Pub Date : 2020-04-01DOI: 10.1117/1.JMM.19.2.024801
Dhruv V. Patel, R. Bonam, A. Oberai
Abstract. Defects in semiconductor processes can limit yield, increase overall production cost, and also lead to time-dependent critical component failures. Current state-of-the-art optical and electron beam (EB) inspection systems rely on rule-based techniques for defect detection and classification, which are usually rigid in their comparative processes. This rigidity limits overall capability and increases relative engineering time to classify nuisance defects. This is further challenged due to shrinkage of pattern dimensions for advanced nodes. We propose a deep learning-based workflow that circumvents these challenges and enables accurate defect detection, classification, and localization in a unified framework. In particular, we train convolutional neural network-based models using high-resolution EB images of wafers patterned with various types of intentional defects and achieve robust defect detection and classification performance. Furthermore, we generate class activation maps to demonstrate defect localization capability of the model “without” explicitly training it with defect location information. To understand the underlying decision-making process of these deep models, we analyze the learned filters in pixel space and Fourier space and interpret the various operations at different layers. We achieve high sensitivity (97%) and specificity (100%) along with rapid and accurate defect localization. We also test performance of the proposed workflow on images from two distinct patterns and find that in order to retain high accuracy a modest level of retraining is necessary.
{"title":"Deep learning-based detection, classification, and localization of defects in semiconductor processes","authors":"Dhruv V. Patel, R. Bonam, A. Oberai","doi":"10.1117/1.JMM.19.2.024801","DOIUrl":"https://doi.org/10.1117/1.JMM.19.2.024801","url":null,"abstract":"Abstract. Defects in semiconductor processes can limit yield, increase overall production cost, and also lead to time-dependent critical component failures. Current state-of-the-art optical and electron beam (EB) inspection systems rely on rule-based techniques for defect detection and classification, which are usually rigid in their comparative processes. This rigidity limits overall capability and increases relative engineering time to classify nuisance defects. This is further challenged due to shrinkage of pattern dimensions for advanced nodes. We propose a deep learning-based workflow that circumvents these challenges and enables accurate defect detection, classification, and localization in a unified framework. In particular, we train convolutional neural network-based models using high-resolution EB images of wafers patterned with various types of intentional defects and achieve robust defect detection and classification performance. Furthermore, we generate class activation maps to demonstrate defect localization capability of the model “without” explicitly training it with defect location information. To understand the underlying decision-making process of these deep models, we analyze the learned filters in pixel space and Fourier space and interpret the various operations at different layers. We achieve high sensitivity (97%) and specificity (100%) along with rapid and accurate defect localization. We also test performance of the proposed workflow on images from two distinct patterns and find that in order to retain high accuracy a modest level of retraining is necessary.","PeriodicalId":16522,"journal":{"name":"Journal of Micro/Nanolithography, MEMS, and MOEMS","volume":"16 1","pages":"024801 - 024801"},"PeriodicalIF":2.3,"publicationDate":"2020-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84768024","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Guest Editorial: A Transition for JM3","authors":"C. Mack","doi":"10.1117/1.jmm.19.1.010101","DOIUrl":"https://doi.org/10.1117/1.jmm.19.1.010101","url":null,"abstract":"This guest editorial by former Editor-in-Chief Chris Mack introduces JM3’s new co-editors-in-chief, Harry Levinson and Hans Zappe.","PeriodicalId":16522,"journal":{"name":"Journal of Micro/Nanolithography, MEMS, and MOEMS","volume":"272 1","pages":"010101"},"PeriodicalIF":2.3,"publicationDate":"2020-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77824453","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.1117/1.JMM.19.1.015001
Mithlesh Kumar, G. Krishna, B. Mukherjee, S. Sen
Abstract. Background: Design of microelectromechanical system based Bennet’s doubler kinetic energy harvester (KEH) is tricky as it has to satisfy the operating criteria of doubler circuit along with the harvester’s design constraints for its operation. Aim: Design guidelines for an electrostatic KEH using Bennet’s doubler circuit along with its experimental validation are presented. Approach: Bennet’s doubler circuit can work as a KEH only for a specific range of capacitance ratio across interdigitated electrodes of the harvester. The constraints on the resonant frequency of Bennet’s doubler harvester have been deduced to achieve operational capacitance ratio at both low and high vibrational frequencies. Finally, a test structure is fabricated, using silicon-on-insulator multiuser MEMS processes, and tested for capacitance ratio η greater than 1.366, a prerequisite for the operation of Bennet’s doubler circuit. Results: Resonant operation of the test structure achieves capacitance ratio of 1.39 with a capability of harvesting energy density of 4.63 μJ/cm3. Further, an improved harvester design is also presented for η = 1.5, based on the discussed guidelines that increase the energy density to 19.6 μJ/cm3. Conclusions: We will present an insight into the design of Bennet’s doubler harvester for different vibrational frequencies, which is being widely explored for electrostatic energy harvesting.
