SPIE Photomask Technology最新文献

{"title":"From nightmares to sweet dreams: inspection of aggressive OPC on 14nm reticles (and beyond) using a novel high-NA and low-NA dual method","authors":"Karen D. Badger, M. Hibbs, Kazunori Seki, William H. Broadbent, Trent Hutchinson, Vincent Redding","doi":"10.1117/12.2197729","DOIUrl":"https://doi.org/10.1117/12.2197729","url":null,"abstract":"To prevent catastrophic failures in wafer manufacturing lines from reticle defects, mask manufacturers employ sophisticated reticle inspection systems to examine every shape on every reticle for defects. The predominant inspection systems in use today compare the reticle directly with the design database using high-NA optics (typically 3x higher resolution at the reticle plane than advanced wafer scanners). High-NA optical inspection with its high signal to noise ratio (SNR) can readily detect small defects before they have lithographic impact, thus ensuring reticle quality. However, when inspecting certain aggressive OPC, high-NA inspection can overload on small OPC defects which do not have lithographic impact and thus, should generally be ignored. Whereas, inspecting a reticle as imaged in the wafer plane (low-NA in the reticle plane) will generally ignore such small OPC defects; however, the SNR is often too low for certain defect types to provide the needed defect detection sensitivity to ensure reticle quality. This paper discusses the design and performance of a novel reticle inspection method using high-NA and low-NA dual optical imaging and processing. This method offers the high defect sensitivity of high-NA inspection with the OPC tolerance of low-NA inspection. These two imaging methods are blended together into a seamless inspection mode suitable for aggressive OPC of the 14nm generation and beyond. The test reticles include 14nm logic designs containing aggressive OPC and native defects, as well as a 14 nm test reticle containing relevant programmed defects. Defect lithographic significance is judged using a Zeiss AIMS™ system.","PeriodicalId":308777,"journal":{"name":"SPIE Photomask Technology","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116117400","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":"Novel CD control of HTPSM by advanced process for sub-20nm tech","authors":"S. Jo, C. Choi, Sunghyun Oh, Tae-Joong Ha, Youngmo Lee, Sangpyo Kim, D. Yim","doi":"10.1117/12.2196938","DOIUrl":"https://doi.org/10.1117/12.2196938","url":null,"abstract":"As the design rule of the semiconductor shrinks, the CD MTT (Critical Dimension Mean-to-Target) specification for photomask becomes tighter. So, more precise control of CD MTT is required. We have investigated the CD MTT control and applied it to the attenuated PSM (Phase Shift Mask) successfully for several years. We can control the CD MTT of MoSi pattern by measuring Cr/MoSi pattern to estimate MoSi pattern CD and additional etch to shrink MoSi pattern as reported in previous study. At first, the MoSi pattern CD can be estimated with the Cr/MoSi pattern CD because the CD gap between MoSi pattern and Cr/MoSi pattern is relatively constant. Additional MoSi etch is performed to shrink the MoSi pattern CD after then. The CD gap alwasys exists and the variation of the CD gap is enough small to be not considered in conventional photomask production until now. However, the variation of the CD gap is not ignorable in case of sub-20 nm tech. In this study, we investigated new method to measure MoSi pattern CD before Cr strip process to eliminate the CD gap between MoSi pattern and Cr/MoSi pattern. To eliminate the CD gap, we attempt three solutions – 1) Optimize etch process to perform perfect Cr/MoSi pattern profile without the CD gap, 2) Improve CD measurement accuracy by developing new SEM measuring mechanism, 3) Develop of new process to modify Cr/MoSi pattern profile to be measured without the CD gap. It was found that the CD gap can be eliminated and MoSi pattern CD can be measured perfectly. Finally, MoSi pattern CD control was improved because of CD gap elimination.","PeriodicalId":308777,"journal":{"name":"SPIE Photomask Technology","volume":"34 8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116385295","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":"New method of detection and classification of yield-impacting EUV mask defects","authors":"Ioana Graur, Dmitry Vengertsev, A. Raghunathan, I. Stobert, J. Rankin","doi":"10.1117/12.2197871","DOIUrl":"https://doi.org/10.1117/12.2197871","url":null,"abstract":"Extreme ultraviolet lithography (EUV) advances printability of small size features for both memory and logic semiconductor devices. It promises to bring relief to the semiconductor