Double patterning has become one of the candidates to bring us to the next node of the ITRS-roadmap. As an alternative to immersion lithography with higher index fluids and EUV lithography which both require considerable changes in infrastructure, double patterning makes use of the existing infrastructure. Because of this, double patterning has gained considerable attention during the past few years. It has become a serious candidate to reach the 45 nm node and even the 32 nm node. Most of the currently known double patterning techniques have relatively complex process flows, which may prevent them from being used in production. One of the complicating factors is the use of an etch step in between the two lithography steps. This etch step is necessary to transfer the pattern of the first resist layer into an underlying hard mask before a second exposure can be done. Another complicating element, arising in several known double patterning techniques, is the translation of overlay error in CD-error. This translation occurs when a feature is printed in two exposures, i.e. not features but the spaces between them are patterned, patterning the left and right edge of a feature in different exposures. In this paper, we examine and evaluate a novel double patterning method that does not include transfer etch in between the lithography steps. This method would simplify the double patterning process. Furthermore, each feature is patterned completely in one exposure, for which CD-value is not affected by overlay error. This paper discusses the feasibility of the new double patterning method and compares it to conventional double patterning schemes. Furthermore, an assessment will be made whether the proposed technique has the potential to be used in production.
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