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Extreme ultraviolet lithography ppt


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Extreme ultraviolet lithography ppt

  1. 1. Department of Electronics & Communication Engineering Submitted by: SUMAN G (1AY13EC109) Technical seminar presentation on: Under the guidance of Mr.VASANTH KUMAR T R Assistant Professor, Dept. of E&C A.I.T
  2. 2. OUTLINE  Lithography  Introduction to EUVL  Basic concepts  Why do we need EUVL?  EUVL Process  Basic technology for EUV  EUV masks  All Reflective Optics  Advantages  Disadvantages  Conclusion
  3. 3. WHAT IS LITHOGRAPHY Lithography is akin to photography in that it uses light to transfer images onto a substrate The term lithography is derived from the words ‘lithos’ meaning stone and ‘graphy’ meaning write. Our stone is silicon wafer and writing is done using a photo sensitive polymer.
  4. 4. INTRODUCTION Extreme ultraviolet lithography is an advanced technology for making microprocessors a hundred times more powerful than those made today. Optical projection lithography has been the lithographic technique used in the high-volume manufacture of integrated circuits. The key to creating more powerful microprocessors is the size of the light's wavelength.
  5. 5. BASICCONCEPT BEHIND EUV Minimum lithographic feature size = k1: “Process complexity factor” λ: Exposure wavelength NA: Numerical aperture of the lens.Higher NA means smaller depth of focus. k1*λ NA
  6. 6. WHY EUVL EUVL is required for the continuity of Moore’s law The number of transistors that can be placed inexpensively on an integrated circuit doubles approximately every two years. EUVL is a next generation lithography technique.
  7. 7. Glass lens replaced by mirrors…. λ= 13.5nm… Reflective masks are to be used. more power…faster mp This wafer was patterned on a prototype device using extreme- ultraviolet lithography (EUVL). EUVL
  8. 8. EUVL PROCESS Laser is directed to a jet of xenon gas to produce plasma To create the IC, light is directed to a mask. Light reflects from the mask then through a series of mirrors that shrinks the image down. Projected to wafer covered with photoresist Light hardens the photoresist. Region not exposed remain gooey and the remaining is hardened photoresist and exposed silicon wafer.
  9. 9. All solids, liquids, and gases absorb 13.5nm – so system is under vacuum Mask must be reflective and exceptionally defect-free 13.5nm photons generated by plasma source All-reflective optics (all lens materials are opaque) BASICTECHNOLOGY FOR EUV
  10. 10. EUV MASKS
  11. 11. All solids, liquids, and gases absorb 13.5nm photons - So fused silica lenses are not used - all refracting lenses are not used Making EUV mirrors is no cakewalk, either …  50 or more alternating Mo/Si layers give the mirror its reflectivity  Each layer is 6.7nm thick and requires atomic precision  Since the angle of incidence changes across the mirror, so do the required Si layer thicknesses Net reflectance: ~70% All-Reflective Optics
  12. 12. IMAGE FORMATION Top: EUV multilayer and absorber constituting mask pattern for imaging a line. Bottom: EUV radiation reflected from the mask pattern is absorbed in the resist and substrate, producing photoelectrons and secondary electrons. These electrons increase the extent of chemical reactions in the resist.
  13. 13. EUVL ADVANTAGES Microprocessors made by euvl are much faster than today's most powerful chips  Decrease in size of chip but the speed increases.  EUVL technology achieves good depth of focus and linearity.  Increase in storage capacity.  The low thermal expansion substrates provide good image placement.
  14. 14. EUVL DEFECTS Contamination deposition on the resist from out gassed haydrocarbons, which results from EUV- or electron-driven reactions. Entire process has to be carried out in vacuum. Mirrors used are only 70% reflective.
  15. 15. CONCLUSION EUVL will opens a new chapter in semiconductor technology. Successful implementation of EUVL would enable processors to operate very high speed with small size. Much work is to be done to overcome disadvantages.
  16. 16. THANK YOU