Dr. Alain Moussa Profile

Dr. Alain Moussa

at imec

SPIE Involvement:

Author

Publications (31)

Proceedings Article | 10 April 2024 Poster

High throughput, angstrom-level metrology for copper-copper hybrid bonding

Arseniy Kalinin, Niranjan Saikumar, Irene Battisti, Erik Simons, Seokhan Kim, ShihWei Yu, Hokyun Chin, Artem Khachaturiants, Cong Chen, Bensu Tunca Altintas, Soon Aik Chew, Boyao Zhang, Nelda Antonovaité, Rudolf Wilhelm, Alain Moussa, Janusz Bogdanowicz, Anne-Laure Charley, Hamed Sadeghian

Proceedings Volume 12955, 129552T (2024) https://doi.org/10.1117/12.3010482

KEYWORDS: Metrology, Semiconducting wafers, Copper, Chemical mechanical planarization, Surface roughness, High volume manufacturing, Atomic force microscopy, Wafer bonding, Wafer testing, System integration

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Proceedings Article | 10 April 2024 Presentation + Paper

Cu pad surface height evaluation technique by in-line SEM for wafer hybrid bonding

Hiroaki Kasai, Mayuka Osaki, Kazuhisa Hasumi, Nobuyuki Mise, Maki Tanaka, Bensu Tunca Altintas, Soon Aik Chew, Janusz Bogdanowicz, Alain Moussa, Mohamed Saib, Boyao Zhang, Anne-Laure Charley

Proceedings Volume 12955, 129551N (2024) https://doi.org/10.1117/12.3008658

KEYWORDS: Copper, Semiconducting wafers, Scanning electron microscopy, Wafer bonding, Sensors, Atomic force microscopy, Signal detection, Image sensors, Chemical mechanical planarization, Target detection

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Proceedings Article | 10 April 2024 Presentation + Paper

Detection of crystalline defects in Si/SiGe superlattices towards 3D-DRAM applications

M. Beggiato, D. Cerbu, R. Loo, W. Sun, A. Moussa, G. Bast, K. Fukaya, C. Beral, A.-L. Charley, N. Janardan, A. Cross, G. Lorusso, M. Isawa, A. Belmonte, G. Sankar Kar, J. Bogdanowicz

Proceedings Volume 12955, 129551F (2024) https://doi.org/10.1117/12.3011279

KEYWORDS: Semiconducting wafers, Optical inspection, Inspection, Crystals, Sampling rates, Laser phosphor displays, Superlattices, Optical testing, Defect detection, Signal processing

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Si/SiGe heterostructures are gaining traction as a starting template in applications such as Gate-All-Around Field-Effect Transistor (GAAFET), complementary FET (CFET), and 3-dimensional dynamic random access memory (3D-DRAM), where the SiGe alloy plays the role of sacrificial material for channel release. However, the formation of crystalline defects (e.g. crosshatch) in the epitaxially grown layers plays a critical part in determining the overall device performance. As such, it is key to be able to control the defectivity level using large surface area inspection techniques. The challenge of such inspection is that it must combine a high enough throughput to detect low-density defects together with sensitivity to nanometer size defects. In addition, the technique should also be able to distinguish these elongated one-dimensional crystalline defects from other types of defects. In this study, we investigate the impact of the number of Si/SiGe bilayers on the crystal defect distribution utilizing a combined approach of optical inspection and extensive e-beam review for both qualitative and quantitative defect characterization. In-line optical inspection techniques revealed that the crosshatch density and distribution varied significantly with the number of Si/SiGe bilayers. These observations were then confirmed by high-resolution e-beam review coupled with image analysis and signal processing to enable crosshatch quantification. Our approach considers an initial investigation on thin Si/SiGe bilayers (up to ~5x bilayers) and is further extended to thick stacks (up to 60x bilayers) to evaluate the capability of optical inspection as the high-throughput reference technique. In conclusion, this study aims to develop a methodology to investigate the crosshatch density in Si/SiGe superlattices, using optical inspection and e-beam review as main characterization tools. These techniques offer valuable insights in terms of defect distribution at the wafer level for the design and fabrication of next-generation semiconductor devices.

