Metrology, Inspection, and Process Control for Microlithography XXXII最新文献

{"title":"In-line characterization of non-selective SiGe nodule defects with scatterometry enabled by machine learning","authors":"Kong Dexin, R. Chao, M. Breton, Chi-Chun Liu, G. R. Muthinti, S. Seo, N. Loubet, P. Montanini, J. Gaudiello, V. Basker, A. Cepler, Susan Ng-Emans, M. Sendelbach, Itzik Kaplan, G. Barak, D. Schmidt, Frougier Julien","doi":"10.1117/12.2297377","DOIUrl":"https://doi.org/10.1117/12.2297377","url":null,"abstract":"As device scaling continues, controlling defect densities on the wafer becomes essential for high volume manufacturing (HVM). One type of defect, the non-selective SiGe nodule, becomes more difficult to control during SiGe epitaxy (EPI) growth for p-type field effect transistor (pFET) source and drain. The process window for SiGe EPI growth with low nodule density becomes extremely tight due to the shrinking of contact poly pitch (CPP). Any tiny process shift or incoming structure shift could introduce a high density of nodules, which could affect device performance and yield. The current defect inspection method has a low throughput, so a fast and quantitative characterization technique is preferred for measuring and monitoring this type of defect.\u0000\u0000Scatterometry is a fast and non-destructive in-line metrology technique. In this work, novel methods were developed to accurately and comprehensively measure the SiGe nodules with scatterometry information. Top-down critical dimension scanning electron microscopy (CD-SEM) images were collected and analyzed on the same location as scatterometry measurement for calibration. Machine learning (ML) algorithms are used to analyze the correlation between the raw spectra and defect density and area fraction. The analysis showed that the defect density and area fractions can be measured separately by correlating intensity variations. In addition to the defect density and area fraction, we also investigate a novel method – model-based scatterometry hybridized with machine learning capabilities – to quantify the average height of the defects along the sidewall of the gate. Hybridizing the machine learning method with the model-based one could also eliminate the possibility of misinterpreting the defect as some structural parameters. Furthermore, cross-sectional TEM and SEM measurement are used to calibrate the model-based scatterometry results. In this work, the correlation between the SiGe nodule defects and the structural parameters of the device is also studied. The preliminary result shows that there is strong correlation between the defect density and spacer thickness. Correlations between the defect density and the structural parameters provides useful information for process engineers to optimize the EPI growth process. With the advances in the scatterometry-based defect measurement metrology, we demonstrate such fast, quantitative, and comprehensive measurement of SiGe nodule defects can be used to improve the throughput and yield.","PeriodicalId":391935,"journal":{"name":"Metrology, Inspection, and Process Control for Microlithography XXXII","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129438098","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A holistic metrology sensitivity study for pattern roughness quantification on EUV patterned device structures with mask design induced roughness","authors":"S. Levi, Ishai Swrtsband, Vladislav Kaplan, I. Englard, K. Ronse, B. Kutrzeba-Kotowska, G. Dai, F. Scholze, Kenslea Anne, Hayley Johanesen, L. Kwakman, I. Turovets, Maxim Rabinovitch, S. Krannich, N. Kasper, B. Connolly, R. Wende, M. Bender","doi":"10.1117/12.2297265","DOIUrl":"https://doi.org/10.1117/12.2297265","url":null,"abstract":"Monitoring of pattern roughness for advanced technology nodes is crucial as this roughness can adversely affect device yield and degrade device performance. The main industry work horse for in-line roughness measurements is the CD-SEM, however, today no adequate reference metrology tools exist that allow to evaluate its roughness measurement sensitivity and precision. To bridge this gap, in this work the roughness measurement capabilities of different analytical techniques are investigated. Different metrology methods are used to evaluate roughness on a same set of samples and results are compared and used in a holistic approach to better characterize and quantify the measured pattern roughness. To facilitate the correlation between the various metrology techniques and the evaluation of CD-SEM sensitivity, an effective approach is to induce pattern roughness in a controlled