New Approaches in Optical Lithography Technology for Subwavelength Resolution

New Approaches in Optical Lithography Technology for Subwavelength Resolution PDF Author: Hoyoung Kang
Publisher:
ISBN:
Category : Extreme ultraviolet lithography
Languages : en
Pages : 204

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Book Description
"Advances in the semiconductor industry are mainly driven by improvements in optical lithography technology, which have enabled the continual shrinking of integrated circuit devices. However, optical lithography technology is approaching its limit, and within ten years, it may be substituted by new non-optical approaches. These may include Extreme Ultra Violet (EUV) lithography and charged particle beam projection lithography. While these technologies may have potentially better resolution, they can be very difficult to implement into manufacturing. During the course of the research presented here, the extension of optical lithography to sub 70nm resolution has been investigated. Since optical lithography is mature and well understood, extending it to allow for higher resolution can dramatically reduce manufacturing difficulties, compared to EUV or charged particle beam projection lithography. A majority of the existing infrastructure, such as photoresist materials, sources, optics, and photo-masks, remain applicable with the optical methods explored here. The avenues investigated in this research have concentrated on spatial frequency filtering in alternative Fourier Transform planes, vacuum UV wavelength lithography, and achieving ultra high numerical aperture imaging through the use of liquid immersion imaging. More specifically, novel spatial frequency filtering using angular transmission filters was developed and demonstrated. Multiple filter designs were proposed, one of which was successfully fabricated and implemented for lithographic imaging. Spatial filtering, using angular transmission filtering, proved to enhance the resolution of contact hole images by approximately 20%. Vacuum UV imaging at the 126nm wavelength was carried out but deemed likely to be less practical for commercial viability due to source, optics, and materials issues. Immersion lithography, using the 193nm wavelength ArF excimer laser, was investigated and demonstrated for very high numerical aperture imaging. Requirements for immersion lithography were established, including the necessary design of imaging fluids, optics, sources, and photoresist materials. As a development tool, an interference lithography system was built using the 193nm ArF excimer laser and water as an immersion fluid. Patterns below 70nm were printed using the process developed, which has established the potential to extend optical lithography further than was believed at the onset of this project. This research provides proof of the concept of extending optical lithography to the 70nm generation and below"--Abstract.

New Approaches in Optical Lithography Technology for Subwavelength Resolution

New Approaches in Optical Lithography Technology for Subwavelength Resolution PDF Author: Hoyoung Kang
Publisher:
ISBN:
Category : Extreme ultraviolet lithography
Languages : en
Pages : 204

Get Book Here

Book Description
"Advances in the semiconductor industry are mainly driven by improvements in optical lithography technology, which have enabled the continual shrinking of integrated circuit devices. However, optical lithography technology is approaching its limit, and within ten years, it may be substituted by new non-optical approaches. These may include Extreme Ultra Violet (EUV) lithography and charged particle beam projection lithography. While these technologies may have potentially better resolution, they can be very difficult to implement into manufacturing. During the course of the research presented here, the extension of optical lithography to sub 70nm resolution has been investigated. Since optical lithography is mature and well understood, extending it to allow for higher resolution can dramatically reduce manufacturing difficulties, compared to EUV or charged particle beam projection lithography. A majority of the existing infrastructure, such as photoresist materials, sources, optics, and photo-masks, remain applicable with the optical methods explored here. The avenues investigated in this research have concentrated on spatial frequency filtering in alternative Fourier Transform planes, vacuum UV wavelength lithography, and achieving ultra high numerical aperture imaging through the use of liquid immersion imaging. More specifically, novel spatial frequency filtering using angular transmission filters was developed and demonstrated. Multiple filter designs were proposed, one of which was successfully fabricated and implemented for lithographic imaging. Spatial filtering, using angular transmission filtering, proved to enhance the resolution of contact hole images by approximately 20%. Vacuum UV imaging at the 126nm wavelength was carried out but deemed likely to be less practical for commercial viability due to source, optics, and materials issues. Immersion lithography, using the 193nm wavelength ArF excimer laser, was investigated and demonstrated for very high numerical aperture imaging. Requirements for immersion lithography were established, including the necessary design of imaging fluids, optics, sources, and photoresist materials. As a development tool, an interference lithography system was built using the 193nm ArF excimer laser and water as an immersion fluid. Patterns below 70nm were printed using the process developed, which has established the potential to extend optical lithography further than was believed at the onset of this project. This research provides proof of the concept of extending optical lithography to the 70nm generation and below"--Abstract.

