Focused electron beam induced etching of copper in sulfuric acid solutions

We show here that copper can be locally etched by an electron-beam induced reaction in a liquid. Aqueous sulfuric acid (H₂SO₄) is utilized as the etchant and all experiments are conducted in an environmental scanning electron microscope. The extent of etch increases with liquid thickness and dose, and etch resolution improves with H₂SO₄ concentration. This approach shows the feasibility of liquid phase etching for material selectivity and has the potential for circuit editing.