OPT application lab:
anisotropic RIE etch of 2.2 µm SiN (PR mask not removed)
SiN can be etched isotropic at high rate
(RIE up to 500 nm/ min, ICP > 1 µm/ min) or
anisotropic by RIE as well as ICP-RIE by sidewall polymerisation.
- anisotropic etch: RIE 50 - 150 nm/ min*, ICP ca 0.5 µm/ min
- maximum etch rates dependent on mask and temperature limitations
- uniformity ± 2 - 4 % for the anisotropic etch
*High rates require Helium cooling,
if a PR mask is used.
Even higher rates are possible with hard masks.