euv radiation chemistry fundamentals 2euvlsymposium.lbl.gov/pdf/2015/oral_tuesday... · euv...

21
EUV Radiation Chemistry Fundamentals: Novel Experiments and Simulations Molecular Foundry D. Frank Ogletree, Paul Ashby, Kristina Closser, Yi Liu, David Prendergast, Deirdre Olynick CSD/ALS Musa Ahmed, Oleg Kostko, Bo Xu, CXRO Suchit Bhattarai, Patrick Naulleau, Lawrence Berkeley National Lab Berkeley CA USA

Upload: others

Post on 03-Jun-2020

24 views

Category:

Documents


0 download

TRANSCRIPT

Page 1: EUV Radiation Chemistry Fundamentals 2euvlsymposium.lbl.gov/pdf/2015/Oral_Tuesday... · EUV Radiation Chemistry Fundamentals Novel Experiments and Simulations Molecular Foundry D

EUV Radiation Chemistry Fundamentals: Novel Experiments and Simulations

Molecular Foundry D. Frank Ogletree, Paul Ashby, Kristina Closser, Yi Liu, David Prendergast, Deirdre Olynick

CSD/ALS Musa Ahmed, Oleg Kostko, Bo Xu, CXRO Suchit Bhattarai, Patrick Naulleau,

Lawrence Berkeley National Lab Berkeley CA USA

Page 2: EUV Radiation Chemistry Fundamentals 2euvlsymposium.lbl.gov/pdf/2015/Oral_Tuesday... · EUV Radiation Chemistry Fundamentals Novel Experiments and Simulations Molecular Foundry D

EUVL 2015 Maastricht D. Frank Ogletree LBNL

Limitations of EUV Resists ♦  Sensitivity ♦  Control of Line-edge Roughness ♦  Resolution for sub-10 nm Patterning

2

We need to be able to LOOK at what is happening to UNDERSTAND new radiation chemistry

Page 3: EUV Radiation Chemistry Fundamentals 2euvlsymposium.lbl.gov/pdf/2015/Oral_Tuesday... · EUV Radiation Chemistry Fundamentals Novel Experiments and Simulations Molecular Foundry D

EUVL 2015 Maastricht D. Frank Ogletree LBNL

The Problem

“…it is technically nearly impossible to directly observe the reactions induced in ultrathin resist films

by 92.5 EUV radiation…”

Kozawa & Tagawa EUV CAR review Jpn J Appl Phys 2010

3

Page 4: EUV Radiation Chemistry Fundamentals 2euvlsymposium.lbl.gov/pdf/2015/Oral_Tuesday... · EUV Radiation Chemistry Fundamentals Novel Experiments and Simulations Molecular Foundry D

EUVL 2015 Maastricht D. Frank Ogletree LBNL

Our Program ♦  “New” ways to THINK about EUV reactions

•  Concepts from the Electron Spectroscopy and Radiation Biology communities that are less familiar to the Lithography community

♦  New ways to LOOK at EUV reactions •  Single Molecule Gas-Phase Experiments at X-ray

Synchrotrons •  Follow individual reaction steps in detail

♦  New ways to UNDERSTAND EUV Reactions •  ab-initio theoretical calculations of: •  Molecular Photoemission cross-sections •  Post-excitation Auger Relaxation processes •  Molecular Dynamics of post-excitation events

4

Page 5: EUV Radiation Chemistry Fundamentals 2euvlsymposium.lbl.gov/pdf/2015/Oral_Tuesday... · EUV Radiation Chemistry Fundamentals Novel Experiments and Simulations Molecular Foundry D

EUVL 2015 Maastricht D. Frank Ogletree LBNL

THINK: Excitation and Relaxation

5

Step 1 Photoionization

M + hν è M+ + e-

e- γ

M+ Step 2 Electronic Relaxation

Auger process ? M+ è M++ + e-

e-

M++

Step 3 Atomic Relaxation

Fragmentation? M+ è R1�+ + R2�

R1�+ R2�

e-

M+

e-

e- Step 4

Inelastic Scattering

M + e- è M+ + 2 e-

and more steps…

Page 6: EUV Radiation Chemistry Fundamentals 2euvlsymposium.lbl.gov/pdf/2015/Oral_Tuesday... · EUV Radiation Chemistry Fundamentals Novel Experiments and Simulations Molecular Foundry D

