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

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Results from the acceptance test in February 2011

Acceptance test for Ti etch :

.	Acceptance Criteria	Acceptance Results
Substrate information	50 mm SSP Si wafer 525 µm thick Supplied by Nanolab	.
Material to be etched	E-beam deposited Ti	.
Mask information	E-beam resist mask: 400nm of spin coated ZEP520A e-beam resist Patterned by E-beam lithography	.
Features to be etched	300 nm - 3µm dots and lines + a square of 200µmx200µm	.
Etch depth	300nm	~270 nm
Etch rate	>80 nm/min	22 nm/min +- 0.3nm/min (one standard deviation)
Etch rate uniformity	<+-2%	+-(0.2% +-0.2%)
Reproducibility	<+-2%	+-(0.8% +-0.5%)
Selectivity (Ti etch rate/ZEP etch rate)	At least 1:1	0.7:1
Etch profile	70-90dg.	~65dg @270nm ~77dg @123nm

Process parameters for the acceptance test

Parameter	Ti etch acceptance
Neutralizer current [mA]	550
RF Power [W]	1200
Beam current [mA]	500
Beam voltage [V]	600
Beam accelerator voltage	400
Ar flow to neutralizer [sccm]	6.0
Ar flow to beam [sccm]	6.0
Rotation speed [rpm]	20
Stage angle [degrees]	20

Some SEM profile images of the etched Ti

Ti s10-4: 270nm deep - 500nm line. all zep has gone. Profile: ~65 dg.	Ti s10-5: 270nm deep - 300nm line. All zep has gone. Profile: ~65 dg.	Ti S7 5: 123nm deep - 300nm line. Still zep left. Profile: ~77 dg