Water for Immersion Lithography - SEMATECH

Cumulative Res ;)SOBUTENE=

sist Outgassing

>95% outgassing
within 2 s

nm modeling by
0-9 cm2/s Rod Kunz
0-6 cm2/s MIT/LL
ulse

Outgassing

Ideal Dissolution – The Fickian Interface

• Minimal impact on
refractive index

• Likely outcome for
polar compounds
or any case where
the concentration
is well below the
solubility limit

Phase Segregation – Surface Nucleation

• Phase
inhomogeneities
might be liquid or
gaseous

• Driven by
nucleation
thermodynamics

Immersion Workshop
MS 27 Jan. 2004

Into a Liquid

Phase Segregation – Bubble Formation

• Phase
inhomogeneities
might be liquid or
gaseous

• Driven by
nucleation
thermodynamics

Boundary Reflection – No Net Mass Loss

• Precedent exists for
this to occur for
hydrophobic
products due to the
observed partition
functions seen in
solid-phase
extraction

• Partitioning INTO
solid polymer can
occur

MIT Lincoln Laboratory

Looking for Outgas

APEX resist—high

-

ssing-Induced Bubbles

bubble generation

=

Outgassing Ind

• 2 mJ/cm2/pulse
• model immersion resist
• 2700 images (~ 235 mm2)

– 500 controls with no resist
– 1000 images taken 1 µs after

each isolated pulse (~ 1 Hz)
– 1000 images taken 10 µs after

each isolated pulse (~ 1 Hz)
– 200 images taken 1 µs after a

5 pulse burst (100 Hz)

Immersion Workshop
MS 27 Jan. 2004

duced Bubbles

• Only 1 in focus particle detected

– Persistence makes it unlikely to be a
bubble

MIT Lincoln Laboratory

Out

• Water treatment
• Water–optic interaction
• Bubbles
• Alternative fluids

Immersion Workshop
MS 27 Jan. 2004

tline

MIT Lincoln Laboratory

Alternati

• Some alternatives to pure

water may be desired

– Probably not at first
– Solutions to problems which

arise

• Improved flow dynamics
• Increased index of refraction
• Decreased corrosion or optic

contamination

• Improved resist performance
• etc.

Immersion Workshop
MS 27 Jan. 2004

ive Fluids

0URE

Conclu

• Water treatment is non-trivia

– Careful analysis of construc
– Ions, organics, and fluoroca

• Water–optic interaction

– CaF2 dissolves quickly (hou
– SiO2 coatings protect for da
– Infrastructure in place for lo

• Bubbles

– No bubbles seen in 2200 res
model resist

One bubble candidate but pro

– Infrastructure in place to tes

Immersion Workshop
MS 27 Jan. 2004

usions

al

ction materials required
arbons must be controlled
urs) in water
ays in the dark
ong-term durability testing
sist outgassing images with TOK

obably a particle in the water

st more/different resists

MIT Lincoln Laboratory

Ongoing/Futur

• Multi-pronged analysis of w

determine source of residua

– In situ monitoring of nonvol
– GCMS analysis of nonvolati
– Fluorocarbon analysis

• Durability testing of immers

– In-house
– Vendor supplied

• Resist outgassing images

– Automated collection of a la
images

– Machine-vision search for b
– Different resists

TOK models
eventually vendor supplied

Immersion Workshop
MS 27 Jan. 2004

re experiments

water treatment system to
al contaminants

latile residue
ile residue

sion coatings

arge number of post-exposure
bubbles

MIT Lincoln Laboratory

Acknowle

This work was performed under Co
Development Agreements between
SEMATECH and between MIT Linco
Opinions, interpretations, conclusi
those of the authors, and do not ne
United States Government.
We would like to thank J.Curtin, D.H
technical assistance, R. Kunz for a
contamination, J. Ruberti at Cambr
work, H. Burnett and T. Shedd at UW
outgassing/bubbles experiment, J.
for help with the water purification
simulation data, P. Zhang at Air Pro
Grenville at Intel and SEMATECH fo
Malus at WaveMetrics Inc. for softw

Immersion Workshop
MS 27 Jan. 2004

edgments

ooperative Research and
n MIT Lincoln Laboratory and
oln Laboratory and Air Products.
ions, and recommendations are
ecessarily represent the view of the

Hardy, and S.Palmacci for expert
analysis of the residual water
ridge Polymer for freeze-fracture
W for work on the resist
. Smith and colleagues at Mykrolis

system, M. Yeung at BU for
oducts for OptiFluid samples, A.
or useful discussion, and A.G.
ware support.

MIT Lincoln Laboratory