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1. Materials Development for Thermally-Assisted Magnetic Recording Media

Author

SEAGATE TECHNOLOGY FREMONT CA, Brucker, C. F., McDaniel, T. W., SEAGATE TECHNOLOGY FREMONT CA, Brucker, C. F., and McDaniel, T. W.

Abstract

We have carried out a combined experimental and computer simulation study to specify and identify candidate films to support high areal density, thermally-assisted magnetic recording. The motivation of this work is to utilize the enhanced writability of very high coercivity materials that thermal assistance can provide. Media with high coercivity (and anisotropy K(sub u)) are known to be essential to achieve a sufficiently high ratio of K(sub u)V/k(sub B)T necessary to maintain magnetic stability at temperature T in media switching units (grains; single domains) of volume V. Nominally, we expect V infinity D(exp -3/2, where D is the medium bit density per unit area in recording. A micromagnetic recording simulation tool with a capability of representing realistic grain size distributions, temperature-dependent magnetic properties, and spatially-varying imposed temperature distributions was employed to study the interplay of thermal and magnetic field gradients in the recording process. In addition, a simple LLG-based thermomagnetic switching model supplemented the micromagnetics model. We fabricated improved Co/X multilayer media for recording evaluation, and performed standard materials characterization., Pub. in Materials Research Society symposium proceedings; v. 674 pV2.3.1-V2.3.12, 2001. This article is from ADA402512 Applications of Ferromagnetic and Optical Materials, Storage and Magnetoelectronics: Symposia Held in San Francisco, California, U.S.A. on April 16-20, 2001

Published
2001

12. On the origin of positive exchange bias and coercivity enhancement in proximity to the blocking temperature

Author

A. Vorobiev, P. Warin, D. Givord, A.N. Dobrynin, Seagate Technology, SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), Uppsala University, Micro et NanoMagnétisme (NEEL - MNM), Institut Néel (NEEL), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), and Université Grenoble Alpes (UGA)

Subjects
010302 applied physics, [PHYS]Physics [physics], Materials science, Spins, Condensed matter physics, 02 engineering and technology, Coercivity, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Magnetocrystalline anisotropy, 01 natural sciences, Electronic, Optical and Magnetic Materials, Condensed Matter::Materials Science, Magnetization, Exchange bias, Ferromagnetism, 0103 physical sciences, Antiferromagnetism, Condensed Matter::Strongly Correlated Electrons, 0210 nano-technology, Anisotropy
Abstract

Magnetic properties of two oxidised Co thin films prepared by different sputtering techniques are analysed. Exchange bias (EB) blocking temperatures ( T B ) of the samples were found to be 50 K different due to difference in grain sizes of antiferromagnetic CoO. In proximity to T B the EB changes its sign from negative to positive. This positive EB behaviour is strikingly similar for the two samples with the exception of its position on the temperature scale. A computational model, taking into account temperature dependence of the antiferromagnet’s magnetocrystalline anisotropy and its sublattices’ magnetisation, reproduces positive EB in proximity to T B . This happens when a significant fraction of antiferromagnetic entities becomes involved in magnetisation reversal, and there is antiferromagnetic exchange coupling between those entities. The coercivity enhancement, accompanying positive EB, is due to anisotropy energies of the reversible antiferromagnetic entities contributing to the ferromagnetic layer’s energy barrier. The model suggests that in order for the two samples to have identical positive EB behaviour, the reversible antiferromagnetic entities should represent individual spins.

Published
2021

13. Scheduling and Simulation in wafer fabs: Competitors, Independent Players or Amplifiers?

Author

Georg Seidel, Tina O'Donnell, Peter Lendermann, Leon F. McGinnis, Philippe Vialletelle, Lars Mönch, Stéphane Dauzère-Pérès, D-SIMLAB Technologies, Département Sciences de la Fabrication et Logistique (SFL-ENSMSE), École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-CMP-GC, Institut Mines-Télécom [Paris] (IMT), Laboratoire d'Informatique, de Modélisation et d'Optimisation des Systèmes (LIMOS), Ecole Nationale Supérieure des Mines de St Etienne (ENSM ST-ETIENNE)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Institut national polytechnique Clermont Auvergne (INP Clermont Auvergne), Université Clermont Auvergne (UCA)-Université Clermont Auvergne (UCA), Georgia Institute of Technology [Atlanta], University of Hagen [Allemagne], Seagate Technology, Infineon Technologies AG [Villach] (Infineon), and STMicroelectronics [Crolles] (ST-CROLLES)

Subjects
0209 industrial biotechnology, Focus (computing), 021103 operations research, Job shop scheduling, Computer science, 0211 other engineering and technologies, Scheduling (production processes), Semiconductor device modeling, [INFO.INFO-RO]Computer Science [cs]/Operations Research [cs.RO], 02 engineering and technology, Competitor analysis, Manufacturing engineering, Material flow, Wafer fabrication, 020901 industrial engineering & automation, Wafer
Abstract

This panel will discuss the inherent conflict between the application of (Discrete-Event) Simulation and Scheduling techniques to manage and optimise capacity and material flow in Semiconductor Frontend Manufacturing (wafer fabrication). Representatives from both industry and academia will describe advantages and shortcomings of the respective techniques, with a specific focus on challenges arising from the recent and anticipated future evolution of the nature of such manufacturing environments, and suggest solution approaches as well as research issues that need to be addressed.

