6924 04 Winfried Kaiser

7/27/2019 6924 04 Winfried Kaiser

1/16

The future of EUVL

by

Winfried Kaiser,

Udo Dinger, Peter Kuerz,

Martin Lowisch,

Hans-Juergen Mann,

Stefan Muellender,

. ,

Jos Benshop,

Steven G. Hansen,

Koen van Ingen-Schenau

Outline

Introduction

Imaging requirements of future nodes

High NA optics

Infrastructure and Technology

For public use Seite 20940_tuesday_6924-4_Winfried_Kaiser.ppt

Summary


2/16

Status Alpha Demo Tool

30 nm

42 mJ/cm232 nm

40 mJ/cm2

30 nm

24 mJ/cm232 nm

24 mJ/cm2


1st scanner able to print dense features in single exposure

See also: Emerging Lithographic Technologies XII

Hans Meiling: Field performance of the EUV alpha demo tools

Tuesday, 26 February 2008, 1:20 PM 1:50 PM

(nm)

200

Why EUV?

ASML Product

XT:1400

XT:1700i

AT:1200

Resolution,

Shrin

100

80

60

40 Immersion


Year of Production Start*

Introduction XT:1900iNEXT

EUV30

20

02 10 121107 090804 060503 13 14

EUV

Double patterning

Note: Process development

1.5 ~ 2 years in advance / updated 12/07


3/16

Why EUVL: 22nm SRAM approaches

cell area

0.16u2

approx SE

standard layout

(optimized) more DFM?

asym shrink

??

more DFM?

DPT, 3PT, 4PT

??

higher NA SE

or EUV

1.35NA

0.10u2

limit with

1.35NA and

standard

design

Best 2-way split

k1=0.31

k1=0.31

4

k1 relative to

0.09u2 target

1.7NA

193nm SE

38 nm


EUV allows the patterning of complex, dense features in a single exposure step!