Optimization of Resolution Enhancement Techniques in Optical Lithography

Optimization of Resolution Enhancement Techniques in Optical Lithography PDF Author:
Publisher:
ISBN: 9781109386677
Category : Imaging systems
Languages : en
Pages :

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Book Description
As todays' semiconductor fabrication industry tries to keep up with Moore's Law, which predicts the downscaling of integrated circuit size and the doubling of transistor counts every two years, resolution enhancement techniques (RET) play a much more important role than anytime in the past. Optical proximity correction (OPC), phase shifting mask (PSM), and off-axis illumination (OAI) are RETs used extensively in the semiconductor industry to improve the resolution and pattern fidelity of optical lithography. Preserving the fidelity of the circuit patterns is important for preserving the performance predicted in the design stage of the integrated circuit (IC). Typical circuit patterns exhibit regular geometries, such as lines, L-joint, U-joint and so on. These regular geometries reduce the resistances between nodes and simplify the process of routing. In the past decades, a variety of OPC, PSM and illumination design approaches have been proposed in the literature. In general, these approaches are divided into two subsets: rule-based and model-based approaches. This dissertation focuses on the study and development of model-based OPC, PSM and illumination optimization approaches for both coherent imaging systems and partially coherent imaging systems. For coherent imaging systems, we develop generalized gradient-based RET optimization methods to solve for the inverse lithography problem, where the search space is not constrained to a finite phase tessellation but where arbitrary search trajectories in the complex space are allowed. Subsequent mask quantization leads to efficient design of PSMs having an arbitrary number of discrete phases. In order to influence the solution patterns to have more desirable manufacturability properties, a wavelet regularization framework is introduced offering more localized flexibility than total-variation regularization methods traditionally employed in inverse problems. The algorithms provide highly effective four-phase PSMs capable of generating mask patterns with arbitrary Manhattan geometries. Furthermore, a double-patterning optimization method for generalized inverse lithography is developed where each patterning uses an optimized two-phase mask. These algorithms are computationally efficient, however, they focused on coherent illumination systems. Most practical illumination sources have a nonzero line width and their radiation is more generally described as partially coherent. Partially coherent illumination (PCI) is desired, since it can improve the theoretical resolution limit. PCI is thus introduced in practice through modified illumination sources having large coherent factors or through off-axis illumination. In partially coherent imaging, the mask is illuminated by light travelling in various directions. The source points giving rise to these incident rays are incoherent with one another, such that there is no interference that could lead to nonuniform light intensity impinging on the mask. The gradient-based inverse lithography optimization methods derived under the coherent illumination assumption fail to account for the nonlinearities of partially coherent illumination and thus perform poorly in the partially coherent scenario. For partially coherent imaging systems with inherent nonlinearities, the sum of coherent systems (SOCS) model and the average coherent approximation model are applied to develop effective and computationally efficient OPC optimization algorithms for inverse lithography. Wavelet regularization is added to the optimization framework to reduce the complexity of the optimized masks. Subsequently, a Singular Value Decomposition (SVD) model is used to develop computationally efficient PSM optimization algorithms for inverse lithography. A novel DCT post-processing is proposed to cut off the high frequency components in the optimized PSMs and keep the fabricating simplicity. Furthermore, a photoresist tone reversing technique is exploited in the design of PSMs to project extremely sparse patterns. As traditional RETs, the above mentioned gradient-based inverse OPC and PSM optimization methods fix the source thus limiting the degrees of freedom during the optimization of the mask patterns. To overcome this restriction, computationally efficient, pixel-based, simultaneous source mask optimization (SMO) methods for both OPC and PSM designs are developed in this dissertation. The synergy is exploited in the joint optimization of source and mask patterns. The resulting source and mask patterns fall well outside the realm of known design forms. In these SMO algorithms, the Fourier series expansion model is applied to approximate the partially coherent system as a sum of coherent systems. Cost sensitivity is used to drive the output pattern error in the descent direction. In order to influence the solution patterns to have more desirable manufacturability properties, topological constraints are added to the optimization framework. Several illustrative simulations are presented to demonstrate the effectiveness of the proposed algorithms. The above gradient-based inverse lithography optimization approaches are effective and computationally efficient under the thin-mask assumption, where the mask is considered as a 2-D object. As the critical dimension (CD) printed on the wafer shrinks into the subwavelength regime, the thick-mask effects become prevalent and thus these effects must be taken into account. Thus, OPC and PSM methods derived under the thin-mask assumption have the inherent limitations and perform poorly in the subwavelength scenario. In order to overcome this limitation, the final contribution of this dissertation focuses on developing OPC and PSM optimization methods based on the boundary layer (BL) model to take into account the thick-mask effects. Attributed to the nonlinear properties of the BL model, model-based forward lithography methods are exploited to obtain the optimized binary and phase-shifting masks. The advantages and limitations of the proposed algorithm are discussed and several illustrative simulations are presented.

