20140913 - Multi-Color Lithography Assessment by Simulation for posting

Multi-Color Lithography Assessment by Simulation

John S. Petersen, Periodic Structures, Inc. [email protected]

512.751.6171

John T. Fourkas, Univ. of Maryland Chris A. Mack, Lithoguru

Dave Markle, Periodic Structures, Inc.

12th Fraunhofer IISB Lithography Simulation Workshop 13 September 2014

mailto:[email protected]�

Outline and Comments • Super-resolution with Multi-wavelength lithography (MWL)

– Principles: Improve resolution by trimming an actinic image using a deactivating λ – Resist Background: For non-SC applications resolution to 9 nm using visible λ

• Semiconductor Lithography – Possible Tool Solutions: Modified scanner, Interference litho, Direct-Write – Theoretical Resolution < 10 nm and pitch < 20 nm – Estimated Throughput 30 wafers per hour for grid based designs, 7.8 for arbitrary

• Status – Thick to thin resist challenges ITX, DETC and MGCB – Resist screening test apparatus – CINT transitive absorption spectroscopy

• Conclusions – The technique holds great promise and requires industrial support to make it real – Resist requirements

• 2-color resists will work for small features and large pitches • 3-color resists provide the best avenue to small pitch.

– Material development for SC lithography is required.

Simulators required to accelerate development

12th Fraunhofer IISB Lithography Simulation Workshop p. 2 13 September 2014

Motivation for a New Lithography • Money

– EUV and 193i multi-patterning is prohibitive except for HVM of leading edge devices.

– Scalable maskless multi-wavelength litho enables the rest.

• Enables – Rapid prototyping and limited run products using ODW – EUV mask production – Imprint Templates – Arbitrary and gridded 10 nm DSA piloting structures

• Coulomb – Replaces e-beam in DW of masks, templates and wafers


References

• S. W. Hell and J. Wichmann, Opt. Lett., 1994, 19, 780-782. • J.T. Fourkas; J. S. Petersen , 2-Colour photolithography. Phys Chem Chem Phys 16(19):8731-50 2014. • K. Berggren, A. Bard, J. Wilbur, J. Gillaspy, A. Helg, J. McClelland, S. Rolston, W. Phillips, M. Prentiss and G.

Whitesides, Science, 1995, 269, 1255-1257. • L. J. Li, R. R. Gattass, E. Gershgoren, H. Hwang and J. T. Fourkas, Science, 2009, 324, 910-913. • T. F. Scott, B. A. Kowalski, A. C. Sullivan, C. N. Bowman and R. R. McLeod, Science, 2009, 324, 913-917. • T. L. Andrew, H. Y. Tsai and R. Menon, Science, 2009, 324, 917-921. • J. T. Fourkas, J. Phys. Chem. Lett., 2010, 1, 1221-1227. • J. Fischer, G. von Freymann and M. Wegener, Adv. Mater., 2010, 22, 3578-3582. • J. Fischer and M. Wegener, Opt. Mater. Expr., 2011, 1, 614-624. • B. Harke, P. Bianchini, F. Brandi and A. Diaspro, Chemphyschem, 2012, 13, 1429-1434. • B. Harke, W. Dallari, G. Grancini, D. Fazzi, F. Brandi, A. Petrozza and A. Diaspro, Adv. Mater., 2013, 25, 904-909. • J. Fischer and M. Wegener, Laser Photon. Rev., 2013, 7, 22-44. • M. P. Stocker, L. Li, R. R. Gattass and J. T. Fourkas, Nat. Chem., 2011, 3, 223-227. • Y. Y. Cao, Z. S. Gan, B. H. Jia, R. A. Evans and M. Gu, Opt. Expr., 2011, 19, 19486-19494. • Z. Gan, Y. Cao, R. A. Evans and M. Gu, Nat. Commun., 2013, 4, 2061. • Z. S. Gan, Y. Y. Cao, B. H. Jia and M. Gu, Opt. Expr., 2012, 20, 16871-16879


Photon induced Inhibition of Polymerization

9 nm resolution shown in “E” but consumes reactants and won’t cycle without dose correction. Z. Gan, Y. Cao, R. A. Evans and M. Gu, Nat. Commun., 2013, 4, 2061

Ugly but

9 nm


InSTED Lithography • Interlace Activation

(λA) and Deactivation (λD) interfering beams

• Trims the beam so the resist near the image is not exposed allowing placement of another line beside it.

