DSA: Progress Toward Manufacturing Readiness · Compact and physical model Shortloops with ST Dedicated defectivity tools DSA at Leti: A large panel of materials and process flows

Raluca Tiron

DSA: Progress Toward Manufacturing Readiness

Senior scientist, CEA-Leti, France

3 LITHO PROGRAMS IN LETI

DSA

Imprint

ML2

@LETI

ONE FOCUS

DEVELOP LOW COST PATTERNING SOLUTIONS

Graphoepitaxy

for contactGraphoepitaxy

for L/S

Chemoepitaxy

for L/SFirst high chi

evaluation

PS-b-PMMA High -

22nm < L0 < 60nm L0 < 20nm

200 nm200 nm

Technological Flow:

Materials : PS-b-PMMA L0 = [25:55nm]

Neutral layer

High chi BCP L0 < 25nm

300 mm Process Line:Lithography for guding patternes– 193 i or e-beam

DSA dedicated track– Specific bake

– Solvent annealing

– PMMA removal step

Dedicated metrology– CD-SEM

– SP2

Integration:Compact and physical model

Shortloops with ST

Dedicated defectivity tools

DSA at Leti: A large panel of materials and process flows available

Balancing BCP Thickness over Template Density in Graphoepitaxy

All images are taken on the same processed wafer

DSA Planarization: Full control of BCP self-

assembly through pitch

DSA planarization : A full control of the template

density over the wafer

The POR used to implement statistical monitoring

CD mean 17 nm

CDU wafer 3s 1.3 nm

PE-3σ 1.3 nmNb of defects 0 def/cm2

Inspected area 0.01 mm2

Nb of inspected contacts 6 x 105

Champion wafer

SOC

Si-ARC

PS


300 mm Process Stability Monitoring

BCP coating

Natural period L

200nm

HOY & placement error (PE)

CD & CDU

FINGERPRINT PATTERNED SURFACE

POR on SOKUDO DUO Track using C35 from Arkema

Fingerprint: Thickness (NL and BCP); BCP’s L0 and CD

Grapho: CD, CDU, PE, HOY

Inorganic template: a reworkable process

Inorganic templets added value

Rework of DSA litho step

Thermal stability

Better surface affinity control

SIARC/SOC

Organic template

Silicon Oxide

Inorganic template

Guide template:

CD guide = 40.5 nm

CDU-3σ guide = 4nm

DSA:

CD = 17.2nm

CDU-3σ = 1.3nm

Residue ~ 7nm

HOY = 100%

Rework : NO

Planar: OK

Guiding template:

CD guide = 40nm

CDU-3σ guide = 4.6nm

DSA:

CD = 17.6 nm

CDU-3σ = 1.4nm

Residue ~ 7nm

HOY = 100%

Rework: OK

Planar OK

Equivalent DSA performances were achieved with inorganic guiding template

Inorganic vs .organic template

residue

Embedded neutral layer: fingerprintTo accurately control the polymer residue: selective neutral layer (NL) on the template bottom side

Sacrificial layer : concept validation on bulk substrate

BC

P o

n s

acri

fici

alla

yer

BC

P a

fte

rsa

crif

icia

llay

er

rem

ova

l

NL

on

bo

tto

mP

S af

fin

e PS

PS

NL

The sacrificial layer is

successfully integrated in the

new integration flow

SiARC

SOC

Sacrificiallayer NL

Embedded neutral layer: templates

NL residue thickness: 8 nm (3 = 0.6nm)

NL thickness can be reduced by Mw (e.g. 3nm)

Uniformity & thickness control of the residue is achieved !!!

FIB-STEM (view in transmission throught the thin lamellae) Susbtrate

Metal

SOC

Si-ARC

Si-ARC

SOC

NL Sacrificial layer

SiARC

PS PS

Embedded neutral layer: DSA

PoR Embedded NL

CD mean 18nm 22nm

Guiding CD 40nm 50nm

Residue 7nm 8nm*

Residue - 3σ 3.9nm 0.6nm

Hole open yield 100% 100%

Comparative evaluation / PoR vs New integration

Uniformity of the residue is improved using

embedded NL

*Could be reduced by using thinner NL

F.DELACHAT et al., n°10144-23. | SPIE Advanced Lithography 2017

Embedded neutral layer/ Advanced surface affinity control

DefectivityDefectivity analysis

CD-SEM

DSA

pro

cess

ste

p

Detection limit = 10 nmInspected surface = 20 µm2

Guiding pattern

DSA

SEM REVIEW CPIDetection limit = 10 nmInspected surface = 0.01 mm²

Inspected CHs = 1200Defects = 0HOY = 100%Defect density = 0 cm-2

Inspected wafers = 50

Inspected CHs = 7 x 106

Defects = 0HOY = 100%Defect density = 0 cm-2


Inspected CHs = 1200Defects = 0HOY = 100%Defect density = 0 cm-2


Inspected CHs = 7 x 106

Defects = 0HOY = 100%Defect density = 0 cm-2


F. Delachat et. al., DSA Symposium 2016

Defectivity: no more a blocking point for DSA integration

DSA for contact patterning

Addapted from H. Yi,et al., Nano. Letters, 2015

Elliptical templatePeanuts shapeContact shrink

Template by 193iPS-b-PMMA BCP (L0 = 35 or 46nm)

