Deep silicon etching in an inductively coupled plasma (ICP) reactor offers
a high etch-rate (7 mu m/min), heavily vertical profile with simple oxide m
asking.. Test structures with patterns of different sizes (from a few micro
ns to over 100 mu m) and shapes (square and circular holes and trenches of
variable width/length) have been etched to depths up to 500 mu m. Long narr
ow features are etched falter than wide short features, indicating the thre
e-dimensional nature of the reactive ion etching lag. Experiments have been
done for many different etch times in order to understand aspect ratio dep
endence of deep etching. Simple flow conductance model explains most of the
observed aspect ratio and feature size dependence. (C) 1999 American Vacuu
m Society. [S0734-2101(99)15104-2].