Three-dimensional x-ray metrology for block copolymer lithography line-space patterns

Sunday, Daniel F.; Hammond, Michelle; Wang, Chengqing; Wu, Wen‐Li; Kline, R. Joseph; Stein, Gila E.

doi:10.1117/1.jmm.12.3.031103

Cited by 39 publications

(42 citation statements)

References 30 publications

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“…Bounds for fitting of the model parameters were chosen for each parameter and are detailed in the appendices (see Appendix C). To correspond to previous studies of such systems 33–35 , only a selection of data was used to fit the parameters, with five constant q x values being used to extract the intensity as a function of q z for those five constant values (see Fig. 3(d)).…”

Section: Resultsmentioning

confidence: 99%

“…Previous studies 33–35 have used a Markov chain Monte Carlo (MCMC) algorithm 37 to determine the parameter set for the given structure model that best fits the measured scattering data. This approach requires a relatively good initial guess with tight parameter search bounds for the structure parameters and requires multiple independent chain runs to ensure the algorithm has convergence.…”

Section: Introductionmentioning

confidence: 99%

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Advancing x-ray scattering metrology using inverse genetic algorithms

Hannon

Sunday

Kline

2016

J. Micro/Nanolith. MEMS MOEMS

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We compare the speed and effectiveness of two genetic optimization algorithms to the results of statistical sampling via a Markov chain Monte Carlo algorithm to find which is the most robust method for determining real space structure in periodic gratings measured using critical dimension small angle X-ray scattering. Both a covariance matrix adaptation evolutionary strategy and differential evolution algorithm are implemented and compared using various objective functions. The algorithms and objective functions are used to minimize differences between diffraction simulations and measured diffraction data. These simulations are parameterized with an electron density model known to roughly correspond to the real space structure of our nanogratings. The study shows that for X-ray scattering data, the covariance matrix adaptation coupled with a mean-absolute error log objective function is the most efficient combination of algorithm and goodness of fit criterion for finding structures with little foreknowledge about the underlying fine scale structure features of the nanograting.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Advancing x-ray scattering metrology using inverse genetic algorithms

Hannon

Sunday

Kline

2016

J. Micro/Nanolith. MEMS MOEMS

Self Cite

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“…Some discrepancy is also to be expected since the sample is somewhat different. CD-SAXS [11,12] results come from a relatively large (around 100 µm by 100 µm) area of the sample, and provide excellent quality information on the placement, widths, sizes, 3D shape, etc. and in many cases on overall roughness of dense lines.…”

Section: Resultsmentioning

confidence: 99%

10nm three-dimensional CD-SEM metrology

Vladár

Villarrubia²,

Chawla

et al. 2014

Metrology, Inspection, and Process Control for Microlithography XXVIII

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The shape and dimensions of a challenging pattern have been measured using a model-based library scanning electron microscope (MBL SEM) technique. The sample consisted of a 4-line repeating pattern. Lines were narrow (10 nm), asymmetric (different edge angles and significant rounding on one corner but not the other), and situated in a complex neighborhood, with neighboring lines as little as 10 nm or as much as 28 nm distant. The shape cross-section determined by this method was compared to transmission electron microscopy (TEM) and critical dimension small angle x-ray scattering (CD-SAXS) measurements of the same sample with good agreement. A recently-developed image composition method was used to obtain sharp SEM images, in which blur from vibration and drift were minimized. A Monte Carlo SEM simulator (JMONSEL) produced a model-based library that was interpolated to produce the best match to measured SEM images. Three geometrical and instrument parameterizations were tried. The first was a trapezoidal geometry. In the second one corner was significantly rounded. In the last, the electron beam was permitted to arrive with stray tilt. At each stage, the fit to the data improved by a statistically significant amount, demonstrating that the measurement remained sensitive to the new parameter. Because the measured values represent the average unit cell, the associated repeatabilities are at the tenths of a nanometer level, similar to scatterometry and other area-averaging techniques, but the SEM's native high spatial resolution also permitted observation of defects and other local departures from the average.

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“…For example, Sunday et al . [ 226,227 ] reported a technique using resonant critical dimension small angle x-ray scattering (res-CDSAXS) to three-dimensionally characterize buried features of PS-b -PMMA lamellar fi lms in DSA schemes. The methodology has also been utilized to examine pattern transfer of a Cr-evaporated mask versus SIS infused features of a lamellar forming PS-b -PMMA BCP.…”

Section: Metrology and Incorporation Techniquesmentioning

confidence: 99%

Strategies for Inorganic Incorporation using Neat Block Copolymer Thin Films for Etch Mask Function and Nanotechnological Application

et al. 2016

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Block copolymers (BCPs) and their directed self-assembly (DSA) has emerged as a realizable complementary tool to aid optical patterning of device elements for future integrated circuit advancements. Methods to enhance BCP etch contrast for DSA application and further potential applications of inorganic nanomaterial features (e.g., semiconductor, dielectric, metal and metal oxide) are examined. Strategies to modify, infiltrate and controllably deposit inorganic materials by utilizing neat self-assembled BCP thin films open a rich design space to fabricate functional features in the nanoscale regime. An understanding and overview on innovative ways for the selective inclusion/infiltration or deposition of inorganic moieties in microphase separated BCP nanopatterns is provided. Early initial inclusion methods in the field and exciting contemporary reports to further augment etch contrast in BCPs for pattern transfer application are described. Specifically, the use of evaporation and sputtering methods, atomic layer deposition, sequential infiltration synthesis, metal-salt inclusion and aqueous metal reduction methodologies forming isolated nanofeatures are highlighted in di-BCP systems. Functionalities and newly reported uses for electronic and non-electronic technologies based on the inherent properties of incorporated inorganic nanostructures using di-BCP templates are highlighted. We outline the potential for extension of incorporation methods to triblock copolymer features for more diverse applications. Challenges and emerging areas of interest for inorganic infiltration of BCPs are also discussed.

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Three-dimensional x-ray metrology for block copolymer lithography line-space patterns

Cited by 39 publications

References 30 publications

Advancing x-ray scattering metrology using inverse genetic algorithms

Advancing x-ray scattering metrology using inverse genetic algorithms

10nm three-dimensional CD-SEM metrology

Strategies for Inorganic Incorporation using Neat Block Copolymer Thin Films for Etch Mask Function and Nanotechnological Application

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