Abstract: A method of plating via hole in a substrate includes providing a substrate having a first side and a second side and a plurality of through substrate via holes; depositing a first seed layer on the first side of the substrate; applying a foil on the first seed layer of the substrate closing the first ends of the plurality of via holes; electro-chemical plating of the second side of the substrate; and removing the foil.

Abstract: Therefore, a method of plating wafer via holes in a wafer is provided. A substrate (200) having a first and second side and a plurality of wafer via holes (210) is provided. Each via hole comprises a first and second end extending between the first and second side. A first seed layer (220) is deposited on the first side of the 5 wafer (200). A foil (250) is applied on the first seed layer (220) of the wafer closing the first ends of the plurality of wafer via holes (210). The second side of the wafer (200) is electro-chemically plated and the foil (250) is removed.

Abstract: A method of forming a conductive trench such as a through-silicon-via in a silicon wafer is disclosed. The method includes depositing a mask over a wafer surface; patterning the mask to expose a portion of the wafer; exposing the wafer to a first etching step in which a first portion of the trench is formed; exposing the wafer to an second etching step in which a tapered second portion of the trench is formed, where the first portion has a continuously non-increasing width from the wafer surface to the second portion; and filling the trench with a conductive material. A silicon wafer including such a conductive trench is also disclosed.