Proceedings Article | 10 April 2024 Presentation + Paper

Advanced characterization of 2D materials using SEM image processing and machine learning

Mohamed Saib, Alain Moussa, Matteo Beggiato, Benjamin Groven, Henry Medina Silva, Pierre Morin, Janusz Bogdanowicz, Gouri Sankar Kar, Anne-Laure Charley

Proceedings Volume 12955, 129550X (2024) https://doi.org/10.1117/12.3014378

KEYWORDS: Image segmentation, 2D materials, Scanning electron microscopy, Image processing, Semiconducting wafers, Machine learning, Algorithm development, Image processing algorithms and systems, Atomic force microscopy, Tungsten

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2D materials hold significant potential for enhancing semiconductor device performance. However, their integration necessitates the establishment of a robust metrology that is both accurate and fast, enabling a comprehensive understanding and precise control of their growth processes. Scanning electron microscopy (SEM) ticks all the boxes to be a promising technique for 2D materials characterization due to its sensitivity to monolayers (ML) and its high measurement throughput. Nevertheless, automating its measurement analysis is essential to avoid slow data processing and inaccuracies in results. In this work, I propose a set of image-processing algorithms to extract various 2D material properties from SEM images and reveal hidden aspects of their growth processes. Firstly, I implemented and benchmarked two competing segmentation algorithms to process raw SEM images and localize surface regions corresponding to the substrate, 1ML, and 2ML. The first algorithm employs a statistical approach, named global thresholding, while the second is based on supervised machine Learning. These two algorithms were evaluated on a batch of wafers where tungsten disulfide (WS₂) material was grown, reaching a maximum of 2ML. The machine learning algorithm demonstrated exceptional performance, achieving segmentation success rates that surpassed 98%, outperforming the global thresholding technique, which has a success rate of 86.5%. Subsequently, other algorithms were developed to extract quality indicators of 2D material layers from the segmented images, such as the coverage rate, and the count of basic crystals and islands. Reviewing all extracted properties enabled us to assess the process uniformity on wafers across different facets. On the other hand, the cross-analysis of these features unveiled some fundamental properties of the studied growth process. We determined the 1ML coverage at which crystals transition from a quasi-isolated growth to the coalescence phase, as well as when the formation of a uniform 1ML begins. Finally, we deduced the important relationship between the growth rates of 1ML and 2ML.

Proceedings Article | 21 November 2023 Presentation + Paper

Imaging validation for LS of dark field low-n vs. Ta-based absorber masks

Tatiana Kovalevich, Lieve Van Look, Alain Moussa, Joern-Holger Franke, Vicky Philipsen

Proceedings Volume 12750, 1275005 (2023) https://doi.org/10.1117/12.2687549

KEYWORDS: Printing, 3D mask effects, Extreme ultraviolet, Simulations, Reticles, Photomask technology, Optical lithography, Metals, Lithography, Extreme ultraviolet lithography

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SPIE Journal Paper | 17 November 2023

E-beam metrology and line local critical dimension uniformity of thin dry resist films for high numerical aperture extreme ultraviolet lithography

Mohamed Zidan, Gian Francesco Lorusso, Danilo De Simone, Anuja De Silva, Ali Haider, Elisseos Verveniotis, Alain Moussa, Stefan De Gendt

JM3, Vol. 22, Issue 04, 044001, (November 2023) https://doi.org/10.1117/12.10.1117/1.JMM.22.4.044001

KEYWORDS: Line width roughness, Fourier transforms, Critical dimension metrology, Metrology, Signal to noise ratio, Film thickness, Extreme ultraviolet lithography, Scanning electron microscopy, Photoresist processing, Image analysis

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BackgroundLithography advancements require resist layer thickness reduction, essential to cope with the low depth of focus characteristic of high numerical aperture extreme ultraviolet lithography (High NA EUVL). However, such a requirement poses serious challenges in terms of resist process metrology and characterization, as patterns in thin resist suffer from low contrast, which may affect the performance of the edge detection algorithms used for image analysis, ultimately impacting metrology.AimWe aim to investigate the impact of reducing the film thickness of the dry photoresist on the E-beam metrology and line local critical dimension uniformity (LCDU).ApproachThin dry resist films from 10 to 30 nm are patterned at pitches 24, 28, and 32 nm using EUVL. A standard critical dimension scanning electron microscope (CDSEM) is used to perform E-beam metrology. The captured SEM images are analyzed using software to extract the parameters of interest, such as the critical dimension (CD), power spectral density (PSD), unbiased line width roughness (uLWR), LWR correlation length, signal-to-noise ratio (SNR), and line LCDU for a range of features with lengths from 12 to 50 nm. Furthermore, the experimental results of the line LCDU of a range of feature lengths and roughness parameters are plotted for different process conditions of thickness and pitch in a normalized way.ResultsThe results indicate that the dry resist shows good CDSEM imaging contrast and high SNR even at the thinnest resist thickness. This enables extracting a reliable uLWR measurement without the need to increase the number of frames to modulate the SNR. Moreover, it has LWR correlation length of around 2.5 nm. By thinning the resist thickness, the uLWR and line LCDU increase, and the SNR and the LWR correlation length decrease. Finally, when normalizing the line LCDU to uLWR and the feature length to the correlation length, the resulting curves of the different process conditions of the thickness and pitch overlap with each other, following an analytical model that relates the line LCDU to the resist roughness parameters.ConclusionWe showed the impact of reducing the dry resist thickness on E-beam metrology and line LCDU for features foreseen for High NA EUVL. The dry resist has good imaging contrast, LWR correlation length of around 2.5 nm, and the line LCDU depends on the resist thickness (uLWR and LWR correlation length for each particular thickness). With such a dataset, we demonstrated an overlap between the normalized curves of the line LCDU to the uLWR and the feature length to the correlation length for the different process conditions of thickness and pitch. The uLWR and correlation length are the knobs to achieve good patterning uniformity for a given feature length.

