| CPC H01L 21/02087 (2013.01) [H01L 21/3065 (2013.01)] | 16 Claims |
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1. A method of processing a wafer, the method comprising:
breaking up contaminants that include layers of embedded metals and dielectrics formed on a bevel of the wafer using a bevel dry etch, wherein the dry bevel etch leaves behind structures comprising the remaining portions of the contaminants on the surfaces of the wafer, and wherein at least one of the structures is present on the edge of the wafer and includes portions of a first dielectric layer, a first metal layer, a second dielectric layer, a second metal layer, and a third dielectric layer, and wherein the first metal layer and the second metal layer each comprise a metal selected from the group consisting of: aluminum, copper, iron, ruthenium, tantalum, titanium, chromium, cobalt and combinations thereof, and wherein the first dielectric layer, the second dielectric layer, and the third dielectric layer each comprises a material selected from the group consisting of: silicon oxide, silicon nitride, and combinations thereof, and wherein the bevel dry etch is performed in multiple cycles alternating between a F-containing plasma for etching the first dielectric layer, the second dielectric layer, and the third dielectric layer and a Cl-containing plasma for etching the first metal layer and the second metal layer, in a layer by layer manner;
creating pathways in the wafer undercutting any remaining portions of the contaminants using a first wet etch, the first wet etch further removing a damaged layer resulting from the bevel dry etch;
lifting off the undercut remaining portions of the contaminants using a second wet etch that follows the pathways in the wafer made by the undercutting; and
removing residue and surface roughness from the wafer using a third wet etch.
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