Patent ID: 8894828

Claim:
A method of focused ion beam etching of copper in the presence of a dielectric in a focused ion beam vacuum chamber for circuit editing of a microchip, comprising: directing a focused ion beam onto the copper to sputter said copper for said circuit editing; and exposing the copper and the dielectric to an etch assisting gas comprising a compound selected from the group consisting of Hydrazine Monohydrate, HydroxyEthyl Hydrazine, CyanoEthyl Hydrazine, ButoxyCarbonylMethyl Hydrazine and ButoxyCarbonylMethoxyEthyl Hydrazine, and wherein said compound has a boiling point up to about 220° C., and said etch assisting gas is selected to substantially replenish dielectric sputtered by said ion beam and to render sputtered copper non-conductive during sputtering and re-deposition.