Determining the impact of statistical fluctuations on resist line edge roughness

Leunissen, L. H. A.; Ercken, Monique; Patsis, G. P.

doi:10.1016/j.mee.2004.12.005

Cited by 20 publications

(10 citation statements)

References 20 publications

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“…8,9 To begin with, we will screen those parameters and identify those that could explain LER variations observed during this study. Actually several parameters are identified as roughness contributors.…”

Section: A Contributors To Lermentioning

confidence: 99%

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Study on line edge roughness for electron beam acceleration voltages from 50to5kV

Río

Constancias

Saied

et al. 2009

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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Section: A Contributors To Lermentioning

confidence: 99%

“…9,13,14 They are usually based on complicated models and consider many parameters that are identified as influent on roughness. Many roughness simulations have already been reported in publications.…”

Section: B Simulation Of Shot Noise and Spot Size Influence On Lermentioning

confidence: 99%

Study on line edge roughness for electron beam acceleration voltages from 50to5kV

Río

Constancias

Saied

et al. 2009

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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show abstract

“…In recent years, it has become clear that the CDU and LER requirements set severe lower limits on the resist sensitivity and thus on the current or power required in the illumination [8][9][10][11][12]. This is related to the statistical nature of the radiation: it is impossible to deposit exactly N particles on a pixel, there is always an uncertainty of ± p N. Analysis leads to the conclusion that typically 4000 particles must contribute to the resist exposure in an area of size CD · CD.…”

Section: Requirementsmentioning

confidence: 99%

The role of MEMS in maskless lithography

Kruit

2007

Microelectronic Engineering

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“…Not using a chemically amplified resist, but rather something like polymethylmethacrylate (PMMA), needs a small adaptation to the theory. An extensive study concerning the effects of the resist is performed by Leunissen et al (2005).…”

Section: Shot-noise Effect On Line-width Control In Lithographymentioning

confidence: 99%

Shot noise in electron‐beam lithography and line‐width measurements

Kruit

Steenbrink

2006

Scanning

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Electron-beam lithography is used extensively in nanoscience and technology for making masks for the semiconductor industry and, on a limited scale, for maskless lithography: that is, writing the patterns directly on the chip. We expect the latter application to extend in the years to come. Control of the dimensions of the written structures is essential in the semiconductor industry. For 45 nm generation, which is presently under development and should reach production at the end of the decade, the required control over the line width is between 1.5 and 5 nm, depending on the application. One of the factors of influence on the line-width control is the statistics in the number of electrons illuminating the resist. This effect gives line edge roughness, or in other words a lack of control over the local position of a resist edge. This has long been recognized and often discussed. Recently, we developed an analytic model for the line edge position variation, which we shall illustrate and expand in this paper. The model, supported by Monte Carlo simulations, demonstrates that the line-width variation is inversely proportional to the dose used for the illumination of the resist. This makes it impossible to increase the lithography throughput by developing ultrasensitive resists. For 45 nm features written with a typical resolution of 30 nm, a 30 microC/cm2 resist gives 3 nm line-width variation over line segments of 45 nm long. The line width is usually measured in an adapted critical dimension scanning electron microscope (CD-SEM). This measurement needs to be more precise than the result of the lithography step, so the requirements are typically sub-nm. Apart from all the problems to avoid systematic errors, this measurement also suffers from statistical variations, resulting from the finite number of electrons used for the measurement. In this paper we shall derive an estimate for that variation with a similar model as used for the shot noise effect in the lithography step. One of the conclusions is that for the most precise measurements of the line width it is not advisable to tune the CD-SEM for the best resolution. It is better to allow a larger probe size of the electron beam because that can be accompanied by a much larger current and thus a decrease in the noise level.

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Determining the impact of statistical fluctuations on resist line edge roughness

Cited by 20 publications

References 20 publications

Study on line edge roughness for electron beam acceleration voltages from 50to5kV

Study on line edge roughness for electron beam acceleration voltages from 50to5kV

The role of MEMS in maskless lithography

Shot noise in electron‐beam lithography and line‐width measurements

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