Fabrication of high aspect ratio features in a glass layer by etching

Abstract

Methods, apparatuses, systems, and devices relating to the fabrication of features for semiconductor devices are disclosed. The features may include vias and pillars. In some implementations, the vias may define light pipes for semiconductor image sensor devices that serve to guide electromagnetic radiation directly down to photodiodes or other radiation detecting elements formed on an underlying silicon substrate. These structures significantly improve the light collection efficiency and reduce the scattering and crosstalk losses in the dielectric layer. An etch mask may be used to produce features through a subsequent etching process. More specifically, the etch mask defines sidewalls in the glass layer, provides excellent dry etch resistance, and enables easy lift-off of the etch mask from the glass layer. Two embodiments are disclosed herein: the first using amorphous silicon as the etch mask; and the second employing a photoresist as the etch mask. Both embodiments produce high aspect ratio features having generally vertical and smooth sidewalls.

Dependencies are inferred from the claim text.