EUVL 2015 Maastricht D. Frank Ogletree LBNL

THINK: Molecular Photoemission

6

EUV can ionize any molecular orbital

Methanol Photoelectron energy between 57 and 80 eV

Molecules with N, O, F have

2s orbitals bound by 30-40 eV

accessible 4d levels give atoms like Sn, Sb, Te, I much larger EUV

cross-sections, and make Auger relaxation likely

0 eV

10 eV

20 eV

30 eV

40 ev

Photoemission spectrum of gas-phase methanol CH3OH

Kai Siegbahn

1969

14 valence electrons in 7

molecular orbitals give 7 XPS peaks

#1

Page 7: EUV Radiation Chemistry Fundamentals 2euvlsymposium.lbl.gov/pdf/2015/Oral_Tuesday... · EUV Radiation Chemistry Fundamentals Novel Experiments and Simulations Molecular Foundry D

EUVL 2015 Maastricht D. Frank Ogletree LBNL

THINK: Molecular Relaxation

7

0 eV

10 eV

20 eV

30 eV

40 ev

#1 Suppose a deep MO is ionized,

ejecting a relatively slow e- #2

The molecule is left in a highly excited state, and the

valence electrons adjust within 1 fs

An Auger process can fill the deep core hole, ejecting a very slow electron, leaving the molecule doubly ionized

#2

The molecule is still in a highly excited state, it may

undergo a second Auger process or fragment…

#3

Page 8: EUV Radiation Chemistry Fundamentals 2euvlsymposium.lbl.gov/pdf/2015/Oral_Tuesday... · EUV Radiation Chemistry Fundamentals Novel Experiments and Simulations Molecular Foundry D

EUVL 2015 Maastricht D. Frank Ogletree LBNL

LOOK: Gas-phase Photoemission

Electron energy and angular distributions calculated from maps

Auger and Photo electrons have different

distributions 8

Velocity Map Electron Imaging Spectrometer

VMI trajectories

#1

#2

Page 9: EUV Radiation Chemistry Fundamentals 2euvlsymposium.lbl.gov/pdf/2015/Oral_Tuesday... · EUV Radiation Chemistry Fundamentals Novel Experiments and Simulations Molecular Foundry D

EUVL 2015 Maastricht D. Frank Ogletree LBNL

LOOK: Synchrotron Mass Spec

9

Ionized Molecules and Fragments are

detected by time-of-flight MS

Variable Energy Photons or Electrons excite

gas-phase molecules

#1 #4

Experiment Details: Poster P-RE-10 Oleg Kostko, Bo Xu

Page 10: EUV Radiation Chemistry Fundamentals 2euvlsymposium.lbl.gov/pdf/2015/Oral_Tuesday... · EUV Radiation Chemistry Fundamentals Novel Experiments and Simulations Molecular Foundry D

EUVL 2015 Maastricht D. Frank Ogletree LBNL

LOOK: Model Compounds

Advanced resist materials will also be investigated •  Brainard Group, SUNY, Inpria Inc.

10

2-methylphenol 4-chloro-

2-methylphenol 4-iodo-

2-methylphenol 4-bromo-

2-methylphenol

Explore role of high cross-section

4d elements (iodine)

Nanoparticle Organic

Hybrid Resists

Metal Organic Resists for EUV

(MORE)

Page 11: EUV Radiation Chemistry Fundamentals 2euvlsymposium.lbl.gov/pdf/2015/Oral_Tuesday... · EUV Radiation Chemistry Fundamentals Novel Experiments and Simulations Molecular Foundry D

EUVL 2015 Maastricht D. Frank Ogletree LBNL

LOOK: VMI Electron Spectra

0 10 20 30 40 50 60 70 80 900

1x106

2x106

3x106

4x106

4-Iodo-2-methylphenol

I 4d

Auger electronsInte

nsity

Binding energy (eV)

30 eV 45 eV 60 eV 75 eV 85 eV 92 eV

11

As x-ray energy increases toward EUV, I 4d levels increase cross section, clear signature of Auger relaxation

#1 #2

Page 12: EUV Radiation Chemistry Fundamentals 2euvlsymposium.lbl.gov/pdf/2015/Oral_Tuesday... · EUV Radiation Chemistry Fundamentals Novel Experiments and Simulations Molecular Foundry D

EUVL 2015 Maastricht D. Frank Ogletree LBNL

LOOK: VMI Electron Spectra

12

Calculated energies of I-related orbitals (2e- except for 4d with 10)

Kinetic Energy [eV]

0 eV

10 eV

20 eV

30 eV

40 ev

50 eV 4d

5s

σ π

π* 5p

I 4d is excited, one 92 eV photon in, one 35 eV photoelectron out

~ 55 eV potential energy remains!

