Course #05

Advanced Lithography Technologies: Fundamentals and Applications

October 18-22, 2010. Dresden, Germany

INSTRUCTORS
Dr Roel Gronheid, IMEC, Leuven, Belgium
Dr  Stéfan Landis,  CEA/LETI, Grenoble, France.
Professor Stella W. Pang, University of Michigan, Ann Arbor, USA
Dr  Hans C. Pfeiffer, E-Beam Consulting Services, Monterey, CA, USA

TECHNOLOGY FOCUS 
The explosive growth in the capability of semiconductor devices has to a large extent been due to advances in lithography. Miniaturization has enabled both the number of transistors on a chip and the speed of the transistor to be increased by orders of magnitude. At the same time, one has managed to reduce the power per transistor so that the chips do not overheat. This trend still continues uninterrupted. Sustaining Moore’s Law requires continuous advancements in lithographic resolution. 

Mainstream optical lithography has kept pace with this evolution for several decades and has always been the workhorse for patterning the critical layers in semiconductor applications. However, the physical limits of optical lithography are coming closer and alternative (non-optical) lithography technologies are expected to take over at some point in time. Besides semiconductors, non-semiconductor nano- and micro-technologies, e.g. MEMS, sensors, magnetic storage media, are emerging and will eventually find their 
place in volume markets as well. The lithography requirements for these technologies are often totally different from the semiconductor requirements. As a consequence other types of lithography may be preferred for these applications. The ability to replicate patterns from micro-scale to nano-scale is of crucial importance to the advance of micro- and nano-technologies and the study of nano sciences. 

COURSE CONTENT 
The goal of this course is to give a broad overview of various micro- and nanolithography technologies that are being used or considered for semiconductor and non-semiconductor 
applications. For each technology, the strong and weak points and typical applications will be treated. For all mask based lithographies, the status and challenges for mask (template) manufacturing will be discussed. 

WHO SHOULD ATTEND 
This course is intended for engineers who are active in the field of lithography or have to take strategic decisions on lithography for their company. It will form the basis for a 
better fundamental understanding of the capabilities and limitations of each type of lithography, and may also suggest better, cheaper or alternative lithography technologies 
to be considered for their applications. 

Monday – ROEL GRONHEID 

ADVANCED OPTICAL LITHOGRAPHY 

State-of-the-Art Lithography 

• The Continuous Trend of Miniaturization in Integrated 
  Circuit Manufacturing. ITRS Roadmap
• The Importance of Lithography as Enabling Technology 
• Evolution of the Exposure Tools Towards Advanced Step and Scan Systems 

• The Principle of Image Formation in the Optical Lithography Process
• Formation of Aerial Image by Means of Current Projection Tools
• Performance Parameters: Depth of focus, exposure latitude, E-D windows
• Focus and Exposure Dose Budgets 

Resist Chemistry 

• Chemistry and Processing of I-Line Resists
• Chemically Amplified Resists for 248nm and Beyond
• Environmental Stability: T-top formation, line-width variation
• Possible Solutions to Overcome Problems: Improved chemistry, interfacing of track and stepper, chemically filtered air 

Practical Resist Implementation Issues 

• Contributions to CD Variation Due to Bulk Effect, Reflective Notching, Swing Curve and Standing Waves Correlated to the Optical Parameters of the Resist 
• Advanced Resist Technologies: Addition of dyes, top- and bottom anti reflective coatings, dry development, top surface imaging 

Tuesday – ROEL GRONHEID 

Advanced Optical Imaging 

• Phase Shifting Masks
• Off-Axis Illumination
• Optical Proximity Correction
• Lens Aberrations 

Optical Lithography Roadmap 

• 157nm Lithography Roadblocks
• Immersion Lithography Status and Challenges
• Double Patterning Techniques 

Wednesday – ROEL GRONHEID/STÉFAN LANDIS 

Extreme UV Lithography, EUVL 
Mainstream optical lithography is ultimately limited by diffraction and, since some time, shorter wavelength alternatives have been pursued to prepare for post-optical applications. 
EUVL is being developed for the 22nm or smaller generations. It is currently the most favoured of the emerging lithography options for volume manufacturing due, in part, to its extendibility beyond the 22nm half pitch node without loss in throughput. The CD entry-point, commercial infrastructure, and tool availability are described. The worldwide efforts in EUVL will be summarized. 

