Research On MEMS System-Level Simulation Based On Macromodel

With the appearance of CMOS-MEMS and other various new integrated manufacturing process for the continuous development and compatibility between the micro-nanofabrication technology and integrated circuit manufacturing process, the focus of MEMS production has changed from the early research of individual MEMS device to the current complex system integrated with functional structure of MEMS devices and circuits for mixed-signal processing unit, such as System on Chip (SOC) and System in Package (SIP) representatively. Rapid modeling and simulation on the overall behavior of MEMS devices by computer-aided design tools for MEMS are required for high integration and system functional diversification of MEMS components, and MEMS-design technology inspired by idea of structural designing achieves a significant development. System-level simulation methods based on macromodel which can get behavior characteristic of MEMS have become a famous research field specific to the across multiple coupled energy domains. Aiming at the requirements of fast system-level modeling and simulation as well as the characteristics of multiple energy domains interaction, research works in this paper are presented as follows:Analytical macromodels for linear beam, nonlinear beam, rigid plate, flexible plate, electrostatic gap, electrostatic comb, "V" shaped drive and other common regular structure for MEMS are established using the analytical method based on the basic theory of structural mechanics. Macromodels are described by MAST hardware language and put into the model library of ARCHITECT module in the CoventorWare software. An on-chip tensile testing structure is designed and optimized by the combined use of the self-built component models and the library structure and circuit elements in commercial software, achieving a high model accuracy according to system-level simulation results.A refined approach producing MEMS numerical macromodels is proposed by generating the iterative Krylov subspace using a refined Arnoldi algorithm, and project polycondensing the degree of freedom (DOF) of the original system equations described by the state space method in the Krylov subspace based on the transfer function moment matching principle. Compared with traditional methods, the refined approach improves approximation accuracy of the system matrix eigenvalues equivalent to a more accurate approximation to the poles of the system transfer function, obtaining a reduced-order model accuracy. Finite element reduced-order macromodel for V-shaped driven electrothermal microgripper is achieved using this method, and simulation results show that accuracy meets with general requirement. A new Model Order Reduction- Precise Integration Method (MOR-PIM) method for the solution of nonlinear dynamic problems in MEMS area is provided. Model Order Reduction method based on Krylov subspace projection is applied to the precise integration method to enhance its computing and storage efficiency by reduced-order processing the index matrix, therefore precise integration algorithm is more suitable for the nonlinear and non-conservative dynamical systems with multi-degree of freedom and variable coefficients, offering new ideas to system-level simulation.MEMS_DUT platform for system-level simulation is developed according to MEMS CAD structural idea. Finite element model (FEM) of the device developed secondary by ANSYS software is transformed to macromodel after reduced-order processing by the dynamic link library with MATLAB language of reduced-order algorithm encapsulated on the platform of VC++6.0 compiler throughout the whole flow, and dynamic characteristic of MEMS system is performed by the system-level simulation of macromodel built by embedding in Simulink which is the system-level simulation platform emulator.Finally, the on-chip tensile testing structures actuated by electrothermal V-shape beam and fatigue testing structures actuated by electrothermal and electrostatic methods respectively are system-level simulated on the MEMS_DUT simulation platform to verify the whole flow and the performance for accuracy and efficiency of the MEMS_DUT platform. And several advices about improving model order reduction algorithm and optimizing the system-level simulation tool has been proposed.