Proceedings Article | 27 April 2023 Presentation + Paper

300mm in-line metrologies for the characterization of ultra-thin layer of 2D materials

A. Moussa, J. Bogdanowicz, B. Groven, P. Morin, M. Beggiato, M. Saib, G. Santoro, Y. Abramovitz, K. Houtchens, S. Ben Nissim, N. Meir, J. Hung, A. Urbanowicz, R. Koret, I. Turovets, G. Lorusso, A.-L. Charley

Proceedings Volume 12496, 124961X (2023) https://doi.org/10.1117/12.2657968

KEYWORDS: Semiconducting wafers, Scanning electron microscopy, Monolayers, Scatterometry, 2D materials, Metrology, Atomic force microscopy, Raman spectroscopy, Silicon, Histograms

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Proceedings Article | 27 April 2023 Presentation + Paper

Detection of bonding voids for 3D integration

Cong Chen, Dieter Van Den Heuvel, Matteo Beggiato, Bensu Tunca Altintas, Alain Moussa, Anne Vandooren, Bart Baudemprez, Michael Schöbitz, Wassim Khaldi, Janusz Bogdanowicz, Christophe Beral, Anne-Laure Charley

Proceedings Volume 12496, 124961B (2023) https://doi.org/10.1117/12.2657950

KEYWORDS: Inspection, Wafer bonding, Silicon, Microscopes, Scanning electron microscopy, Optical microscopes, Infrared microscopy

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Proceedings Article | 27 April 2023 Presentation + Paper

Alignment and overlay through opaque metal layers

V. Blanco Carballo, E. Canga, C. Jehoul, A. Moussa, A. Tamaddon, C. Tabery, G. Gunjala, B. Menchtchikov, V. Zacca, S. Lalbahadoersing, A. den Boef, R. Synowicki

Proceedings Volume 12496, 124960I (2023) https://doi.org/10.1117/12.2658084

KEYWORDS: Ruthenium, Optical alignment, Semiconducting wafers, Overlay metrology, Oxides, Silicon, Metals, Etching, Scanners, Copper

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Proceedings Article | 27 April 2023 Presentation + Paper

Dry resist metrology readiness for high-NA EUVL

Gian Francesco Lorusso, Dieter Van Den Heuvel, Mohamed Zidan, Alain Moussa, Christophe Beral, Anne-Laure Charley, Danilo De Simone, Anuja De Silva, Elisseos Verveniotis, Ali Haider, Tsuyoshi Kondo, Hiroyuki Shindo, Yasushi Ebizuka, Miki Isawa

Proceedings Volume 12496, 1249612 (2023) https://doi.org/10.1117/12.2658280

KEYWORDS: Fourier transforms, Signal to noise ratio, Bridges, Inspection, Printing, Metrology, Film thickness, Extreme ultraviolet lithography, Atomic force microscopy, Defect detection

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SPIE Journal Paper | 10 December 2022

Role of landing energy in e-beam metrology of thin photoresist for high-numerical aperture extreme ultraviolet lithography

Mohamed Zidan, Daniel Fischer, Joren Severi, Danilo De Simone, Alain Moussa, Angelika Müllender, Chris Mack, Anne-Laure Charley, Philippe Leray, Stefan De Gendt, Gian Francesco Lorusso

JM3, Vol. 22, Issue 02, 021002, (December 2022) https://doi.org/10.1117/12.10.1117/1.JMM.22.2.021002

KEYWORDS: Signal to noise ratio, Metrology, Scanning electron microscopy, Shrinkage, Line scan image sensors, Semiconducting wafers, Photoresist materials, Critical dimension metrology, Extreme ultraviolet lithography, Line width roughness

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Proceedings Article | 1 December 2022 Presentation + Paper

Influence of photoresist thinning and underlayer film on e-beam using eP5 for high-NA patterning

Mahmudul Hasan, Christophe Beral, Gian Francesco Lorusso, Danilo De Simone, Alain Moussa, Dieter Van Den Heuvel, Anne-Laure Charley, Philippe Leray

Proceedings Volume 12292, 122920M (2022) https://doi.org/10.1117/12.2641768

KEYWORDS: Scanning electron microscopy, Signal to noise ratio, Image quality, Defect detection, Fourier transforms, Extreme ultraviolet lithography, Coating, Inspection, Metrology, Electron beam lithography

