Recipe

Gasses:

CHF3

50 sccm

O2

2.5 sccm
Pressure0.8 Pa (as low as possible)
RF Power50 W
Bias potential-350 V

Etch characteristics

Etch rate: 45 nm/min
Etching is anisotropic

Selectivity

Etch rate of AZ 1420: 10 nm/min (selectivity: 1)
Etch rate of Si: 10 nm/min (selectivity: 1)

Remarks

Etch rate is somewhat aspect ratio dependent
The wafer heats up considerably during etching (Mask choice)
Wafer uniformity: 10 %
Reproducibility: 15%
Etch rate is almost proportional to RF power
PMMA inhibits etching at high pressure
Recommended mask is hard baked AZ 1420