CONFORMAL COATING BY PHOTORESIST OF SHARP CORNERS OF ANISOTROPICALLY ETCHED THROUGH-HOLES IN SILICON

A new photoresist treatment is presented yielding conformal coating of three-dimensional silicon structures, including the sharp corners of through-holes obtained by anisotropic etching in (100)-silicon. Resist reflow from these corners is avoided by replacing the conventional ba king procedure with a vacuum treatment. The investigated photoresist i s Shipley's Eagle 2100 ED, a negative-working electrodepositable photo resist. Additionally, the vacuum treatment allows the photoresist to b e used for lift-off processes. Electrical frontside to backside interc onnections suitable for solder bonding have been realized applying the latter technique. (C) 1998 Elsevier Science S.A. All rights reserved.