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The introduction of Extreme Ultraviolet Lithography (EUVL) has been an extraordinary achievement in keeping Moore’s law alive, as it minimizes the cost, time, and number of patterning steps required for device fabrication. However, as the advanced technology nodes require further scale down of the semiconductor devices, the current state-of-art EUVL tool, equipped with 0.33 Numerical Aperture (NA) and 13.5nm wavelength cannot print the features of interest with an acceptable yield. As a solution, a new generation of EUVL tool has been proposed (High-NA EUVL), having 0.55 NA and 8nm resolution. As a result of the increased NA, the depth of focus is reduced, thus thinner resist is required. Moreover, we need to restrict the aspect ratio of the features to avoid pattern collapse. For instance, resist thickness of approximately 30nm, which is typically used to print a 16nm half-pitch feature, cannot be applied to print an 8nm half-pitch feature, resist thickness must be lowered significantly to circumvent pattern collapse. However, the use of thin resist may have several negative effects on metrology and defect inspection. In this paper, we will discuss the influence of resist thickness and underlayer films on Scanning Electron Microscope (SEM) using ASML’s eP5. For this study, we prepared a set of wafers with 16nm line-space (LS) patterns at different resist thicknesses using either Metal-Oxide Resist (MOR) or Chemically Amplified Resist (CAR). The case study compares both resist platforms on Spin on Glass (SoG) and Organic Underlayer (OUL). To conduct this study our BKM ADI eP5 SEM condition has been used. We observed that thinning down film thickness leads to deterioration of SEM image quality as well as loss of defect sensitivity during the inspection. In addition, varying the underlayers greatly affects both image quality and sensitivity. By decreasing the resist thickness, MOR and CAR were observed to behave in the same way, in terms of both image degradation and loss of sensitivity, although image quality did not degrade in the same way in the two cases.

Proceedings Article | 16 September 2022 Paper

High-NA EUV photoresist metrology using high-throughput scanning probe microscopy

M. Mucientes, A. Khachaturiants, R. Trussell, A. Kalinin, Y. Guo, E. Simons, S. Kim, O. Nadyarnykh, A. Moussa, J. Bogdanowicz, J. Severi, G. Lorusso, D. De Simone, A.-L. Charley, P. Leray, M. van Reijzen, C. Bozdog, H. Sadeghian

Proceedings Volume 12325, 123250M (2022) https://doi.org/10.1117/12.2641698

KEYWORDS: Scanning probe microscopy, Semiconducting wafers, Metrology, Optical lithography, Bridges, Extreme ultraviolet lithography, Defect inspection, Photoresist materials, Inspection, Atomic force microscopy

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Proceedings Article | 13 June 2022 Presentation

High throughput scanning probe metrology for high-NA EUV photoresist profiling

Artem Khatchaturiants, Marta Mucientes, Arseniy Kalinin, Yan Guo, Seokhan Kim, Alain Moussa, Janusz Bogdanowicz, Joren Severi, Gian Lorusso, Danilo De Simone, Anne-Laure Charley, Philippe Leray, Maarten van Reijzen, Cornel Bozdog, Hamed Sadeghian

Proceedings Volume PC12053, PC120530I (2022) https://doi.org/10.1117/12.2616089

KEYWORDS: Scanning probe microscopy, Metrology, Photoresist materials, Extreme ultraviolet lithography, Scanning probe metrology, Profiling, Process control, Extreme ultraviolet, Atomic force microscopy, Stochastic processes

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Proceedings Article | 31 May 2022 Presentation + Paper

Deep learning-enabled vertical drift artefact correction for AFM images

Dorin Cerbu, Kristof Paredis, Alain Moussa, Anne-Laure Charley, Philippe Leray

Proceedings Volume PC12053, PC120530L (2022) https://doi.org/10.1117/12.2614029

KEYWORDS: Atomic force microscopy, Neural networks, Metrology, Image processing, Convolution, Line scan image sensors, Scanning probe microscopy, Semiconductors

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Proceedings Article | 26 May 2022 Presentation + Paper

Metrology of thin resist for high NA EUVL

Gian Francesco Lorusso, Christophe Beral, Janusz Bogdanowicz, Danilo De Simone, Mahmudul Hasan, Christiane Jehoul, Alain Moussa, Mohamed Saib, Mohamed Zidan, Joren Severi, Vincent Truffert, Dieter Van den Heuvel, Alex Goldenshtein, Kevin Houchens, Gaetano Santoro, Daniel Fischer, Angelika Muellender, Joey Hung, Roy Koret, Igor Turovets, Kit Ausschnitt, Chris Mack, Tsuyoshi Kondo, Tomoyasu Shohjoh, Masami Ikota, Anne-Laure Charley, Philippe Leray

