abcd

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. 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. 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. 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. 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. 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. 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. 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.

10. 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

11. EUV MASKS

12. 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

13. 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.

14. 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.

15. 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.

16. 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.

17. THANK YOU