Sacrificial layer
The term sacrificial layer refers to a layer that is applied to protect the underlying material. It is commonly used in microsystem technology and as a preventive measure against vandalism .
Microsystem technology
In microsystem technology, it serves as a spacer, carries the functional layer and defines the distance between the functional layer and the substrate . A sacrificial layer is applied to the top silicon layers , which can be completely removed again in a later wet etching process. This sacrificial layer is now specifically scratched or etched away. In the subsequent process step, polycrystalline silicon layers are deposited in the resulting gaps, which are connected to the lower layer by supports. This method is used, for example, in the lift-off process or in the production of microfluidic components.
Surface cleaning
Graffiti made of water-insoluble colors, on porous material, scratched and etched motifs ( scratching or etching ) can often not be removed, but must be painted over or removed (by grinding or blasting) or glass panes replaced. The use of clear protective films (usually made of PET ), for example for shop windows and window panes in public transport, is cheaper and less expensive, and is then removed and replaced without leaving any residues as required or at regular intervals, as carried out by the Berlin transport company . Tags from spray cans and marker pens stick like a normal pane of glass, the sound and feel should appear as authentic as possible during scratching , and thus prevent removal by the sprayer. There are also permanent protective layers that seal the porous material and enable or facilitate conventional cleaning.
literature
- Lars Metzger: Silicon sacrificial layer technology for the production of sensors in surface micromechanics . VDI-Verlag, Düsseldorf 2003, ISBN 3-18-336509-X (As Ms. dr.)
Individual evidence
- ↑ Utility model DE202006014552U1 : Arrangement and foils for protecting glass. Published on December 7th, 2006 , Applicant: LINSE glasfolien.com GmbH.
- ↑ Wolfgang Menz, Oliver Paul: Microsystem technology for engineers . Ed .: Jürgen Mohr. 3. Edition. John Wiley & Sons, 2012, ISBN 978-3-527-66346-0 , pp. 230 ( limited preview in Google Book search).