107 nm @ 0.4 Intensity λA=405nm λD=532nm; before STED 174 nm

Relative Intensity

Horizontal Position (nm)


InSTED Lithography Examples

20 nm on 300 nm Pitch @ 0.4 Intensity λA=405nm λD=532nm (50X Intensity)

107 nm on 300 nm Pitch @ 0.4 Intensity λA=405nm λD=532nm (1.2X Intensity)

Before STED trimming: 174 nm @ 0.4 Intensity

Relative Intensity


Relative Intensity



InSTED Lithography 20 nm on 40 nm Pitch @ 0.4 Intensity λA=405nm λD=532nm

1 1 1 2 2 2 3 3 3 4 4 4


Super-resolution Lithography System Schematic

Camera

Telecentric Relay

DMD B B R

Beam-splitter

Objective

Light Pipe

Frustrated Prism

Dose Detector

Stage

Grating Phase Shifter

Laser Diodes

Inhibition Laser

US8642232 B2


Image Log-Slope

mask mask

mask

image

Image Log-Slope (or the Normalized Image Log-Slope, NILS) is the best single metric of image quality for lithographic applications.


Effective Latent Image Log-Slope

)),,(exp(),,( tzyxCIzyxm r−=Relationship latent image to exposure

xImm

xm

∂∂

=∂∂ ln)ln(Latent image log-slope

dxdm

mmILSeff )ln(

1≡Effective Latent image

log-slope


STED Litho Exposure

)exp( tkm STED−=

( )( ) ( )NRFAIVRIVRNRADD

IVRDDA

EEIVR

EEIVRSTED kkkkkkkIk

kIkkIkk

Ikkk+++++

+

+

=

This rate constant can be simplified under the reasonable assumption that kIVR is large compared to kEIE, kDID, and kA+kNR. In this case,

Where,

NRFADD

EEASTED kkkIk

Ikkk+++

=

STED Exposure

JT Fourkas; JS Petersen , 2-Colour photolithography. Phys Chem Chem Phys 16(19):8731-50 2014.


The STED ILS

1+=

DD

EESTED IC

ICk

+

−=dx

IdIC

ICdx

Idmmdxdm D

DD

DDE ln1

ln)ln(

Grouping constants:

NRFA

EAE kkk

kkC++

=NRFA

DD kkk

kC++

=and

Where,

Taking the spatial derivative of photoproduct m,


STED ILSEFF

dxId

ICIC

dxIdILS D

DD

DDEeff

ln1

ln

+

−=

dxId

dxIdILS DE

efflnln

max−=

At the maximum when:

And, when complementary images are used:

dxId

dxId DE lnln

−= And dx

IdILS Eeff

ln2=

ILSEFF is:


NILS vs Feature Size


Lithography projection using InSTED

JT Fourkas; JS Petersen , 2-Colour photolithography. Phys Chem Chem Phys 16(19):8731-50 2014.


3-C Flare Technical Requirements

Challenge: 3-color flare must be understood – Deactivation Flare – Activation Flare – Exposure Flare

• Impact – Aerial Image formed with 2-beam Interference – Latent Image – Developed Image

• Today we have only looked at Aerial Image


Flare: Non-Ideal IL Imaging

( )2/41

4

pwFNILS

π+

≈When w/p ≤ 0.1 so that the sinusoids of I(x) can be replaced by their small-angle approximations:

( ) ( )( )

+−

=Fpw

pwpwNILS2/cos1

/sin/2πππ

How the flare affects the quality of the interferometric image:

( ) FpxxI +−= /2cos21

21)( π

Interference of two ideal plane waves + flare (F):


Aerial Image Resolution Limit of Deactivation Alone

−

≈

4/1

1

min

min

min NILSNILSF

pw

π

Where w/p ≤ 0.1, the minimum w/p that still produces images of acceptable quality will be:

At a NILS of 1.5 this means a resolution limit of Pitch/20 considering aerial image alone.


Pitch/20 Implied Resolution Limit Width (nm)

1% FlareWidth (nm)

2% FlareWidth (nm)

3% FlarePitch Wavelength NA

5.3 7.5 9.2 107.5 200 0.93

7.1 10.0 12.2 143.0 266 0.93

9.7 13.7 16.8 196.2 365 0.93

10.7 15.2 18.6 217.7 405 0.93

14.1 19.9 24.4 286.0 532 0.93

16.8 23.7 29.0 339.8 632 0.93

21.2 30.0 36.7 430.1 800 0.93


Pitch/20 Implied Resolution Limit Width (nm)

1% FlareWidth (nm)

2% FlareWidth (nm)

3% FlarePitch Wavelength NA

3.7 5.2 6.3 74.1 200 1.35

4.9 6.9 8.4 98.5 266 1.35

6.7 9.4 11.5 135.2 365 1.35

7.4 10.5 12.8 150.0 405 1.35

9.7 13.7 16.8 197.0 532 1.35

11.5 16.3 20.0 234.1 632 1.35

14.6 20.7 25.3 296.3 800 1.35


Resist Technical Requirements Challenge: Has to work as a resist

– Fast with good LWR – No pattern collapse, Swelling mitigated, Good etch selectivity & I2 – Minimal diffusion of active components

• Has to act as an optical switch need to recycle hundreds of times with no discernible functional drift – 50 µs full process cycle which is the max frame rate of DMD – Correctable and accountable reactant consumption – Restrict unwanted reaction pathways – Thermal effects during exposure (chemistry and wafer-scale) – Sublimation and outgassing – 3-wavelength (make mask, expose mask, erase mask) is best.

