The critical physical dimensions of MEMS devices can vary from well below one micron on the lower end of the dimensional spectrum, all the way to several millimeters. Likewise, the types of MEMS devices can vary from relatively simple structures having no moving elements, to extremely complex electromechanical systems with multiple moving elements under the control of integrated microelectronics.
Lithography[ edit ] Lithography in MEMS context is typically the transfer of a pattern into a photosensitive material by selective exposure to a radiation source such as light.
A photosensitive material is a material that experiences a change in its physical properties when exposed to a radiation source. If a Using a microelectromechanical system material is selectively exposed to radiation e.
This exposed region can then be removed or treated providing a mask for the underlying substrate. Photolithography is typically used with metal or other thin film deposition, wet and dry etching.
Sometimes, photolithography is used to create structure without any kind of post etching. One example is SU8 based lens where SU8 based square blocks are generated. Then the photoresist is melted to form a semi-sphere which acts as a lens. Electron beam lithography[ edit ] Main article: Electron beam lithography Electron beam lithography often abbreviated as e-beam lithography is the practice of scanning a beam of electrons in a patterned fashion across a surface covered with a film called the resist "exposing" the resist and of selectively removing either exposed or non-exposed regions of the resist "developing".
The purpose, as with photolithographyis to create very small structures in the resist that can subsequently be transferred to the substrate material, often by etching.
It was developed for manufacturing integrated circuitsand is also used for creating nanotechnology architectures. The primary advantage of electron beam lithography is that it is one of the ways to beat the diffraction limit of light and make features in the nanometer range.
The key limitation of electron beam lithography is throughput, i. A long exposure time leaves the user vulnerable to beam drift or instability which may occur during the exposure.
Also, the turn-around time for reworking or re-design is lengthened unnecessarily if the pattern is not being changed the second time.
It is capable of generating holes in thin films without any development process. Structural depth can be defined either by ion range or by material thickness. Aspect ratios up to several can be reached. The technique can shape and texture materials at a defined inclination angle.
Random pattern, single-ion track structures and aimed pattern consisting of individual single tracks can be generated. X-ray lithography[ edit ] X-ray lithography is a process used in electronic industry to selectively remove parts of a thin film. It uses X-rays to transfer a geometric pattern from a mask to a light-sensitive chemical photoresist, or simply "resist", on the substrate.
A series of chemical treatments then engraves the produced pattern into the material underneath the photoresist.
Diamond patterning[ edit ] A simple way to carve or create patterns on the surface of nanodiamonds without damaging them could lead to a new photonic devices. It is achieved by the lithographic application of diamond films to a substrate such as silicon.
The patterns can be formed by selective deposition through a silicon dioxide mask, or by deposition followed by micromachining or focused ion beam milling. In the former, the material is dissolved when immersed in a chemical solution.
In the latter, the material is sputtered or dissolved using reactive ions or a vapor phase etchant. Etching microfabrication Wet chemical etching consists in selective removal of material by dipping a substrate into a solution that dissolves it.
The chemical nature of this etching process provides a good selectivity, which means the etching rate of the target material is considerably higher than the mask material if selected carefully.
Isotropic etching[ edit ] Etching progresses at the same speed in all directions.Micro-Electro-Mechanical Systems, or MEMS, is a technology that in its most general form can be defined as miniaturized mechanical and electro-mechanical elements (i.e., devices and structures) that are made using the techniques of microfabrication.
2 MICROELECTROMECHANICAL SYSTEMS (MEMS) end of s, most of MEMS devices with various sensing or actuating mechanisms were fabricated using silicon bulk micromachining, surface micromachining, and lithography, galvanoforming, moulding (LIGA).
The topics of interest include, but are not limited to: devices ranging in size from microns to millimeters, IC-compatible fabrication techniques, other fabrication techniques, measurement of micro phenomena, theoretical results, new materials and designs, micro actuators, micro robots, micro.
Microelectromechanical systems (MEMS, also written as micro-electro-mechanical, MicroElectroMechanical or microelectronic and microelectromechanical systems and the related micromechatronics) is the technology of microscopic devices, particularly those with moving parts.
The MEMS Technology Department at Sandia National Laboratories conducts research and development for advanced microelectromechanical systems that push the technology. Micro-Electro-Mechanical Systems, or MEMS, is a technology that in its most general form can be defined as miniaturized mechanical and electro-mechanical elements (i.e., devices and structures) that are made using the techniques of microfabrication.