{"title":"Design of SOI MEMS-based Bennet’s doubler kinetic energy harvester","authors":"Mithlesh Kumar, G. Krishna, B. Mukherjee, S. Sen","doi":"10.1117/1.JMM.19.1.015001","DOIUrl":"https://doi.org/10.1117/1.JMM.19.1.015001","url":null,"abstract":"Abstract. Background: Design of microelectromechanical system based Bennet’s doubler kinetic energy harvester (KEH) is tricky as it has to satisfy the operating criteria of doubler circuit along with the harvester’s design constraints for its operation. Aim: Design guidelines for an electrostatic KEH using Bennet’s doubler circuit along with its experimental validation are presented. Approach: Bennet’s doubler circuit can work as a KEH only for a specific range of capacitance ratio across interdigitated electrodes of the harvester. The constraints on the resonant frequency of Bennet’s doubler harvester have been deduced to achieve operational capacitance ratio at both low and high vibrational frequencies. Finally, a test structure is fabricated, using silicon-on-insulator multiuser MEMS processes, and tested for capacitance ratio η greater than 1.366, a prerequisite for the operation of Bennet’s doubler circuit. Results: Resonant operation of the test structure achieves capacitance ratio of 1.39 with a capability of harvesting energy density of 4.63 μJ/cm3. Further, an improved harvester design is also presented for η = 1.5, based on the discussed guidelines that increase the energy density to 19.6 μJ/cm3. Conclusions: We will present an insight into the design of Bennet’s doubler harvester for different vibrational frequencies, which is being widely explored for electrostatic energy harvesting.","PeriodicalId":16522,"journal":{"name":"Journal of Micro/Nanolithography, MEMS, and MOEMS","volume":"8 1","pages":"015001 - 015001"},"PeriodicalIF":2.3,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72914878","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.1117/1.JMM.19.1.015002
Rui Hao, B. Peng, Huijun Yu, Hu Zhao, Wu Zhou
Abstract. Background: The piezoelectric microvibratory stage as a microelectromechanical system (MEMS) actuator can tilt around the X / Y axis and translate along the Z axis. However, when the vibratory stage is tilted around the X axis, it also has an undesirable tilting angle around the Y axis. It means that the X axis tilting and the Y axis tilting are not independent; therefore, it is significant to eliminate the coupling of two motions. Aim: The coupling of X / Y tilting motion is studied theoretically and decoupled by optimization of structural parameters. Approach: A structural model was established to analyze the reasons of the X / Y tilting coupling. Reasonable structure parameters of L-shaped piezoelectric beam were designed to eliminate the off-axis errors caused by X / Y tilting coupling. Results: The reason of X / Y tilting coupling is that the stiffness of the L-shaped piezoelectric support beam mismatch in the X axis and Y axis directions. The appropriate width ratio of the two segments of the L-shaped piezoelectric beam can reduce the off-axis error effectively. Conclusions: The test results show that the piezoelectric MEMS vibratory stage can achieve X / Y tilting motion with the relative off-axis error only at 1%.
