OPT application lab: 
5 µm holes etched in Si with stop on SiO₂

ICP Technology

Plasmalab System 100
with ICP380

0.75 µm diameter holes etched to the bottom

etch stop on SiO₂

etch rate 50 - 100 nm/ min

uniformity over 6": +/- 4 %

anisotropic profile

HBr based process

etch depth up to 10 µm at 5 : 1 aspect ratio