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.

• Etching of Al by wet etch
• Etching of Al by dry etch
• Sputtering of Al

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: See Cross Contamination Sheet for 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