{"title":"Improved MEMS piezoelectric vibratory stage with reduced off-axis error","authors":"Rui Hao, B. Peng, Huijun Yu, Hu Zhao, Wu Zhou","doi":"10.1117/1.JMM.19.1.015002","DOIUrl":"https://doi.org/10.1117/1.JMM.19.1.015002","url":null,"abstract":"Abstract. Background: The piezoelectric microvibratory stage as a microelectromechanical system (MEMS) actuator can tilt around the X / Y axis and translate along the Z axis. However, when the vibratory stage is tilted around the X axis, it also has an undesirable tilting angle around the Y axis. It means that the X axis tilting and the Y axis tilting are not independent; therefore, it is significant to eliminate the coupling of two motions. Aim: The coupling of X / Y tilting motion is studied theoretically and decoupled by optimization of structural parameters. Approach: A structural model was established to analyze the reasons of the X / Y tilting coupling. Reasonable structure parameters of L-shaped piezoelectric beam were designed to eliminate the off-axis errors caused by X / Y tilting coupling. Results: The reason of X / Y tilting coupling is that the stiffness of the L-shaped piezoelectric support beam mismatch in the X axis and Y axis directions. The appropriate width ratio of the two segments of the L-shaped piezoelectric beam can reduce the off-axis error effectively. Conclusions: The test results show that the piezoelectric MEMS vibratory stage can achieve X / Y tilting motion with the relative off-axis error only at 1%.","PeriodicalId":16522,"journal":{"name":"Journal of Micro/Nanolithography, MEMS, and MOEMS","volume":"16 1","pages":"015002 - 015002"},"PeriodicalIF":2.3,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78411824","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.1117/1.JMM.19.1.014002
I. Mochi, Sara Fernández, R. Nebling, U. Locans, R. Rajeev, A. Dejkameh, D. Kazazis, L. Tseng, S. Danylyuk, L. Juschkin, Y. Ekinci
Abstract. Background: Reliable photomask metrology is required to reduce the risk of yield loss in the semiconductor manufacturing process as well as for the research on absorber materials. Actinic pattern inspection (API) of EUV reticles is a challenging problem to tackle with a conventional approach. For this reason, we developed RESCAN, an API platform based on coherent diffraction imaging. Aim: We want to verify the sensitivity of our platform to absorber and phase defects. Approach: We designed and manufactured two EUV mask samples with absorber and phase defects, and we inspected them with RESCAN in die-to-database mode. Results: We reconstructed an image of an array of programmed absorber defects, and we created a defect map of our sample. We inspected two programmed phase defect samples with buried structures of 3.5 and 7.8 nm height. Conclusions: We verified that RESCAN, in its current configuration, can detect absorber defects in random patterns and buried (phase) defects down to 50 × 50 nm2.
{"title":"Quantitative characterization of absorber and phase defects on EUV reticles using coherent diffraction imaging","authors":"I. Mochi, Sara Fernández, R. Nebling, U. Locans, R. Rajeev, A. Dejkameh, D. Kazazis, L. Tseng, S. Danylyuk, L. Juschkin, Y. Ekinci","doi":"10.1117/1.JMM.19.1.014002","DOIUrl":"https://doi.org/10.1117/1.JMM.19.1.014002","url":null,"abstract":"Abstract. Background: Reliable photomask metrology is required to reduce the risk of yield loss in the semiconductor manufacturing process as well as for the research on absorber materials. Actinic pattern inspection (API) of EUV reticles is a challenging problem to tackle with a conventional approach. For this reason, we developed RESCAN, an API platform based on coherent diffraction imaging. Aim: We want to verify the sensitivity of our platform to absorber and phase defects. Approach: We designed and manufactured two EUV mask samples with absorber and phase defects, and we inspected them with RESCAN in die-to-database mode. Results: We reconstructed an image of an array of programmed absorber defects, and we created a defect map of our sample. We inspected two programmed phase defect samples with buried structures of 3.5 and 7.8 nm height. Conclusions: We verified that RESCAN, in its current configuration, can detect absorber defects in random patterns and buried (phase) defects down to 50 × 50 nm2.","PeriodicalId":16522,"journal":{"name":"Journal of Micro/Nanolithography, MEMS, and MOEMS","volume":"35 1","pages":"014002 - 014002"},"PeriodicalIF":2.3,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85057773","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.1117/1.JMM.19.1.013501
Z. Fradkin, M. Roitman, A. Bardea, Roy Avrahamy, Yeoshua Bery, H. Ohana, M. Zohar
Abstract. Dip-pen nanolithography (DPN) is a low-cost, versatile, bench-top technology for direct patterning of materials over surfaces. Our study reports on the production of two-dimensional optical grating nanostructures based on polymers, using DPN. The influence of both the ink composition and the dwell time were investigated. Prototypes of phase masks were manufactured, and their main characteristics were analyzed. The results in our work may contribute to improving the fabrication process of optical structures, including the production of microlenses with controlled focal length.