manufacturing industry, removing the need for multiple masks in rendering a single design layer on wafer. However, EUV also brings new challenges, one of which is of mask defectivity. For this purpose, much of the focus in recent years has been in finding ways to adequately detect, characterize, and reduce defects on both EUV blanks and patterned masks. In this paper we will present an efficient way to classify and disposition EUV mask defects through a new algorithm developed to classify defects located on EUV photomasks. By processing scanning electronmicroscopy images (SEM) of small regions of a photomask, we extract highdimensional local features Histograms of Oriented Gradients (HOG). Local features represent image contents compactly for detection or classification, without requiring image segmentation. Using these HOGs, a supervised classification method is applied which allows differentiating between nondefective and defective images. In the new approach we have developed a superior method of detection and classification of defects, using mask and supporting mask printed data from several metallization masks. We will demonstrate that use of the HOG method allows realtime identification of defects on EUV masks regardless of geometry or construct. The defects identified by this classifier are further divided into subclasses for mask defect disposition: foreign material, foreign material from previous step, and topological defects. The goal of disposition is to categorize on the images into subcategories and provide recommendation of prescriptive actions to avoid impact on the wafer yield.","PeriodicalId":308777,"journal":{"name":"SPIE Photomask Technology","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129955767","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":"Accurate mask registration on tilted lines for 6F2 DRAM manufacturing","authors":"K. D. Roeth, W. Choi, Y. Lee, S. Kim, D. Yim, F. Laske, M. Ferber, M. Daneshpanah, E. Kwon","doi":"10.1117/12.2202818","DOIUrl":"https://doi.org/10.1117/12.2202818","url":null,"abstract":"193nm immersion lithography is the mainstream production technology for the 22nm half pitch (HP) DRAM manufacturing. Considering multi-patterning as the technology to solve the very low k1 situation in the resolution equation puts extreme pressure on the intra-field overlay, to which mask registration error may be a significant error contributor [3]. The International Technology Roadmap for Semiconductors (ITRS [1]) requests a registration error below 4 nm for each mask of a multi-patterning set forming one layer on the wafer. For mask metrology at the 22nm HP node, maintaining a precision-to-tolerance (P/T) ratio below 0.25 will be very challenging. Mask registration error impacts intra-field wafer overlay directly and has a major impact on wafer yield. DRAM makers moved several years ago to 6F2 (figure 1, [2]) cell design and thus printing tilted lines at 15 or 30 degree. Overlay of contact layer over buried line has to be well controlled. However, measuring mask registration performance accurately on tilted lines was a challenge. KLA Tencor applied the model-based algorithm to enable the accurate registration measurement of tilted lines on the Poly layer as well as the mask-to-mask overlay to the adjacent contact layers. The metrology solution is discussed and measurement results are provided.","PeriodicalId":308777,"journal":{"name":"SPIE Photomask Technology","volume":"77 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128774407","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":"MPC model validation using reverse analysis method","authors":"Sukho Lee, So-Eun Shin, J. Shon, Ji-Soong Park, In-kyun Shin, Chan-uk Jeon","doi":"10.1117/12.2197162","DOIUrl":"https://doi.org/10.1117/12.2197162","url":null,"abstract":"It became more challenging to guarantee the overall mask Critical Dimension (CD) quality according to the increase of hot spots and assist features at leading edge devices. Therefore, mask CD correction methodology has been changing from the rule-based (and/or selective) correction to model-based MPC (Mask Process Correction) to compensate for the through-pitch linearity and hot spot CD errors. In order to improve mask quality, it is required to have accurate MPC model which properly describes current mask fabrication process. There are limits on making and defining accurate MPC model because it is hard to know the actual CD trend such as CD linearity and through-pitch owing to the process dispersion and measurement error. To mitigate such noises, we normally measure several sites of each pattern types and then utilize the mean value of each measurement for MPC modeling. Through