Department of Electronics & Communication
Technical seminar presentation on:
Under the guidance of
Mr.VASANTH KUMAR T R
Assistant Professor, Dept. of
Introduction to EUVL
Why do we need EUVL?
Basic technology for EUV
All Reflective Optics
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.
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
The key to creating more powerful microprocessors is
the size of the light's wavelength.
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.
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
EUVL is a next generation lithography technique.
Glass lens replaced by
Reflective masks are to
more power…faster mp
This wafer was patterned on a
prototype device using extreme-
ultraviolet lithography (EUVL).
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.
All solids, liquids, and gases
absorb 13.5nm – so system is
Mask must be reflective and
13.5nm photons generated by
(all lens materials are
BASICTECHNOLOGY FOR EUV
All solids, liquids, and gases absorb 13.5nm
- 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
Since the angle of incidence changes across
the mirror, so do the required Si layer
Net reflectance: ~70%
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.
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
Increase in storage capacity.
The low thermal expansion substrates provide good
Contamination deposition on the resist from out
gassed haydrocarbons, which results from EUV- or
Entire process has to be carried out in vacuum.
Mirrors used are only 70% reflective.
EUVL will opens a new chapter in semiconductor
Successful implementation of EUVL would enable
processors to operate very high speed with small
Much work is to be done to overcome