Selective plating without photoresist

Abstract

A method including forming a stack of layers on top of a dielectric layer and within an opening in the dielectric layer, the stack of layers comprising a first layer, a second layer, a third layer, and a fourth layer, each formed successively one on top of another, removing a first portion of the fourth layer outside the opening to expose a portion of the third layer, a second portion of the fourth layer remains within the opening, filling the opening with a metal by applying an electrical potential to the second layer during an electroplating technique in which the metal plates out on the fourth layer but does not plate out on the third layer, and removing portions of the first layer, the second layer, and the third layer to expose an upper surface of the dielectric layer between the opening and an adjacent opening.

Dependencies are inferred from the claim text.