Computational Lithography

Computational Lithography PDF Author: Xu Ma
Publisher: John Wiley & Sons
ISBN: 111804357X
Category : Technology & Engineering
Languages : en
Pages : 225

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Book Description
A Unified Summary of the Models and Optimization Methods Used in Computational Lithography Optical lithography is one of the most challenging areas of current integrated circuit manufacturing technology. The semiconductor industry is relying more on resolution enhancement techniques (RETs), since their implementation does not require significant changes in fabrication infrastructure. Computational Lithography is the first book to address the computational optimization of RETs in optical lithography, providing an in-depth discussion of optimal optical proximity correction (OPC), phase shifting mask (PSM), and off-axis illumination (OAI) RET tools that use model-based mathematical optimization approaches. The book starts with an introduction to optical lithography systems, electric magnetic field principles, and the fundamentals of optimization from a mathematical point of view. It goes on to describe in detail different types of optimization algorithms to implement RETs. Most of the algorithms developed are based on the application of the OPC, PSM, and OAI approaches and their combinations. Algorithms for coherent illumination as well as partially coherent illumination systems are described, and numerous simulations are offered to illustrate the effectiveness of the algorithms. In addition, mathematical derivations of all optimization frameworks are presented. The accompanying MATLAB® software files for all the RET methods described in the book make it easy for readers to run and investigate the codes in order to understand and apply the optimization algorithms, as well as to design a set of optimal lithography masks. The codes may also be used by readers for their research and development activities in their academic or industrial organizations. An accompanying MATLAB® software guide is also included. An accompanying MATLAB® software guide is included, and readers can download the software to use with the guide at ftp://ftp.wiley.com/public/sci_tech_med/computational_lithography. Tailored for both entry-level and experienced readers, Computational Lithography is meant for faculty, graduate students, and researchers, as well as scientists and engineers in industrial organizations whose research or career field is semiconductor IC fabrication, optical lithography, and RETs. Computational lithography draws from the rich theory of inverse problems, optics, optimization, and computational imaging; as such, the book is also directed to researchers and practitioners in these fields.

Subwavelength Optics Theory and Technology

Subwavelength Optics Theory and Technology PDF Author: Yongqi Fu
Publisher: Bentham Science Publishers
ISBN: 1608050505
Category : Science
Languages : en
Pages : 214

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Book Description
"From the beginning of this century, there has been a dramatic increase in interest in the study of surface plasmon polaritons-based metallic subwavelength structures and learning. This is a refreshing concise book on issues and considerations in designing"

Nanoengineering

Nanoengineering PDF Author: Michael Berger
Publisher: Royal Society of Chemistry
ISBN: 1839160411
Category : Technology & Engineering
Languages : en
Pages : 348

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Book Description
While our five senses are doing a reasonably good job at representing the world around us on a macro-scale, we have no existing intuitive representation of the nanoworld, ruled by laws entirely foreign to our experience. This is where molecules mingle to create proteins; where you wouldn't recognize water as a liquid; and where minute morphological changes would reveal how much 'solid' things, such as the ground or houses, are constantly vibrating and moving. Following in the footsteps of Nano-Society and Nanotechnology: The Future is Tiny, this title introduces a new collection of stories demonstrating recent research in the field of nanotechnology. This drives home the fact that a plethora of nanotechnology R&D will become an integral part of improved and entirely novel materials, products, and applications yet will remain entirely invisible to the user. The book gives a personal perspective on how nanotechnologies are created and developed, and will appeal to anyone who has an interest in the research and future of nanotechnology. Reviews of Nanotechnology: The Future is Tiny: 'The book is recommended not only to all interested scientists, but also to students who are looking for a quick and clear introduction to various research areas of nanotechnology' Angew. Chem., 2017, 56(26), 7351–7351 'Once you start reading you will find it very difficult to stop' Chromatographia, 2017, 80, 1821

