Etching & Cleaning Reactors

Plasma reactors designed for etching and cleaning are essentially the same as PECVD reactors, except for one important difference: PECVD deposits material whereas etching and cleaning remove material. This has some implications for the detailed reactor design, especially regarding the process gases used, but the basic arrangement of the hardware is the same.

Plasmionique manufactures reactors for the following applications:

Plasma Etching (PE)
This traditionally refers to purely chemical etching where the plasma produces the required reactive species. It is isotropic and selective, with high etch rates. The simplest reactor is a symmetric parallel-plate geometry where a capacitively-coupled plasma (CCP) is produced by a RF-biased electrode, with the sample to be etched fixed to the lower (grounded) electrode. Gas injection is usually in a showerhead arrangement.

Reactive Ion Etching (RIE)
If RF power is applied to the sample electrode in an asymmetric parallel-plate arrangement, a significant negative self-bias is induced. This results in an enhanced ion energy and directionality, and physical etching begins to play a role. It is characterised by high etch rates and good selectivity as for PE, but with the added feature of improved anisotropy.

Ion Beam Etching (IBE)
When physical etching is the predominant process, it is referred to as ion beam etching (IBE). Ions must have a significant directed energy, and are usually produced in a plasma discharge chamber remote from the etching chamber. The ions are extracted and directed toward the substrate with an electrostatic grid. Reactive components may be injected for enhanced functionality. IBE is of course anisotropic, but is non-selective and has a low etch rate.

Plasma Cleaning
The chemical and physical processes which are the basis of plasma etching may also be used to remove contaminants from surfaces. The piece to be cleaned is immersed in a plasma from gases such as oxygen, hydrogen, and argon. The choice depends on the surface material and the contaminant to be removed. As an example, sensitive optical components which have been contaminated by interaction with high-power lasers, synchrotron beams, or electron beams may be effectively cleaned and returned to service.

Plasmionique systems for etching and cleaning are summarised below:

Application Reactor Type Configuration View brochure
PE parallel-plate
  • symmetric
  • biased top electrode
  • grounded substrate
  • substrate cooling option
  • showerhead gas injection
RIE parallel-plate
  • asymmetric
  • biased (smaller) substrate electrode
  • grounded (larger) upper electrode
  • substrate cooling option
  • biased substrate
  • high-density plasma
  • decoupling of ion density and energy
  • substrate heating/cooling option
FLARION Series Plasma Reactors and Sources (PDF)
PLUME Series
  • ion beam source (remote ICP with extraction grids)
  • tiltable substrate
  • substrate cooling option
PLUME Series ICP Plasma and Ion Sources (PDF)
Plasma Cleaning
  • parallel plate
  • PE/RIE/IBE configurations as appropriate for material
  • gases appropriate for the contaminant
see links above

*DRIE: Deep Reactive Ion Etching