In 1959, Richard Feynman proposed the possibility of ultra-miniaturisation (size reductions by as much as a factor of 4000) of mechanical systems as well as miniaturising computers to levels involving the manipulation of atoms. While these ideas were undoubtedly prophetic, the technique envisaged, of three-dimensional machines iteratively making ever-smaller versions of themselves, is unlikely ever to be practical (a point acknowledged by Feynman himself, after revising the concept in 1983).
An important factor in the recent progress of miniaturisation technologies is the development of microelectromechanical systems (MEMS), also known as (micro)mechatronics. MEMS consist of integral micromechanical and microelectronic elements fabricated by established semiconductor processing techniques. Examples of miniature components which can be produced in this way include pressure and acceleration sensors, linear actuators, valves, grippers, tweezers, motors, gear trains, turbines, nozzles, and pumps.
MEMS are now regarded as a critical technology in fields such as the aerospace, automotive, biomedical, and communications industries. Commercial applications of MEMS include microfluidic manipulators for implantable drug dispensers, navigation gyros for aerospace use and magnetic and optical storage, switching devices and displays for information technology.
Currently, the most significant technologies for the fabrication of three-dimensional MEMS microstructures are bulk micromachining, surface micromachining, LIGA (from the German "Lithographie, Galvanoformung, Abformung" - a process involving X-ray lithography, electroplating and plastic moulding), electrical discharge machining (EDM), and substrate bonding.
All aspects of MEMS and micromanufacturing technology are covered comprehensively in the Inspec Database. Papers can be found in Section A (Physics), Section B (Electrical and Electronics Abstracts), Section C (Computer and Control Abstracts) and Section E (Mechanical and Production Engineering). The most important classification sections are:
- A0710C: Micromechanical devices and systems
- A4283: Micro-optical devices and technology
- B2550: Semiconductor device technology
- B2575: Micromechanical device technology
- B4145: Micro-optical devices and technology
- B7230: Sensing devices and transducers
- B8340: Small and special-purpose electric machines
- B8380M: Microactuators
- C3240: Transducers and sensing devices
- C3260: Actuating and final control devices
- E1528A: Machining
- E2160: Micromechanics
- E3644V: Mechatronics industry
Inspec controlled indexing terms for MEMS technology include:
- micro-optomechanical devices
- micromechanical devices
- micromechanical resonators
Other relevant controlled index terms for some of the ideas discussed in this article are:
- automotive electronics
- electrical discharge machining
- pressure sensors
- semiconductor technology
- sputter etching
- wafer bonding
- X-ray lithography