Dry Etching

The goal of dry etching processes is the fabrication of high resolution, complex microstructures. 

Service Catalog

  • Fabrication of microstructures out of silicon and glass
  • Removal of metals and photoresist materials
  • Surface cleaning
  • Surface activation in preparation for wet chemical processes (etching, electroplating)

Typical Applications

  • Fabrication of high resolution, high aspect ratio structures in silicon (sensors, actuators, ...)
  • Patterning of oxides, nitrides and oxinitrides
  • Oxide mask patterning, especially for pre-designed openings
  • Cleaning and surface conditioning (controlling hydrophilicity) in preparation for electroplating
  • Ashing of resist materials

Description

Plasma based dry etching is carried out using reactive gases in order to selectively remove material, optionally assisted with particle bombardment (e.g.: Argon ions). 

Physical dry etching occurs with solely as a result of material removal through the impact of accelerated particles (ions, electrons or photons) on the chosen surface. The impact atomizes the substrate material. Exclusive physical etching processes have the disadvantages that they are slow and not highly selective. An example of such processes is sputter etching.

Chemical dry etching processes rely on a chemical reaction mechanism, in most cases with plasma activation, for the material removal to take place. The requirement for chemical dry etching is that a volatile bond results from the reaction of an activated particle (radical) and the substrate surface. A constant flow of etch gases is required for the process to be isotropic and highly selective (depending on the materials). A typical application of chemical dry etching is the removal of photoresist through an oxygen plasma. 

The combination of physical and chemical dry etching processes is of high interest to current fabrication methods for integrated circuits and micromechanical components. These processes enable us to produce very small structures with high aspect ratios with material specific approaches. 

Process Examples

  • Fast Si Etch 1
  • Fast Si Etch 2
  • Slow Si Etch 90°
  • Amorphous Si Etch

Fast Si Etch 1

Fast silicon etch process with slightly opening profile. Suitable for deep etchings

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Fast Si Etch 2

Fast silicon etch process, alternative to Fast Si Etch 1, suitable for deep etchings

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Slow Si Etch 90°

Silicon etch process with low etch rates but almost 90° side wall angle. Suitable for etchings of low depth (up to 100 μm) where vertical side walls are crucial. Also suitable for SOI-processes (Silicon On Insulator).

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Amorphous Si Etch

Patterning of amorphous silicon, suitable for thin films (up to 1 μm) of amorphous or polycrystalline silicon.

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