A method has been developed for correcting line width variations due to midrange flare with a scattering range of over a few tens of micrometers (which we call local flare). It is shown that the conventional single Gaussian point spread function (PSF) is not sufficient and that a double Gaussian point spread function is needed to explain the line width variation caused by local flare. The remaining errors after correction are discussed under the assumptions that the mask correction is linear with respect to local flare intensity and is independent of pattern layout considering the order of the local flare correction (LFC) and optical proximity correction (OPC). This simple sizing method can reduce the critical dimension (CD) variation regardless of whether LFC is done before or after OPC. The LFC performance was evaluated using actual 90-nm-node LSI data. A much faster correction time than that of OPC was achieved by introducing the area density map method. The CD variation due to local flare was reduced from 22 to 5 nm.
A simple technique for fabricating an array of isolated nanometer-size Si dots is reported. The processing procedures consist of electron beam lithography and reactive ion etching followed by wet etching in NH4OH/H2O2/H2O. The resulting array has isolated crystalline Si dots, each 10 nm in diameter and 10 nm high. To our knowledge, these are the smallest isolated crystalline Si dots reported to date.
Due to the importance of errors in lithography scanners, masks, and computational lithography in low-k1 lithography, application software is used to simultaneously reduce them. We have developed "Masters" application software, which is all-inclusive term of critical dimension uniformity (CDU), optical proximity effect (OPE), overlay (OVL), lens control (LNS), tool maintenance (MNT) and source optimization for wide process window (SO), for compensation of the issues on imaging and overlay.In this paper, we describe the more accurate and comprehensive solution of OPE-Master, LNS-Master and SO-Master with functions of analysis, prediction and optimization. Since OPE-Master employed a rigorous simulation, a root cause of error in OPE matching was found out. From the analysis, we had developed an additional knob and evaluated a proofof-concept for the improvement. Influence of thermal issues on projection optics is evaluated with a heating prediction, and an optimization with scanner knobs on an optimized source taken into account mask 3D effect for obtaining usable process window. Furthermore, we discuss a possibility of correction for reticle expansion by heating comparing calculation and measurement.
Extreme ultraviolet lithography (EUVL) requires flare variation compensation technology and highly accurate critical dimension (CD) control for the fabrication of devices with feature sizes of 32 nm and beyond. To deal with these issues, a mask pattern suitable for evaluating flare and CD variation was designed based on the power spectral density (PSD) of the projection optics of the EUV1. The CD of the replicated patterns clearly varied with the local density of mask patterns, and the variation was affected by mask CD error and flare level. The impact of flare on CD variation was estimated very precisely (
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.