Fabrication of metrology test structures for future technology nodes using high-resolution variable-shaped e-beam direct write

Szikszai, Laszlo; Jaschinsky, Philipp; Keil, Katja; Hauptmann, Marc; Mört, Manfred; Seifert, Uwe; Hohle, Christoph; Choi, Kang‐Hoon; Thrum, F.; Kretz, Johannes; Paz, Valeriano Ferreras; Boef, Arie den

doi:10.1117/12.814181

Cited by 4 publications

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“…The analyzed structure was an e-beam written line-grating with a CD of 200 nm and a period of 400 nm. 12 The images show good agreement (see Fig. 9), 27 but the differences between simulation and measurement still does not allow a reconstruction from a library search.…”

Section: Experimental Setup and Resultsmentioning

confidence: 96%

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Development of functional sub-100 nm structures with 3D two-photon polymerization technique and optical methods for characterization

Paz¹,

Emons²,

Obata³

et al. 2012

Journal of Laser Applications

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Investigations of two-photon polymerization (TPP) with sub-100 nm in the structuring resolution are presented by using photosensitive sol-gel material. The high photosensitivity of this material allows for TPP using a large variety in laser pulse durations covering a range between sub-10 fs and ≈140 fs. In this study, the authors demonstrate TPP structuring to obtain sub-100 nm in resolution by different approaches, namely, by adding a cross-linker to the material and polymerization with sub-10 fs short pulses. Additionally, a simulation and model based characterization method for periodic sub-100 nm structures was implemented and applied in an experimental white light interference Fourier-Scatterometry setup.

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Section: Experimental Setup and Resultsmentioning

confidence: 96%

“…Not only in the research field of TPP but also in semiconductor industry, structures well below 100 nm are produced. 12 For that the characterization of such structures is a demanding and very important task. 13 Classical microscopy methods do not allow direct imaging in this regime because of the Abbe diffraction limit.…”

Section: Introductionmentioning

confidence: 99%

Development of functional sub-100 nm structures with 3D two-photon polymerization technique and optical methods for characterization

Paz¹,

Emons²,

Obata³

et al. 2012

Journal of Laser Applications

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show abstract

“…Evaluations of the ability of scatterometry to measuring CD, SWA, and overlay have been made [4][5][6][7] . Feature sizes down to 20 nm have been evaluated and correlated to critical dimension scanning electron microscopy (CD-SEM) with good results 1,8 .…”

Section: Introductionmentioning

confidence: 99%

Electron-beam proximity effect model calibration for fabricating scatterometry calibration samples

et al. 2012

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Scatterometry has been proven to be effective in critical dimension (CD) and sidewall angle (SWA) measurements with good precision and accuracy. In order to study the effectiveness of scatterometry measurement of line edge roughness (LER), calibration samples with known LER have to be fabricated precisely. The relationship between ITRS LER specifications and the feature dimension design of the LER calibration samples is discussed. Electron-beam-direct-write lithography (EBDWL) has been widely used in nanoscale fabrication and is a natural selection for fabricating the designed calibration samples. With the increasingly demanding requirement of lithography resolution in ITRS, the corresponding LER feature of calibration samples becomes more and more challenging to fabricate, even for EBDWL. Proximity effects in EBDWL due to electron scattering can cause significant distortion of fabricated patterns from designed layouts. Model-based proximity effect correction (MBPEC) is an enhancement method for EBDWL to precisely define fine resist features. The effectiveness of MBPEC depends on the availability of accurate electron-beam proximity effect models, which are usually described by point spread functions (PSFs). In this work, a PSF in a doubleGaussian function form at a 50 kV accelerating voltage, an effective beam size, and a development threshold energy level of the resist are calibrated with EBDWL exposure tests. Preliminary MBPEC results indicate its effectiveness in calibration sample fabrication.Keywords: scatterometry, programmed LER structures, electron beam direct write lithography, proximity effect, proximity effect correction, model calibration INTRODUCTIONAs the minimum half pitch of integrated circuits is approaching 32 nm and below, urgent needs for near-ideal metrology technology are being called. Typical requirements for metrology include richness of measurement information, measurement speed, non-destructiveness of measurement processes, and capability of measuring process fluctuation 1 . Amongst various techniques, scatterometry is a promising candidate for meeting all the requirements. It can rapidly acquire average properties of periodic features over a relatively large area, and with proper set-ups by connecting to a scanner and a track, sub-nanometer variations can be identified and achieved 2, 3 . Evaluations of the ability of scatterometry to measuring CD, SWA, and overlay have been made 4-7 . Feature sizes down to 20 nm have been evaluated and correlated to critical dimension scanning electron microscopy (CD-SEM) with good results 1, 8 .Line edge roughness (LER) and line width roughness (LWR) are among the factors influencing device performances because they can affect dopant concentration profile and are responsible for gate leakage 9, 10 . Scatterometry has shown good sensitivity to roughness of 7.5 to 10 nm 10, 11 . The performance of scatterometery has been compared to alternative tools such as CD-SEM, atomic force microscopy, dual beam focused ion beam, and high-voltage SEM. It appears th...

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Optical scatterometry system for detecting specific line edge roughness of resist gratings subjected to detector noises

Lee¹,

Li²,

Wang³

et al. 2014

J. Opt.

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The Fourier scatterometry model was used to measure the ZEP 520A electron beam resist lines with specific line edge roughness (LER). By obtaining the pupils via an objective lens, the angle-resolved diffraction spectrum was collected efficiently without additional mechanical scanning. The concavity of the pupil was considered as the weight function in specimen recognition. A series of white noises was examined in the model, and the tolerant white noise levels for different system numerical apertures (NAs) were reported. Our numerical results show that the scatterometry model of a higher NA can identify a target with a higher white noise level. Moreover, the fabricated ZEP 520A electron beam resist gratings with LER were measured by using our model, and the fitting results were matched with scanning electron microscope measurements.

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Fabrication of metrology test structures for future technology nodes using high-resolution variable-shaped e-beam direct write

Cited by 4 publications

References 0 publications

Development of functional sub-100 nm structures with 3D two-photon polymerization technique and optical methods for characterization

Development of functional sub-100 nm structures with 3D two-photon polymerization technique and optical methods for characterization

Electron-beam proximity effect model calibration for fabricating scatterometry calibration samples

Optical scatterometry system for detecting specific line edge roughness of resist gratings subjected to detector noises

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