New Directions in Thin Film Nanophotonics

New Directions in Thin Film Nanophotonics PDF Author: Sreekanth K. V.
Publisher: Springer
ISBN: 9811388911
Category : Science
Languages : en
Pages : 172

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Book Description
This book highlights recent advances in thin-film photonics, particularly as building blocks of metamaterials and metasurfaces. Recent advances in nanophotonics has demonstrated remarkable control over the electromagnetic field by tailoring the optical properties of materials at the subwavelength scale which results in the emergence of metamaterials and metasurfaces. However, most of the proposed platforms require intense lithography which makes them of minor practical relevance. Stacked ultrathin-films of dielectrics, semi-conductors, and metals are introduced as an alternative platform that perform unique or similar functionalities. This book discusses the new era of thin film photonics and its potential applications in perfect and selective light absorption, structural coloring, biosensing, enhanced spontaneous emission, reconfigurable photonic devices and super lensing.​

Engineering Optics 2.0

Engineering Optics 2.0 PDF Author: Xiangang Luo
Publisher: Springer
ISBN: 9811357552
Category : Technology & Engineering
Languages : en
Pages : 690

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Book Description
This book provides comprehensive information on the history and status quo of a new research field, which we refer to as Engineering Optics 2.0. The content covers both the theoretical basis and the engineering aspects in connection with various applications. The field of Engineering Optics employs optical theories to practical applications in a broad range of areas. However, the foundation of traditional Engineering Optics was formed several hundred years ago, and the field has developed only very gradually. With technological innovations in both the fabrication and characterization of microstructures, the past few decades have witnessed many groundbreaking changes to the bases of optics, including the generalizing of refraction, reflection, diffraction, radiation and absorption theories. These new theories enable us to break through the barriers in traditional optical technologies, yielding revolutionary advances in traditional optical systems such as microscopes, telescopes and lithography systems.

Nanolithography

Nanolithography PDF Author: M Feldman
Publisher: Woodhead Publishing
ISBN: 0857098756
Category : Technology & Engineering
Languages : en
Pages : 599

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Book Description
Integrated circuits, and devices fabricated using the techniques developed for integrated circuits, have steadily gotten smaller, more complex, and more powerful. The rate of shrinking is astonishing – some components are now just a few dozen atoms wide. This book attempts to answer the questions, “What comes next? and “How do we get there? Nanolithography outlines the present state of the art in lithographic techniques, including optical projection in both deep and extreme ultraviolet, electron and ion beams, and imprinting. Special attention is paid to related issues, such as the resists used in lithography, the masks (or lack thereof), the metrology needed for nano-features, modeling, and the limitations caused by feature edge roughness. In addition emerging technologies are described, including the directed assembly of wafer features, nanostructures and devices, nano-photonics, and nano-fluidics. This book is intended as a guide to the researcher new to this field, reading related journals or facing the complexities of a technical conference. Its goal is to give enough background information to enable such a researcher to understand, and appreciate, new developments in nanolithography, and to go on to make advances of his/her own. Outlines the current state of the art in alternative nanolithography technologies in order to cope with the future reduction in size of semiconductor chips to nanoscale dimensions Covers lithographic techniques, including optical projection, extreme ultraviolet (EUV), nanoimprint, electron beam and ion beam lithography Describes the emerging applications of nanolithography in nanoelectronics, nanophotonics and microfluidics

Annual Symposium on Photomask Technology

Annual Symposium on Photomask Technology PDF Author:
Publisher:
ISBN:
Category : Integrated circuits
Languages : en
Pages : 606

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Book Description


Japanese Journal of Applied Physics

Japanese Journal of Applied Physics PDF Author:
Publisher:
ISBN:
Category : Physics
Languages : en
Pages : 860

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Book Description