those procedures, the noise level of mask data will be reduced but it does not always guarantee improvement of model accuracy, even though measurement overhead is increasing. Root mean square (RMS) values which is usually used for accuracy indicator after modeling actually does not give any information on accuracy of MPC model since it is only related with data noise dispersion. In this paper, we reversely approached to identify the model accuracy. We create the data regarded as actual CD trend and then create scattered data by adding controlled dispersion of denoting the process and measurement error to the data. Then we make MPC model based on the scattered data to examine how much the model is deviated from the actual CD trend, from which model accuracy can be investigated. It is believed that we can come up with appropriate method to define the reliability of MPC model developed for optimized process corrections.","PeriodicalId":308777,"journal":{"name":"SPIE Photomask Technology","volume":"90 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126535825","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":"Accurate mask model implementation in OPC model for 14nm nodes and beyond","authors":"Nacer Zine El Abidine, F. Sundermann, E. Yesilada, V. Farys, Frederic Huguennet, A. Armeanu, I. Bork, M. Chomat, P. Buck, I. Schanen","doi":"10.1117/12.2203267","DOIUrl":"https://doi.org/10.1117/12.2203267","url":null,"abstract":"In a previous work [1] we demonstrated that current OPC model assuming the mask pattern to be analogous to the designed data is no longer valid. Indeed as depicted in figure 1, an extreme case of line-end shortening shows a gap up to 10 nm difference (at mask level). For that reason an accurate mask model, for a 14nm logic gate level has been calibrated. A model with a total RMS of 1.38nm at mask level was obtained. 2D structures such as line-end shortening and corner rounding were well predicted using SEM pictures overlaid with simulated contours. The first part of this paper is dedicated to the implementation of our improved model in current flow. The improved model consists of a mask model capturing mask process and writing effects and a standard optical and resist model addressing the litho exposure and development effects at wafer level. The second part will focus on results from the comparison of the two models, the new and the regular, as depicted in figure 2.","PeriodicalId":308777,"journal":{"name":"SPIE Photomask Technology","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132068001","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":"Automatic defect review for EUV photomask reticles by atomic force microscope","authors":"Ardavan Zandiatashbar, Byong Kim, Y. Yoo, Keibock Lee, Ahjin Jo, Ju Suk Lee, Sang-Joon Cho, Sang-il Park","doi":"10.1117/12.2197382","DOIUrl":"https://doi.org/10.1117/12.2197382","url":null,"abstract":"Defects on a reticle are inspected, reviewed, and repaired by different tools. They are located by automated optical inspection (AOI); however, if the characteristic size of defects is similar to that of light and electron beam wavelengths, they are often unclassified or misclassified by AOI. Atomic force microscopes (AFM) along with electron microscopes are used for investigating defects located by AOI to distinguish false defects from real defects and effectively classify them. Both AFM and electron microscopes provide high resolution images. However, electron microscopy is known to be destructive and have less accuracy in 3rd dimension measurement compared to AFM [1]. On the other hand, AFM is known to have low throughput and limited tip life in addition to requiring significant effort to finding the defects. These limitations emanate from having to perform multiple large scans to find the defect locations, to compensate for stage coordinate inaccuracies, and to correct the mismatch between the AFM and the AOI tools. In this work we introduce automatic defect review (ADR) AFM for defect study and classification of EUV mask reticles that overcomes the aforementioned limitations of traditional AFM. This metrology solution is based on an AFM configuration with decoupled Z and XY scanners that makes it possible to collect large survey images with minimum out of plane motion. To minimize the stage errors and mismatch between the AFM and the AOI coordinates, the coordinates of fiducial markers are used for coarse alignment. In addition, fine alignment of the coordinates is performed using enhanced optical vision on marks on the reticle. The ADR AFM is used to study a series of phase defects identified by an AOI tool on a reticle. Locating the defects, imaging, and defect