Proceedings Volume 12053, 120530O (2022) https://doi.org/10.1117/12.2614046

KEYWORDS: Fourier transforms, Signal to noise ratio, Metrology, Line width roughness, Scanning electron microscopy, Semiconducting wafers, Atomic force microscopy, Scatterometry, Extreme ultraviolet lithography, Image quality

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One of the many constrains of High Numerical Aperture Extreme Ultraviolet Lithography (High NA EUVL) is related to resist thickness. In fact, one of the consequences of moving from current 0.33NA to 0.55NA (high NA) is the Depth of Focus (DOF) reduction. In addition, as the resist feature lines shrink down to 8nm half pitch, it is essential to limit the aspect ratio to avoid pattern collapse. The direct consequence of such a situation is that a resist thickness of 30nm, usually used for 32nm pitch dense line/space (LS), will not be suitable for 16nm pitch, where the target thickness is expected to be 15nm thickness or less to ensure a similar aspect ratio. The question we need to answer is how the resist thickness reduction will impact the various metrology techniques needed to properly set up a process. To address this question, a set of wafers using both Chemical Amplified Resist (CAR) and Metal Oxide Resist (MOR) at different thicknesses and with different types of underlayer have been generated for LS patterns at 32nm pitch. We first investigated the impact of film thickness by scanning electron microscope (SEM) on the imaging of CAR resist lines. To start with, our current Best-Known Methods (BKM’s) were used to acquire the SEM images. As resist thickness decreases, noise level and image contrast are observed to degrade dramatically. Such an image quality degradation may directly impact the quality of the CD measurements both in terms of accuracy and precision. In this paper we investigated the thin resist wafer set described above using various techniques, such as Critical Dimension Scanning Electron Microscope (CD SEM), Atomic Force Microscopy (AFM), Low Voltage SEM (LV SEM), scatterometry, Pattern Shift Response (PSR), and optical defect inspection. The impact of the resist thickness is estimated for each approach, and optimal settings were investigated to minimize the relative impact on metrology. Our results indicated that, in most cases, alternative operation conditions and BKM settings, sometimes drastically different from the usual operation condition, must be used to guarantee the metrology requirements. Our results show that, despite the impact of thinning resist materials, it is possible to find appropriate settings to strengthen the metrology quality output.

Proceedings Article | 26 May 2022 Presentation + Paper

Low-voltage aberration-corrected SEM metrology of thin resist for high-NA EUVL

Mohamed Zidan, Daniel Fischer, Gian Francesco Lorusso, Joren Severi, Danilo De Simone, Alain Moussa, Angelika Müllender, Chris Mack, Anne-Laure Charley, Philippe Leray, Stefan De Gendt

Proceedings Volume 12053, 120530P (2022) https://doi.org/10.1117/12.2613990

KEYWORDS: Scanning electron microscopy, Metrology, Critical dimension metrology, Extreme ultraviolet lithography, Line width roughness

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Proceedings Article | 26 May 2022 Presentation + Paper

Subsurface scanning probe metrology for overlay through opaque layers

I. Battisti, K. Makles, M. S. Mucientes, Y. Guo, E. Simons, J. Bogdanowicz, A. Moussa, V. Blanco, F. Yasin, D. Crotti, A.-L. Charley, P. Leray, M. van Reijzen, C. Bozdog, H. Sadeghian

Proceedings Volume 12053, 1205310 (2022) https://doi.org/10.1117/12.2616093

KEYWORDS: Overlay metrology, Semiconducting wafers, Opacity, Atomic force microscopy, Scanning probe metrology, Image resolution, Pixel resolution, Photomasks

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SPIE Journal Paper | 5 April 2022 Open Access

Chemically amplified resist CDSEM metrology exploration for high NA EUV lithography

Joren Severi, Gian Lorusso, Danilo De Simone, Alain Moussa, Mohamed Saib, Rutger Duflou, Stefan De Gendt

JM3, Vol. 21, Issue 02, 021207, (April 2022) https://doi.org/10.1117/12.10.1117/1.JMM.21.2.021207

KEYWORDS: Fourier transforms, Signal to noise ratio, Metrology, Optical lithography, Extreme ultraviolet lithography, Chemically amplified resists, Atomic force microscopy, Line width roughness, Scanning electron microscopy, Image quality

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Proceedings Article | 19 October 2021 Presentation + Paper

Towards high NA patterning readiness: materials, processes and etch transfer for P24 Line Space

A. Thiam, J. G. Santaclara, J-H. Franke, F. Schleicher, R. Blanc, P. Bezard, A. Moussa, P. Wong, E. Hendrickx, M. Maslow

Proceedings Volume 11854, 118540A (2021) https://doi.org/10.1117/12.2601839

KEYWORDS: Etching, Photoresist materials, Semiconducting wafers, Optical lithography, Scanning electron microscopy, Photoresist processing, Lithography, Atomic force microscopy, Photoresist developing, Oxides

