Research on multi-step positioning for nano imprint lithography

In multi-step imprinting lithography process, the gap existing in the hinges of the stage structure and the random motion during the stage position adjustment usually lead to errors quite different from ones in the traditional precision positioning. To avoid these nonlinear errors, a radial basis function proportional integral differential (RBF-PID) and monotony position controlling algorithm is introduced, which enables the motion locus to appear monotone, non-oscillatory and multi-step approaching, and the random errors from single direction driving mode and the backlash errors by pre-loading control are eliminated completely. The experimental results within motion range of 100 mm confirm that this nonlinearity compensation is very effective to improve the positioning accuracy up to 10 nm during the multi-step imprinting process.