way by adding well defined levels of roughness to the designed patterns on a EUV mask and to measure the response and sensitivity of CD-SEM and of the other techniques to these different pattern roughness levels once printed on wafers. This paper presents the roughness measurement results obtained with various metrology technologies including CD-SEM, OCD, S-TEM and XCD on EUV Lithography patterned wafers both postlithography and post-etch. The benefits of recently developed metrology enhancements are demonstrated as well; automated TEM allows to generate accurate and rather precise reference roughness data, Machine Learning enables OCD based roughness metrology with good correlation to CD-SEM and STEM, and the improved sensitivity of EUV and X-ray scattering systems allows to extract roughness information that does correlate to CD-SEM.","PeriodicalId":391935,"journal":{"name":"Metrology, Inspection, and Process Control for Microlithography XXXII","volume":"70 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126480783","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mueller matrix spectroscopic ellipsometry based scatterometry simulations of Si and Si/SixGe1-x/Si/SixGe1-x/Si fins for sub-7nm node gate-all-around transistor metrology","authors":"S. Dey, A. Diebold, Nick Keller, M. Korde","doi":"10.1117/12.2296988","DOIUrl":"https://doi.org/10.1117/12.2296988","url":null,"abstract":"In this paper, we report on Muller Matrix (MM) based scatterometry (aka. optical critical dimension or OCD) simulation strategies for two sub-7nm fin structures: one with a SixGe1-x/Si/SixGe1-x/Si/SixGe1-x/Si nanosheet structure and its comparison with a hypothetical Si-only fin structure of similar dimensions at sub-7nm semiconductor technology nodes. Si-fins are providing the performance improvements necessary for the transistors used in current generation integrated circuits. Development of sub-7nm technology nodes requires further performance improvements including advanced structures including new materials. This demand for improved performance has created the need for new fabrication processes such as extreme ultraviolet lithography, self-aligned quadruple patterning etc., along with new metrology challenges for adequately monitoring the semiconductor process control during fabrication of these advanced nanostructures.1 New materials and structures, such as, Si/Si1-xGex (0≤x≤1) stacked nanosheet structures have recently been developed as one of the potential replacement for Si-based FinFETs.2,3 We have simulated two fin structures: one with Si-fins and another with 3 alternating stacks of Si1-xGex/Si (x=0.3). We have used Rigorous Coupled Wave Approximation (RCWA) to simulate OCD spectra for 0° – 360° azimuthal angles in 10° steps by keeping the fin pitch fixed at 24nm while systematically changing (1) the fin critical dimension (CD) from 5.0–7.5nm in 0.5nm steps, (2) thickness of the Si and Si1-xGex (x=0.3) nanosheets (NST) from 8.0–1.5nm in 0.5nm steps, (3) the fin bending angle (FBA) from 0°–2.5° in 0.5° steps, and (4) the undercut angle (ED) of the Si1-xGex NSTs from 0°–10° in 2° steps. Difference in etch-rate of Si and Ge could give rise to non-zero ED during NST formation. Both the fin structures possess mirror symmetry about two orthogonal planes perpendicular to the substrate and with one of the planes along the fin long-axis. For angles 0°, 90°, 180°, and 270°, this mirror symmetry leads to absence of the cross-polarization terms in the simulated OCD spectra such that off-diagonal MM elements are zero over the simulated wavelength range. The broken mirror symmetry in other azimuthal angles leads to cross-polarization of the electrical field vectors which is seen in the off-diagonal MM elements becoming non-zero. Additionally, the off-diagonal MM elements show increased sensitivity and reduced correlation between the parameters under study which leads to a powerful metrology means for studying the critical fin-parameters for fast and reliable semiconductor process control in sub 7-nm technology nodes. All the non-zero MM-elements are found to be sensitive to changes in CD and NST with the off-diagonal elements showing greater sensitivity to the changes. At azimuthal angles <15°, MM23, MM31, and MM34 are highly sensitive to changes in etch undercut and fin bending angle defects. \u0000\u0000References:\u0000[1] D. Dixit et al., “Advanced applicatio","PeriodicalId":391935,"journal":{"name":"Metrology, Inspection, and Process Control for Microlithography XXXII","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127699941","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}