{"title":"Fabrication of polymeric photonic structures using dip-pen nanolithography","authors":"Z. Fradkin, M. Roitman, A. Bardea, Roy Avrahamy, Yeoshua Bery, H. Ohana, M. Zohar","doi":"10.1117/1.JMM.19.1.013501","DOIUrl":"https://doi.org/10.1117/1.JMM.19.1.013501","url":null,"abstract":"Abstract. Dip-pen nanolithography (DPN) is a low-cost, versatile, bench-top technology for direct patterning of materials over surfaces. Our study reports on the production of two-dimensional optical grating nanostructures based on polymers, using DPN. The influence of both the ink composition and the dwell time were investigated. Prototypes of phase masks were manufactured, and their main characteristics were analyzed. The results in our work may contribute to improving the fabrication process of optical structures, including the production of microlenses with controlled focal length.","PeriodicalId":16522,"journal":{"name":"Journal of Micro/Nanolithography, MEMS, and MOEMS","volume":"39 1","pages":"013501 - 013501"},"PeriodicalIF":2.3,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81432743","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.1117/1.JMM.19.1.014003
R. Kizu, I. Misumi, A. Hirai, S. Gonda
Abstract. Line edge roughness (LER) measurement is one of the metrology challenges for three-dimensional device structures, and LER reference metrology is important for reliable LER measurements. For the purpose of LER reference metrology, we developed an LER measurement technique that can analyze LER distribution along the height of a line pattern, with high resolution and repeatability. A high-resolution atomic force microscopy (AFM) image of a vertical sidewall of a line pattern was obtained using a metrological tilting-AFM, which offers SI-traceable dimensional measurements. The tilting-tip was controlled with an inclined servo axis, and it scans the vertical sidewall along a line pattern with a high sampling density to enable an analysis of the LER height distribution at the sidewall. A horizontal cross-section of the sidewall shows sidewall roughness with sub-nm resolution. Power spectral density (PSD) analysis of the sidewall profile showed that the PSD noise in the high-frequency region was several orders of magnitude lower than the noise of typical scanning electron microscopy methods. AFM measurements were sequentially repeated three times to evaluate the repeatability of the LER measurement; results indicated a high repeatability of 0.07 nm evaluated as a standard deviation of LER at each height.
{"title":"Line edge roughness measurement on vertical sidewall for reference metrology using a metrological tilting atomic force microscope","authors":"R. Kizu, I. Misumi, A. Hirai, S. Gonda","doi":"10.1117/1.JMM.19.1.014003","DOIUrl":"https://doi.org/10.1117/1.JMM.19.1.014003","url":null,"abstract":"Abstract. Line edge roughness (LER) measurement is one of the metrology challenges for three-dimensional device structures, and LER reference metrology is important for reliable LER measurements. For the purpose of LER reference metrology, we developed an LER measurement technique that can analyze LER distribution along the height of a line pattern, with high resolution and repeatability. A high-resolution atomic force microscopy (AFM) image of a vertical sidewall of a line pattern was obtained using a metrological tilting-AFM, which offers SI-traceable dimensional measurements. The tilting-tip was controlled with an inclined servo axis, and it scans the vertical sidewall along a line pattern with a high sampling density to enable an analysis of the LER height distribution at the sidewall. A horizontal cross-section of the sidewall shows sidewall roughness with sub-nm resolution. Power spectral density (PSD) analysis of the sidewall profile showed that the PSD noise in the high-frequency region was several orders of magnitude lower than the noise of typical scanning electron microscopy methods. AFM measurements were sequentially repeated three times to evaluate the repeatability of the LER measurement; results indicated a high repeatability of 0.07 nm evaluated as a standard deviation of LER at each height.","PeriodicalId":16522,"journal":{"name":"Journal of Micro/Nanolithography, MEMS, and MOEMS","volume":"82 1","pages":"014003 - 014003"},"PeriodicalIF":2.3,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83926013","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.1117/1.JMM.19.1.013502
Y. Granik
Abstract. Background: Modern one-digit technological nodes demand strict reproduction of the optical proximity corrections for repeatable congruent patterns. To ensure this property, the optical and process simulations must be invariant to the geometrical transformations of the translation, rotation, and reflection. Simulators must support invariance both in theory, mathematically, and in practice, numerically. The invariance of compact modeling operators has never been scrutinized before. Aim: We aim to examine manner and conditions under which optical simulations preserve or violate intrinsic invariances of exact imaging. We analyze invariances of Volterra operators, which are widely used in compact process modeling. Our goal is to determine necessary and sufficient conditions under which such operators become fully invariant Approach: We use theoretical analysis to deduce full invariance conditions and numerical simulations to illustrate the results. Results: The linear fully invariant operators are convolutions with rotationally symmetrical kernels. The fully invariant quadratic operators have special functional form with two radial and one polar argument and are not necessarily rotationally symmetrical. We deduced invariance conditions for the kernels of high-order Volterra operators. Conclusions: We suggest to use fully invariant nonlinear Volterra operators as atomic construction blocks in machine learning and neural networks for compact process modeling.
