Monte Carlo modeling of secondary electron imaging in three dimensions

Villarrubia, John S.; Ritchie, Nicholas W. M.; Lowney, Jeremiah R.

doi:10.1117/12.712353

Cited by 43 publications

(31 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Therefore, the main available simulation tools [1][2][3] are often limited to the simulation of either uncharged samples, or to the implementation of analytical solutions of the Poisson equation. This obviously represents a strong simplification of the problem to be solved, which turns into wrong results.…”

Section: Problem Definitionmentioning

confidence: 99%

See 1 more Smart Citation

Exact 3D simulation of Scanning Electron Microscopy images of semiconductor devices in the presence of electric and magnetic fields

Ciappa

Illarionov

Ilgünsatiroglu

2014

Microelectronics Reliability

View full text Add to dashboard Cite

Section: Problem Definitionmentioning

confidence: 99%

“…(a) Longitudinal cross-section across the neutral SiO 2 three-lines sample with the electric field isolines, as calculated by the TCAD environment[2]. (b) Linescans along previous sample without (curve A, solid) and with (curve B, dashed) the electrostatic extraction field.…”

mentioning

confidence: 99%

Exact 3D simulation of Scanning Electron Microscopy images of semiconductor devices in the presence of electric and magnetic fields

Ciappa

Illarionov

Ilgünsatiroglu

2014

Microelectronics Reliability

View full text Add to dashboard Cite

“…The physics models of electron scattering and secondary electron generation in solids were exactly the same as those used originally in MONSEL. (In fact, NIST has already developed another new SEM simulator based on MONSEL but capable of modeling general 3-dimensional structures 12 .) In addition to the shape model update, the electron beam model was also extended.…”

Section: Sem Simulator Updatementioning

confidence: 99%

“…In our ongoing study of MBL SEM metrology, we have been using MONSEL, a Monte Carlo SEM simulation developed at NIST. [10][11][12] MONSEL was the first program to model low-energy secondary electron generation, an important phenomenon in CD-SEM image formation. In fact, this software was intended primarily for applications in linewidth metrology.…”

Section: Sem Simulator Updatementioning

confidence: 99%

Application of model-based library approach to Si 3 N 4 hardmask measurements

et al. 2008

View full text Add to dashboard Cite

The model-based library (MBL) matching technique was applied in hardmask linewidth metrology with a criticaldimension scanning electron microscope (CD-SEM). The MBL matching measures the edge positions and shapes of samples by comparing simulated images to measured images. To achieve reliable, stable measurements, two important simulation parameters were determined empirically. One was the beam width, and the other was a material parameter, the residual energy loss rate. This parameter is especially important for measurement of hardmask patterns, which have relatively high SEM image contrast. These simulation parameters were estimated so as to fit to actual SEM images, and then pinned to the estimated values during MBL matching. Hardmask patterns made of Si 3 N 4 were measured by MBL matching with the estimated parameters. The accuracy of the measurements was evaluated by one-to-one comparison with atomic force microscope (AFM) results. The pattern profile deduced from only the top-down CD-SEM image with MBL matching agreed well with the AFM profile and a scanning transmission electron microscope (STEM) crosssectional image. The average measurement bias between the MBL matching and AFM results was 1.58 nm for the bottom CD and -0.64 nm for the top CD, with a standard deviation of about 1.3 nm.

show abstract

“…Physics-based models account for the shape and allow for much better dimensional metrology. [2,3] Such model-based metrology may be able to determine the 3D shape of IC structures with accuracy approaching a few atomic spacings, in many cases starting with a single, top-down-view image. The various model-based methods need the realistic range of possible shape, material and other parameters to find the best fitting 3D shape and sizes of the measured structure.…”

Section: Introductionmentioning

confidence: 99%

10nm three-dimensional CD-SEM metrology

Vladár

Villarrubia²,

Chawla

et al. 2014

SPIE Proceedings

Self Cite

View full text Add to dashboard Cite

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.

show abstract

Monte Carlo modeling of secondary electron imaging in three dimensions

Cited by 43 publications

References 17 publications

Exact 3D simulation of Scanning Electron Microscopy images of semiconductor devices in the presence of electric and magnetic fields

Exact 3D simulation of Scanning Electron Microscopy images of semiconductor devices in the presence of electric and magnetic fields

Application of model-based library approach to Si 3 N 4 hardmask measurements

10nm three-dimensional CD-SEM metrology

Contact Info

Product

Resources

About