Specific Process Knowledge/Etch/IBE⁄IBSD Ionfab 300/IBE Au etch

Results from the acceptance test in February 2011

Acceptance test for Au etch:

.	Acceptance Criteria	Acceptance Results
Substrate information	50 mm SSP Si wafer 525 µm thick Supplied by Danchip	.
Material to be etched	E-beam deposited Au	.
Mask information	E-beam resist mask: 400nm of spin coated ZEP520A e-beam resist Patterned by E-beam lithography	.
Features to be etched	300nm - 3µm dots and lines + a square of 200µmx200µm	.
Etch depth	300nm	~272 nm
Etch rate	>80nm/min	54.5nm/min +- 0.6nm/min (one standard deviation)
Etch rate uniformity	<+-2%	+-(0.2% +-0.2%)
Reproducibility	<+-2%	+-0.9%
Selectivity (Au etch rate/ZEP etch rate)	At least 1:1	1.2:1
Etch profile	70-90dg.	75dg

Process parameters for the acceptance test

Parameter	Au etch acceptance
Neutalizer current [mA]	550
RF Power [W]	1300
Beam current [mA]	500
Beam voltage [V]	600
Beam accelerator voltage	400
Ar flow to neutralizer [sccm]	5.0
Ar flow to beam [sccm]	10.0
Rotation speed [rpm]	20
Stage angle [degrees]	30

Some SEM profile images of the etched Au

s18-Au-ZEP3	s18-Au-ZEP5

IBE Au etch with Ti mask

Work has been started to find a good process for etching gold with a Titanium mask with high selektivity.

	Ti etch test with Zep520A as mask - To etch the Ti mask	Au etch test with high selectivity to Ti
Generel description	Generel description - method 1	Generel description - method 2
Recipe name	test Ti acceptance 20111129	Au_acceptance_with_O2
IBE parameters	A B C	A
Results
Etch rate in resist	12.8nm/min (15-12-2011)	72nm/min (13-12-2011)
Etch rate in Au	32.7nm/min (15-12-2011)	42.6nm/min (13-12-2011)
Etch rate in Ti	8.3nm/min (15-12-2011)	4.3nm/min (13-12-2011)
Selectivity Ti/Zep	0.65 (15-12-2011)	0.06 (13-12-2011)
Selectivity Au/Ti	3.9nm/min (15-12-2011)	9.9nm/min (13-12-2011)