Algorithm to Derive Optimal Mask and Movement Patterns in Moving Mask Deep X-ray Lithography (M~2DXL)

摘要

The final purpose of this study is to establish a method to realize three dimensional (3-D) microstructures with free arbitrary shaped sidewalls in "Moving Mask Deep X-ray Lithography (M~2DXL)". In this paper, a new algorithm named "Inverse approach" applying Fourier transformation technique was proposed to theoretically determine a suitable mask movement pattern for a target shape. As a first step toward completion of this approach, the algorithm in 2-D space, i.e. vertical and lateral, has been developed. In order to confirm the validity of 2-D Inverse approach, a V-shaped groove with a cross -sectional shape of 40 μm opening and 20 μm depth was adopted as a target microstructure. The straightforward application of the 2-D Inverse approach to the V-shaped groove fabrication did not yield a satisfying result. However, one simple correction of a distributed dose profile firstly expected to realize the target microstructure in this algorithm allowed the successful fabrication of the target V-shaped groove microstructure. Furthermore, we showed that the Inverse approach provides derivations of not only the suitable mask movement pattern but also the optimal mask and movement patterns which contribute to reduce the time and cost for prototyping.