200nm

Pitch = 60nm

200nm

Pitch = 46nm

Fast material & processevaluation

DSA Pitch modulation

by 193i pattern engineering

Pitch densityimprovement

by BCP natural period


Full control of BCP self-assembly through pitch All images are taken on the same processed wafer

Summary

DSA has moved beyond the initial excitement of a new discovery.

DSA can easily meet resolution requirements down to N5.

Defectivity is still the main challenge, but the industry is making steady, order-of-magnitude progress each year.

DSA is on track to be adopted in manufacturing within two to five years.

DSA integration of lamellae-forming PS-b-PMMA (L0=38nm)

Targeted application in Leti:

“tri-gate nanowires”

Intel's 22-nm transistors, Nature 481,

152–153,12 January 2012

Template litho

TrenchDSA

assemblyPMMA etching SiO2 etching DSA - copolymer

removal

25nm TBOX

20nm LG ISPD SiCRSD

Si channel

Planar transistor Trigate Nanowire Stacked nanowires

2D channel 3D channel Multi 3D channels

CMOS architecture evolution

DSA: PS Affine Process

Claveau et al., Journal of Micro/Nanolith, MEMS and MOEMS. 15(3), 031604 (Aug 25, 2016).

1. 193-d L/S pattern

2. PS homopolymergrafting

3. PS-b-PMMA coating and self-assembly (250°C for 5min)

SiARCSOCSiO2SiNSi

BCP @ 120nm

Periodic like variations of residual PS bottom layer

UV expo to selectively tune surface affinity

UV-assisted graphoepitaxy process:

neutral bottom / PMMA sidewall affinity

Post DSA: CDU = 1.4nm / LWR = 2.2nm /

LER = 3.8nm

G.Claveau et al., SPIE 2017, 10144-36,

UV expo improve patterns after etching

Sta

nd

ard

pro

cess

Bridge

at bottom

SiO

2 e

tch

ing

Dry

PM

MA

re

mo

va

l

Str

ip/

lith

o/e

tch

cu

t

UV

assis

ted

pro

cess

Si

etc

hin

g

UV exposure avoid pattern collapse and reduce bridging defects

G.Claveau et al. SPIE 2017, 10144-36,

Process overview

CUT demonstrated on Si nanowire level

Guiding Pattern vs DSA Line Edge Roughness Characterization

Guiding Pattern vs DSA LER Characterization with PSD

Summary

UV-assisted graphoepitaxy approach for a precise control of template affinity.

300mm compatible silicon nanowires patterning with DSA process (litho, etch, cut).

Next:

Electrical performances meas. and comparison to double patterning.

DSA patterning for stacked nanowire devices.

Investigation of BCPs with lower resolution. SiN HMSiSiGeSiSiO2 (SOI BOX)

Si etched~ 45nmCD lam~ 11nmSiO2rest~ 3nm (N1) / 16,5nm (zone)

300mm Chemoepitaxy Process

200 nm 200 nm 200 nm 200 nm

DMF = 2 DMF = 3 DMF = 4 DMF = 5

PS-b-PMMA Nanostrength® EO L28 blends, from Arkema

DMF: Density multiplication factorSEM images w/a removing PMMA

Blends enable to achieve higher multiplication factors L/S patterns with low defectivity.

L. Evangelio Araujo et al. Proc of SPIE 2017, 10146-71

Ebeam cut on DSA patterning

E-beam exposure induces selective PMMA removal

E-beam cut on DSA:DSA only:

G.Claveau et. al., DSA Symposium 2016

20nm x 60nm CUT

DSA technology: from PS-b-PMMA to High-

Nodes

L0 (nm)

N10 N7 N3

FIN Pitch

N14

30nm48nm 36nm -[193i + SADP] [193i + SAQP] [193i + SAOP] or [EUV]

PS-b-PMMA High-

38

30

24

18

24nm

N5

DSA of High- materials: a real competitive

patterning option for sub-7nm nodes

100nm100nm

100nm 100nm

Fin

gerp

rin

tp

erf

orm

ance

sG

rap

ho

ep

itax

yp

erf

orm

ance

s

Standard PS-b-PMMA Organic High-χ

L0 (nm) 22 18

CD (nm)

L/S12.0 / 9.0 9.6 / 8.2

LWR (nm)

L/S2.7 / 1.6 1.5 / 1.1

CD (nm)

L/S11.8 / 9.4 11.5 / 6.0

LWR (nm)

L/S2.0 / 1.1 2.0 / 1.22

Organic High-χ implemented on 300mm pilot line, compatible with the standard PS-b-PMMA process

Silicon free High-

A.Gharbi et al., 10146-31 , Proc. of SPIE 2017

Silicon containing high : PS-b-PDMSB

Detailed lithographic performances under investigation on large areas.Next step: process transfer from samples to the track.

