Using electroless deposition as a metrology tool to highlight contamination, residue, and incomplete via etch

A method for detecting contamination on a patterned substrate, comprising:

• performing a via etch operation on a substrate, wherein the via etch operation is configured to define a plurality of via features on the substrate and expose an etch-stop layer at a bottom of each via feature;
• performing an etch-stop removal operation on the substrate, wherein the etch-stop removal operation is configured for removing the etch-stop layer at the bottom of each via feature to expose a metallic feature underlying the etch-stop layer;
• applying an electroless deposition solution to the substrate, the applied electroless deposition solution being configured for selectively depositing a metallic material over the exposed metallic feature and on metallic contaminants on exposed surfaces of the substrate, the metallic contaminants being generated from the metallic feature during the etch-stop removal operation;
• performing an inspection operation on the substrate to identify the metallic contaminants that have been deposited with the metallic material, wherein the inspection operation is further configured to identify whether a blockage exists at the bottom of one or more of the plurality of via features that at least partially prevents the electroless deposition solution from depositing the metallic material on the metallic feature.