Patent ID: 6596632
Filing Date: 2003-07-22
Classification: H01L

Abstract:
A method for forming an electrical interconnect, comprising:creating a first electrically conductive layer overlying a substrate; creating a first etch stop layer overlying said first electrically conductive layer; patterning said first electrically conductive layer and said etch stop layer to create a masked region and an unmasked region; exposing the substrate in said unmasked region, thereby forming a via having a sidewall comprising said first electrically conductive layer and said etch stop layer; creating a second electrically conductive layer to overlie said etch stop layer and the substrate, the first and the second electrically conductive layers comprising polycrystalline silicon; etching a portion of said second electrically conductive layer to expose said etch stop layer; at least a portion of said second electrically conductive layer remaining in electrical contact with the substrate to form an electrical plug portion of the electrical interconnect; creating, overlying said first etch stop layer and the electrical plug portion, a layer which is capable of reacting with said second electrically conductive layer to form a layer which is irresponsive to an etchant which is capable of etching said second electrically conductive layer; creating a reaction between said layer which is capable of reacting with said second electrically conductive layer and the electrical plug portion to form a second etch stop layer overlying the electrical plug portion of the second electrically conductive layer, said first etch stop layer protecting said first electrically conductive layer from reacting with said layer which is capable of reacting with said second electrically conductive layer during said step of creating said reaction; removing unreacted portions of said layer which is capable of reacting with said second electrically conductive layer; removing at least portions of said first etch stop layer while retaining said second etch stop layer; and removing at least portions of said first electrically conductive layer, while retaining the electrical plug in its entirety during said removing to form the electrical interconnect of the electrical plug and the remaining portion of the first electrically conductive layer.