Biology Reference
In-Depth Information
The self-assembly process consists of the following steps: First,
gold contact sites of hydrophobic/hydrophilic nature are created
by applying a self-assembled monolayer film with the appropriate
functionality. Second, a cross-linkable liquid polymer is added,
which selectively adsorbs to hydrophobically functionalized contact
sites. Third, as the microcomponents are agitated and surfaces are
brought in contact at random, favorable surface interaction between
polymer-covered sites will lead to adhesion. This will cause the
components to agglomerate in a specific pattern, directed by the
drive to minimize surface energy at the contact interface.
12.4
Conclusions
When assessing the practical importance of self-assembly
techniques, a comparison with existing technologies is necessary.
The prevalent technology in electronics manufacturing is robotic
assembly, which can process
∼
30000 parts per hour and handle
∼
µ
components down to
m in size. Robotic technology does not
require a fluid environment, elevated temperature, or agitation,
which gives it a significant advantage for practical applications. Self-
assembly is, however, a promising alternative for processes where
the performance criteria are out of reach for robotic methods. Its key
advantage is the ability to process a large number of components in
parallel, whereas robots are limited to serial operations.
300
[8] have identified three main areas where self-
assembly holds an advantage over existing robotic technologies:
1. A very large number of parts needs to be handled.
2. The parts are small.
3. The final assembled geometry is a complicated nonplanar
structure.
These features are often required for packaging
microelectromechanical systems (MEMS) and therefore self-
assembly appears particularly well suited for manufacturing MEMS
devices.
Some obstacles still have to be resolved before self-assembly can
become a practical manufacturing tool. One of them is the necessity
to create components of complex, distinct geometries so that they can
be directed to their correct locations on the template. A recognition
Morris
et al.
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