Published
2020

22. ETP4HPC's Strategic Research Agenda for High-Performance Computing in Europe 4

Author

Malms, Michael, Ostasz, Marcin, Gilliot, Maike, Bernier-Bruna, Pascale, Cargemel, Laurent, Suarez, Estela, Cornelius, Herbert, Duranton, Marc, Koren, Benny, Rosse-Laurent, Pascale, Pérez-Hernández, María S., Marazakis, Manolis, Lonsdale, Guy, Carpenter, Paul, Antoniu, Gabriel, Narasimhamurthy, Sai, Brinkman, André, Pleiter, Dirk, Tate, Adrian, Krueger, Jens, Hoppe, Hans-Christian, Laure, Erwin, Wierse, Andreas, European Technology Platform (ETP) for High-Performance Computing (HPC) (ETP4HPC), IBM Research Lab. - Zürich, TERATEC [Bruyères-le-Chatel], Atos, Jülich Supercomputing Centre (JSC), Forschungszentrum Jülich GmbH | Centre de recherche de Juliers, Helmholtz-Gemeinschaft = Helmholtz Association-Helmholtz-Gemeinschaft = Helmholtz Association, Megware Computer Vertrieb und Service GmbH (Megware), Laboratoire d'Intégration des Systèmes et des Technologies (LIST (CEA)), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Mellanox Technologies [Sunnyvale], Universidad Politécnica de Madrid (UPM), Foundation for Research and Technology - Hellas (FORTH), Scapos AG (SCAPOS), Departament d'Arquitectura de Computadors - Universitat Politècnica de Catalunya (DAC), Universitat Politècnica de Catalunya [Barcelona] (UPC), Scalable Storage for Clouds and Beyond (KerData), Inria Rennes – Bretagne Atlantique, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-SYSTÈMES LARGE ÉCHELLE (IRISA-D1), Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Seagate Technology, Johannes Gutenberg - Universität Mainz = Johannes Gutenberg University (JGU), Helmholtz-Gemeinschaft = Helmholtz Association, Numerical Algorithms Group [New Mexico] (NAG), Fraunhofer (Fraunhofer-Gesellschaft), Intel Corporation [Santa Clara], Intel Corporation [USA], Royal Institute of Technology [Stockholm] (KTH ), SICOS BW [Stuttgart] (SICOS), ETP4HPC: European Technology Platform for High Performance Computing, with the support of the EXDCI-2 project, IBM Systems Development, TERATEC, Philips France Semiconducteurs, C and C Research Laboratories NEC Eur. Ltd., NEC Europe Ltd. [Middlesex], Université de Bretagne Sud (UBS)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National de Recherche en Informatique et en Automatique (Inria)-École normale supérieure - Rennes (ENS Rennes)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-CentraleSupélec-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université de Bretagne Sud (UBS)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-École normale supérieure - Rennes (ENS Rennes)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Johannes Gutenberg - Universität Mainz (JGU), Intel Corporation, Santa Clara CA, SICOS BW (SICOS), and European Technology Platform for High-Performance Computing (ETP4HPC)

Subjects
[INFO.INFO-DC]Computer Science [cs]/Distributed, Parallel, and Cluster Computing [cs.DC]
Abstract

International audience; This Strategic Research Agenda is the fourth High Performance Computing (HPC) technology roadmap developed and maintained by ETP4HPC, the European High-Performance Computing Platform with the support of the EXDCI-2 project. It continues the tradition of a structured approach to the identification of key research objectives. The main objective of this SRA is to identify the European technology research priorities in the area of High-Performance Computing (HPC) and High-Performance Data Analytics (HPDA), which should be used by EuroHPC to build its 2021 – 2024 Work Programme.Over eighty HPC experts associated with member organisations of ETP4HPC created this document in collaboration with external technical leaders representing those areas of technology that together with HPC form what we have come to call “The Digital Continuum”. This new concept well reflects the main trend of this SRA – it is not only about developing HPC technology in order to build competitive European HPC systems but also about making our HPC solutions work together with other related technologies - the material included in this SRA is also a result of our interactions with Big Data, Internet of Things (IoT), and Artificial Intelligence (AI) and Cyber Physical Systems (CPS).

Published
2020

31. Review article: recommended reading list of early publications on atomic layer deposition - outcome of the 'virtual Project on the History of ALD'