0.06u2

22nm node

target range

-

k1=0.55

k1=0.53

k1=0.48

k1=0.48

0.25NA EUV

m cm

Outline

Introduction


High NA optics



Summary


4/16

EUV Optics: The future

EUV is introduced as a high k1 technology

Node \ NA 0.25 0.32 0.45

32 nm 0.59 0.76 1.07

22 nm 0.41 0.52 0.73

16 nm 0.30 0.38 0.53

11 nm 0.20 0.26 0.37

NAkRES

1=

k1reduction


opportunity

EUV will follow the optical path with high NA and k1 reduction

32 nm features

Dense Lines

conventional illumination0.6

0.7

0.8

1.5

2

2.5

3

0.6

0.7

0.8

1.5

2

2.5

3best focus 75 nm defocus

NILS NILS

lcoherence

Dense contacts

conventional illumination

0.6

0.7

0.8

1.5

2

2.5

3

0.6

0.7

0.8

1.5

2

2.5

3

0.2 0.3 0.4

0.3

0.4

0.5

0

0.5

1

0.2 0.3 0.4

0.3

0.4

0.5

0

0.5

1

tialcoherence

Parti


0.2 0.3 0.4

0.3

0.4

0.5

0

0.5

1

0.2 0.3 0.4

0.3

0.4

0.5

0

0.5

1Pa

NA NA

Flare: 6%, WFE: 0.5 nm rms

NILS target: 2


5/16

0.6

0.7

0.8

1.5

2

2.5

3

0.6

0.7

0.8

1.5

2

2.5

3

NILS NILS

oherence

best focus 50 nm defocus

Dense Lines


22 nm features

0.2 0.3 0.4

0.3

0.4

0.5

0

0.5

1

0.2 0.3 0.4

0.3

0.4

0.5

0

0.5

1

Partialc

centerA

0.6

0.7

0.8

1.5

2

2.5

3

0.6

0.7

0.8

1.5

2

2.5

3

Dense contacts



NA NA

Sigm

0.2 0.3 0.4

0.3

0.4

0.5

0

0.5

1

0.2 0.3 0.4

0.3

0.4

0.5

0

0.5

1

NA 0.32 enables 22nm patterning with conventional illumination

NILS NILS

acenterA


Dense Lines

annular illumination

0.6

0.7

0.8

2

2.5

3

0.6

0.7

0.8

2

2.5

3

16 nm features

0.6

0.7

0.8

1.5

2

2.5

3

0.6

0.7

0.8

1.5

2

2.5

3

Sig

acenterQ

A

Dense contacts

quasar illumination

0.2 0.3 0.4

0.3

0.4

0.5

0

0.5

1

1.5

0.2 0.3 0.4

0.3

0.4

0.5

0

0.5

1

1.5


0.2 0.3 0.4

0.3

0.4

0.5

0

0.5

1

0.2 0.3 0.4

0.3

0.4

0.5

0

0.5

1

NA NA

Sigm

Q

and even 16nm with off axis illumination


6/16

NILS NILS

centerA


Dense Lines

annular illumination

0.6

0.7

0.8

1.5

2

2.5

3

0.6

0.7

0.8

1.5

2

2.5

3

11 nm features

0.6

0.7

0.8

1.5

2

2.5

3

0.6

0.7

0.8

1.5

2

2.5

3

Sigm

centerQ

A

Dense contacts

quasar illumination

0.4 0.5 0.6

0.3

0.4

0.5

0

0.5

1

0.4 0.5 0.6

0.3

0.4

0.5

0

0.5

1


0.4 0.5 0.6

0.3

0.4

0.5

0

0.5

1

0.4 0.5 0.6

0.3

0.4

0.5

0

0.5

1

NA NA

Sigm

Q

11nm can be imaged with NA > 0.45 and off axis illumination

Outline

Introduction


High NA optics



Summary


7/16

The path to NA = 0.32

Slit length 26mm

MAG = 4x

Enabling for higher NA:

Larger mirror sizes

Stronger aspheres


NA 0.25 NA 0.32

Full field 6 mirror designs can be extended to NAs around 0.32

Apodization is limiting 6M designs

center of field (x=0)

edge of field (x=13mm)


The larger NA introduce a high angular load on surfaces which cause significant apodisation effects

Balancing of optical and coating design is needed to achieve a (quasi) rotational symmetric

apodisation uniform over the field


8/16

full field

NA > 0.4 : Way out with central

obscuration

M5

reduced

field


M5Central obscuration solves the apodisation issue but limits the field size.

Full field designs show big central obscurations.

In addition stopping down increases the obscuration ratio.

NA 0.5

NA 0.32,

Annular 0.6-0.8

16nm feature size

Imaging effect of apodisation and

central obscuration

Model pupil:

2/3

1/3


Area with reduced

transmission/obscuration

Transmission100%

The prime effect of apodisation and central obscuration

can be compensated by CD biasing


9/16

Alternative with NA>0.4

8M designs allow unobscured full field

systems with NA 0.5.

The two additional mirrors cause a


reduction of system transmission by

at least a factor of 2.

NA 0.5

Extending NA to 0.7


NA 0.7

For NA 0.7 the only

design solutions are

obscured 8M systems


10/16

High NA solution roadmap

Solution overview:

8M

6M

..

unobscured

..


central obscured

(smaller fields)

There are design solutions for high NA systems enabling 11 nm and beyond

Res 2014 201520132010 2011 2012

EUVL Roadmap down to 11nm

11nm

16nm

22nm

same lens,

enhanced

off axis

illumination 0.32NA, 3nm OVL, >100wph

0.32NA +off axis illumination

0.4xNA


27nm 0.25NA, 4nm OVL


11/16

Outline

Introduction


High NA optics



Summary

Z-graded multilayers

EUV Coatings

8 1dR0(0-18)=72%

0.7

0.8

0

2

4

6

2

3

Layerthickness,nm

dSi

dMoperiod. ML

R0(0-18)=64%R0=60%

R0=58%

0.0

0.1

0.2

0.3

0.4

0.5

0.6

Reflectivity


Z-grading of EUV multilayers improves the angular acceptance

on cost of peak reflectivity and therefore system transmission

Bi-layer numberIncidence angle, degrees


12/16

0,45

0,50

0,55

des)

Set 1

MET2 mirrors

on-axis

AD-tool6 mirrors

off-axis

Preproduction

tool

Productiontoolstestmirror

Progress in flare reduction

0,15

0,20

0,25

0,30

0,35

0,40

MSFR

[nmrms]

(evaluatedover4.6dec

Set 3

Set 2

test mirror

setup

POB

a us: are eve

Figure = 0.04 nm rms

MSFR = 0.13 nm rms

HSFR = 0.07 nm rms

8% flare


0,05

0,10

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009

2010

2011

2012

2013

2014

2015

(MSFR

opt.)

