3D Imprint Lithography Using Sixny Molds

Abstract

Three-dimensional patterning reduces more complicated alignment steps in the fabrication of micro and nano-scale structures. Multiple lithography processes with interlevel alignment or single lithography with multi layer resist is essential for three dimensional patterning. A number of 3D structures have found immediate applications in a range of microelectronic systems such. as micro-optics, micro-electromechanical systems, and in monolithic microwave integrated circuits. We have previously demonstrated that imprint at low temperatures (well below the glass transition of the resist) is possible for a number of structures using silicon nitride (SixNy) molds. A low temperature process is important for pattering substrates or polymer-based materials that are intolerant of high temperatures. The advantages of using SixNy for mold making are the capability of forming reliable nanoscale structures and its surface properties that allows imprint without sticking. In this work we will present pattering results for three-dimensional structures using nanoimprint lithography with SixNy molds. The mold material consists of a 1?m thick low stress SixNy layer deposited by low-pressure chemical vapour deposition (LPCVD) on to a silicon substrate. Patterning of the SixNy was performed using electron beam lithography at 50keV into ma-N 24033 negative tone resist.