Digital Light Processing (DLP) Mirror
Coventor offers a comprehensive suite of software tools for designing integrated MEMS+IC devices. SEMulator3D is used to build 3D models of complex MEMS structures and CMOS circuits and to visualize the electrical connectivity between them. One of the best known examples of a monolithically integrated CMOS circuit and MEMS device is the Texas Instruments Digital MicroMirror Device, wherein MEMS digital light switches are rotated by electrostatic attraction depending on the state of an underlying SRAM cell.
The images below are SEM photomicrographs (courtesy of Texas Instruments) on the left with the equivalent SEMulator3D model view on the right.
Each DMD is addressed by an SRAM memory cell. SEMulator3D can accurately model both the underlying CMOS circuit as well as the MEMS device integrated above it.
Additionally, SEMulator3D is able to discretize the voxel model with mesh elements to generate simulation-quality meshes. Both triangle surface and tetrahedral volume meshes can be exported from SEMulator3D.
Advanced options in SEMulator3D allow for meshes to be refined in areas where a denser mesh is required.
SEMulator3D meshes can be used with the FEA tool of choice. Surface meshes are exported in .ans, .dxf, .stl and .obj formats with volume meshes exported in .unv and .ans formats. The image below is a .unv mesh imported into the CoventorWare Preprocessor.
Once the discrete model has been imported, surfaces, parts, conductors, etc. can be named for boundary conditions to be assigned as part of electrostatic-mechanics simulations.
A CoSolveEM voltage trajectory analysis predicts the mechanical response of the device from electrostatic actuation, including deflection until contact is achieved.
The geometric fidelity of the SEMulator3D model improves simulation accuracy with FEA results based on the device expected from the actual microfabrication process rather than the idealized geometry customary to FEA analyses. Obtaining mechanical analysis details such as predicting regions of stress concentration for realistic MEMS device geometry is simple and intuitive with SEMulator3D.