Metal-assisted chemical etching of a semiconductive substrate with high aspect ratio, high geometic uniformity, and controlled 3d profiles

Abstract

An embodiment of a method for metal-assisted chemical etching of a semiconductive substrate comprises forming a patterned coating on a top surface of a substrate layer of a silicon wafer; applying a noble metal layer over the patterned coating such that a portion of the noble metal layer is in contact with the top surface of the substrate layer; and immersing the silicon wafer in a wet etching solution to form a trench under the portion of the noble metal layer that is contact with the top surface of the substrate layer. Further, the trench may be filled with copper material to form a through silicon via structure. Such embodiments provide etching techniques that enable etched formations that are deep (e.g., high-aspect-ratio) and uniform as opposed to shallow etchings (i.e., low-aspect-ratio) or non-uniform deep etchings.