Reactive Ion Etching with Inductive Coupled Plasma Source (ICP)
Plasmalab System 100 with ICP380 sources
Si Lens ICP Etching
Rate: > 200 nm /min
Selectivity to PR: 2:1 (adjustable)
uniformity ± 3 % (6)
Lenses: smooth, no residues
Fluorine based process
(Lower 2 SEMs from ECR etching in 1993)
The photoresist profile is reproduced in silicon. Lens profile may
be produced in photoresist either by reflowing or by grey-scale exposure.
This process can be adjusted to give the desired selectivity silicon to
resist around 2:1. This adjustment can be made during the process, to
create changing radius lenses. Laser endpoint detection can be used on
large areas of resist, to identify when all the resist has been removed.