Ion beam aperture-array lithography

We explore a new technique, ion beam aperture-array lithography (AAL), for fabricating low cost, large area nanostructure arrays. In this approach, a broad beam of light ions illuminates a stencil mask containing a periodic array of circular apertures. The array of transmitted beamlets is moved over the substrate, thereby printing an array with the same period but arbitrary unit cell. AAL has several advantages over ion beam proximity lithography: (1) the mask pattern density is lower, (2) the unit cell patterns are defined by software, and (3) dose and shape correction can be applied to compensate for system blur. Dose optimization methods are discussed and experimental results with 150 nm apertures presented.