Plasma Technology  

ARDE effect mimimized

110 µm deep etch without ARDE effect

aspect ratio 44 : 1

44 : 1 aspect ratio

novel twin spot laser interferometry/ "polarimetrie"
for in situ depth measurement

Bosch Process Optimisation Options

Reactive Ion Etching

Inductive Coupled Plasma Source

room temperature “Bosch” process

He backside cooling

The process can often be optimised for very high rates/ aspect ratios/ uniformities/ selectivities.
The optimisation options strongly depend on mask details !

100 µm deep etch at
400 : 1 selectivity to the SiO2 mask

100 µm deep etch at 17 µm/ min
using the ICP accelerator technology

Plasmalab System 100
with ICP Source and loadlock

400 µm deep etch with reproducible
wall angle (91°) at 3.5 µm/ min and
75 : 1 selectivity to PR
courtesy of Acreo Kista

150 µm deep etch with
reproducible wall angle (91°)
at 6.5 µm/ min and
60 : 1 selectivity to PR
uniformity over a 6" wafer ±1.7 %


100 µm very high aspect ratio etch

ICP layout

21 µm deep anisotropic etch
stopping on SiO2
courtesy of Uni Kassel

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