Aft

erp

lan

ari

zati

on

& P

S re

mo

val

Etch

ing

into

Si ~

80

nm

Bio sourced High

Djamila Ouhab PhD

a//=13.9nm a ┴ = 12.5nm

-11

20

qz

(nm

-1)

qy (nm-1)

GISAXS

DSA at LetiPS-b-PMMA High -

22nm < L0 < 60nm L0 < 20nm

Graphoepitaxyfor contact

Shrink and doubling Process stability

monitoring Integration

Graphoepitaxyfor L/S

Benchmark materials Prepare metrology

for high chi

200 nm

Chemoepitaxyfor L/S

Benchmark chemo vs grapho

Prepare high chi

First high chi evaluation

Next generationmaterial and processes

200 nm

A large panel of materials and process flows available.

Acknowledgements

Maxime ArgoudSandra BosShayma BouananiZdenek ChalupaGaelle Chamiot-MaitralGuillaume ClaveauFlorian DelachatAhmed GharbiJerome HazartMayssa Al KharboutlyCeline LapeyreLaurent PainAnne PaquetPatricia Pimenta-BarrosJonathan PradellesIsabelle Servin

Masami AsaiIan CayrefourcqXavier ChevalierLaura Evangelio AraujoMarta Fernandez RegulezGuillaume FleuryDouglas GuerreroMasahiko HarumotoChristophe NavarroCelia NicoletRemi LetiecAntoine LegrainFrancesc Perez MuranoKaumba SakavuyiHarold StokesMarc Zelsmann

YOU ARE WARMLY INVITED TO ATTEND

We hope you will help us do this by sponsoring the 4th International Symposium on DSA.On the behalf of program chairs: Tsukasa Azuma, Geert Vandenburghe, Raluca Tiron, and Joe Kline

Organized by: in collaboration with:

http://dsasymp.org/

http://dsasymp.org/

| 34

INTEGRATION CONCERNS

POTENTIAL SHOWSTOPPER FOR DSA

P.Pimenta Barros et al. Proc of SPIE 2014, 9054-15

BCP performances depends on guiding patterns densityeMRS | 14th of May 2015 | Raluca Tiron et al

| 35

0

20

40

60

80

100

120

100 200 300 400 500

Ho

le O

pen

Yie

ld (

%)

pitchguiding (nm)

old process

0,0

0,2

0,4

0,6

0,8

1,0

1,2

1,4

1,6

1,8

100 200 300 400 500

No

rmal

ize

dB

CP

th

ickn

ess

pitchguiding (nm)

old process

« OLD PROCESS »

Hole Open Yield = f (pitch)BCP thickness= f (pitch)

(a) pitch = 110nm (b) pitch = 250nm (c) pitch = 450nm

(a)

(a)

(b)

(b)

(c)

(c)

old process old process old process

Defectivity over template density induced by BCP film thickness variation

eMRS | 14th of May 2015 | Raluca Tiron et al

| 36

A NEW METHOD TO CONTROL BCP FILM THICKNESS OVER PITCH

DSA PLANARIZATION PROCESS

1/ Guiding pattern 2/ Gap filling with BCP 3/ BCP bake

4/ Etch back5/ Etching transfer

patent pending


P.Pimenta-Barros et al, Proc. of SPIE 2015 , 9428-12

| 37

« NEW PROCESS » VS. « OLD PROCESS »

0,0

0,2

0,4

0,6

0,8

1,0

1,2

1,4

1,6

1,8

100 200 300 400 500

No

rmal

ize

dB

CP

th

ickn

ess

pitchguiding (nm)

old process



(a)

(a)

(b)

(b)

(c)

(c)

old process old process old process

Old process filling guiding patternes directly with final film thickness




0,0

0,2

0,4

0,6

0,8

1,0

1,2

1,4

1,6

1,8

100 200 300 400 500

No

rmal

ize

dB

CP

th

ickn

ess

pitchguiding (nm)

old process

new process

(a)

(b)

(c) (a)

(b)

(c)

old process old process old processnew process new process new process

Old process filling guiding patternes directly with final film thickness

New process: using DSA planarization

Documents

DSA: Progress Toward Manufacturing Readiness · Compact and physical model Shortloops with ST Dedicated defectivity tools DSA at Leti: A large panel of materials and process flows