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Nano Lithography

Book Description

Lithography is an extremely complex tool - based on the concept of "imprinting" an original template version onto mass output - originally using relatively simple optical exposure, masking, and etching techniques, and now extended to include exposure to X-rays, high energy UV light, and electron beams - in processes developed to manufacture everyday products including those in the realms of consumer electronics, telecommunications, entertainment, and transportation, to name but a few. In the last few years, researchers and engineers have pushed the envelope of fields including optics, physics, chemistry, mechanics and fluidics, and are now developing the nanoworld with new tools and technologies. Beyond the scientific challenges that are endemic in this miniaturization race, next generation lithography techniques are essential for creating new devices, new functionalities and exploring new application fields.

Nanolithography is the branch of nanotechnology concerned with the study and application of fabricating nanometer-scale structures − meaning the creation of patterns with at least one lateral dimension between the size of an individual atom and approximately 100 nm. It is used in the fabrication of leading-edge semiconductor integrated circuits (nanocircuitry) or nanoelectromechanical systems (NEMS).

This book addresses physical principles as well as the scientific and technical challenges of nanolithography, covering X-ray and NanoImprint lithography, as well as techniques using scanning probe microscopy and the optical properties of metal nanostructures, patterning with block copolymers, and metrology for lithography.

It is written for engineers or researchers new to the field, and will help readers to expand their knowledge of technologies that are constantly evolving.

