Pattern transfer fidelity of nanoimprint lithography on six-inch wafers

We studied the pattern transfer fidelity of nanoimprint lithography (NIL) by patterning sub-micron MESFET gates on six-inch wafers. The critical dimensions (CD) of the gate patterns on the mould, imprinted in resist, as well as after oxygen reactive ion etching (RIE) and metal lift-off were measured, separately, using an ultrahigh-resolution scanning electron microscope. Comparison of the measurements reveals that the as-imprinted gates in resist are 5.2% (or 37 nm) on average larger than those on the mould with a standard deviation of 1.2% (or 8 nm), and the gates after oxygen RIE and metal lift-off are 42% (or 296 nm) on average larger than those on the mould with a standard deviation of 8% (or 30 nm). Compared with photolithography, NIL has better pattern transfer fidelity with CD controls about four times smaller.