Fourier analysis of line-edge roughness in calixarene fine patterns

Quantitative evaluation of line-edge roughness (LER) on nano-scale resist patterns is indispensable in clarifying the origin of LER and in refining nanofabrication. We developed an algorithm for the quantitative analysis of LER that can elicit an edge profile from a scanning electron micrograph by fitting a Gaussian curve to an intensity profile across the edge. We also calculated the power spectrum of the edge profile using fast Fourier transformation (FFT). Because of the wide latitude of digital micrographs, conditions of SEM image acquisition, such as the brightness, contrast, or focus, had little influence on the LER spectrum. We examined four types of negative electron beam (EB) resists with methyl-acetoxy calix[n]arenes.