Evaluating the performance of a 193-nm hyper-NA immersion scanner using scatterometry

Kritsun, Oleg; Fontaine, Bruno La; Sandberg, Richard L.; Acheta, Alden; Levinson, Harry; Lensing, Kevin; Dusa, Mircea V.; Hauschild, Jan; Pici, Anita; Saravanan, Chandra Saru; Primak, K. N.; Korlahalli, Rahul; Nirmalgandhi, S.

doi:10.1117/12.715971

Cited by 4 publications

(4 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In principle, any spectroscopic or angle-resolved optical system can measure the diffraction signature from specially designed DBO targets. The intensity distribution of the diffracted orders contains profile and overlay information of the stacked periodic structures [11][12][13][14][15]. In this study, we use near-normal incidence spectroscopic scatterometry for DBO measurements.…”

Section: Spectroscopic Scatterometry -General Methodsmentioning

confidence: 99%

“…H.-T. Huang et al use spectra from reflection symmetry gratings and a rigorous coupled-wave analysis (RCWA) regression approach to calculate the overlay error [10]. W. Yang et al [11] and D. Kandel et al [12] use specially constructed pads with programmed offsets to determine regression-free overlay vectors. These DBO techniques offer significant promise to meet the demanding overlay metrology budget for sub-45 nm technology nodes.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Evaluating diffraction based overlay metrology for double patterning technologies

Saravanan¹,

Liu²,

Dasari³

et al. 2008

SPIE Proceedings

Self Cite

View full text Add to dashboard Cite

Demanding sub-45 nm node lithographic methodologies such as double patterning (DPT) pose significant challenges for overlay metrology. In this paper, we investigate scatterometry methods as an alternative approach to meet these stringent new metrology requirements. We used a spectroscopic diffraction-based overlay (DBO) measurement technique in which registration errors are extracted from specially designed diffraction targets for double patterning. The results of overlay measurements are compared to traditional bar-in-bar targets. A comparison between DBO measurements and CD-SEM measurements is done to show the correlation between the two approaches. We discuss the total measurement uncertainty (TMU) requirements for sub-45 nm nodes and compare TMU from the different overlay approaches.

show abstract

Section: Spectroscopic Scatterometry -General Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Evaluating diffraction based overlay metrology for double patterning technologies

Saravanan¹,

Liu²,

Dasari³

et al. 2008

SPIE Proceedings

Self Cite

View full text Add to dashboard Cite

show abstract

“…In principle, any spectroscopic or angle resolved system such as a scatterometer, ellipsometer, or a reflectometer can be used to measure the diffraction signature of specially designed DBO targets. The intensity distribution of the diffracted orders contains profile and overlay information of the stacked periodic structures [11][12][13][14][15]. We use near normal incidence spectroscopic scatterometry for DBO measurements.…”

Section: Spectroscopic Scatterometry -General Ideamentioning

confidence: 99%

Diffraction based overlay metrology for α-carbon applications

Saravanan¹,

Tan²,

Dasari³

et al. 2008

SPIE Proceedings

View full text Add to dashboard Cite

Applications that require overlay measurement between layers separated by absorbing interlayer films (such as α-carbon) pose significant challenges for sub-50nm processes. In this paper scatterometry methods are investigated as an alternative to meet these stringent overlay metrology requirements. In this article, a spectroscopic Diffraction Based Overlay (DBO) measurement technique is used where registration errors are extracted from specially designed diffraction targets. DBO measurements are performed on detailed set of wafers with varying α-carbon (ACL) thicknesses. The correlation in overlay values between wafers with varying ACL thicknesses will be discussed. The total measurement uncertainty (TMU) requirements for these layers are discussed and the DBO TMU results from sub-50nm samples are reviewed. Downloaded From: http://proceedings.spiedigitallibrary.org/ on 06/28/2016 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx Proc. of SPIE Vol. 6922 69222W-3 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 06/28/2016 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx Proc. of SPIE Vol. 6922 69222W-11 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 06/28/2016 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx

show abstract

“…Especially, scatterometry possesses excellent throughput and sampling frequency due to its macroscopic measurement ability of rapidly yielding relative large region information 12 . It is highly seen as the preferable metrology technique by chipmakers, and some on-site in-line evaluations have been made to prove its ability of improving CD, CD uniformity (CDU), overlay, focus, and dose by feeding back measurement results to the tracks and the scanners [14][15][16] .…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2012

View full text Add to dashboard Cite

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...

show abstract

Evaluating the performance of a 193-nm hyper-NA immersion scanner using scatterometry

Cited by 4 publications

References 7 publications

Evaluating diffraction based overlay metrology for double patterning technologies

Evaluating diffraction based overlay metrology for double patterning technologies

Diffraction based overlay metrology for α-carbon applications

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

Contact Info

Product

Resources

About