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Proceedings Article | 19 October 2021 Presentation + Paper

Printability and propagation of stochastic defects through a study of defects programmed on EUV mask

Poulomi Das, Alain Moussa, Christophe Beral, Mihir Gupta, Mohamed Saib, Sandip Halder, Anne Laure Charley, Philippe Leray

Proceedings Volume 11854, 118540Z (2021) https://doi.org/10.1117/12.2602034

KEYWORDS: Photomasks, Semiconducting wafers, Etching, Atomic force microscopy, Scanning electron microscopy, Bridges, Stochastic processes, Lithography, Extreme ultraviolet, Inspection

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Proceedings Article | 12 October 2021 Presentation + Paper

High NA EUV: a challenge for metrology, an opportunity for atomic force microscopy

A. Moussa, J. Severi, G. F. Lorusso, D. De Simone, A.-L. Charley

Proceedings Volume 11854, 1185410 (2021) https://doi.org/10.1117/12.2601677

KEYWORDS: Atomic force microscopy, Statistical analysis, Metrology, Extreme ultraviolet, Extreme ultraviolet lithography, Scanning electron microscopy, Thin films, Signal attenuation, Photons, Lithography

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Proceedings Article | 22 February 2021 Presentation + Paper

Spectroscopy: a new route towards critical-dimension metrology of the cavity etch of nanosheet transistors

J. Bogdanowicz, Y. Oniki, K. Kenis, Y. Muraki, T. Nuytten, S. Sergeant, A. Franquet, V. Spampinato, T. Conard, I. Hoflijk, J. Meersschaut, N. Claessens, A. Moussa, D. Van Den Heuvel, J. Hung, R. Koret, A.-L. Charley, P. Leray

Proceedings Volume 11611, 116111Q (2021) https://doi.org/10.1117/12.2581800

KEYWORDS: Etching, Metrology, Transistors, Spectroscopes, Raman spectroscopy, Critical dimension metrology, Spectroscopy, Photoemission spectroscopy, X-rays, Scanning electron microscopy

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Proceedings Article | 12 May 2020 Paper

Ruthenium direct etch scatterometry solution for self-aligning semi-damascene

Sara Paolillo, Alain Moussa, Gayle Murdoch, Frederic Lazzarino, Anne-Laure Charley, Philippe Leray, Joey Hung, Roy Koret, Shay Wolfling, Avron Ger

Proceedings Volume 11325, 1132519 (2020) https://doi.org/10.1117/12.2550366

KEYWORDS: Ruthenium, Etching, Semiconducting wafers, Machine learning, Metals, Transmission electron microscopy, Scatterometry, Photomasks, Resistance, Line edge roughness

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Beyond the 5nm technology node, interconnect scaling has an impact on metal material selection: usage of copper may hit a limit with respect to resistance and reliability performance [1]. Thickness of barrier and liner (required for copper) cannot be reduced further, meaning that trench width reduction will have a negative effect on the relative copper volume. Grain boundary scattering increases as well, which in turn further increases resistivity and resistance. One of the best alternatives is Ruthenium (Ru), but dual-damascene processing is difficult with Ru (requires improvements in Ru filling of narrow high aspect ratio trenches and in Ru CMP selectivity and defects). So, a Back End of Line (BEOL) material change may require a move to a semi-damascene integration with direct Ruthenium metal etch [2]. This shift from a well-known dual-damascene flow, based on metal CMP, to a semi-damascene flow, based on metal etch integration, will require a new set of metrology capabilities, which are studied in this paper. In the current study, Scatterometry is widely used in all semi-damascene process steps to monitor both dimensional and material properties. Important measured parameters include thickness, full profile details, grain size, and roughness of metal lines—all parameters that are required for feedback and in-line process control. We will describe how these parameters can be monitored using a single Scatterometry metrology system. The semi-damascene process development described in this paper exploits EUV lithography at a critical dimension (CD) of 16 nm and 32 nm pitch and includes the optimization of the following process steps: 1. Metal deposition techniques: ALD and PVD, with a wide range of metal thickness. 2. Anneal , affecting grain size. 3. Etch process , for optimal metal line profile and roughness. The Scatterometry results were evaluated and verified by reference techniques such as CDSEM, and HAADF-STEM. The goal of the process optimization was Ru resistivity and resistance. In-line Scatterometry was shown to accurately predict the resistance of the Ru lines — parameter that is measured at the end of the processing, and is affected by all processes, including deposition, annealing, and etch. Prediction was carried out by a machine learning algorithm, based on an E-test, combining the contribution of all three process steps into a single output, at the post-etch measurement phase.

