One MEMS Design Tool with Maximal Six Design Flows

ONE MEMS DESIGN TOOL WITH MAXIMAL SIX DESIGN FLOWS

Honglong Chang, Jinghui Xu, Jianbing Xie, Chengliang Zhang, Zijian Yan, Weizheng Yuan

Micro and Nano Electromechanical System Laboratory, Northwestern Polytechnical University, China, email: changhl@nwpu.edu.cn, tel: +86-29-88495102

ABSTRACT

This paper presents one MEMS design tool with total six design flows, which makes it possible that the MEMS designers are able to choose the most suitable design flow for their specific devices. The design tool is divided into three levels and interconnected by six interfaces. The three levels are lumped-element model based system level, finite element analysis based device level and process level, which covers nearly all modeling and simulation functions for MEMS design. The six interfaces are proposed to automatically transmit the design data between every two levels, thus the maximal six design flows could be realized. The interfaces take the netlist, solid model and layout as the data inlet and outlet for the system, device and process level respectively. The realization of these interfaces are presented and verified by design examples, which also proves that the enough flexibility in the design flow can really increase the design efficiency.

1. INTRODUCTION

MEMS design tools help the designers to model and simulate various MEMS devices, which have been expected to play an important role in the commercialization of MEMS as the EDA tool did in the success of microelectronics industry. Consequently the development of the MEMS CAD is directed toward one EDA-like software suite to a large extent. The system level behavior simulation and mask layout design tools are all borrowed from EDA directly. And it seems like that the top-down design concept, which dominates the mainstream in microelectronics, has become one impressing feature for almost all current commercial MEMS CAD software suites. It addresses the hierarchical synthesis and optimization from the system to the final mask layout. [1-5] However, the diversities of MEMS devices are more and more challenging for this structured design method for MEMS.
By now various MEMS devices such as gyroscopes, pressure sensors and micro mirrors with different principles, structures and processes have been invented, which makes it nearly impossible to use such one unified design flow to maximize the design efficiency of every MEMS device. For example, for the capacitive gyroscopes the top down design flow starting from the system level then directly to the process level could increase the efficiency as expectation, but for the capacitive pressure sensors the flow doesn’t work properly because the system level behavior modeling based on lumped-element model can not solve such space-continuous models properly. Therefore to establish one design tool that could provide the most suitable design flow according to the specific device’s need is one practical and effective way to accelerate the MEMS design process. Actually many commercial MEMS CAD software have begun to include various design entries at different levels to increase the flexibility of the design flow.
This paper will focus on the techniques about how to increase the flexibility of choosing design flows. And one MEMS design tool with maximal six design flows under the current popular three-level structure will be established, based on which the designers can start the design process from any level and finish it as a whole closed loop.

2. FRAMEWORK OF THE MEMS CAD

System Level Module (5) Layout to Solid Model (2) Solid Model to Layout (1) Netlist to Solid Model (6) Macromodeling (3) Layout Extraction (4) Netlist to Layout Schematic Netlist Material & Process Library Solid Model Device Level Module Process Level Module FEA & BEA Process Simulation

Mask Layout Figure 1: Framework of the proposed MEMS design tool with six data transmitting interfaces.

As shown in Fig.1 the proposed MEMS design tool consists of three levels and six interfaces. Same as other ©EDA Publishing/DTIP 2007 ISBN: 978-2-35500-000-3

Honglong Chang, Jinghui Xu, Jianbing Xie, Chengliang Zhang, Zijian Yan, Weizheng Yuan One MEMS Design Tool with Maximal Six Design Flows

commercial MEMS CAD software, the three levels include most modeling and simulation functions such as parameterized component library to support the behavior modeling and simulation, FEA simulation for the device level and layout design with process simulation in the process level, etc. Therefore the three levels are the foundation of the MEMS design tool and the order of appearance for these levels will decide the design flow of one MEMS device.
To reach the maximal flexibility of the design flow, total six interfaces are proposed to connect the different levels by transmitting the design data. The number of the inte

…(Full text truncated)…