24 March 2016 Scatterometry-based metrology for SAQP pitch walking using virtual reference
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Advanced technology nodes, 10nm and beyond, employing multi-patterning techniques for pitch reduction pose new process and metrology challenges in maintaining consistent positioning of structural features. Self-Aligned Quadruple Patterning (SAQP) process is used to create the Fins in FinFET devices with pitch values well below optical lithography limits. The SAQP process bares compounding effects from successive Reactive Ion Etch (RIE) and spacer depositions. These processes induce a shift in the pitch value from one fin compared to another neighboring fin. This is known as pitch walking. Pitch walking affects device performance as well as later processes which work on an assumption that there is consistent spacing between fins. In SAQP there are 3 pitch walking parameters of interest, each linked to specific process steps in the flow. These pitch walking parameters are difficult to discriminate at a specific process step by singular evaluation technique or even with reference metrology such as Transmission Electron Microscopy (TEM). In this paper we will utilize a virtual reference to generate a scatterometry model to measure pitch walk for SAQP process flow.
© (2016) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Taher Kagalwala, Taher Kagalwala, Alok Vaid, Alok Vaid, Sridhar Mahendrakar, Sridhar Mahendrakar, Michael Lenahan, Michael Lenahan, Fang Fang, Fang Fang, Paul Isbester, Paul Isbester, Michael Shifrin, Michael Shifrin, Yoav Etzioni, Yoav Etzioni, Aron Cepler, Aron Cepler, Naren Yellai, Naren Yellai, Prasad Dasari, Prasad Dasari, Cornel Bozdog, Cornel Bozdog, "Scatterometry-based metrology for SAQP pitch walking using virtual reference", Proc. SPIE 9778, Metrology, Inspection, and Process Control for Microlithography XXX, 97781W (24 March 2016); doi: 10.1117/12.2228329; https://doi.org/10.1117/12.2228329

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