Silicon etch with cooled sample

Aleksandrs Marinins, 2014-12-08

• 8 mTorr work pressure, 35 mTorr strike pressure, 7 mTorr ramp
• 40 sccm SF6 and 5 sccm O2 (and He 5 sccm)
• 90 W RF-power, 100 W ICP-power

Etches were performed at -115°C and -120°C. A big difference in the amount of "grass" can be seen, greatly reduced at -115°C, at the cost of reduced anisotropy. The side walls are less vertical at -115°C.

Etch at -115°C

Etch at -115°C

Etch at -115°C

Etch at -120°C, more "grass" but straighter sidewalls.

Etch at -120°C, more "grass" but straighter sidewalls.