Specific Process Knowledge/Etch/Etching of Aluminium

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Etching of Aluminium

Etching of aluminium can be done either by wet etch, dry etch or by sputtering with ions.


Comparison of Aluminium Etch Methods

Aluminium Etch Developer TMAH manual ICP metal IBE (Ionfab300+)
Generel description Wet etch of Al Wet etch/removal: TMAH

Mainly used for removing Al on e-beam resist after e-beam exposure, see process flow here

Dry plasma etch of Al Sputtering of Al - pure physical etch.
Etch rate range
  • ~60-100nm/min
  • ~0.5nm/min (pure Al)
  • ~350 nm/min (depending on features size and etch load)
  • ~30nm/min (not tested yet)
Etch profile
  • Isotropic
  • Isotropic
  • Anisotropic (vertical sidewalls)
  • Anisotropic (angles sidewalls, typical around 70 dg)
Substrate size
  • 100 mm wafers (in bath)
  • 150 mm wafers (in bath)
  • Any size (in beaker)
  • Chips (6-60 mm)
  • 100 mm wafers
  • 150 mm wafers
  • smaller pieces on a carrier wafer
  • #1 100mm wafers (when set up to 100mm wafers)
  • #1 150mm wafers (when set up to 150mm wafers)

Smaller pieces glued to carrier wafer

  • #1 50mm wafer
  • #1 100mm wafer
  • #1 150mm wafer
  • #1 200mm wafer
Allowed materials In 'Aluminium Etch' bath:

In beaker:

  • Any material
  • Every thing that is allowed in the Developer: TMAH Manual
  • Silicon
  • Quartz/fused silica
  • Photoresist/e-beam resist
  • PolySilicon,
  • Silicon oxide
  • Silicon (oxy)nitride
  • Aluminium
  • Titanium
  • Chromium
  • Silicon
  • Silicon oxides
  • Silicon nitrides
  • Metals from the +list
  • Metals from the -list
  • Alloys from the above list
  • Stainless steel
  • Glass
  • III-V materials
  • Resists
  • Polymers
  • Capton tape