classification are performed using the ADR automation software and with the throughput of several defects per hour. In order to preserve tip life and data consistency, AFM imaging is performed in non-contact mode. The ADR AFM provides high throughput, high resolution, and non-destructive means for obtaining 3D information for defect review and classification. Therefore this technology can be used for in-line defect review and classification for mask repair.","PeriodicalId":308777,"journal":{"name":"SPIE Photomask Technology","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129258238","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":"EUV or 193i: Who wins the center stage for 7nm node HVM in 2018?","authors":"Yoshinori Nagaoka, J. Miyazaki","doi":"10.1117/12.2208944","DOIUrl":"https://doi.org/10.1117/12.2208944","url":null,"abstract":"","PeriodicalId":308777,"journal":{"name":"SPIE Photomask Technology","volume":"138 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121551965","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":"Mask process matching using a model based data preparation solution","authors":"Brian Dillon, M. Saib, T. Figueiro, P. Petroni, C. Progler, P. Schiavone","doi":"10.1117/12.2199273","DOIUrl":"https://doi.org/10.1117/12.2199273","url":null,"abstract":"Process matching is the ability to precisely reproduce the signature of a given fabrication process while using a different one. A process signature is typically described as systematic CD variation driven by feature geometry as a function of feature size, local density or distance to neighboring structures. The interest of performing process matching is usually to address differences in the mask fabrication process without altering the signature of the mask, which is already validated by OPC models and already used in production. The need for such process matching typically arises from the expansion of the production capacity within the same or different mask fabrication facilities, from the introduction of new, perhaps more advanced, equipment to deliver same process of record masks and/or from the re-alignment of processes which have altered over time. For state-of-the-art logic and memory mask processes, such matching requirements can be well below 2nm and are expected to reduce below 1nm in near future. In this paper, a data preparation solution for process matching is presented and discussed. Instead of adapting the physical process itself, a calibrated model is used to modify the data to be exposed by the source process in order to induce the results to match the one obtained while running the target process. This strategy consists in using the differences among measurements from the source and target processes, in the calibration of a single differential model. In this approach, no information other than the metrology results is required from either process. Experimental results were obtained by matching two different processes at Photronics. The standard deviation between both processes was of 2.4nm. After applying the process matching technique, the average absolute difference between the processes was reduced to 1.0nm with a standard deviation of 1.3nm. The methods used to achieve the result will be described along with implementation considerations, to help assess viability for model driven data solutions to play a role in future, critical mask matching efforts.","PeriodicalId":308777,"journal":{"name":"SPIE Photomask Technology","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123006736","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":"Ruthenium capping layer preservation for 100X clean through pH driven effects","authors":"D. Dattilo, U. Dietze, J. Hsu","doi":"10.1117/12.2202188","DOIUrl":"https://doi.org/10.1117/12.2202188","url":null,"abstract":"In the absence of pellicle a EUVL reticle is expected to withstand up to 100x cleaning cycles. Surface damage upon wet and dry cleaning methods has been investigated and reported in recent years. [1] Thermal stress, direct photochemical oxidation and underlying Silicon layer oxidation are reported as the most relevant root-causes for metal damage and peeling off. [2,3] An investigation of final clean performance is here reported as a function of operating pH; the results show increased Ruthenium durability in moderately alkaline environment. The electrochemical rationale and the dependency of the reducing strength of the media with the pH will be presented as possible explanations for reduced damage.","PeriodicalId":308777,"journal":{"name":"SPIE Photomask Technology","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121964745","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}