Author

Riikka L. Puurunen, Mikhail Chubarov, Tommi Kääriäinen, Cheol Seong Hwang, Çaǧla Özgit-Akgün, Geert Rampelberg, Erwan Rauwel, Rong Chen, Anjana Devi, David Campbell Cameron, Thomas E. Seidel, Jussi Lyytinen, Liliya Elnikova, A. A. Malkov, Markku Leskelä, Georgi Popov, Henrik Pedersen, Tanja Kallio, A. Outi I. Krause, Jaana Kanervo, Jakob Kuhs, Tobias Törndahl, Gloria Gottardi, A. A. Malygin, Nathanaelle Schneider, Fred Roozeboom, Małgorzata Norek, Marja-Leena Kääriäinen, Adam A. Łapicki, Dohan Kim, Irina Kärkkänen, Fabien Piallat, Harri Lipsanen, Esko Ahvenniemi, Oili Ylivaara, Lev Klibanov, Jyrki Molarius, Claudia Wiemer, Shih Hui Jen, J. Ruud van Ommen, Andrew R. Akbashev, Kestutis Grigoras, Dmitry Suyatin, Christian Militzer, Yury Koshtyal, Hele Savin, Jonas Sundqvist, Timo Sajavaara, Luca Lamagna, Véronique Cremers, Stefan Ivanov Boyadjiev, Mikhail Panov, Saima Ali, Oksana Yurkevich, Dennis M. Hausmann, Ivan Khmelnitskiy, Hossein Salami, Viktor Drozd, Mikhael Bechelany, Robin H. A. Ras, Abdelkader Mennad, Maria Berdova, Publica, Institut Européen des membranes (IEM), Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM), University hospital of Zurich [Zurich], Science et Ingénierie des Matériaux et Procédés (SIMaP ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Functional Imaging Unit Glostrup Hospital, Glostrup Hospital, Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information (CEA-LETI), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire de Mathématiques Jean Leray (LMJL), Centre National de la Recherche Scientifique (CNRS)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN), Istituto per la Microelettronica e Microsistemi [Catania] (IMM), Consiglio Nazionale delle Ricerche (CNR), Plasma & Materials Processing, Applied Physics and Science Education, Department of Chemistry, Stanford University, Department of Materials Science and Engineering, Centre National de la Recherche Scientifique (CNRS), University of Twente, Bulgarian Academy of Sciences, Masaryk University, Huazhong University of Science and Technology, Université Grenoble Alpes, Ghent University, Ruhr University Bochum, St. Petersburg State University, Alikhanov Institute for Theoretical and Experimental Physics, Fondazione Bruno Kessler, VTT Technical Research Centre of Finland, Lam Research Corporation, Seoul National University, Global Foundries, Inc., St. Petersburg State Electrotechnical University, Massachusetts Institute of Technology, Techinsights, Ioffe Institute, SENTECH Instruments GmbH, NovaldMedical Ltd Oy, STMicroelectronics, Seagate Technology (Ireland), University of Helsinki, Department of Micro and Nanosciences, St. Petersburg State Institute of Technology, Renewable Energy Development Center, Chemnitz University of Technology, Summa Semiconductor Oy, Military University of Technology Warsaw, ASELSAN Inc., Linköping University, KOBUS, Department of Chemical and Metallurgical Engineering, Department of Applied Physics, Tallinn University of Technology, Netherlands Organisation for Applied Scientific Research, University of Jyväskylä, University of Maryland, College Park, Institut de recherche et développement sur l’énergie photovoltaïque, Seitek50, Fraunhofer Institute for Ceramic Technologies and Systems, Lund University, Uppsala University, Delft University of Technology, National Research Council of Italy, Immanuel Kant Baltic Federal University, Department of Chemistry and Materials Science, Department of Electronics and Nanoengineering, Aalto-yliopisto, Aalto University, Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Centre National de la Recherche Scientifique (CNRS), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), and ANR-11-LABX-0020,LEBESGUE,Centre de Mathématiques Henri Lebesgue : fondements, interactions, applications et Formation(2011)

Subjects
semiconductor manufacturing, Thin films, Patent literature, 2015 Nano Technology, HOL - Holst, Library science, Nanotechnology, 02 engineering and technology, deposition, 01 natural sciences, Poster presentations, Atomic layer deposition, 0103 physical sciences, Atomic layer epitaxy, [CHIM]Chemical Sciences, Reading list, Patents, ComputingMilieux_MISCELLANEOUS, gas-solid reaction, 010302 applied physics, TS - Technical Sciences, Industrial Innovation, inorganic material, Physics, Silica, Surfaces and Interfaces, atomikerroskasvatus, Atomic layer, 021001 nanoscience & nanotechnology, Condensed Matter Physics, history of technology, Surfaces, Coatings and Films, ALD, 0210 nano-technology, Soviet union, Atomic layer epitaxial growth, Epitaxy
Abstract

Atomic layer deposition (ALD), a gas-phase thin film deposition technique based on repeated, self-terminating gas-solid reactions, has become the method of choice in semiconductor manufacturing and many other technological areas for depositing thin conformal inorganic material layers for various applications. ALD has been discovered and developed independently, at least twice, under different names: atomic layer epitaxy (ALE) and molecular layering. ALE, dating back to 1974 in Finland, has been commonly known as the origin of ALD, while work done since the 1960s in the Soviet Union under the name "molecular layering" (and sometimes other names) has remained much less known. The virtual project on the history of ALD (VPHA) is a volunteer-based effort with open participation, set up to make the early days of ALD more transparent. In VPHA, started in July 2013, the target is to list, read and comment on all early ALD academic and patent literature up to 1986. VPHA has resulted in two essays and several presentations at international conferences. This paper, based on a poster presentation at the 16th International Conference on Atomic Layer Deposition in Dublin, Ireland, 2016, presents a recommended reading list of early ALD publications, created collectively by the VPHA participants through voting. The list contains 22 publications from Finland, Japan, Soviet Union, United Kingdom, and United States. Up to now, a balanced overview regarding the early history of ALD has been missing; the current list is an attempt to remedy this deficiency.