{"title":"Transformational invariance in compact process modeling","authors":"Y. Granik","doi":"10.1117/1.JMM.19.1.013502","DOIUrl":"https://doi.org/10.1117/1.JMM.19.1.013502","url":null,"abstract":"Abstract. Background: Modern one-digit technological nodes demand strict reproduction of the optical proximity corrections for repeatable congruent patterns. To ensure this property, the optical and process simulations must be invariant to the geometrical transformations of the translation, rotation, and reflection. Simulators must support invariance both in theory, mathematically, and in practice, numerically. The invariance of compact modeling operators has never been scrutinized before. Aim: We aim to examine manner and conditions under which optical simulations preserve or violate intrinsic invariances of exact imaging. We analyze invariances of Volterra operators, which are widely used in compact process modeling. Our goal is to determine necessary and sufficient conditions under which such operators become fully invariant Approach: We use theoretical analysis to deduce full invariance conditions and numerical simulations to illustrate the results. Results: The linear fully invariant operators are convolutions with rotationally symmetrical kernels. The fully invariant quadratic operators have special functional form with two radial and one polar argument and are not necessarily rotationally symmetrical. We deduced invariance conditions for the kernels of high-order Volterra operators. Conclusions: We suggest to use fully invariant nonlinear Volterra operators as atomic construction blocks in machine learning and neural networks for compact process modeling.","PeriodicalId":16522,"journal":{"name":"Journal of Micro/Nanolithography, MEMS, and MOEMS","volume":"20 1","pages":"013502 - 013502"},"PeriodicalIF":2.3,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79115089","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-12-18DOI: 10.1117/1.jmm.18.4.040501
Kiseok Lee, Kim Dong-Oh, C. Yoon, Taejin Park, Han Sung-hee, Y. Hwang, Kyupil Lee, Hokyu Kang, Hyoungsub Kim
Background: With continuous decrease in the technology node of dynamic random access memories (DRAMs) down to sub-20 nm, the self-aligned double patterning (SADP) is an effective approach to generate two-dimensional (2-D) patterns, particularly contact arrays. Aim: We demonstrate a patterning scheme using the SADP technique to produce active trim contacts with anisotropic pattern pitches. Approach: The proposed scheme uses two consecutive spacer-formation processes. Results: By making the ellipsoidal core pillars and minimizing the spacer thickness, 2-D critical dimensions (CDs) for self-generated contacts match well with those for core contacts. In addition, an interesting cross-dependence of X -CD and Y -CD variations for the core and self-generated contacts is observed. Conclusion: This patterning approach is useful for forming active trim contacts in sub-20 nm DRAMs using fewer numbers of ArF immersion photolithography steps.