Proceedings Article | 20 March 2020 Presentation + Paper

EUV photoresist reference metrology using TEM tomography

Mark Biedrzycki, Umesh Adiga, Andrew Barnum, Alain Mousa, Jason Arjavac, Rose Marie Haynes, Anne-Laure Charley, Phillipe Leray, Dmitry Batuk

Proceedings Volume 11325, 113251T (2020) https://doi.org/10.1117/12.2552139

KEYWORDS: Transmission electron microscopy, Metrology, Tomography, Image segmentation, Photoresist materials, Atomic force microscopy, Extreme ultraviolet lithography, Semiconducting wafers, Atomic layer deposition, Image filtering

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Proceedings Article | 20 March 2020 Paper

The application of a Rapid Probe Microscope (RPM) for investigating 1D and 2D structures from EUV lithography

Andrew D. Humphris, Alain Moussa, Mircea Dusa, Anne-Laure Charley, Elis Newham, Jenny Goulden, Lei Feng, Christopher Bevis

Proceedings Volume 11325, 113251M (2020) https://doi.org/10.1117/12.2552054

KEYWORDS: 3D image processing, Extreme ultraviolet lithography, Microscopes, 3D metrology, Extreme ultraviolet, Data analysis, Metrology, Statistical analysis, Finite element methods, Microscopy

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Proceedings Article | 26 March 2019 Presentation + Paper

Scatterometry and AFM measurement combination for area selective deposition process characterization

Mohamed Saib, Alain Moussa, Anne-Laure Charley, Philippe Leray, Joey Hung, Roy Koret, Igor Turovets, Avron Ger, Shaoren Deng, Andrea Illiberi, Jan Willem Maes, Gabriel Woodworth, Michael Strauss

Proceedings Volume 10959, 109591N (2019) https://doi.org/10.1117/12.2515177

KEYWORDS: Zirconium dioxide, Scatterometry, Metrology, Chemical species, Atomic force microscopy, Semiconducting wafers, Deposition processes, Data modeling, Machine learning, Scatter measurement

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Proceedings Article | 26 March 2019 Presentation + Paper

Localized power spectral density analysis on atomic force microscopy images for advanced patterning applications

Alain Moussa, Mohamed Saib, Sara Paolillo, Frederic Lazzarino, Andrea Illiberi, Shaoren Deng, Jan Willem Maes, Anne-Laure Charley, Philippe Leray

Proceedings Volume 10959, 109591O (2019) https://doi.org/10.1117/12.2515178

KEYWORDS: Atomic force microscopy, Image processing, Photoresist processing, Statistical analysis, Signal processing, Scanning electron microscopy, Optical lithography, Image analysis, Metrology, Algorithm development

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SPIE Journal Paper | 12 September 2018

Need for LWR metrology standardization: the imec roughness protocol

Gian Francesco Lorusso, Takumichi Sutani, Vito Rutigliani, Frieda van Roey, Alain Moussa, Anne-Laure Charley, Chris Mack, Patrick Naulleau, Chami Perera, Vassilios Constantoudis, Masami Ikota, Toru Ishimoto, Shunsuke Koshihara

JM3, Vol. 17, Issue 04, 041009, (September 2018) https://doi.org/10.1117/12.10.1117/1.JMM.17.4.041009

KEYWORDS: Metrology, Line width roughness, Scanning electron microscopy, Digital filtering, Atomic force microscopy, Standards development, Semiconductors, Image acquisition, Image quality, Electron microscopes

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As semiconductor technology keeps moving forward, undeterred by the many challenges ahead, one specific deliverable is capturing the attention of many experts in the field: line width roughness (LWR) specifications are expected to be <2 nm in the near term, and to drop below 1 nm in just a few years. This is a daunting challenge and engineers throughout the industry are trying to meet these targets using every means at their disposal. However, although current efforts are surely admirable, we believe they are not enough. The fact is that a specification has a meaning only if there is an agreed methodology to verify if the criterion is met or not. Such standardization is critical in any field of science and technology and the question that we need to ask ourselves today is whether we have a standardized LWR metrology or not. In other words, if a single reference sample were provided, would everyone measuring it get reasonably comparable results? We came to realize that this is not the case and that the observed spread in the results throughout the industry is quite large. In our opinion, this makes the comparison of LWR data among institutions, or to a specification, very difficult. We report the spread of measured LWR data across the semiconductor industry. We investigate the impact of image acquisition, measurement algorithm, and frequency analysis parameters on LWR metrology. We review critically some of the International Technology Roadmap for Semiconductors (ITRS) metrology guidelines [such as measurement box length >2 μm and the need to correct for scanning electron microscope (SEM) noise]. We compare the SEM roughness results to AFM measurements. Finally, we propose a standardized LWR measurement protocol—the imec roughness protocol—intended to ensure that every time LWR measurements are compared (from various sources or to specifications), the comparison is sensible and sound. We deeply believe that the industry is at a point where it is imperative to guarantee that when talking about a critical parameter such as LWR, everyone speaks the same language, which is not currently the case.