Published
2017

32. Mitigating shock of operating HDDs using smart suspensions

Author

Djati Wibowo Djamari, Nader Vahdati, School of Mechanical and Aerospace Engineering, and Seagate Technology International

Subjects
Engineering::Mechanical engineering [DRNTU], Engineering, business.industry, Mechanical engineering, business, Shock (mechanics)
Abstract

Small form factor (1” HDD) and 2.5” hard disk drives are widely used in mobile consumer electronics. Due to their mobile applications, mobile HDDs are susceptible to an environmental shock/ vibration. The shock/ vibration can be very severe that can damage the HDDs and the data stored in it. In this thesis, we propose several different shock/ vibration isolation techniques to reduce the risk of head slap which can happen if the HDD is subjected to a very severe shock. These techniques are compared and documented in this thesis. The core of this thesis is divided into two parts. The first part discusses the techniques to mitigate the shock in 1” HDD, in which we use Seagate ST1 as our case study. The first technique is to use a cantilever beam as an external shock isolator. The technique covers the study of the cantilever beam natural frequency, the cantilever beam damping ratio, and the mechanical properties of the HDD’s mountings; which can reduce the shock input significantly. A Simulink model is first created to help develop the shock isolator. The model is created using mode superposition and reduced mode method. The final design which is created in Simulink – MATLAB® is then compared with a finite element model in ANSYS. Simulation results show that the cantilever beam shock isolator is able to protect the micro HDD from operational shock up to 1000 G’s 0.5 ms and has increased the ST1 shock tolerance by 77%. As a comparison, we have designed another type of external shock isolator for the ST1 using elastomeric materials. The elastomer layers are added beneath the base plate of the ST1 and outside of the ST1 case. The analysis of the elastomeric shock isolator system is done in ANSYS. The results show that the cantilever beam performs better than the elastomeric system to reduce the shock to the HDD. MASTER OF ENGINEERING (MAE)

Published
2019

33. Design-oriented prediction of operational shock and vibration for hard disk drives

Author

Hendri. Harmoko, Nader Vahdati, Yap Fook Fah, School of Mechanical and Aerospace Engineering, Seagate Technology International, and Centre for Mechanics of Micro-Systems

Subjects
Vibration, Engineering::Manufacturing::Product engineering [DRNTU], Engineering, business.industry, Mechanical engineering, Aerospace engineering, business, Shock (mechanics)
Abstract

The hard disk drives have been increasingly used in consumer electronics and mobile computing, in which they may experience severe shock and vibration. Additionally, there is a fierce competition from the solid state drives. Hence, there is a need for rapid innovation, especially in the ever shorter drives design cycle. This in turn requires faster and accurate simulation method. This dissertation focuses on the formulation of an efficient theoretical model for design parametric studies and optimization in modern hard disk drives. It integrates both drive structural model and air bearing model. The structural models are developed using flexible multi body dynamics formulation and state-space mode superposition theory. The air bearing model is developed using finite volume formulation and modified quasi-static concept. The coupled structural and air bearing models can simulate the shock response at drive level and also predict the operational shock tolerance effectively. Hertz elastic contact theory is incorporated to deal with structural discontinuities. A modified state-space formulation is also included to simulate the dynamic air bearing location due to disk rotation. In the analysis of the quasi-static air bearing, it is found that air bearing equilibrium condition does not occur almost-immediately due to the squeeze term effect. Addition of optimized damping elements to quasi-static air bearing model can increase its accuracy and enable it to predict the same air bearing force as the finite volume model. From parametric studies, it is found that lower contact stiffness between suspension (dimple) and slider (flexure) yield higher shock tolerance. A more rigid cover is also found to increase the shock tolerance. Shock response analysis shows that the first-three most dominant actuator modes that affect the read/write head shock response are induced by the flexibility of suspension and flexure. It is also discovered that updating the position on the disk, at which the air bearing forces act, at every simulation time-step does not have significant effect on the shock response. Hence, it is not necessary to update the air bearing force location on the disk. From HDD vibration isolation studies, it can be observed that to survive a harsh shock and random vibration defined in MIL-STD-810E, the natural frequencies of the external vibration isolation system should be between 10 to 20 Hz. The damping ratio required is relatively high (> 10%). To reduce the peak-to-peak displacement during shock event, combination of soft and stiff isolators can be used. DOCTOR OF PHILOSOPHY (MAE)

Published
2019

34. Closed-Circuit Versus Open-Circuit Characterization of Hard Magnets

Author

D. Givord, J. Fliegans, G. Delette, A. N. Dobrynin, Nora M. Dempsey, Laboratoire d'Innovation pour les Technologies des Energies Nouvelles et les nanomatériaux (LITEN), Institut National de L'Energie Solaire (INES), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Seagate Technology, Micro et NanoMagnétisme (NEEL - MNM), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Universidade Federal do Rio de Janeiro (UFRJ), Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and Micro et NanoMagnétisme (MNM )

Subjects
010302 applied physics, Materials science, Condensed matter physics, Magnetometer, Demagnetizing field, Coercivity, Magnetic hysteresis, 01 natural sciences, Electronic, Optical and Magnetic Materials, law.invention, Magnetic circuit, Hysteresis, Magnetization, law, Magnet, 0103 physical sciences, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Electrical and Electronic Engineering, ComputingMilieux_MISCELLANEOUS
Abstract

Two effects must be considered for the purpose of comparing hysteresis loops of hard magnetic materials (e.g., Nd–Fe–B magnets), measured in open circuit (e.g., vibration sample magnetometer or extraction magnetometer) to those measured in closed circuit (i.e., in a hysteresigraph). The first of these is related to the influence of magnetic viscosity during magnetization reversal, which reduces coercivity. Due to longer measurement times with magnetometers compared to hysteresigraphs (typically 100 s versus 1 s), the coercive field is reduced more in open-circuit measurements than in closed-circuit ones, by typically 20 kA/m. The second effect to be considered is due to differences in various contributions to the demagnetizing field. The slope of the magnetization variation in open-circuit loops is different to that due to the usually considered demagnetizing effects (applicable to soft materials). A reduction in the open-circuit coercive field value compared to the closed-circuit one is found, which is of the order of 25 kA/m for the systems discussed here. This is attributed to the fact that the reversal process itself is affected by how the measurement is made. Reversal has less collective character during open-circuit than during closed-circuit measurements.

