The requirement of larger common overlap process window in EUV patterning is getting stronger when the design pitch continues to shrink. The reflective optics in EUV generate various imaging issues due to mask 3-dimensional (M3D) effects. Therefore, sub-resolution assistant features (SRAFs) insertion is preferred for the resolution enhancement technology. SRAFs insertion can create a dense optical environment that will prevent strong best focus shift between semi-isolated and isolated features. From the previous study, SRAFs insertion and stochastic printing can be modeled and verified with a flow utilizing a compact resist 3D model (R3D) in conjunction with stochastic model. In this work, additional SRAFs investigations and studies extend to a better choice of alternative EUV mask absorbers that can mitigate M3D effects and have better lithography performance. In this paper, a low-n dark field EUV mask with regular hole grid design and positive tone development (PTD) is considered. The SEM (scanning electron microscope) images of through pitches with various SRAFs sizes and combination of SRAF to main space are collected. The SRAFs printing pixels can be captured and modeled with compact resist stochastic modeling. The results can be verified using average printed area (APA) metric with a R3D model and the simulation studies have proved the SRAFs printing sensitivity to the photomask biases.
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