Cryogenic Process
In cryogenic-DRIE, the wafer is chilled to −110 °C (163 K). The low temperature slows down the chemical reaction that produces isotropic etching. However, ions continue to bombard upward-facing surfaces and etch them away. This process produces trenches with highly vertical sidewalls. The primary issues with cryo-DRIE is that the standard masks on substrates crack under the extreme cold, plus etch by-products have a tendency of depositing on the nearest cold surface, i.e. the substrate or electrode.
Read more about this topic: Deep Reactive-ion Etching
Famous quotes containing the word process:
“That which endures is not one or another association of living forms, but the process of which the cosmos is the product, and of which these are among the transitory expressions.”
—Thomas Henry Huxley (1825–95)