Table of Contents

  1. Cover
  2. Title Page
  3. Copyright
  4. Foreword
  5. Introduction
  6. Chapter 1: X-ray Lithography: Fundamentals and Applications
    1. 1.1. Introduction
    2. 1.2. The principle of X-ray lithography
      1. 1.2.1. The irradiation system for XRL
      2. 1.2.2. Properties of synchrotron radiation
      3. 1.2.3. High Resolution and Deep XRL
      4. 1.2.4. Examples of X-ray lithography beamlines
      5. 1.2.5. Scanner/stepper
      6. 1.2.6. The mask
    3. 1.3. The physics of X-ray Lithography
      1. 1.3.1. How phase and intensity of X-rays are altered by interaction with matter
      2. 1.3.2. X-ray lithography as a shadow printing technique
      3. 1.3.3. X-ray absorption in a resist and physical mechanisms involved in its exposure
      4. 1.3.4. Physical model of electron energy loss in resists
      5. 1.3.5. Diffraction effects in X-ray lithography
      6. 1.3.6. Coherence of synchrotron radiation from bending magnet devices
      7. 1.3.7. Basic formulation of diffraction theory for a scalar field
      8. 1.3.8. Rayleigh–Sommerfeld formulation of diffraction by a planar screen
      9. 1.3.9. An example of diffraction effects: Poisson's spot in X-ray lithography
    4. 1.4. Applications
      1. 1.4.1. Optimal photon energy range for High resolution and Deep X-ray lithography
      2. 1.4.2. Diffraction effects on proximity lithography
      3. 1.4.4. 3D polymer structures by combination of NanoImprint (NIL) and X-ray lithography (XRL)
      4. 1.4.5. Micromachining and the LIGA process
        1. 1.4.5.1. Micro-mixer
        2. 1.4.5.2. Micro-needle fabricated by LIGA and casting
        3. 1.4.5.3. Microturbine rotors for power generation in portable systems
      5. 1.4.9. Micro-optical element for distance measurement
    5. 1.5. Appendix 1
    6. 1.6. Bibliography
  7. Chapter 2: NanoImprint Lithography
    1. 2.1. From printing to NanoImprint
    2. 2.2. A few words about NanoImprint
    3. 2.3. The fabrication of the mold
    4. 2.4. Separating the mold and the resist after imprint: de-embossing
      1. 2.4.1. The problem
      2. 2.4.2. Adhesion
      3. 2.4.3. Adhesion and physico-chemical surface properties
      4. 2.4.4. Surface treatment of the mold
      5. 2.4.5. Treatment of the resist
      6. 2.4.6. Characterization of the demolding process
    5. 2.5. The residual layer problem in NanoImprint
      1. 2.5.1. The residual layer: a NanoImprint specific issue
      2. 2.5.2. Is the thickness of the residual layer predictable?
      3. 2.5.3. How can the process impact the thickness of the residual layer?
    6. 2.6. Residual layer thickness measurement
      1. 2.6.1. Macro-scale approach: coherence between film color and thickness
      2. 2.6.2. Microscopic approach
        1. 2.6.2.1. Scanning electron microscopy (SEM)
        2. 2.6.2.2. Atomic force microscopy (AFM)
        3. 2.6.2.3. Optical scatterometry characterization
          1. 2.6.2.3.1. Quantitative approach
          2. 2.6.2.3.2. Quantitative usage
          3. 2.6.2.3.3. Using real-time tracking of the imprint
        4. 2.6.2.4. Characterization by X-ray specular reflectivity
    7. 2.7. A few remarks on the mechanical behavior of molds and flow properties of the NanoImprint process
      1. 2.8. Conclusion
    8. 2.9. Bibliography
  8. Chapter 3: Lithography Techniques Using Scanning Probe Microscopy
    1. 3.1. Introduction
    2. 3.2. Presentation of local-probe microscopes
    3. 3.3. General principles of local-probe lithography techniques
    4. 3.4. Classification of surface structuring techniques using local-probe microscopes
      1. 3.4.1. Classification according to the physical nature of the interaction
      2. 3.4.2. Comparison with competing advanced lithography techniques
      3. 3.4.3. Industrial development perspectives
    5. 3.5. Lithographic techniques with polymer resist mask
      1. 3.5.1. Electron beam exposure of resists by scanning probe microscopes
      2. 3.5.2. Development of a resist dedicated to AFM nano-lithography
      3. 3.5.3. Lithography using mechanical indentation
    6. 3.6. Lithography techniques using oxidation-reduction interactions
      1. 3.6.1. Direct fabrication by matter deposition induced by STM microscopy
        1. 3.6.1.1. Hydrogenated silicon depassivation by STM
        2. 3.6.1.2. Local chemical vapor deposition under STM
      2. 3.6.2. Local anodization under the AFM tip
        1. 3.6.2.1. Application to the fabrication of silicon nanostructures
        2. 3.6.2.2. Application to ultra-thin metallic film oxidation
        3. 3.6.2.3. Advantage of tips grafted by carbon nanotubes
    7. 3.7. "Passive" lithography techniques
      1. 3.7.1. Dip-pen lithography