Published
2019

36. Off-Axis Electron Holography for the Quantitative Study of Magnetic Properties of Nanostructures: From the Single Nanomagnet to the Complex Device

Author

Mark Anthony Gubbins, Christophe Gatel, M. A. Bashir, Thomas Blon, Aurélien Masseboeuf, F. Bonnilla, Joshua F. Einsle, Etienne Snoeck, Robert M. Bowman, Anca Meffre, Lise-Marie Lacroix, Interférométrie, In situ et Instrumentation pour la Microscopie Electronique (CEMES-I3EM), Centre d'élaboration de matériaux et d'études structurales (CEMES), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA), Laboratoire de physique et chimie des nano-objets (LPCNO), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie de Toulouse (ICT-FR 2599), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC), Centre for Nanostructured Media, International Research Centre for Experimental Physics, Queen's University [Belfast] (QUB), Seagate Technology, Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), and Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS]Physics [physics], Nanostructure, Materials science, Nanotechnology, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Nanomagnet, Electron holography, 0104 chemical sciences, 0210 nano-technology, Instrumentation, ComputingMilieux_MISCELLANEOUS
Abstract

Electron holography (EH) is a powerful interferometric TEM method particularly efficient for the quantitative studies of local electrostatic and magnetic fields at the nanoscale over a field of view as large as few microns. We applied this method to study the magnetic properties of two very different systems: single 20 nm Fe nanocubes and a hard-disk drive writer in operando.

Published
2015

37. The effect of FeF2on the magneto-optic response in FeF2/Fe/FeF2sandwiches

Author

Zbigniew Celinski, Jaroslav Vlček, Michal Lesňák, Štefan Višňovský, Radek Lopusnik, Jan Mistrik, Jaromír Pištora, Ian Harward, P Maslankiewicz, Tomuo Yamaguchi, K Balin, Eva Liskova, Institute of Physics, Technical University of Ostrava [Ostrava] (VSB), Charles University [Prague] (CU), Center for Magnetism and Magnetic Nanostructures, University of Colorado [Colorado Springs] (UCCS), August Chełkowski Institute of Physics [University of Silesia], University of Silesia in Katowice, Research Institute of Electronics, University of Shizuoka, Department of Physics, University of Pardubice, Seagate Technology, and Department of Mathematics and Descriptive Geometry [Bratislava]

Subjects
Acoustics and Ultrasonics, Magnetic domain, Chemistry, Analytical chemistry, 02 engineering and technology, Substrate (electronics), Photon energy, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Spectral line, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Magnetization, Nuclear magnetic resonance, Ellipsometry, Physical Sciences, 0103 physical sciences, 010306 general physics, 0210 nano-technology, Spectroscopy, Molecular beam epitaxy
Abstract

International audience; The room temperature optical constants n and k of MBE grown FeF 2 films are reported. Because of poor chemical stability, FeF 2 had to be coated with a protective Au layer. Reflection spectral ellipsometry in the photon energy range between 1.3 and 5.2 eV was performed on structures with a typical profile Au(0.5 nm)/FeF 2 (120 nm)/Au(30 nm) /Ag(20 nm) /Fe(0.6 nm) grown on GaAs(001) substrate. The spectra of n and k in FeF 2 were subsequently employed in the design of FeF 2 /Fe/FeF 2 sandwiches considered as magneto-optic (MO) sensors for weak microwave currents. Their MO response was evaluated using reflection MO (Kerr) spectroscopy at polar magnetization. The present results may be of interest in MO studies of magnetic nanostructures with Fe/FeF 2 /Fe, including MO magnetometry and MO magnetic domain imaging.

Published
2010

38. Temperature dependence of spin transport behavior in Heusler alloy CPP-GMR.

Author

Saenphum N, Khamtawi R, Chureemart J, Chantrell RW, and Chureemart P

Abstract

In this study, we investigate the effect of temperature on the performance of a read sensor by utilizing an atomistic model coupled with a spin transport model. Specifically, we study the temperature dependence of spin transport behavior and MR outputs in a Co 2 FeAl 0.5 Si 0.5 (CFAS)(5nm)/Cu(5nm)/CFAS(5nm) trilayer with diffusive interfaces. Initially, the two-channel model of spin-dependent resistivity is used to calculate the temperature dependence of spin transport parameters which serves as essential input for the spin accumulation model. Our findings demonstrate that as the temperature increases, the spin transport parameters and magnetic properties decrease due to the influence of thermal fluctuation. At a critical temperature, where the ferromagnet transitions to a paramagnetic state, we observe zero spin polarization. Furthermore, at elevated temperatures, the spin accumulation deviates from the equilibrium value, leading to a reduction in the magnitude of spin current and spin transport parameters due to thermal effects. As a consequence, the MR ratio decreases from 65% to 20% with increasing temperature from 0 to 400 K. Our results are consistent with previous experimental measurements. This study allows to deeply understand the physical mechanism in the reader stack which can significantly benefit reader design., (© 2024. The Author(s).)

