SolidWorks 3D mechanical design software is accelerating cost-effective product development in one of the world’s fastest-growing technology areas, the production of micro-electromechanical systems (MEMS).
MEMS is a technology that combines computers with tiny mechanical devices such as sensors, valves, gears, mirrors, and actuators embedded in semiconductor chips. The multibillion-dollar industry’s most widely used application is airbag sensors. These sensors use extremely small accelerometers – shaped like diving boards – to detect the abrupt deceleration that triggers airbags. Other current MEMS applications include pressure sensors, gyroscopes, and inkjet print heads.
SolidWorks now offers an expansive range of MEMS-specific design functions in its market-leading 3D mechanical design software. SolidWorks lets engineers design the MEMS structure, analyze it, generate the photomasks and design all the related product packaging and assembly equipment. The software is saving companies time, money, and effort by letting them use a familiar and easy-to-learn environment for MEMS design. These capabilities were previously available only with specialized, often expensive, MEMS-focused tools that often required proprietary hardware and offered little integration to other design and analysis software.
Axsun Technologies (Billerica, Massachusetts) specializes in the design and manufacture of miniaturized optical micro-instrumentation for use in a variety of industries. The company standardized on SolidWorks at its founding in 1998.
“One of the reasons we chose SolidWorks software at the very beginning was that we needed to be able to show visually compelling images of very complex micro-electro-optical instrumentation and telecommunications devices to both investors and customers before building them,” said Chief Technology Officer Dale Flanders. “We also wanted to leverage the software’s assembly and interference-checking capabilities as well as the associative nature of 3D solid models to support other engineering functions, such as mechanical, thermal, and sophisticated electromagnetic analyses. SolidWorks models integrate nicely with finite element analysis (FEA), support rapid prototyping, and work well with our optical design tools, which we use for diffractive optics and beam propagation,” he added.
MEMS are designed a lot like computer chips, by depositing layers of materials on a substrate. MEMS, however, feature 3D elements, such as miniature springs, hinges, joints, or levers. Traditional chip design tools may severely limit the MEMS designer since they are 2D tools oriented to the planar, or flat, aspect of integrated circuits. And while computer chips are typically made of silicon, MEMS use a wide range of structural materials besides silicon, including other semiconductors, insulators, and electroplatable metals.
SolidWorks easily handles these materials and moving parts at the miniature level. SolidWorks also meets the challenge of working with photomasks at the sub-micron level, even for a device packaged in a much larger assembly. Engineers can simply zoom into the MEMS detail and zoom out to the larger assembly, providing full 3D visualization of the MEMS component and its packaging without changing applications.
SolidWorks software automatically cross-sections the MEMS component and creates fully associative photomasks for each layer, eliminating the time and effort involved in manually creating each 2D layout. As the design is modified and refined, changes propagate to all associated design documents, including components, assemblies, detail, and photomask drawings. SolidWorks’ sub-micron feature definition, collision/interference detection of components, and the creation of feature patterns and patterns of patterns are also useful for MEMS design.
Microfabrica Inc. (formerly known as MEMGen Corporation) is a SolidWorks partner developing new MEMS fabrication methods. “The ability to create arbitrary 3D geometries rather than the planar features utilized by the semiconductor industry opens a whole new world of possibilities to MEMS designers,” said Chris Bang, vice president of design and applications at Microfabrica. “In other words, you usually can’t optimize a mechanical design on the microscale using traditional planar silicon micro manufacturing. We are working with SolidWorks to eliminate these types of limitations for mechanical engineers using micro designs. SolidWorks automates many of the steps involved with MEMS, making much of the complexity and tedium completely transparent to the user.”
The value of integrated analysis software
To ensure these microstructures perform reliably in their operating environments, MEMS engineers must rely on FEA software. FEA determines stress, deformation, resonance, temperature distribution, electromagnetic interference, and electrical properties. The COSMOS suite of analysis products from SolidWorks is useful in a wide range of MEMS applications because of its capabilities in areas of mutliphysics and coupled-field analysis. Available analysis types include structural, thermal, electromagnetics, and fluid-flow (CFD). Thermal and fluid flow analysis can determine the heating of solids and fluids in MEMS devices that are used in electronic circuits. With electromagnetic analysis, engineers can calculate electrical and magnetic field activated forces needed for small switching devices.
“Designing the entire product from the chip level to the entire system in one mechanical design package, and analyzing it with an integrated FEA package, can save upfront investment and training and also the incremental efforts in design optimization,” said Suchit Jain, vice president of analysis products at SolidWorks Corporation.
MEMS was a $3.9 billion industry in 2001. The market is expected to reach $9.6 billion by 2006, with a combined annual growth rate of nearly 20 percent, according to the MEMS Industry Group. Potential MEMS applications are almost limitless. Any miniaturized electrical system that requires a mechanical component is a candidate for MEMS, including inertial sensors, switches and relays, resonators and mechanical filters, micro-capacitors, micro-inductors, micro-probes, inclinometers, valves, DNA sequencers, and chemical and biological agent sensors.
“Choice of solid modeling tools is critical to meeting MEMS’ potential,” said Ilya Mirman, SolidWorks vice president of marketing. “Although MEMS designers have created impressive structures using 2D layout software, 3D visualization provides MEMS designers a first check of design intent, proper operation, collision avoidance, and package stack-up. Moreover, it’s easy to master SolidWorks, even if you’re a part-time designer. The result is that important MEMS innovations move more quickly to market. At the same time, SolidWorks addresses a host of other business considerations, including low cost, ease of use, additional functionality, support, and a broad range of integrated, complementary software for tolerance analysis, electrochemical etching and plating simulation, animation, PCB design integration, and more.”