Optical emission during Cr ion beam etching:
A quarter wafer was loaded in a non center position.
with kind permission of: Uni Jena
Inst. fuer Angewandte Physik, Dr J Fuchs
The SEM-picture shows a 200 nm period grating.
It is fabricated by EBL of a primary resist.
Afterwards the underlying 10 nm chromium layer
is structured by Ar-IBE. The polymer is subsequently
structured by Ar-O2-RIBE. Both etch stops
are controlled by OES for enhanced reproducibility.
Necessary open area for reliable etch stop:
Cr, polymer: 8 cm²
Al, Au, Si, SiO2,W 20 cm²
clear end point signal