Mechatronics Assignment#1 Topic: MEMS ACTUATORS Prepared by: Sandeep Sharma Dept of Electrical and Computer Engineering Utah State University

OUTLINE WHAT IS MEMS? MEMS ACTUATORS APPLICATIONS CHALLENGES

REFERENCES www.memsnet.org The Investigation of MEMS-Fabricated Actuators for Use in Optical and Mechanical Applications, 14-9158 Applications of MEMS Actuators in Optical and Ultrasound Imaging www.memx.com

WHAT IS MEMS? Micro-Electro-Mechanical Systems (MEMS) is the integration of mechanical elements, sensors, actuators, and electronics on a common silicon substrate through microfabrication technology. While the electronics are fabricated using integrated circuit (IC) process sequences (e.g., CMOS, Bipolar, or BICMOS processes), the micromechanical components are fabricated using compatible "micromachining" processes that selectively etch away parts of the silicon wafer or add new structural layers to form the mechanical and electromechanical devices .

WHAT IS MEMS? MEMS promises to revolutionize nearly every product category by bringing together silicon-based microelectronics with micromachining technology, making possible the realization of complete systems-on-a-chip. MEMS is an enabling technology allowing the development of smart products, augmenting the computational ability of microelectronics with the perception and control capabilities of microsensors and microactuators and expanding the space of possible designs and applications

WHAT IS MEMS? MEMS is an emerging technology which uses the tools and techniques that were developed for the Integrated Circuit industry to build microscopic machines. These machines are built on standard silicon wafers.  The real power of this technology is that many machines can be built at the same time across the surface of the wafer, with no assembly required. Since it is a photographic-like process, it is just as easy to build a million machines on the wafer as it would be to build just one.

WHAT IS MEMS Microelectronic integrated circuits can be thought of as the "brains" of a system and MEMS augments this decision-making capability with "eyes" and "arms", to allow microsystems to sense and control the environment. Sensors gather information from the environment through measuring mechanical, thermal, biological, chemical, optical, and magnetic phenomena. The electronics then process the information derived from the sensors and through some decision making capability direct the actuators to respond by moving, positioning, regulating, pumping, and filtering, thereby controlling the environment for some desired outcome or purpose. Because MEMS devices are manufactured using batch fabrication techniques similar to those used for integrated circuits, unprecedented levels of functionality, reliability, and sophistication can be placed on a small silicon chip at a relatively low cost.

MEMS ACTUATORS The greatest promise of microelectromechanical systems (MEMS) lies in their ability to produce mechanical motion on a very small scale. Such devices are typically low power and fast, taking advantage of such microscale phenomenon as strong electrostatic forces and rapid thermal responses. Although MEMS-based sensors have been widely deployed, few MEMS-based actuators have achieved more than laboratory-level development due to their technical challenges. The market for such devices is growing rapidly, especially for optical and electronic applications.

MEMS ACTUATORS The explosive growth of data traffic, such as the Internet, has produced a pressing need for large-capacity optical networks. Optical switches are now in high demand in the telecommunications industry for their ability to reconfigure an optical network for traffic management or circuit protection without having to resort to low-bandwidth, protocol-dependant, opto-electronic conversions. To be widely deployed, such switches must be small, low-cost, batch-fabricated, and have a high port count. A MEMS-based optical switch is well suited to addressing these requirements.

MEMS ACTUATORS The traditional method of creating a timed electronic switch requires a timer circuit or discrete mechanical components. Such devices tend to be large or unable to handle high currents. There are a number of applications where a small, timed relay would be desirable, such as military and computer industries. For instance, the device could be incorporated into a computer, so that after a series of incorrect password entries, the computer locks out all communications and cannot be overcome without physical access. Again, MEMS actuators can provide such a solution.

Applications Data Storage

ULTRASOUND IMAGING

OPTICAL IMAGING

                                                                                                                        ELECTRIC RELAY SWITCH

PATCH ANTENNA

CHALLENGES Limited Options Most companies who wish to explore the potential of MEMS and Nanotechnology have very limited options for prototyping or manufacturing devices, and have no capability or expertise in microfabrication technology. Few companies will build their own fabrication facilities because of the high cost. A mechanism giving smaller organizations responsive and affordable access to MEMS and Nano fabrication is essential.

Packaging The packaging of MEMS devices and systems needs to improve considerably from its current primitive state. MEMS packaging is more challenging than IC packaging due to the diversity of MEMS devices and the requirement that many of these devices be in contact with their environment. Currently almost all MEMS and Nano development efforts must develop a new and specialized package for each new device.

Most companies find that packaging is the single most expensive and time consuming task in their overall product development program. As for the components themselves, numerical modeling and simulation tools for MEMS packaging are virtually non-existent. Approaches which allow designers to select from a catalog of existing standardized packages for a new MEMS device without compromising performance would be beneficial

Fabrication Knowledge Required Currently the designer of a MEMS device requires a high level of fabrication knowledge in order to create a successful design. Often the development of even the most mundane MEMS device requires a dedicated research effort to find a suitable process sequence for fabricating it. MEMS device design needs to be separated from the complexities of the process sequence.