Patent ID: 8778804

Claim:
A method of making visible in a cross section of an integrated circuit an interface in between an oxide material and a nitride material, comprising: exposing a cross section of an integrated circuit by focused ion beam micromachining; directing an electron beam toward the exposed cross section; and directing a first gas and a second gas toward the exposed cross section, the first gas reacting in the presence of the electron beam to etch a first material of the cross section and the second gas inhibiting etching of a second material of the cross section, the first material including a compound of oxygen and silicon, the second material containing a compound of nitrogen and silicon, the electron beam induced reactions making the etching rate of the first material substantially faster than the second material so that the interface between the first material and the second material is visible in an electron beam image of the cross section and a lower etch rate of the second material is used to differentiate layers that are silicon-oxygen compound and layers that are silicon-nitrogen compound.