Hyperspectral Infrared Characterization of Extremely Thin ...€¦ · Hyperspectral Infrared...

Hyperspectral Infrared Characterization of Extremely Thin Films with 10 nm Spatial Resolution

TFUG, Oct. 17, 2019

Sung Park, [email protected]

Copyright © 2019 Molecular Vista – All Rights Reserved – Proprietary and ConfidentialApplications Lab

Molecular Vista Inc (Introduction to the Company)

2


Chemical Mapping: Elemental Analysis via Electron Microscopy

http://www.nanolabtechnologies.com/TEM-STEM-EELS-EDShttps://www.aif.ncsu.edu/tem-lab/

Image credit: North Carolina State Univ. Analytical Instrumentation Facility Image credit: Nanolab Techologies

Atomic Resolution Elemental Mapping on SrTiO3 crystal by Super X EDS (EDX) system on Titan 80-300 Aberration Corrected Scanning Transmission Electron Microscope

• Advanced capability for elemental mapping• Atomic-scale resolution in certain circumstances

Elemental mapping of a device structure by EDS (EDX)


FTIR: Infrared absorption “chemical fingerprint” spectrum

https://en.wikipedia.org/wiki/Fourier_transform_infrared_spectroscopy#/media/File:FTIR_Interferometer.png

Image credit: Wikipedia Image credit: Mudunkotuwa et al., Analyst 139, 870-881 (2014).

• Detailed spectra for analysis and identification of molecular materials• Spatial mapping resolution limited by optical diffraction limit (~ 1 mm)

Detailed absorption spectrum – chemical “fingerprint”

FTIR apparatus


PiFM Measurement – Sideband BimodalTM

f0 – 1st cantilever resonancef1 – 2nd cantilever resonancefm – laser pulse frequency

Spectrum acquired with PiFM

f1 – fm = f0


Agreement between Nanoscale PiFM and Bulk FTIR Spectra

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Topography

100 nm

47.4 nm

0.0 nm

15

1015

2025

30

Fiber

Resin

500 mV

15

9

Wavenumber (cm-1)

Ph

oto

-in

du

ce

d F

orc

e

8009001000110012001300140015001600170018001900

8281738

15081095

1264

16 - 30

1 - 8

Interfacial Chemistry (QCL: 760 – 1960 cm-1)


Exceptional Spatial Resolution in Chemical Mapping

Ps-b-PMMA Block Copolymer, L0 = 22 nm


Surface Sensitivity

l2

triple helix collagen

1 ~ 2 nm

Sample: Courtesy of Jinhui Tao, PNNL


Complements other Analytical Techniques

IR PiFM Raman FTIR TOF-SIMS XPS TXRF SEM/EDS TEM Auger

Species Detected

M.I. M.I. M.I. M.I. M.I. E.I. E.I. E.I. E.I.

Imaging/Mapping Yes Yes Yes Yes Yes Yes Yes Yes Yes

Lateral Resolution < 10 nm > 0.5 mm > 10 mm > 0.2 mm

10 mm – 2 mm

~ 10 mm1 nm*

0.5mm EDS 0.2 nm > 10 nm

Depth Probed 20 nm > 500 nm 1 mm 1 nm 10 nm 10 nm 1 mm ~ 100 nm 10 nm

* Imaging M.I. Molecular information E.I. Elemental information


Semiconductor Applications


Area Selective Deposition (ASD)

Cu SiO2 Cu SiO2 Cu SiO2 Cu SiO2

SAM

Cu SiO2 Cu SiO2

ALD Layer

Ideal Selective Area Deposition

Real World Selective Area Deposition

• SAM Layer• Inhomogeneous and incomplete coverage• Intrusion to SiO2 area, some of which desorb during ALD process

• ALD Layer• Inhomogeneous coverage

Difficult to verify processes with existing tools

metal oxide


Characterization of EUV Resist Exposure

l2

Chemically amplified photoresist (tBOC)

Exposed to EUV light (l = 13.5 nm) at

ALS Lawrence Berkeley National

Laboratory.

Exposure creates shrinkage, resulting

in depression in topography (a).

topography phase

PiFM

Blue – Unexposed

Orange – Exposed


Visualization of Local Strain

Topography

200 nm

11.8 nm

0.0 nm

SiGe

SiO2

SiGe

SiO2

1 3 5 7

2 4 6

PiFM 1122 cm-1

morestrain

lessstrain

1 3 5 7

2 4 680010001200140016001800

Ph

oto

-in

du

ce

d F

orc

e (

Arb

. U

nit)

10871122

1

2

3

456

7

SiGe channel area

a)

SiO2

SiGe

wavenumber (cm-1)

400 nm

CombinedSiO2 @1113 cm-1

SiGe @900 cm-1

b)


Topography

500 nm

45.4 nm

0.0 nm

Phase PiFM

protective layerPET substrate

silver nanowires

Imaging Buried Conductive Layer

hint of a wire


120.0 µV

0.0 µV2.00 1.50 1.00 0.50 0

µm

2.00

1.50

1.00

0.50

0

120.0 µV

0.3 µV2.00 1.50 1.00 0.50 0

µm

2.00

1.50

1.00

0.50

0

Working with 1D/2D Materials

100 nm

691 µV

335 µV100 nm

2.90 nm

0.00 nm

PiFM @ 1122 cm-1Topography

PiFM @ 800 cm-1

topography500 nm

Graphene

11.1 nm

0.0 nm

ML

MoSe2

PiFM @ 683 nm PiFM @ 683 nm

single wall carbon nanotube

semiconducting metallic

Ab

sorp

tio

n

wavelength (nm)


Summary

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• AFM IR technique, PiFM, is introduced.• PiFM measures sample’s complex polarizability via mechanical force detection.• It provides for exceptional spatial resolution (< 10 nm), excellent surface sensitivity

(monolayer), and ease-of-use.• Vista-IR is a turnkey PiFM systems with visible to mid-IR lasers.• Vista-IR can chemically map and identify organic and inorganic materials via

localized IR spectrum (from 10 nm x 10 nm region by monolayer volume).• PiFM is useful for many semiconductor applications.

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