AssemblyObviously, if microsystems consisting of many microscopic parts have to be assembled by hand, this can be a costly and time consuming process. Although hand assembly may be acceptable for device development or prototyping. Unfortunately because the very small parts have to be lined up very accurately, or else they won't go together, or will stick, conventional robotic assembly tools are not particularly suited to the task. Consequently, a method for assembling the microsystem / component has to be considered at a relatively early stage and, ideally, designed for.
Auto or self alignment, and self assemblyVarious techniques can be used to automatically align different components of a microsystem. "V" grooves are relatively easy to fabricate in silicon, and these can be used to align optical fibres to waveguides on the chip, for integrated optics applications (Figure 18).
 Figure 18. Due to the small size of the parts involved, surface tension forces (in liquids, such as water) can be used to assemble microengineered devices. For example, surface micromachined devices can be produced with hinges and latches, so that surface tension can be used to draw plates up and latch them into place to form vertical walls. When parts are soldered or brazed together, careful design may enable the use of surface tension in the molten metal to correctly align the components. Another possibility that has been proposed is the use of hydrophobic and hydrophilic areas on the surfaces of the parts. When the parts are floated on water, they line up so that the hydrophobic surfaces come together.
Future possibilitiesAssembling microparts into microsystems is an area that is receiving more research and development attention, as the processes for producing the parts are becoming better developed. One of the areas receiving attention under a ten year "Micromachines" research programme sponsored by the Japanese government, is the development of a desk-top micromachines factory. |
![[Water Assembled Microstructures (image from UCLA - 60k).]](http://synergy.icsl.ucla.edu/ftp/pub/micrographs/wam4.jpg){kind=link}