• Description of EUVL and Overview of Worldwide Efforts 
• Status and Challenges of EUV Sources, EUV Optics, EUV 
• Masks and EUV Resists 

IMPRINT LITHOGRAPHY 
Since the mid-90th, Nano Imprint Lithography (NIL) has become an emerging lithographic technology that promises high throughput patterning of nanostructures on large areas. 
Based on the mechanical embossing principle of a polymer, NIL can achieve pattern resolutions beyond the limitations set by the light diffractions or beam scatterings in other conventional techniques. It has been recently demonstrated that it was possible to achieve sub-10nm resolution and alignment with NIL, and large area pattern fidelity. This technology has been applied to fabrication of various devices, including patterned magnetic disk, microoptics, compact disk, micro-fluidics and Micro-Electro-Mechanical System (MEMS) devices, field-effect transistors. 

• Principles of Imprint Lithography: Hot embossing, microcontact printing, step and flash, and reversal imprint technologies 
• Fabrication of Imprint Stamps (hard and soft) 
• Adhesive Properties of the Molds: Issues and solutions 
• Process Issues: Large area, high resolution, defects 
• Associated metrology 
• Applications 

Thursday – STELLA PANG/HANS PFEIFFER 

Nanoimprint Technology and Applications 
Nanoimprint technology can greatly simplify the production of nanostructures by creating molds that can emboss intricate patterns onto various substrates and materials. This technique allows for the creation of devices and microsystems with nanometer features at higher rate and lower cost than possible in today’s high resolution patterning techniques. Nanoimprint could be used in the future manufacturing of nanometer scale integrated circuits and a broad range of nanosystems for use in optics, storage, sensor, and biomedical applications. 

In this lecture, various nanoimprint technologies and systems will be reviewed including thermal, UV, and reversal nanoimprint. Reversal UV nanoimprint will be highlighted, which can be used to fabricate three-dimensional nanostructures, fluidic channels, and microsystems. Conventional semiconductor fabrication processes for 3D structures 
involve multiple and costly process steps such as deposition, planarization, lithography, and etching. In contrast, reversal UV nanoimprint has the unique capability of building 3D nanosystems with simpler technology and better control. 

• Thermal, UV, and Reversal Nanoimprint Technology 
• Nanoimprint Systems
• Electronic, Photonic, Storage, Sensor, and Biomedical Applications of Nanoimprint 

ELECTRON-BEAM LITHOGRAPHY, MASK-MAKING 
Electron beam lithography has been pursued for many years as a means to achieve higher pattern feature resolution, needed for the advancing miniaturization, and to generate integrated circuit patterns without the need for masks. This pattern generation capability, in combination with high resolution, has also made electron beams the technology of choice for mask making. 
This lecture provides a comprehensive knowledge of recent advances in electron beam lithography based on an in-depth understanding of the challenges and opportunities in charged particle optics. We present the physics factors limiting throughput and compare the various techniques developed to overcome these limitations. A specific focus is on massively parallel pixel exposure, which has been achieved with Electron beam Projection Lithography (EPL) and which is currently being developed for Maskless Lithography (ML2).The advantages of using advanced electron beam tools, in a mix and match lithography with optical tools, will be presented. 

Introduction 

• Competitive Position/ITRS Roadmap
• Basic Electron Optics
• Challenges and Opportunities 

State-of-the-Art of Various E-Beam Techniques 

• Gaussian Beam, Shaped Beam, Character, Cell, Block Exposure
• Multi-Beams, Multi-Columns, and Multi-Emitters
• Electron-beam Projection Lithography (EPL) 
• Progress and Recent Results with EPL 

Friday –HANS PFEIFFER 

Maskless Lithography (ML2) 

• Direct Write Experience
• Review of Worldwide ML2 Activities
• Progress in Projection Maskless Lithography (PML2)
• Issues and Prospects 

E-Beam Mask-Making 

• Mask-Making Trends and Challenges
• Electron Beam Pattern Generators in Photomask Production 
• Resolution Limits Imposed by Coulomb Interaction of Beam Electrons 
• Proximity Effect 

Ion-Beam Lithography 

• Unique Physical Characteristics of Ion-Beams 
• Ion-Beam use in Lithography Compared with the Use of Electron Beams
• Possible Application of Scanning and Projection Ion Beam Systems for Mask and Wafer Exposure 
• Application of Ion Beams for Mask Repair and Inspection 

Regular Course Fee: EUR 2995

Early Registration Course Fee: EUR 2725
This applies to firm registrations received 2 months before course start. 

University Student and Faculty Rate:
Two university participants are welcome to attend for one course fee if payment is to be made from university funds.

Deliverables:
The course fee covers tuition, course material, and the day conference packages (morning/afternoon refreshments, lunches etc.) paid on your behalf to the course venue. Accommodation is not included.