Extreme ultraviolet lithography (EUVL) is an advanced lithography technique needed to continue following Moore's Law and make more powerful microprocessors. EUVL uses light with a wavelength of 13.5nm, which is much shorter than visible light, allowing for smaller feature sizes. The EUVL process involves projecting a mask pattern through a series of reflective mirrors onto a photoresist-coated wafer under vacuum. Key aspects of EUVL include the use of reflective masks and all-reflective optical systems since materials absorb 13.5nm light. EUVL promises increased processor speeds and storage capacity but faces challenges like low mirror reflectivity and contamination control required for the vacuum environment.

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