One of the major challenges in high-resolution μ-printing is the cross-talk between features written in close proximity-the proximity effect. This effect prevents, e.g., gratings with periods below a few hundred nanometers. Surprisingly, the dependence of this effect on space and time has not thoroughly been investigated. Here, we present a spatial-light-modulator based method to dynamically measure the strength of the proximity effect on length and timescales typical to μ-printing. The proximity strength is compared in various photo resists. The results indicate that molecular diffusion strongly contributes to the proximity effect.
Keywords: 3D μ-printing; direct-laser-writing; photo resist; polymerization.