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

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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:
  1. 400nm of spin coated ZEP520A e-beam resist
  2. 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)