Sources of line-width roughness for EUV resists

Cao, Heidi B.; Yueh, Wang; Rice, Bryan J.; Roberts, J. M.; Bacuita, Terence; Chandhok, Manish

doi:10.1117/12.536041

Cited by 18 publications

(10 citation statements)

References 17 publications

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“…Extensive results on the effects of resist variation and the role of image quality have been reported for EUV by Shumway et al [7] and Cao et al [8], and for DUV by Palowski et al [9] and Williamson et al [10]. Important new experimental work on acid generation has been reported for electron beams by Yamamoto et al [11] and for EUV by Brainard et al [12].…”

Section: Introductionmentioning

confidence: 92%

Shot noise models for sequential processes and the role of lateral mixing

Neureuther

Pease

Yuan

et al. 2006

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

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Shot-noise in electron-beam and EUV exposure fundamentally limits the useful sensitivity of resists. Here the exposure, amplification and deprotection of chemically amplified resists are treated as a sequence of statistical events to determine the effect of shot noise. Noise among processes is additive and a sequential Poisson process is used to illustrate the 'acid bottleneck' that occurs when less than one acid electron is generated per input electron. Lateral mixing, due to effects such as electron scattering and acid diffusion, are accounted for in a Binomial sorting model that shows the effect is simply a function of the total number of quanta reaching the voxel irrespective of their path.Electron exposure is estimated to generate on average one acid every 3.8, 21 and 36 nm along the trajectories of 5, 50 and 100 KeV electrons. Acid generation appears well correlated with energy deposition, at about 22 eV/acid required for EUV and electron exposure, or three times the DUV level. The model was validated by observing the fraction of small (24 nm and 32 nm across) contacts that cleared as a function of exposure dose at 100 KeV. Approximately 4,500 electrons were EIPBN 05 revised June 6, 2006 2 required to clear, independent of contact size. However, the slope was indicative of a process with only 50 effective events possibly owing to resist surface effects. Circular dissolution smoothing and mechanical fracture are suggested as speculative sources for the near feature size correlation length of the line-edge roughness.

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Section: Introductionmentioning

confidence: 92%

Shot noise models for sequential processes and the role of lateral mixing

Neureuther

Pease

Yuan

et al. 2006

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

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“…Small PAG sizes and high PAG concentrations have low LWRs, and high quencher concentrations at good aerial image contrast ratios also reduce LWRs [82]. Resist properties and process conditions affect the final resist LWR.…”

Section: Resistmentioning

confidence: 99%

Next-generation lithography for 22 and 16 nm technology nodes and beyond

2011

Sci. China Inf. Sci.

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In this paper, next-generation lithography (NGL) for the 22 and 16 nm technology nodes and beyond is reviewed. A broad range of topics, including history, technologies, critical challenges, and the most plausible candidates are discussed. The 22 and 16 nm technology nodes rely on NGL. NGLs have been extensively studied. Because of technological issues, the semiconductor industry has stopped pursuing several NGLs, such as X-ray proximity lithography, ion projection lithography, and scattering with angular limitation projection electron lithography. Currently, the primary candidate technologies are extreme ultraviolet lithography (EUVL), maskless lithography (ML2), and nanoimprint lithography (NIL), with EUVL being the leading candidate. Since EUVL was first proposed in 1988, many studies have been conducted. Currently, there is no "show stopper" for EUVL. Moreover, challenges are present in almost all aspects of EUVL technology. Almost all primary semiconductor manufacturing companies plan to implement commercial pre-production step-and-scan exposure tools in 2011. However, EUVL power at an intermediate focusing level has not yet met the volume manufacturing requirements. EUVL resists have been significantly improved recently, but there is still a critical need to meet requirements on resolution, line width roughness, and sensitivity. Creating a defect-free EUVL mask is another obstacle to the application of EUVL. ML2 and NIL, like EUVL, have also undergone significant progress recently, but throughput, defect control, and cost remain the critical impediments for practical application.

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“…It can originate from a myriad of factors such as the photon or chemical shot noise, molecular stacking, development process, and low image contrast [1,[13][14][15][16][17][18][19][20][21]. Recently, mask roughness gained significant attention as one of the contributors to the wafer LER [2-9, 22, 23].…”

Section: Introductionmentioning

confidence: 99%

Mitigating mask roughness via pupil filtering

et al. 2014

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The roughness present on the sidewalls of lithographically defined patterns imposes a very important challenge for advanced technology nodes. It can originate from the aerial image or the photoresist chemistry/processing [1]. The latter remains to be the dominant group in ArF and KrF lithography; however, the roughness originating from the mask transferred to the aerial image is gaining more attention [2-9], especially for the imaging conditions with large mask error enhancement factor (MEEF) values. The mask roughness contribution is usually in the low frequency range, which is particularly detrimental to the device performance by causing variations in electrical device parameters on the same chip [10][11][12]. This paper explains characteristic differences between pupil plane filtering in amplitude and in phase for the purpose of mitigating mask roughness transfer under interference-like lithography imaging conditions, where onedirectional periodic features are to be printed by partially coherent sources. A white noise edge roughness was used to perturbate the mask features for validating the mitigation.

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Sources of line-width roughness for EUV resists

Cited by 18 publications

References 17 publications

Shot noise models for sequential processes and the role of lateral mixing

Shot noise models for sequential processes and the role of lateral mixing

Next-generation lithography for 22 and 16 nm technology nodes and beyond

Mitigating mask roughness via pupil filtering

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