The accelerometer is one of the most common uses of microelectromechanical systems (MEMS), but scientists and engineers also are starting to use them in devices ranging from angioplasty pressure sensors and pacemakers to optical disk drives.
MEMS, also known as micromachines, are a relatively new technology that uses existing microelectronics manufacturing methods to create complex machines with micrometer feature sizes. MEMS devices represent a rapidly growing component of the semiconductor industry.
Many micromachines contain moving parts that are combined with integrated circuits. Like most high-tech devices, they must be made with precise dimensions and materials properties to operate properly. To help manufacturers ensure that their devices meet these exacting specifications, National Institute of Standards and Technology (NIST) scientists and engineers helped develop three ASTM International standard test methods for the thin films used to make micromachines.
The test procedures, which are the first such standards in the world, will be published in The Annual Book of ASTM International Standards this month. The standards are expected to facilitate global commerce in MEMS technologies by enabling measurements that will lead to the development of more reliable and reproducible MEMS devices. The three standards provide detailed instructions for measuring thin-film dimensions and "strain," a property related to the stress in the thin film. NIST researchers have created a Web site to help semiconductor manufacturers perform the complex mathematical calculations required by the new standard test methods. For further information, see http://www.eeel.nist.gov/812/test-structures.