form the acceleration sensing structure. The experiment indicates that the fabricated circuit has the function of sensing capacitive variation and with a scale factor of 100mV/g.

Abstract: A micromachining technique has been developed for the fabrication of microscale polymer-bonded magnet. Two types of lithographically defined molds, photoresist mold and electroplated metal mold, were introduced. Photoresist mold is convenient, while electroplated metal mold can be fabricated on the glass or steel substrate which can bear much more compression. NdFeB films of thickness between 50 and 500 µm were prepared by micro-patterning of composites containing 83-95wt% of commercial NdFeB powder after curing at the room temperature. Magnetic properties mainly depend on the types and percentage of volume loading of magnetic powder. Coercivity of 772.4kA/m (9.70kOe), remanence of 275.1mT (2.751kG), and energy product of 22.6kJ/m³ (2.8MGOe) have been achieved. This easily developed magnet could be a promising candidate for applications in magnetic microelectromechanical systems (MEMS).

Abstract: The fabrication process of three-dimensional (3D) high-aspect-ratio MEMS devices entirely made of electroplated metals with suspending multilayered microstructures is reported. The technology used is a LIGA-liked micromachining process, called the laminated positive photoresist sacrificial layer process (LPSLP). The LPSLP allows in UV-lithography not only for thick resist mould for electroplating of cascaded metal structures but also for the sacrificial layer for supporting mechanically the suspensions. So far the LPSLP procedure has incorporated with more than five sacrificial layers, which allows for the creation of overhanging structures and freely moving parts like out-of-plane cantilever stacks. A description of the underlying fabrication principle and processing details is discussed in this paper. Thus the proposed procedures open a low-cost route for fabricating micro-components such as cantilevers, bridges, movable electrodes, and freestanding parts.