Submicron electron‐beam patterning of aluminum by a double‐layer pattern transfer technique

A double‐layer pattern transfer technique has been developed for submicron aluminum patterning. The double‐layer consists of an electron beam resist and an inorganic material ’’spacer’’ having high resistance to reactive ion etching of aluminum. When plasma‐deposited silicon dioxide is used as a spacer, severe side‐etch of aluminum occurs. On the other hand, by using plasma‐deposited silicon nitride as a spacer, submicron aluminum patterns are formed without any etch bias. On profiled surfaces, aluminum patterns with 0.75 μm lines and 0.75 μm spaces are produced without linewidth variations due to the surface topography, by applying etch‐back technique to the silicon nitride spacer before resist coating.