Low temperature oxidation of conductive layers for semiconductor fabrication

A method for etching trenches in a semiconductor substrate comprising the steps of:

• providing a semiconductor substrate;
• forming a pad stack of the substrate;
• depositing a valve metal material on the pad stack;
• patterning the valve metal material;
• placing the substrate in an electrochemical cell such that a solution including electrolytes interacts with the patterned valve metal material to form a metal oxide when a potential difference is provided between the patterned valve metal material and the solution;
• and
• employing the metal oxide as an etch mask for etching trenches into the substrate.

A method for forming a valve metal oxide for semiconductor fabrication comprising the steps of:

• providing a semiconductor wafer including a substrate having at least one layer formed thereon;
• depositing a dielectric layer on the at least one layer;
• depositing a valve metal material on the dielectric layer;
• patterning the valve metal material;
• oxidizing the patterned valve metal material by placing the wafer in an electrochemical cell such that a solution including electrolytes interacts with the patterned valve metal material to form a metal oxide when a potential difference is provided between the patterned valve metal material and the solution, the dielectric layer for providing protection for the at least one layer during the oxidizing step;
• and
• patterning structures underlying the patterned valve metal using the metal oxide layer as an etch mask.