Page 1

Characterization of periodic nano-structures by Spectroscopic

Ellipsometry

2018-1-31

Page 2

Out line

Principles of Ellipsometry

Applications of Ellipsometry

About Eoptics

Page 3

Basic Principle of Ellipsometry

Polarization state change of the light after

interacting with the sample

2 ellipsometric angles

tan exppp

ss

ri

r

q0

q1

qi

qk

第i层

薄膜di

第1层

薄膜第2层

薄膜

第k层

薄膜

q2

W0

U1

W1

U2

Ui

Uk

W2

Wi-1

Wi

Wk-1

Wk

E0+

E0-

基底 Es+

Page 4

Psi ()

Delta ()

Film Thickness (d)

Refractive Index (n)

Extinction Coefficient (k)

Measurement

Analysis

Measurement information of Ellipsometry for thin films

kn

Wavelength (nm)

d

200 400 600 800 100015

20

25

30

35

40

wavelength (nm)

Psi

200 400 600 800 1000100

120

140

160

180

De

lta

Psi

Delta

Fit

Ellipsometry is model-based measurement (indirect approach)

From Ellipsometry to Scatterometry

Optical scatterometry measures the polarization state change of the zeroth-order diffraction beam that is scattered from the periodic structure.

Polarizer

Compensator

Analyzer

Source Detector

q

0

+1

-1

Optical modeling

(RCWA, EMA...)

Sample

Signature matching

θ0

x

y

z

φ0

Detector

Source

Measurement

θ*

x

y

φ*

α

w

h

Measured signature

Parameter extraction

(LM, library search...)

Reconstructed structure

α

w

h

From conventional Ellipsometry to Mueller Matrix Ellipsometry

Jones matrix

0

0

rp ippp

ssrs is

E Er

rE E

0.45 0.5 0.55 0.6 0.65 0.7 0.75 0.835

40

45

50

55

60

65

70

75

Ψ(°)

Wavelength (m)

0.45 0.5 0.55 0.6 0.65 0.7 0.75 0.8-200

-150

-100

-50

0

50

100

150

200

Δ(°)

Ei

Eip

Eis

Erp

Ersθ

α

WD

-1

0

1

-1

0

1

-1

0

1

-1

0

1

Wavelength ()

rp ippp ps

sp ssrs is

E Er r

r rE E

Conventional Ellipsometry

Mueller Matrix Ellipsometry

α

W

D

φ

Z

Y

X

θ

Eis

Eip

Ei

tanrp ip ppi

rs is ss

E E re

E E r

1

4 4( ) ( )M U J J Uijm

More data, more information!

Mueller matrix

• Not limited to fully polarized light.• Be able to deal with depolarization effect.

Development Mueller Matrix Ellipsometer

Specifications

✓15 Mueller matrix elements (normalized by m11)

✓ Spectral range: 200~1000 nm

✓ Incidence angle range: 45~90

✓ Spot size: < 200 m

✓ Measurement time with full spectrum: 1~15 s

✓ Measurement repeatability: < 0.002 nm (1σ)

✓Accuracy：0.1nm （for ~100nm SiO2 film）

Page 8

Out line

Principles of Ellipsometry

Applications of Ellipsometry

About Eoptics

Typical Nanostructure Metrology

E-beam patterned

nanostructure

Nanopillar

array structure

Photoresist with

line edge roughness

Nanoimprinted

structure

Etched trench

nanostructure

Asymmetric

nanostructure

Critical dimension Critical dimension

Line edge

roughness (LER)

Residual

layer

thickness

Parameters MME SEM

p1 [nm] 60.37±0.04 61.2

p2 [deg] 96.91±0.03

p3 [nm] 62.51±0.06

78 [nm]p4 [deg] 15.79±0.14

p5 [nm] 13.95±0.06

0

1

2

-1

0

1

-0.4

-0.2

0

-0.1

0

0.1

-1

0

1

0.95

1

1.05

-0.1

0

0.1

-0.2

0

0.2

0

0.2

0.4

-0.1

0

0.1

-1

-0.5

0

-1

0

1

200 400 600 800-0.1

0

0.1

200 400 600 800-0.2

0

0.2

200 400 600 800-1

0

1

200 400 600 800-1

-0.5

0

Critical dimensionp2

p1

p4

p3

p5

HSQ

Silicon

Critical Dimensions of E-beam Patterned Structures

Parameter

SEM MME

D (nm) 33.99 36.9

H (nm) 290.69 284

High aspect ratio ~10:1

Critical Dimensions of Nanopillars

Page 12

Nano-Imprinted Structures

Residual layer

thickness

p2

p1

p4

p3

p5

p6

Resist

Silicon

200 300 400 500 600 700 800

0.85

0.90

0.95

1.00

Wavelength [nm]

Dep

ola

rizati

on

in

dex

DI data

DI1

DI2

300 350 400 450

1 2T 2

11

2

11

Tr( ), 0 1,

3

MM mDI DI

m

Depolarization Index (DI)

Parameters MME SEM

p1 [nm] 352.29±0.16 352.2

p2 [deg] 87.11±0.03 87.5

p3 [nm] 442.83±1.01

472.1p4 [deg] 25.41±1.47

p5 [nm] 29.65±0.97

p6 [nm] 61.42±0.08 57.8

t [nm] 3.19±0.06

Asymmetric Nano-Imprinted Structures

Conventional ellipsometry techniques have difficulties in measuring asymmetric grating structures due to the lack of sensitivity to the direction of profile asymmetry.

-1.0

0

1.0

-0.2

0

0.2

-0.2

0

0.2

-1.0

0

1.0

0.7

0.8

0.9

1.0

-0.4

0

0.4

-0.2

0

0.2

-0.2

0

0.2

-0.4

0

0.4

-1.0

0

1.0

-1.0

0

1.0

200 400 600 800-0.2

0

0.2

200 400 600 800-0.2

0

0.2

200 400 600 800-1.0

0

1.0

Wavelength [nm]200 400 600 800

-1.0

0

1.0

data

fit

500 nm

Deep-Etched Trench Profile

Parameters MME TEM

D1 [nm] 75.32 75.01

H1 [nm] 135.51 135.60

H2 [nm] 9.12 9.92

H3 [nm] 132.79 134.29

SWA1 [deg] 87.45 87.49

SWA2 [deg] 82.74 82.29

Si3N4 SiO2 Si

SWA2

ArF resist

Photoresist removing

(a) (b)

D1

H1

P

H2

H3

SWA1

D1

H1

P

H2

H3

SWA2

SWA1

(c) (d)

Model A Model B

SWA1

Page 15

Other applications

OPVOLED

Optical coating Solution based coating

Layer1#：TiO2Layer2#：SiO2Layer3#：TiO2

glass

Page 16

Out line

Principles of Ellipsometry

Applications of Ellipsometry

About Eoptics

Page 17

Supported by the first scientific instruments and equipment development plan

Supported by the seventh batch of 3551 Optics Valley talent programs

Awarded the 40th Geneva International Invention Gold Award

Supported by innovation and entrepreneurship strategy team of Hubei province

Introduction

Specialized in ellipsometry technology in China

Provide measurement solutions for ultra-thin layered nano-structures

Applied in integrated circuits, semiconductors, photovoltaic, flat panel

display, LED, biological and so on

超薄层状纳米器件

IC芯片

Page 18

Eoptics Series of ellipsometers for scientific research and industry application

Products

Page 19

Thanks!