Back-End Processes
Following micro structuring, precision dicing is often used to separate micro components from the substrate. By the use of anodic bonding we can encapsulate mems parts, by wire bonding we add interconnections from the mems parts to circuit boards for instance.
Precision dicing:
By precision dicing with diamond coated saw blades, fine cuts are made in the substrate. This way several on one substrate fabricated micro components can be separated. Also by precision dicing functional components can be manufactured. For example, larger optical filters can be cut into small elements, which are then integrated into micro systems.
Typical properties:
- Thickness of substrate: some 10µm – 3mm
- Size of substrate: up to 150mm
Materials:
- Silicon, Glass, Metals and Plastics
2 mm Thickness
Anodic bonding:
By anodic bonding a silicon substrate can be connected to a further silicon substrate or a glass substrate with elevated temperature and the presence of an electric field. The resulting compound has a very high strength, is suitable for UHV, chemically inert and biocompatible. The substrates can already be patterned before bonding.
Typical properties:
- Substrate thickness: up to about 1mm
- Adhesive free connection
on top side glass, on bottom side silicon
Wire bonding:
For electrical contacting of micro components, we use wire bonding. In this case thin gold or aluminum wires are bonded on a metallic contact pad on the micro component and on the other side to a printed conductor of a circuit board or the contact tab of a chip housing.
printed circuit board