Specific Process Knowledge/Etch/Etching of Aluminium

Etching of Aluminium

Etching of aluminium is done wet at Danchip. We have two different solutions:

1. H$_{2}$O:H$_{3}$PO$_{4}$ 1:2 at 50 ^oC
2. Pre-mixed etch solution: PES 77-19-04 at 20 ^oC

	Aluminium Etch 1	Aluminium Etch 2
General description	Etch of pure aluminium	Etch of aluminium + 1.5% Si
Possible masking materials:	Photoresist Silicon nitride	Photoresist (Poly)Silicon Aluminium Chromium (ONLY RIE2!) Other metals that covers less the 5% of the wafer area (ONLY RIE2!)	Photoresist (Poly)Silicon Aluminium
Etch rate	~70-90 nm/min (Thermal oxide)	Typically 40-120 nm/min can be increased or decreased by using other recipe parameters.	Typically 200-600 nm/min can be increased or decreased by using other recipe parameters.
Batch size	1-25 wafers at a time	1 wafer at a time	1 wafer at a time
Size of substrate	4" wafers	4" wafers or smaller pieces	6" or 4" depending on the setup (smaller pieces if you have a carrier wafer)
Allowed materials	Silicon Silicon Oxide Silicon Nitride Silicon Oxynitride Photoresist Blue film Gold (Au) and Nickel (Ni) (but only in BHF2 (KOH)!)	Silicon Silicon Oxide Silicon Nitride Silicon Oxynitride Photoresist E-beam resist Aluminium Chromium (ONLY RIE2!) Other metals that covers less the 5% of the wafer area (ONLY RIE2!)	Silicon Silicon Oxide Silicon Nitride Silicon Oxynitride Photoresist E-beam resist Aluminium