Process modeling of MEMS + IC DLP Mirror Device
Posted by Brian Van Dyk on Mon, Oct 19, 2009 @ 07:54 AM
Coventor software tools provide effective solutions for designing "MEMS+IC" devices. SEMulator3D offers the ability to build 3-dimensional models of complex MEMS structures and CMOS circuits as well as visualize the electrical connectivity between circuits and the MEMS devices with which they interact. One of the best known examples of a monolithically integrated CMOS circuit and MEMS device is Texas Instruments Digital MicroMirror Device, wherein MEMS digital light switches are rotated by electrostatic attraction depending on the state of an underlying SRAM cell.
Isometric and Cross Section View of single pixel model created with SEMulator3D
The following images show SEM photomicrographs (courtesy of Texas Instruments) and the equivalent SEMulator3D model view.
Ion Mill & SEMulator3D model Cross Section
DMD with mirror removed (Left: SEM image, right: SEMulator3D model)
Each DMD is addressed by an SRAM memory cell. SEMulator3D can effectively model both the underlying CMOS circuit as well as the MEMS device integrated above it. The following image shows an example 6T SRAM CMOS model - before the micromirror is built.
(top left) Exploded view of DLP mirror and memory cell. (bottom left) 6T SRAM. (top right) 3D model of circuitry. (bottom right) top view of MEMS DLP 3D model.
Once the complete model is built, the SEMulator3D Viewer allows you to visualize the model in terms of its electrical connectivity. As such, you can see to which part of the circuit each address electrode connects - in 3D - with the ability to rotate, zoom, explode and physically manipulate the model to verify that your design is correct.
To find out how SEMulator3D works visit www.coventor.com
- L. J. Hornbeck, "Current Status and Future Applications for DMD-Based Projection Displays", in Proceedings of the Fifth International Display Workshop IDW ‘98, Kobe, Japan (1998).
- L.J. Hornbeck, "Digital Light Processing and MEMS: Timely Convergence for a Bright Future." SPIE Micromachining and Micro-fabrication ‘95, Austin, Texas (1995).