Published
2024
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39. Magnetic droplet soliton pairs.

Author

Jiang S, Chung S, Ahlberg M, Frisk A, Khymyn R, Le QT, Mazraati H, Houshang A, Heinonen O, and Åkerman J

Abstract

We demonstrate magnetic droplet soliton pairs in all-perpendicular spin-torque nano-oscillators (STNOs), where one droplet resides in the STNO free layer (FL) and the other in the reference layer (RL). Typically, theoretical, numerical, and experimental droplet studies have focused on the FL, with any additional dynamics in the RL entirely ignored. Here we show that there is not only significant magnetodynamics in the RL, but the RL itself can host a droplet driven by, and coexisting with, the FL droplet. Both single droplets and pairs are observed experimentally as stepwise changes and sharp peaks in the dc and differential resistance, respectively. While the single FL droplet is highly stable, the coexistence state exhibits high-power broadband microwave noise. Furthermore, micromagnetic simulations reveal that the pair dynamics display periodic, quasi-periodic, and chaotic signatures controlled by applied field and current. The strongly interacting and closely spaced droplet pair offers a unique platform for fundamental studies of highly non-linear soliton pair dynamics., (© 2024. The Author(s).)

Published
2024
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40. Soft-Sensing Regression Model: From Sensor to Wafer Metrology Forecasting.

Author

Fan A, Huang Y, Xu F, and Bom S

Abstract

The semiconductor industry is one of the most technology-evolving and capital-intensive market sectors. Effective inspection and metrology are necessary to improve product yield, increase product quality and reduce costs. In recent years, many types of semiconductor manufacturing equipments have been equipped with sensors to facilitate real-time monitoring of the production processes. These production-state and equipment-state sensor data provide an opportunity to practice machine-learning technologies in various domains, such as anomaly/fault detection, maintenance scheduling, quality prediction, etc. In this work, we focus on the soft-sensing regression problem in metrology systems, which uses sensor data collected during wafer processing steps to predict impending inspection measurements that used to be measured in wafer inspection and metrology systems. We proposed a regressor based on Long Short-term Memory network and devised two distinct loss functions for the purpose of the training model. Although the assessment of our prediction errors by engineers is subjective, a novel piece-wise evaluation metric was introduced to evaluate model accuracy in a mathematical way. Our experimental results showcased that the proposed model is capable of achieving both accurate and early prediction across various types of inspections in complicated manufacturing processes.

Published
2023
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41. Nonlinear multi-magnon scattering in artificial spin ice.

Author

Lendinez S, Kaffash MT, Heinonen OG, Gliga S, Iacocca E, and Jungfleisch MB

Subjects
Microwaves, Nephelometry and Turbidimetry, Magnetic Phenomena, Ice, Nanostructures
Abstract

Magnons, the quantum-mechanical fundamental excitations of magnetic solids, are bosons whose number does not need to be conserved in scattering processes. Microwave-induced parametric magnon processes, often called Suhl instabilities, have been believed to occur in magnetic thin films only, where quasi-continuous magnon bands exist. Here, we reveal the existence of such nonlinear magnon-magnon scattering processes and their coherence in ensembles of magnetic nanostructures known as artificial spin ice. We find that these systems exhibit effective scattering processes akin to those observed in continuous magnetic thin films. We utilize a combined microwave and microfocused Brillouin light scattering measurement approach to investigate the evolution of their modes. Scattering events occur between resonance frequencies that are determined by each nanomagnet's mode volume and profile. Comparison with numerical simulations reveals that frequency doubling is enabled by exciting a subset of nanomagnets that, in turn, act as nanosized antennas, an effect that is akin to scattering in continuous films. Moreover, our results suggest that tunable directional scattering is possible in these structures., (© 2023. The Author(s).)

Published
2023
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42. Self-consistent computation of spin torques and magneto-resistance in tunnel junctions and magnetic read-heads with metallic pinhole defects.

Author

Lepadatu S and Dobrynin A

Abstract

A three-dimensional self-consistent spin transport model is developed, which includes both tunnelling transport, leading to tunnelling magneto-resistance, as well as metallic transport, leading to giant magneto-resistance. An explicit solution to the drift-diffusion model is also derived, which allows analysing the effect of both the reference and free layer thickness on the spin-transfer torque polarization and field-like coefficient. It is shown the model developed here can be used to compute the signal-to-noise ratio in realistic magnetic read-heads, where spin torque-induced fluctuations and instabilities limit the maximum operating voltage. The effect of metallic pinhole defects in the insulator layer is also analysed. Increasing the area covered by pinholes results in a rapid degradation of the magneto-resistance, following an inverse dependence. Moreover, the spin torque angular dependence becomes skewed, similar to that obtained in fully metallic spin valves, and the spin-transfer torque polarization decreases. The same results are obtained when considering tunnel junctions with a single pinhole defect, but decreasing cross-sectional area, showing that even a single pinhole defect can significantly degrade the performance of tunnel junctions and magnetic read-heads below the 40 nm node., (© 2023 IOP Publishing Ltd.)

