Single rotated strings for THz Skin

Rot_strings01

First test with strings: different width and fillets. Frame size: \(300 \mu m\)

Wafer: 100 nm SiN, low stress

For technical reasons I started with the etching process, followed up by metal evaporation.

STEP 1

Spin&bake
AR 300.80	4000 RPM, 150°C, 1'
AR.P 6200.13	3000 RPM, 130°C, 1'

EBL
EHT: 30 kV
D: 140 \(\mu\)C/cm\(^2\)
step-size: 20 nm

RIE
\(SF_6\)/\(O_2\): 32/8 sccm
50 W, P = \(5 \times 10^{-2}\) mbar

STEP 2

Spin&bake
AR 679.04	4000 RPM, 120°C, 10'

EBL
EHT: 20 kV
D: 240 \(\mu\)C/cm\(^2\)
step-size: 20 nm

I made use of several layer 63 + patches to avoid stitching

EVAPORATION
Ti/Au: 5/60 nm	[SZ@NEST]

Rot_strings02

Frame size: \(300 \mu m\), wafer: 100 nm SiN, low stress

STEP 1

Spin&bake
AR 679.04	4000 RPM, 120°C, 15'

EBL
EHT: 20 kV
D: 240 \(\mu\)C/cm\(^2\)
step-size: 20 nm

I made use of several layer 63 + patches to avoid stitching

EVAPORATION
Cr/Au: 5/50 nm

STEP 2

Spin&bake
AR.P 6200.13	2000 RPM, 150°C, 1'

EBL
EHT: 30 kV
D: 140 \(\mu\)C/cm\(^2\)
step-size: 20 nm

RIE
\(SF_6\)/\(O_2\): 32/8 sccm
50 W, P = \(5 \times 10^{-2}\) mbar

Rot_strings03

Frame size: \(300 \mu m\), wafer: 100 nm SiN, low stress

STEP 1

Spin&bake
AR 679.04	4000 RPM, 120°C, 15'

EBL
EHT: 20 kV
D: 250 \(\mu\)C/cm\(^2\)
step-size: 20 nm

I made use of several layer 63 + patches to avoid stitching

EVAPORATION
Cr/Au: 10/43 nm

The initial evaporation did not result in Au deposition on the sample. The sample had been placed at the center of the sample holder in the hope that it would be fully covered by the shutter in both positions 1 and 4. However, during Au deposition, the sample was shadowed by the quartz crystal, preventing Au from reaching the sample. The evaporation was therefore repeated; however, since a 5 nm Cr layer had already been deposited during the first evaporation, the final Cr thickness was doubled.

STEP 2

Spin&bake
AR.P 6200.13	2000 RPM, 150°C, 1'

EBL
EHT: 30 kV
D: 140 \(\mu\)C/cm\(^2\)
step-size: 20 nm

RIE
\(SF_6\)/\(O_2\): 32/8 sccm
50 W, P = \(5 \times 10^{-2}\) mbar

STEP 3

KOH etching
60-80°C for 15 min