In this paper, we present a methodology for the characterization of Contact Edge Roughness (CER) using top-down SEM images and an algorithm for the generation of model contact edges with controlled roughness as well as synthesized SEM images with CER. The characterization methodology is applied to the determination of the effects of exposure dose on the amplitude and frequency parameters of the CER of an EUV resist, while the model edges are used for understanding the results and connecting RMS to CD variation. Experiments show us that the RMS value of CER decreases as dose decreases contrary to what happens to LER/LWR. Modeling shows that RMS decreases and CD variation increases as the sampled edge length is decreased, in agreement with LER/LWR. Thus, modelling may offer an explanation of the RMS reduction with reduced dose: Indeed, decrease of dose causes reduction of Critical Dimension (CD) (i.e. diameter) of the hole and therefore reduction of its circumference (i.e. measurement edge length), which in turn causes reduction of RMS and increase in CD variation.

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