      2. 3.7.2. Alignment technique by means of a mechanical masking (stencil mask)
    8. 3.8. Conclusions and perspectives
    9. 3.9. Bibliography
  9. Chapter 4: Lithography and Manipulation Based on the Optical Properties of Metal Nanostructures
    1. 4.1. Introduction
    2. 4.2. Surface plasmons
      1. 4.2.1. Definition of a volume plasmon
      2. 4.2.2. Delocalized surface plasmons
        1. 4.2.2.1. Definition
        2. 4.2.2.2. Dispersion equation
        3. 4.2.2.3. Attenuation distances
      3. 4.2.3. Localized surface plasmons
        1. 4.2.3.1. Definition
        2. 4.2.3.2. Plasmon resonance
      4. 4.2.4. Application to lithography
    3. 4.3. Localized plasmon optical lithography
      1. 4.3.1. Near-field optical lithography by optical edge effect
        1. 4.3.1.1. Polymer nanophotostructuring
        2. 4.3.1.2. Structuring of inorganic layers
      2. 4.3.2. Use of nanoparticle resonances
    4. 4.4. Delocalized surface plasmon optical lithography
      1. 4.4.1. Coupling between nanostructures and delocalized surface plasmons
      2. 4.4.2. Surface plasmon launch and interferences
    5. 4.5. Conclusions, discussions and perspectives
    6. 4.6. Bibliography
  10. Chapter 5: Patterning with Self-Assembling Block Copolymers
    1. 5.1. Block copolymers: a nano-lithography technique for tomorrow?
    2. 5.2. Controlling self-assembled block copolymer films
    3. 5.3. Technological applications of block copolymer films
    4. 5.4. Bibliography
  11. Chapter 6: Metrology for Lithography
    1. 6.1. Introduction
    2. 6.2. The concept of CD in metrology
      1. 6.2.1. CD measurement after a lithography stage: definitions
      2. 6.2.2. What are the metrological needs during a lithography step?
        1. 6.2.2.1. Notions of accuracy and reproducibility during measurement
          1. 6.2.2.1.1. Measurement accuracy
          2. 6.2.2.1.2. Measure reproducibility
        2. 6.2.2.2. Notions of local measurement, average local measurement and variability
          1. 6.2.2.2.1. Local measurement
          2. 6.2.2.2.2. Averaged local measurement
          3. 6.2.2.2.3. Variability
    3. 6.3. Scanning electron microscopy (SEM)
      1. 6.3.1. SEM principle
        1. 6.3.1.1. X-SEM imaging (cross-section)
        2. 6.3.1.2. CD-SEM imaging
      2. 6.3.2. Matter–electron interaction
        1. 6.3.2.1. Emission and spatial resolution
        2. 6.3.2.2. Secondary electrons
      3. 6.3.3. From signal to quantified measurement
      4. 6.3.4. Provisional conclusion on scanning electron microscopy
    4. 6.4. 3D atomic force microscopy (AFM 3D)
      1. 6.4.1. AFM principle
        1. 6.4.1.1. Piezoelectric ceramics
        2. 6.4.1.2. Tips
        3. 6.4.1.3. Tip shape
        4. 6.4.1.4. Detection methods
        5. 6.4.1.5. Van der Waals forces and distance–force curves
        6. 6.4.1.6. AFM working modes
          1. 6.4.1.6.1. DC or contact mode
          2. 6.4.1.6.2. AC or non-contact modes
      2. 6.4.2. 3D AFM (AFM 3D) special features
        1. 6.4.2.1. Measuring time
        2. 6.4.2.2. CD tips
        3. 6.4.2.3. CD tip characterization
      3. 6.4.3. Provisional conclusion on AFM 3D
    5. 6.5. Grating optical diffractometry (or scatterometry)
      1. 6.5.1. Principle
        1. 6.5.1.1. Object lightning
        2. 6.5.1.2. Making the optical signature
        3. 6.5.1.3. Modeling
      2. 6.5.2. Example: ellipsometry characterization of post development lithography
        1. 6.5.2.1. Ellispsometry measurements
        2. 6.5.2.2. Sensitivity to parameter variations
        3. 6.5.2.3. Signatures analysis
        4. 6.5.2.4. The different optical configurations
        5. 6.5.2.5. Spectroscopic and angular configurations
      3. 6.5.3. Pros and cons
      4. 6.5.4. Optical measurements analysis
        1. 6.5.4.1. Electromagnetic modeling
        2. 6.5.4.2. Statistic modeling
        3. 6.5.4.3. Parameters determination
        4. 6.5.4.4. Library search
        5. 6.5.4.5. Limits
          1. 6.5.4.5.1. Statistical limits
          2. 6.5.4.5.2. Practical limits
      5. 6.5.5. Specificities of scatterometry for CD metrology
        1. 6.5.5.1. Nondestructive measurement
        2. 6.5.5.2. Unlocalization
        3. 6.5.5.3. Indirect measurement
        4. 6.5.5.4. Background effects
      6. 6.5.6. Scatterometry implementation: R&D versus production
        1. 6.5.6.1. R&D
        2. 6.5.6.2. Production
      7. 6.5.7. New fields for scatterometry
    6. 6.6. What is the most suitable technique for lithography?
      1. 6.6.1. Technique correlation
      2. 6.6.2. Technique calibration
      3. 6.6.3. Process development
      4. 6.6.4. Evaluation of morphological damage generated by the primary electron beam from CD-SEM
  12. List of Authors
  13. Index