LER/LWR performance is currently considered as one of the major stumbling blocks complicating
progress in the semiconductor technology. Line edge scans show that low frequency components clearly
dominate the LER Power Spectral Density (PSD), thus implying a large characteristic length (>100-500 nm)
phenomenon as the major LER source.
Most of the theoretical analyses aimed to identify the origin of the LER were focused on the
combined effect of exposure and CAR action statistics, and failed to explain the origin of this limit, which
resulted in suggestions that there is more than just one phenomenon involved in LER generation.
Depth profiling experiments were performed for a broad set of Polymer-PAG-Base combinations.
Depth profiling PSD spectra have demonstrated that higher RMS values and correspondingly higher PSD
amplitudes are associated with tighter PSD spectrum shifted towards lower frequencies (larger sizes of
roughness features), which is very typical for all the cases investigated. The set of the PSD spectra obtained
exhibit a pronounced bi-modal structure, indicating that there are at least two clearly noticeable independent