1. 2-D Plasmonic Imaging For
Optical Lithography
Josh Conway
Prof. Eli Yablonovitch
Opto-Electronics Group
Electrical Engineering Department
UCLA

2. Push the boundaries of optical lithography
Motivation
Push the boundaries of optical lithography
by exploiting the very large k vectors obtainable at optical frequencies using surface plasmons
Imaging could be accomplished with very short wavelength surface plasmons
light
plasmon wave
image
plane

3. Dispersion Curves Plasmon Wavelength in nm h Plasmon Energy in eV k
200 50 30 20 15 10 4
100 40
3.2eV 3
t=5nm
t=20nm
t=2nm
Plasmon Energy in eV 2
t=1nm
t=thickness of silver film 1 k
0.1
0.2
0.3
0.4
0.5
0.6
Plasmon Wave-Vector (2/wavelength in nm)

4. Constant Energy Curvesp
400
300
Plasmon Wavelength in nm
200
100 t 20 40 60 80
Silver Film Thickness in nm

5. Concept light h=2.5eV sapphire superstrate - - + + + - - +
plasmon wave
image plane
photoresist
plasmon wave

6. Plasmon Imaging far-field from conventional lens in-coupling grating
n9> n8>       >n1>n0
dimple lens
out-coupling slot
Rayleigh Limit is /n9

7. Overall System light Plasmon wave imaging:
metal film supports plasmon waves
photoresist
object
image
conventional
refractive
lens
plasmon wave
plasmon lens array
curved grating coupler
plane
Plasmon wave imaging:
Optical frequencies, but with X-ray wavelengths!

8. Demonstrate the change of plasmon wavelength along the taper
Experimental Goals
Use Apertureless NSOM to map field distribution of surface plasmon in flat and tapered films
Demonstrate the change of plasmon wavelength along the taper
Experimentally determine effects of scattering to the near and far field at large k-vectors due to roughness
collection optics
detector
AFM cantilever
NSOM tip
laser
source
gimble
silver film
sapphire
hemisphere