We derive an imaging budget from the performance of extreme ultraviolet (EUV) optics with NA = 0.32, and demonstrate that the requirements for 22-nm applications are met. Based on aerial image simulations, we analyze the impact of all relevant contributors, ranging from conventional quantities like straylight or aberrations, to EUV-specific topics, namely the influence of 3-D mask effects and faceted illumination pupils. As test structures we consider dense to isolated lines, contact holes, and 2-D elbows. We classify the contributions in a hierarchical order according to their weight in the critical dimension uniformity (CDU) budget and identify the main drivers. The underlying physical mechanisms causing different contributions to be critical or less significant are clarified. Finally, we give an outlook for the 16- and 11-nm nodes. Future developments in optics manufacturing will keep the budgets controlled, thereby paving the way to enable printing of these upcoming nodes.
We derive an imaging budget from the performance of EUV optics with NA = 0.32, and demonstrate that the
22nm node requirements are met. Based on aerial image simulations, we analyze the impact of all relevant
contributors, ranging from conventional quantities, like straylight or aberrations, to EUV-specific topics, namely
influence of 3D mask effects and facetted illumination pupils. As test structures we consider dense to isolated
lines, contact holes, and 2D elbows. We classify the contributions in a hierarchical order according to their
weight in the CDU budget and identify the main drivers. The underlying physical mechanisms causing different
contributions to be critical or less significant are clarified. Finally, we give an outlook for the 16nm and 11nm
nodes. Future developments in optics manufacturing will keep the budgets controlled, thereby paving the way
to enable printing of these upcoming nodes.
We present a comprehensive modeling study of polarization effects for the whole optical chain including exposure tool and mask, with strong emphasis on the impact of the Jones Matrix of the projection lens. First we start with the basic of polarization and then the polarization effect of each components of the optical chain will be discussed. Components investigated are source polarization, rigorous EMF effect, mask blank birefringence, pellicle effect and projection lens. We also focus on comparing the relative merits of different types of representation of Jones matrix of the projection lens and outlined ways to decompose the Jones Matrix. Methodologies such as Pauli matrix, PQM, Jones-Zernike expansion and IPS-Zernike expansion are among the ones investigated. The polarization impact on lithography and OPC on realistic 45nm and 32nm node process levels is discussed. Issues in OPC modeling with Jones Matrix is highlighted. Concerns regarding the standardization of the implementation of Jones Matrix in the lithography community are considered and a standard has been proposed and received wide acceptance. Last we discuss the challenge of using polarization and some novel ideas to deal with polarization in hyper NA era. Throughout the paper the resist component is not included so as to isolate the effect of resist from that of the other components.
We give a general introduction into polarized imaging and report on a Jones pupil approach for a complete evaluation of the resulting optical performance. The Jones pupil assigns a Jones matrix to each point of the exit pupil, describing the impact of both the global phase and the polarization on imaging. While we already can learn much about the optical system by taking a close look at the Jones pupil-and starting imaging simulations from it-a quantitative assessment is necessary for a complete evaluation of imaging. To do this, we generalize the concept of scalar Zernike aberrations to Jones-Zernike aberrations by expansion of the Jones pupil into vector polynomials. The resulting method is nonparaxial, i.e., the effect of the polarization-dependent contrast loss for high numerical apertures is included. The aberrations of the Jones matrix pupil are a suitable tool to identify the main drivers determining polarization performance. Furthermore, they enable us to compare the polarized and unpolarized performance of such a characterized lithographic system.
We give a general introduction into polarized imaging and report on a Jones-pupil approach for a complete evaluation of the resulting optical performance. The Jones pupil assigns a Jones matrix to each point of the exit pupil describing the impact of both the global phase and the polarization on imaging. While we can learn already a lot about the optical system by taking a close look at the Jones pupil - and starting imaging simulations from it - a quantitative assessment is necessary for a complete evaluation of imaging. To do this, we generalize the concept of scalar Zernike aberrations to Jones-Zernike aberrations by expansion of the Jones pupil into vector polynomials. The resulting method is non-paraxial, i.e. the effect of the polarization dependent contrast loss for high numerical apertures is included. The aberrations of the Jones-matrix pupil are a suitable tool to identify the main drivers determining the polarization performance. Furthermore, they enable us to compare the polarized and the unpolarized performance of the such characterized lithographic system.
This paper presents a comprehensive study of the impact of wavefront errors on low-k1-imaging performance using high numerical aperture NA lithographic systems. In particular, we introduce a linear model that correctly describes the aberration induced imaging effects. This model allows us to quantify the aberration requirements for future lithographic nodes. Moreover, we derive scaling laws characterizing the imaging performance in dependence on the key parameters exposure wavelength λ, NA, and k1. Our investigations demonstrate, first, that an accurate control of coma is and will be crucial, and, second, that spherical requirements will be very tight for k1<0.3 due to isolated contact printing. Finally, we summarize the results of this paper in a roadmap covering the aberration requirements in optical lithography down to the 45nm node. We conclude that the improvement of wavefront quality is necessary to enable imaging enhancement techniques, but is not sufficient to replace these techniques.
This study assesses the various approaches to printing contacts in the sub 100nm regime using 193nm. Traditional techniques are analyzed along with the use of tri-tone contacts and pupil filtering. Approaches using attPSM masks looks promising down to pitches of 300nm. Below this, assist features may be needed to prevent residual artifacts due to sidelobes. For pitches > 400nm the use of tri-tone masks show a significant improvement in process latitude and ease of overlapping process windows. The pupil filter solution does not seem provide any significant improvement as compared to other solutions with the exception that it provides the lower MEF. Realization of this solution will increase machine complexity and will possibly impact throughput, especially if using transmission filters. However, pupil filtering can be an option for isolated contact layers that are printed with binary masks. We find that the process and enhancement techniques to print a dense contacts and isolated contacts to be vastly different. This may require a split into two exposures if an extensive pitch range is needed.
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