20140211 - Paper 9052-6 Next-generation multi-wavelength lithography Printout

Next-generation multi-wavelength lithography: survey and roadmap

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

512.751.6171

John T. Fourkas, Univ. of Maryland Steven R. J. Brueck, The Univ. of New Mexico

Dave Markle, Periodic Structures, Inc. Rudi Hendel, Periodic Structures, Inc.

Paper 9052-6 Time: 11:40 AM - 12:00 PM

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.

Paper 9052-6 Next-generation multi-wavelength lithography 2

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


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

Lateral 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


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

2/23/2014 IEUVI Resist TWG Meeting

Periodic Structures, Inc. 11

Presenter

Presentation Notes

Photophysical schemes for multi-color photolithography. The photosensitizer begins in its electronic ground state S0, and is promoted to its first excited electronic state, S1, via absorption (blue arrow). The electronically-excited molecule relaxes to its ground vibrational state via intramolecular vibrational redistribution (IVR). The molecule can then activate a reaction, relax nonradiatively, fluoresces, undergo stimulated emission, or transfer to its triplet via intersystem-crossing. It can also be driven to a higher electronic state Sn by the deactivation beam. If ISC occurs it moves to the triplet state where analogous paths exist with the addition of reverse and phosphorescence and stimulated phosphorescence, triplet EEA by absorbing ID, or by absorbing the phosphorescence deactivation beam. In the triplet it can move on to react or form intermediate excited state compounds that may form diffusion limited solvated electrons.

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

12 Paper 9052-6 Next-generation multi-wavelength lithography 12

Photo-shutter MGCB Demo

Courtesy of Zuleykhan Tomova, Fourkas Group, UMD 2014

Activation

+ Deactivation

Activation

Activation


Thin Resist Result

NA=1.45 Resolution Pitch Limit: 673-551 nm Achieved 400 nm w/pattern collapse Fourkas Group Set up


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)


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

Simple 2-Color Resist

Paper 9052-6 Next-generation multi-wavelength

lithography 17

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

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


Molecular Switch Write Mask → Image Mask → Erase Mask (Repeat)

• Photo chromic has limited potential: – Absorbance shutter – May work but requires a multilayer process – Challenge partial exposure in undesired areas limits

pixel size and pitch resolution

• Photochemical (believe this is the best option) – OFF is no actinic functionality: OFF is OFF & ON is ON – Single image layer capable – Rich legacy in the development of switches for

storage and molecular electronics


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

Pixels Projected to the Wafer


US8642232 B2

Deactivation Pattern Activation Pattern

Superimposed at the wafer

Lithography projection using InSTED

J. T. Fourkas and J. S. Petersen, Phys. Chem. Chem. Phys., (to be published 2014).


Presenter

Presentation Notes

Fig. 4 Lithography projection of the imaging capability of a tool using 2-color interference. (a) The critical dimension for images with a NILS of 1.5 or slightly larger relative to the ratio of the depletion intensity to the switch intensity. (b) NILS for 2-color interference lithography as a function of critical dimension for different deactivation intensities. The images were formed using two-beam interference of a 532-nm deactivation source with an effective NA of 0.9 and a blanket exposure of a 405-nm excitation source. The pitch for each individual exposure is 295.556 nm.

Throughput varies with the type of Pattern and the Line Edge Resolution

Pattern Type

Continuous Lines

Broken Lines

Arbitrary Pattern

Assumptions: 2560 by 1600 pixel DMD 20 kHz frame rate, 7.8 μm DMD pixel spacing 20 nm image pixel 50 mm by 75 mm footprint, 0.5 m/s maximum scan rate 266 nm interference wavelength 0.95 NA Period = λ/2NA = 140 nm Magnification = 7.8/.14 = 55.7 Acceleration = 1g


Line Edge Placement

Time/Footprint

20 nm 35.3 s (102/hr)

117.5 s (30.6/hr) 20 nm

2.5 nm 460.2 s (7.82/hr)

Throughput Estimates for a Fully Populated Super-Resolution System having 20nm Pixel

Size and 2.5 nm Edge Position Grid DMD No of Pixels Frame Rate Pixel size Time/Footprint Throughput*

Generation Million kHz (microns) seconds Substrates/hr

0 4.096 20 7.8 458.414 7.604

1 8.192 30 7.8 153.764 21.332

2 16.384 40 5 58.522 48.965

3 32.768 50 5 24.544 91.039

* Includes 15 second substrate change time


Cost versus Throughput Estimates for a 20 nm Super-Resolution System Using

3rd Generation DMD Technology

0

10

20

30

40

50

60

70

80

90

100

0 5 10 15 20 25

Thro

ughp

ut (3

00 m

m W

afer

s/hr

)

Cost ($Millions)

X 1-Column

X 6-Columns

X 20-Columns


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


PSI Enables Material Development • Develop and supply tools for:

– Material R & D – Lithography test – Lab-2-fab imaging tools

• Litho • Inspection

• PSI Connections and Capability – Fourkas Group at UMD – Resist screening lab and equipment at UNM – CINT transient absorption measurement in film

From this meeting we propose creating an effort to develop a commercially available multi-color resist !!!


InSTED Apparatus Activation Lasers Delivery Through

Beam Splitter

Activation Lasers Activation Lasers Delivery Through Beam

Splitter and Deactivation via Split and Angled Mirrors

405 nm Solid-State Diode Laser (Multi-mode)

364 nm Argon Ion Laser Single Mode


Thank You Work supported by NSF Grant: IIP-1318211

0

0.2

0.4

0.6

0.8

1

1.2

-0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4

Expo

sure

Dos

e

Image Position (Microns)

Exposure Dose Profile for Various Inhibition to Exposure Intensity Ratios

1 2 4 8 16 32

Fourkas: RAPID1

800 nm CW

800 nm pulsed

Intiation(solvated)ePI](solvated)ePI[PI diffusionhνexpose →+ →+ → −+−+

hνdeactivate

1Resolution augmentation through photo-induced deactivation (RAPID) lithography

L. Li, R. R. Gattass, E. Gershgoren, H. Hwang, John T. Fourkas, "Achieving l/20 Resolution by One-Color Initiation and Deactivation of Polymerization", Science, 324, pp. 910-913 (15 May 2009).

Vertical Imaging forms ridges in the tower structure.

USA Patent: 8432533


J. Fischer, G. von Freymann, and M. Wegener, “The materials challenge in diffraction-unlimited direct-laser writing optical lithography,” Adv. Mater. 22, 3578–3582 (2010).

Fischer, Freyman and Wegener: Evidence for Trimming but not STED

STED

Not STED

2/23/2014 IEUVI Resist TWG Meeting

Periodic Structures, Inc. 33


• Three basic components – Photoinitiator

• 2,5-bis(p-dimethylaminocinn amylidene)-cyclopentanone

– Polymerization photo inhibitor

• tetraethylthiuram disulphide

– Monomer matrix

• Capable of high resolution but consumes

TED

BDCC





52 nm Pitch is good but reactant consumption limits ability to make smaller pitches


Menon: AMOL

R. Menon, H-Y Tsai and S. W. Thomas III, "Far-Field Generation of Localized Light Fields using Absorbance Modulation", PRL 98, 043905 (2007).

Control


References

• S. W. Hell and J. Wichmann, Opt. Lett., 1994, 19, 780-782. • J. T. Fourkas and J. S. Petersen, Phys. Chem. Chem. Phys., (to be published 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


20140211 - Paper 9052-6 Next-generation multi-wavelength lithography Printout

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