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

Tanaka, Maki; Shishido, Chie; Nagatomo, Wataru; Watanabe, Kenji

doi:10.1117/12.772097

Cited by 15 publications

(10 citation statements)

References 13 publications

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“…We previously began a study of the MBL approach through collaboration with NIST 6 . Most previous studies improved the measurement accuracy, the physics based mathematical model and the library [7][8][9][10][11] .…”

Section: Introductionmentioning

confidence: 99%

Application of model-based library approach to photoresist pattern shape measurement in advanced lithography

et al. 2010

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The model-based library (MBL) matching technique was applied to measurements of photoresist patterns exposed with a leading-edge ArF immersion lithography tool. This technique estimates the dimensions and shape of a target pattern by comparing a measured SEM image profile to a library of simulated line scans. In this study, a double trapezoid model was introduced into MBL library, which was suitable for precise approximation of a photoresist profile. To evaluate variously-shaped patterns, focus-exposure matrix wafers were exposed under three-illuminations. The geometric parameters such as bottom critical dimension (CD), top and bottom sidewall angles were estimated by MBL matching. Lithography simulation results were employed as a reference data in this evaluation. As a result, the trends of the estimated sidewall angles are consistent with the litho-simulation results. MBL bottom CD and threshold method 50% CD are also in a very good agreement. MBL detected wide-SWA variation in a focus series which were determined as in a process window by CD values. The trend of SWA variation, which is potentiality to undergo CD shift at later-etch step, agreed with litho-simulation results. These results suggest that MBL approach can achieve the efficient measurements for process development and control in advanced lithography.

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Section: Introductionmentioning

confidence: 99%

Application of model-based library approach to photoresist pattern shape measurement in advanced lithography

et al. 2010

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“…was scanned using another CNT probe with a length of 230 nm and a diameter of 30 nm. The sample and the results of advanced CD-SEM metrology will be described in detail in another paper 32 . Figure 18 shows a bird's eye view of raw and corrected AFM data of pattern "B" on the sample.…”

Section: Correction Results For Various Samplesmentioning

confidence: 99%

A novel AFM method for sidewall measurement of high-aspect ratio patterns

et al. 2008

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To use atomic force microscope (AFM) to measure dense patterns of 32-nm node structures, there is a difficulty in providing flared probes that go into narrow vertical features. Using carbon nanotube (CNT) probes is a possible alternative. However, even with its extremely high stiffness, van der Waals attractive force from steep sidewalls bends CNT probes. This probe deflection effect causes deformation (or "swelling") of the measured profile. When measuring 100-nm-high vertical sidewalls with a 24-nm-diameter and 220-nm-long CNT probe, the probe deflection can cause a bottom CD bias of 13.5 nm. This phenomenon is inevitable when using long, thin probes whichever scanning method is used.We have developed a method of deconvolving this probe deflection effect that is well suited to our AFM scanning mode, AdvancedStep-in TM mode. In this scanning mode, the probe is not dragged on the sample surface but approaches the sample surface vertically at each measurement point. The CNT probe deformation is stable because we do not use cantilever oscillation that can cause instability, but we detect static flexure of the cantilever. Consequently, it is possible to estimate the amount of CNT probe deflection by detecting the degree of cantilever torsion. Using this information, we have developed a technique for deconvolving the probe deformation effect from measured profiles. This technique in combination with deconvolution of the probe shape effect makes vertical sidewall profile measurement possible.

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“…We have also shown the correlation between resist loss and TR by simulation and confirmation using cross-section SEM images [2] [3]. Based on our previous work, we have demonstrated the potential to enhance the precision PW (Process Window) by introducing MPPC indices such as TR as an additional limiting factor to overlap the process windows such that exposure and focus process window and be effectively derived.…”

Section: The Basis Experiments Which Uses Wb For Practical Applicationmentioning

confidence: 90%

A practical application of multiple parameters profile characterization (MPPC) using CD-SEM on production wafers using Hyper-NA lithography

Ishimoto

Sekiguchi

Hasegawa

et al. 2009

Metrology, Inspection, and Process Control for Microlithography XXIII

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With the improved resolution of immersion lithography by Hyper-NA (Numerical Aperture) and Low-k1 scaling factor, lithographers face the problem of decreasing Depth of Focus and in turn reduced process latitude. It is important for high precision process monitoring the decrease in process latitude which comes with Hyper-NA and Low-k1, in order to be able to successfully introduce RET (Resolution Enhancement Techniques) lithography into high volume production. MPPC (Multiple ParametersProfile Characterization) is a function which provides the ability to extract pattern shape information from a measured e-beam signal. MPPC function becomes key technique of pattern profile verification by top down SEM images for the Hyper-NA lithography, for that reason it can be detected to relate to pattern profile change.In this work, we explored a practical application of MPPC function by making clear the relationship between MPPC indices and Litho parameters concerning specific lithography application. We performed the two kinds of experiment for verifying effectiveness of the MPPC function. First experiment explored printing image contrast by using the WB with exposure pattern shape change related from image printing condition. Second experiment explored pattern shape change due to resist contrast with changing the process conditions by using WB behavior. In consequence, we demonstrated a practical application of MPPC function by quantification using WB and assessed the process monitoring capability.Our challenge of this research is the practical application of the MPPC function on production wafers concerning specific lithography application. We believe that this application can be effectual in process monitoring and control for Hyper-NA lithography.

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

Cited by 15 publications

References 13 publications

Application of model-based library approach to photoresist pattern shape measurement in advanced lithography

Application of model-based library approach to photoresist pattern shape measurement in advanced lithography

A novel AFM method for sidewall measurement of high-aspect ratio patterns

A practical application of multiple parameters profile characterization (MPPC) using CD-SEM on production wafers using Hyper-NA lithography

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