16% flare

tools

Flare is calculated for a 2 m

line in a bright field

arget: are

Flare will be improved further to secure high imaging performance

for smaller feature sizes

Impact of CRAO change (1)

ChiefRay Angle on Object side ()

EUV optics has to be non-telecentric on reticle side.

Actual standard is 6 this limits the NA to < 0.4 Ma 4x .

For larger NAs the CRAO has to be increased accordingly.

Example:

3

4

5

6

7

8

Vmaskbias(nm)


0

1

2

5 6 7 8 9 10

CRAO

required

H

NA=0.45, annular illumination

Mask stack wih 67nm TaN absorber


13/16

Impact of CRAO change (2)

Required delta bias HV

5

6

7

)

Att PSM Stack (11nm)

17nm TaN (magenta)

Required delta bias HV

0

1

2

3

4

6 7 8 9

CRAO (deg)

bias

(nm

required delta bias HV21nm Ru (green)

11nm Si (blue)

40 MoSi bilayer

The impact of a change of CRAO is not well understood today in full extent.

Our view is that there are no showstoppers for an increase to 9 - 10 allowing full

CRAO (deg)Source: Samsung

11nm DL

NA=0.45

Quasar


.

where on the effect on imaging by larger CRAOs can be compensated by biasing

without critical impact.

The only alternative for NA > 0.4 would be to go to higher Mag (5x, 6x, 8x) whichwould limit the usable field size in 2 dimensions with significant impact on

productivity or require larger mask sizes.

EUV Source power

wp

(full field optics)


Source: Cymer


14/16

EUV source power vs. resist sensitivity

1400

16008 mirror POB

6 mirror POB

200

400

600

800

1000

1200

Power[Watt@I

FIB]

@ 100 wph


To keep the required source power (at intermediate focus in band)

in a realistic range, resist sensitivity must target 10 mJ /cm2

0

0 10 20 30 40

Resist sensitivity [mJ/cm^2]

Effective etendue for

off axis illumination

out

Conventional

out in

Annular Quasar 45

out in

-

1.40.70.40.6-0.8Annular

3.21.61.00.8Conventional

NA=0.45NA=0.32NA=0.25Setting

relative etendue (@fixed slit size)

out= 0.8 in = 0.0 out= 0.8 in = 0.6 out= 1.0 in = 0.6


... - .

Off axis illumination will reduce the effective etendue the illumination system

can accept from the source. Therefore the source etendue covering the full

source power has to be small enough to avoid any productivity loss for these

settings. Since the etendue grows with NA, in future larger source etendues

can be accepted or more aggressive off axis settings can be used.


15/16

0.8

1.0

stloss

flare

flare + aberrations

Resist effect on imaging

1:1 L/S

0.0

0.2

0.4

0.6

12 17 22 27 32 37

relativecontr

5nm resist blur

flare + aberrations +

10nm resist blur

flare + aberrations +

15nm resist blur

Assumptions:

Flare: 4% system, 50% mask trans

Aberration: 0.5nm RMS

Resist treated as a Gaussian (1) image blur Relative contrast loss calculated based on


a -p tc nm MTF contrast

See also:

Advances in Resist Materials and Processing Technology XXV

K. van Ingen Schenau: Photoresist-induced contrast loss and

its impact on EUV imaging extendibility

Wednesday, 27 February 2008 9:40 AM 10:00 AM

Resist diffusion has strongest effect on contrast loss.

For pattern transfer of very fine features significant improvement

of resist blur (diffusion) to finally 5nm are needed

Outline

Introduction


High NA optics



Summary


16/16

Summary: the extendibility of EUVL

There are solutions visible for high NA design to 0.7 NA.The challenge will be to find full field designs with optimum

transmission to enable high productivity.

~ . .

These together will enable the printing of 11nm dense features in

single exposure mode and even beyond. Improvements in polishing

and coating technologies are expected to support this progress.

Mask technology has to follow the resolution roadmap accordingly.

For larger NAs the CRAO has to be increased and the layer stack to be

adapted. The expectation is that neither increase of Mag and no larger


.

Very important are improvements of resists:

Resist sensitivity have to target 10mJ/cm2 to keep the required sourcepower in a realistic target range of some 100W @ 100 wph tput.

To enable pattern transfer of features down to 11nm the resist blur

(diffusion length) has to be reduced to at least 5nm .

ACKNOWLEDGEMENT

Thanks

The activities received funding

by the European Commission in the project "More Moore"

and by various national European governments

including the German Federal Ministry of Education and Research

in the program MEDEA+ .


6924 04 Winfried Kaiser

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