#2

92 eVAuger

Page 13: EUV Radiation Chemistry Fundamentals 2euvlsymposium.lbl.gov/pdf/2015/Oral_Tuesday... · EUV Radiation Chemistry Fundamentals Novel Experiments and Simulations Molecular Foundry D

EUVL 2015 Maastricht D. Frank Ogletree LBNL

LOOK: VMI Electron Spectra

13

0 eV

10 eV

20 eV

30 eV

40 ev

50 eV 4d

5s

σ π

π* 5p

#2 35 eV photoelectron

16 eV Auger

6 eV Auger

Page 14: EUV Radiation Chemistry Fundamentals 2euvlsymposium.lbl.gov/pdf/2015/Oral_Tuesday... · EUV Radiation Chemistry Fundamentals Novel Experiments and Simulations Molecular Foundry D

EUVL 2015 Maastricht D. Frank Ogletree LBNL

LOOK: Molecular Fragmentation

PHOTONS ELECTRONS

14

(I-MePh)+ I� + (MePh)+

I� + R� + R+

ring-breaking events

#3

Page 15: EUV Radiation Chemistry Fundamentals 2euvlsymposium.lbl.gov/pdf/2015/Oral_Tuesday... · EUV Radiation Chemistry Fundamentals Novel Experiments and Simulations Molecular Foundry D

EUVL 2015 Maastricht D. Frank Ogletree LBNL

UNDERSTAND: Ionized Molecules

I 4d level is ionized, Molecular orbital density

increases (blue) or decreases (green)

This generates forces on the

atoms (red arrows) and fragmentation, (probable

loss of I radical)

other orbitals produce OH radicals or stable ions

15

#3

Theory Details: Poster P-RE-12 Kristi Closser

Page 16: EUV Radiation Chemistry Fundamentals 2euvlsymposium.lbl.gov/pdf/2015/Oral_Tuesday... · EUV Radiation Chemistry Fundamentals Novel Experiments and Simulations Molecular Foundry D

EUVL 2015 Maastricht D. Frank Ogletree LBNL

Condensed Resist Films?

♦  Photoemission and Auger relaxation processes are almost unchanged •  dielectric environment reduces binding

energies ~ 4 eV •  sharp lines are broadened

♦  Electrons are elastically scattered before leaving the electric field of the photo-ion •  Photoelectrons may be recaptured by primary

or other ions

16

Page 17: EUV Radiation Chemistry Fundamentals 2euvlsymposium.lbl.gov/pdf/2015/Oral_Tuesday... · EUV Radiation Chemistry Fundamentals Novel Experiments and Simulations Molecular Foundry D

EUVL 2015 Maastricht D. Frank Ogletree LBNL

Condensed Resist Films?

♦ Inelastic electron scattering • plasmon excitation in condensed films

(~ 20 eV) •  followed by decay to hot electrons, which

interact with molecules ♦ Molecular fragmentation changes •  fragments are trapped in polymer matrix,

may recombine or generate secondary reactions…

17

Page 18: EUV Radiation Chemistry Fundamentals 2euvlsymposium.lbl.gov/pdf/2015/Oral_Tuesday... · EUV Radiation Chemistry Fundamentals Novel Experiments and Simulations Molecular Foundry D

EUVL 2015 Maastricht D. Frank Ogletree LBNL

Condensed Phase Resist Studies

18

Nanoparticles ≥ 50 nm can be coated with resist films of varying thickness and analyzed by VIM and MS

Dynamically-coated size-selected particles are analyzed

Page 19: EUV Radiation Chemistry Fundamentals 2euvlsymposium.lbl.gov/pdf/2015/Oral_Tuesday... · EUV Radiation Chemistry Fundamentals Novel Experiments and Simulations Molecular Foundry D

EUVL 2015 Maastricht D. Frank Ogletree LBNL

Summary and Outlook

♦ New ways to THINK about EUV

♦ New tools to LOOK at EUV molecular processes

♦ Theoretical methods to UNDERSTAND these processes

19

#1 #3 #2

#4

Page 20: EUV Radiation Chemistry Fundamentals 2euvlsymposium.lbl.gov/pdf/2015/Oral_Tuesday... · EUV Radiation Chemistry Fundamentals Novel Experiments and Simulations Molecular Foundry D

EUVL 2015 Maastricht D. Frank Ogletree LBNL

Summary and Outlook

♦ We have confirmed that 4d Iodine, has a higher EUV cross-section

♦ One EUV photon generates multiple secondary electrons in the PRIMARY event

♦ Our theoretical and experimental tools can be applied to more “realistic” resist molecules

20

Page 21: EUV Radiation Chemistry Fundamentals 2euvlsymposium.lbl.gov/pdf/2015/Oral_Tuesday... · EUV Radiation Chemistry Fundamentals Novel Experiments and Simulations Molecular Foundry D

EUVL 2015 Maastricht D. Frank Ogletree LBNL 21

This work was supported by the LBNL Laboratory Directed Research and Development Program. Portions of this work were carried out at the Molecular Foundry and at the Advanced Light

Source under U.S. Department of Energy contract No. DE-AC02-05CH11231