Control-based high-speed direct mask fabrication for lithography via mechanical plowing

Mechanical indentation and plowing is one of the most widely used methods in AFM nanolithography. Compared to other probe-based AFM nanolithography techniques such as the Dip-pen and the milliped, mechanical plowing is not restrictive to conductive materials and/or soft materials. However, like other probe-based nanolithgraphy techniques, the low-throughput has hindered the implementation of this technique in practices. In this paper, a recently-developed iterative learning control technique is utilized to account for the adverse effects encountered in high-speed, large-range mechanical plowing nanolithography, including the hysteresis, the vibrational dynamics, and the cross-axis dynamics-coupling effects. This approach is implemented to directly fabricate patterns on a mask consisting of a nickel layer sandwiched between an aluminum layer on the top and a silicon dioxide substrate on the bottom. The experimental results demonstrated that a relatively large-size pattern of four grooves (20 μm in length) can be fabricated at a high-speed of ~3.8 mm/sec, with the line width and line depth at ~80 nm and 5 nm, respectively.