{"title":"Self-aligned double patterning for active trim contacts with anisotropic pattern pitches in sub-20 nm dynamic random access memories","authors":"Kiseok Lee, Kim Dong-Oh, C. Yoon, Taejin Park, Han Sung-hee, Y. Hwang, Kyupil Lee, Hokyu Kang, Hyoungsub Kim","doi":"10.1117/1.jmm.18.4.040501","DOIUrl":"https://doi.org/10.1117/1.jmm.18.4.040501","url":null,"abstract":"Background: With continuous decrease in the technology node of dynamic random access memories (DRAMs) down to sub-20 nm, the self-aligned double patterning (SADP) is an effective approach to generate two-dimensional (2-D) patterns, particularly contact arrays. Aim: We demonstrate a patterning scheme using the SADP technique to produce active trim contacts with anisotropic pattern pitches. Approach: The proposed scheme uses two consecutive spacer-formation processes. Results: By making the ellipsoidal core pillars and minimizing the spacer thickness, 2-D critical dimensions (CDs) for self-generated contacts match well with those for core contacts. In addition, an interesting cross-dependence of X -CD and Y -CD variations for the core and self-generated contacts is observed. Conclusion: This patterning approach is useful for forming active trim contacts in sub-20 nm DRAMs using fewer numbers of ArF immersion photolithography steps.","PeriodicalId":16522,"journal":{"name":"Journal of Micro/Nanolithography, MEMS, and MOEMS","volume":"10 1","pages":"040501"},"PeriodicalIF":2.3,"publicationDate":"2019-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81315149","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-10-18DOI: 10.1117/1.JMM.19.1.014001
Mika Pflüger, R. J. Kline, A. Herrero, M. Hammerschmidt, V. Soltwisch, M. Krumrey
Abstract. Background: To ensure consistent and high-quality semiconductor production at future logic nodes, additional metrology tools are needed. For this purpose, grazing-incidence small-angle x-ray scattering (GISAXS) is being considered because measurements are fast with a proven capability to reconstruct average grating line profiles with high accuracy. Aim: GISAXS measurements of grating line shapes should be extended to samples with pitches smaller than 50 nm and their defects. The method’s performance should be evaluated. Approach: A series of gratings with 32-nm pitch and deliberately introduced pitchwalk is measured using GISAXS. The grating line profiles with associated uncertainties are reconstructed using a Maxwell solver and Markov-chain Monte Carlo sampling combined with a simulation library approach. Results: The line shape and the pitchwalk are generally in agreement with previously published transmission small-angle x-ray scattering (SAXS) results. However, the line height and line width show deviations of ( 1.0 ± 0.2 ) nm and ( 2.0 ± 0.7 ) nm, respectively. The complex data evaluation leads to relatively high pitchwalk uncertainties between 0.5 and 2 nm. Conclusions: GISAXS shows great potential as a metrology tool for small-pitch line gratings with complex line profiles. Faster simulation methods would enable more accurate results.
{"title":"Extracting dimensional parameters of gratings produced with self-aligned multiple patterning using grazing-incidence small-angle x-ray scattering","authors":"Mika Pflüger, R. J. Kline, A. Herrero, M. Hammerschmidt, V. Soltwisch, M. Krumrey","doi":"10.1117/1.JMM.19.1.014001","DOIUrl":"https://doi.org/10.1117/1.JMM.19.1.014001","url":null,"abstract":"Abstract. Background: To ensure consistent and high-quality semiconductor production at future logic nodes, additional metrology tools are needed. For this purpose, grazing-incidence small-angle x-ray scattering (GISAXS) is being considered because measurements are fast with a proven capability to reconstruct average grating line profiles with high accuracy. Aim: GISAXS measurements of grating line shapes should be extended to samples with pitches smaller than 50 nm and their defects. The method’s performance should be evaluated. Approach: A series of gratings with 32-nm pitch and deliberately introduced pitchwalk is measured using GISAXS. The grating line profiles with associated uncertainties are reconstructed using a Maxwell solver and Markov-chain Monte Carlo sampling combined with a simulation library approach. Results: The line shape and the pitchwalk are generally in agreement with previously published transmission small-angle x-ray scattering (SAXS) results. However, the line height and line width show deviations of ( 1.0 ± 0.2 ) nm and ( 2.0 ± 0.7 ) nm, respectively. The complex data evaluation leads to relatively high pitchwalk uncertainties between 0.5 and 2 nm. Conclusions: GISAXS shows great potential as a metrology tool for small-pitch line gratings with complex line profiles. Faster simulation methods would enable more accurate results.","PeriodicalId":16522,"journal":{"name":"Journal of Micro/Nanolithography, MEMS, and MOEMS","volume":"56 6","pages":"014001 - 014001"},"PeriodicalIF":2.3,"publicationDate":"2019-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72451118","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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