Published
2023
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43. Conventional and Microcellular Injection Molding of a Highly Filled Polycarbonate Composite with Glass Fibers and Carbon Black.

Author

Yilmaz G, Devahastin A, and Turng LS

Abstract

Conventional solid injection molding (CIM) and microcellular injection molding (MIM) of a highly filled polycarbonate (PC) composite with glass fibers and carbon black were performed for molding ASTM tensile test bars and a box-shape part with variable wall thickness. A scanning electron microscope (SEM) was used to examine the microstructure at the fractured surface of the tensile test bar samples. The fine and uniform cellular structure suggests that the PC composite is a suitable material for foaming applications. Standard tensile tests showed that, while the ultimate strength and elongation at break were lower for the foamed test bars at 4.0-11.4% weight reduction, their specific Young's modulus was comparable to that of their solid counterparts. A melt flow and transition model was proposed to explain the unique, irregular "tiger-stripes" exhibited on the surface of solid test bars. Increasing the supercritical fluid (SCF) dosage and weight reduction of foamed samples resulted in swirl marks on the part surface, making the tiger-stripes less noticeable. Finally, it was found that an injection pressure reduction of 25.8% could be achieved with MIM for molding a complex box-shaped part in a consistent and reliable fashion.

Published
2022
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44. Micromagnetic Simulation of L 1 0 -FePt-Based Exchange-Coupled-Composite-Bit-Patterned Media with Microwave-Assisted Magnetic Recording at Ultrahigh Areal Density.

Author

Khunkitti P, Wannawong N, Jongjaihan C, Siritaratiwat A, Kruesubthaworn A, and Kaewrawang A

Abstract

In this work, we propose exchange-coupled-composite-bit-patterned media (ECC-BPM) with microwave-assisted magnetic recording (MAMR) to improve the writability of the magnetic media at a 4 Tb/in 2 recording density. The suitable values of the applied microwave field's frequency and the exchange coupling between magnetic dots, A dot , of the proposed media were evaluated. It was found that the magnitude of the switching field, H sw , of the bilayer ECC-BPM is significantly lower than that of a conventional BPM. Additionally, using the MAMR enables further reduction of H sw of the ECC-BPM. The suitable frequency of the applied microwave field for the proposed media is 5 GHz. The dependence of A dot on the H sw was additionally examined, showing that the A dot of 0.14 pJ/m is the most suitable value for the proposed bilayer ECC-BPM. The physical explanation of the H sw of the media under a variation of MAMR and A dot was given. Hysteresis loops and the magnetic domain of the media were characterized to provide further details on the results. The lowest H sw found in our proposed media is 12.2 kOe, achieved by the bilayer ECC-BPM with an A dot of 0.14 pJ/m using a 5 GHz MAMR.

Published
2021
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45. Current-induced crystallisation in Heusler alloy films for memory potentiation in neuromorphic computation.

Author

Frost W, Elphick K, Samiepour M, and Hirohata A

Abstract

The current information technology has been developed based on von Neumann type computation. In order to sustain the rate of development, it is essential to investigate alternative technologies. In a next-generation computation, an important feature is memory potentiation, which has been overlooked to date. In this study, potentiation functionality is demonstrated in a giant magnetoresistive (GMR) junction consisting of a half-metallic Heusler alloy which can be a candidate of an artificial synapse while still achieving a low resistance-area product for low power consumption. Here the Heusler alloy films are grown on a (110) surface to promote layer-by-layer growth to reduce their crystallisation energy, which is comparable with Joule heating induced by a controlled current introduction. The current-induced crystallisation leads to the reduction in the corresponding resistivity, which acts as memory potentiation for an artificial GMR synaptic junction., (© 2021. The Author(s).)

Published
2021
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46. Free Layer Thickness Dependence of the Stability in Co 2 (Mn 0.6 Fe 0.4 )Ge Heusler Based CPP-GMR Read Sensor for Areal Density of 1 Tb/in 2 .

Author

Khunkitti P, Siritaratiwat A, and Pituso K

Abstract

Current-perpendicular-to-the-plane giant magnetoresistance (CPP-GMR) read sensors based on Heusler alloys are promising candidates for ultrahigh areal densities of magnetic data storage technology. In particular, the thickness of reader structures is one of the key factors for the development of practical CPP-GMR sensors. In this research, we studied the dependence of the free layer thickness on the stability of the Co 2 (Mn 0.6 Fe 0.4 )Ge Heusler-based CPP-GMR read head for an areal density of 1 Tb/in 2 , aiming to determine the appropriate layer thickness. The evaluations were done through simulations based on micromagnetic modelling. The reader stability indicators, including the magnetoresistance (MR) ratio, readback signal, dibit response asymmetry parameter, and power spectral density profile, were characterized and discussed. Our analysis demonstrates that the reader with a free layer thickness of 3 nm indicates the best stability performance for this particular head. A reasonably large MR ratio of 26% was obtained by the reader having this suitable layer thickness. The findings can be utilized to improve the design of the CPP-GMR reader for use in ultrahigh magnetic recording densities.

Published
2021
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47. Large and Local Magnetoresistance in a State-of-the-Art Perpendicular Magnetic Medium.