• Unwanted quenching controlled – Oxygen effect that grows as resist thins


InSTED Lithography Interference STimulated Emission-Depletion Lithography

Absorption 10-15 s

2-photon separation <10-18 s

Fluorescence 10-9 - 10-7 s

Non-Radiative 10-15 - 10-12 s

Vibrational Relaxation 10-14 - 10-11 s

Inter-System Crossing 10-8 - 10-3 s

Ultra-Fast Chemical Rx’s 10-6 - 10-3 s

Phosphorescence 10-4 - 10-1 s

Fast Chemical Reactions 10-6 - 10-3 s

ESA

ST

ED

Fluo

resc

ence

Non

-Rad

iati

ve D

ecay

TTA

T1

Tn

S1

Sn

S0

S0*

S1*

Sn*

Tn*

1-Ph

oton

Abs

orpt

ion

2-Ph

oton

Abs

orpt

ion

Use STED or STED-like to selectively shutdown further reaction to trim the aerial image.

Photochemical reaction time scales (Ref: Modern Molecular Photochemistry by Nicholas J. Turro, University Science Books, Sausalito, CA, copyright 1991, p. 5


Possible Photo Pathways

27 12th Fraunhofer IISB Lithography Simulation Workshop p. 27 13 September 2014

Spectra and Excitation-Depletion Absorbance

Fluorescence

Phosphorescence

STED 2-Photon

1-Photon

Rela

tive

Spe

ctra

l Uni

ts

Wavelength (nm) 300 810 532 400

28 12th Fraunhofer IISB Lithography Simulation Workshop p. 28 13 September 2014

Photo-shutter MGCB Demo

Courtesy of Zuleykhan Tomova, Fourkas Group, UMD 2014

Activation

+ Deactivation

Activation

Activation


Mechanisms Beyond STED for Lithography • Stimulated Emission-Depletion (STED): None

confirmed for lithography • Photo reversible solvated electrons (Fourkas:

Malachite Green using RAPID)) ???? • Triplet-Triplet Absorption (Wegener, also Harke: ITX,

DETC research, thought it was STED at first) ???? • Photon induced inhibition of polymerization (PIP)

McCleod, and Gu • Photo chromic over layers (PCO) (Menon using

AMOL) • Multi-wavelength Molecular switches (PSI proposes)


Simple 2-Color Resist


0

2E+13

4E+13

6E+13

8E+13

1E+14

1.2E+14

1.4E+14

1.6E+14

1.8E+14

2E+14

0 2 4 6 8 10 12 14 16

Num

ber

of M

olec

ules

/Pho

tons

/cm

2

Exposure Time (micro-seconds)

2- Color Model Extended Inhibition, R=10:1, 12.5 μs exposure,

T=5E-5 Using Finite Time Element

Remaining Excited Atoms

Exposed Atoms

Exposure Flux

Exposed Flux

Remaining Excited Species

Irreversible Species


0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

1.00

50.00 60.00 70.00 80.00 90.00 100.00 110.00 120.00 130.00 140.00

Rel

ativ

e Ex

posu

re

Lateral position (nm)

Comparison of Three Resist Exposure Models

2-Color Model Simple Model 3-color model


Stiched Aerial Image: 2-C & 3-C


Molecular Switch (MS)

• There are many processes to do this (presented not distributed). – Bichromic (From optical storage and other literature) – Ground State Depletion (From microscopy) – Others…

• The challenge for simulation is that modeling must comprehend all of them!

ctPhotoproduMSMSMS ActivateddDeactivate ⇒→→← ∗3

2

1λ

λ

λ


2-C and 3-C Molecule Development

• Molecular and Resist Design – 2-C and 3-C molecule development using Density

Functional Theory (DFT) • Exploration and Discovery • Parameters calculated for resist exposure

– Molecular dynamics • Evaluates resist matrix dynamics • Parameters calculated for resist exposure

• Resist Exposure – Use parameters from above to generate latent image – Insert latent image into litho simulator


Summary

• 3-C lithography is in its infancy. • Basic NILS analysis with less than 3% flare

shows that we can attain the 10 nm half-pitch. • Using Molecular modeling we hope to greatly

accelerate development. • Please contact us if you are interested in

exploring ways you can support the development of the science and technology of 3-C lithography.


Thank You

This work was supported in part by the National Science Foundation, Grant IIP-1318211, and previously approved and published material in part by DARPA, 50 grant N66001-10-C-4064 (Excerpt from Fourkas and Petersen paper). The views expressed are those of the authors and do not reflect the official policy or position of the Department of Defense or the U.S. Government. This is in accordance with DoDI 5230.29, January 8, 2009 (JP).


20140913 - Multi-Color Lithography Assessment by Simulation for posting

Documents

Transcript of 20140913 - Multi-Color Lithography Assessment by Simulation for posting