Proceedings Article | 28 March 2018 Presentation + Paper

The need for LWR metrology standardization: the imec roughness protocol

Gian Francesco Lorusso, Takumichi Sutani , Vito Rutigliani, Frieda van Roey, Alain Moussa, Anne-Laure Charley, Chris Mack, Patrick Naulleau, Vassilios Constantoudis , Masami Ikota , Toru Ishimoto, Shunsuke Koshihara

Proceedings Volume 10585, 105850D (2018) https://doi.org/10.1117/12.2294617

KEYWORDS: Line width roughness, Metrology, Standards development, Semiconductors, Scanning electron microscopy, Image acquisition, Atomic force microscopy, Finite element methods, Semiconducting wafers, Time metrology

Read Abstract +

As semiconductor technology keeps moving forward, undeterred by the many challenges ahead, one specific deliverable is capturing the attention of many experts in the field: Line Width Roughness (LWR) specifications are expected to be less than 2nm in the near term, and to drop below 1nm in just a few years. This is a daunting challenge and engineers throughout the industry are trying to meet these targets using every means at their disposal. However, although current efforts are surely admirable, we believe they are not enough. The fact is that a specification has a meaning only if there is an agreed methodology to verify if the criterion is met or not. Such a standardization is critical in any field of science and technology and the question that we need to ask ourselves today is whether we have a standardized LWR metrology or not. In other words, if a single reference sample were provided, would everyone measuring it get reasonably comparable results? We came to realize that this is not the case and that the observed spread in the results throughout the industry is quite large. In our opinion, this makes the comparison of LWR data among institutions, or to a specification, very difficult. In this paper, we report the spread of measured LWR data across the semiconductor industry. We investigate the impact of image acquisition, measurement algorithm, and frequency analysis parameters on LWR metrology. We review critically some of the International Technology Roadmap for Semiconductors (ITRS) metrology guidelines (such as measurement box length larger than 2μm and the need to correct for SEM noise). We compare the SEM roughness results to AFM measurements. Finally, we propose a standardized LWR measurement protocol - the imec Roughness Protocol (iRP) - intended to ensure that every time LWR measurements are compared (from various sources or to specifications), the comparison is sensible and sound. We deeply believe that the industry is at a point where it is imperative to guarantee that when talking about a critical parameter such like LWR, everyone speaks the same language, which is not currently the case.

Proceedings Article | 20 March 2018 Presentation

Exploration of post-lithography smoothening methods applied to 16nm half-pitch EUV lines and spaces (Conference Presentation)

Frederic Lazzarino, Ming Mao, Sara Paolillo, Suseendharan Sakthikumar, Danilo De Simone, Alain Moussa, Nadia Vandenbroeck, Daniele Piumi, Kathy Barla

Proceedings Volume 10589, 105890A (2018) https://doi.org/10.1117/12.2302640

KEYWORDS: Optical lithography, Extreme ultraviolet, Metals, Extreme ultraviolet lithography, Scanning electron microscopy, Semiconductors, High volume manufacturing, Back end of line, Photoresist materials, Line edge roughness

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Year after year, the semiconductor industry overcomes a tremendous amount of technical challenges to satisfy Moore’s law. Through innovative device architectures, smart design, new integration and patterning concepts, better tools and new materials, the industry has successfully reached the 7nm technology node. Both design and patterning options are identified and the high volume manufacturing readiness is expected end of 2018. Today, the industry is preparing for the 5nm technology node (N5) while research centers start identifying and exploring the different patterning options for the 3nm technology node. The former targets a Metal 2 Pitch (M2P) of 32nm and a Contacted Poly Pitch (CPP) of 42nm while the latter aims for a M2P of 24nm and a CPP of 32nm. At such tight metal pitches and in view of the continuous progress in EUV tool performance, a single print EUV lithography is considered as a potential patterning option for N5 to pattern critical Back-End-Of-Line (BEOL) layers such as block, via and unidirectional metal lines. However, without the emergence of improved EUV photoresist (PR) platform that meets requirements for resolution, line edge roughness and sensitivity, we can expect a very limited available PR budget for pattern transfer (between 12nm and 30nm), an increase of defects such as bridging or line interruptions and finally a degradation of the sidewall roughness. These will contribute to the total CD variation and consume an important part of the overall Edge Placement Error (EPE) budget. Hence, actual patterning methods used to smooth and transfer down the PR pattern must be significantly improved and new solutions must be explored to enable the emergence of advanced technologies. In this work, we explore different post-lithography methods to overcome challenges related to EUV-based patterning at tight pitches. Both chemically amplified PR and metal-based PR are considered and the performance of the different approaches are evaluated step-by-step using top down SEM imaging, cross-section SEM and 3D-AFM. Finally, we complete the study showing Power Spectral Density (PSD) analysis that help to understand how the roughness is distributed in the frequency domain for the different studied methods.

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