Author

Williamson M, Wang C, Huang PW, Ju G, and Tsoi M

Abstract

Purpose: Magnetotransport properties of granular oxide-segregated CoPtCr films were studied on both macroscopic and microscopic length scales by performing bulk and point-contact magnetoresistance measurements, respectively. Such a perpendicular magnetic medium is used in state-of-the-art hard disc drives and, when combined with magnetotransport phenomena for read/write operations, may lead to a novel concept for magnetic recording with high areal density., Materials and Methods: The CoPtCr films were deposited by an epitaxy-like sputtering and contained several perpendicularly magnetized granular-media layers with different coercivities; they are very much like the state-of-the-art perpendicular magnetic medium, which can be found in today's hard disc drives. Magnetoresistive properties of bulk films were assessed by measuring the film resistance in the standard Van der Pauw geometry, while the local transport was probed by the point-contact technique., Results: The bulk measurements showed only a negligible magnetoresistance of less than 0.02%. In contrast, the local point-contact measurements revealed giant-magnetoresistance-like changes Δ R in local resistance of the contact R with more than 10,000% ratio Δ R/R ., Conclusion: The observed large and local magnetoresistive effect could be tentatively attributed to a tunnel magnetoresistance between oxide-segregated CoPtCr grains with different coercivities. The tunneling picture of electronic transport in our granular medium was confirmed by the observation of tunneling-like current-voltage characteristics of the contacts and bias dependence of the contact magnetoresistance - both the local point-contact resistance and magnetoresistance were found to decrease with the applied dc bias., Competing Interests: The authors report no conflicts of interest in conducting this work., (© 2021 Williamson et al.)

Published
2021
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48. Facile decoding of quantitative signatures from magnetic nanowire arrays.

Author

Zamani Kouhpanji MR, Ghoreyshi A, Visscher PB, and Stadler BJH

Abstract

Magnetic nanoparticles have been proposed as contact-free minimal-background nanobarcodes, and yet it has been difficult to rapidly and reliably decode them in an assembly. Here, high aspect ratio nanoparticles, or magnetic nanowires (MNWs), are characterized using first-order reversal curves (FORC) to investigate quantitative decoding. We have synthesized four types of nanowires (differing in diameter) that might be used for barcoding, and identified four possible "signature" functions that might be used to quickly distinguish them. To test this, we have measured the signatures of several combination samples containing two or four different MNW types, and fit them to linear combinations of the individual type signatures to determine the volume ratios of the types. We find that the signature which determines the ratios most accurately involves only the slope of each FORC at its reversal field, which requires only 2-4 data points per FORC curve, reducing the measurement time by a factor of 10 to 50 compared to measuring the full FORC.

Published
2020
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49. Optical Photothermal Infrared Microspectroscopy with Simultaneous Raman - A New Non-Contact Failure Analysis Technique for Identification of <10 μm Organic Contamination in the Hard Drive and other Electronics Industries.

Author

Kansiz M, Prater C, Dillon E, Lo M, Anderson J, Marcott C, Demissie A, Chen Y, and Kunkel G

Abstract

Optical Photothermal Infrared (O-PTIR) spectroscopy is a new technique for measuring submicron spatial resolution IR spectra with little or no sample preparation. This speeds up analysis times benefiting high-volume manufacturers through gaining insight into process contamination that occurs during development and on production lines. The ability to rapidly obtain far-field non-contact IR spectra at high spatial resolution facilitates the chemical identification of small organic contaminants that are not possible to measure with conventional Fourier transform infrared (FT-IR) microspectroscopy. The unique pump-probe system architecture also facilitates submicron simultaneous IR + Raman microscopy from the same spot with the same spatial resolution. With these unique capabilities, O-PTIR is finding utilization in the high-volume and high-value industries of high-tech componentry (memory storage, electronics, displays, etc.).

Published
2020
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50. Assessing the Oxidative Degradation of N-Methylpyrrolidone (NMP) in Microelectronic Fabrication Processes by Using a Multiplatform Analytical Approach.

Author

Lennon G, Willox S, Ramdas R, Funston SJ, Klun M, Pieh R, Fairlie S, Dobbin S, and Cobice DF

Abstract

During the construction of recording head devices, corrosion of metal features and subsequent deposition of corrosion by-products have been observed. Previous studies have determined that the use of N-methylpyrrolidone (NMP) may be a contributing factor. In this study, we report the use of a novel multiplatform analytical approach comprising of pH, liquid chromatography/UV detection (LC/UV), inductively coupled plasma optical emission spectroscopy (ICP-OES), and LC/mass spectrometry (LC/MS) to demonstrate that reaction conditions mimicking those of general photoresist removal processes can invoke the oxidation of NMP during the photolithography lift-off process. For the first time, we have confirmed that the oxidation of NMP lowers the pH, facilitating the dissolution of transition metals deposited on wafer substrates during post-mask and pre-lift-off processes in microelectronic fabrication. This negatively impacts upon the performance of the microelectronic device. Furthermore, it was shown that, by performing the process in an inert atmosphere, the oxidation of NMP was suppressed and the pH was stabilized, suggesting an affordable modification of the photolithography lift-off stage to enhance the quality of recording heads. This novel study has provided key data that may have a significant impact on current and future fabrication process design, optimization, and control. Results here suggest the inclusion of pH as a key process input variable (KPIV) during the design of new photoresist removal processes., Competing Interests: All authors have declared no conflicts of interest., (Copyright © 2020 Gavin Lennon et al.)

Published
2020
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