CD - Insight Outside

Directed Self-Assembly of Block Copolymers
an other way to think lithography
R.Tiron et al.
March 14, 2014
Outline
 Lithography: top-down or bottom-up
 CH shrink process implementation
 Perspectives
 High resolution materials
 Contact multiplication
 Summary
R.Tiron
MIDI MINATEC
14 Mars 2014
© CEA. All rights reserved
|2
Optical lithography
a top-down approach
light
mask
optical
system
wafer
Photolithography is a process used in microfabrication to
pattern parts of a thin film. It uses light to transfer a
geometric pattern from a photomask to a light-sensitive
chemical "photoresist“ (resist) on the substrate. (wikipedia)
R.Tiron
MIDI MINATEC
14 Mars 2014
© CEA. All rights reserved
|3
The Sub-Wavelength gap
The big Jump from 193 nm to 13.5 nm
10
Above
wavelength
Near
wavelength
Below
wavelength
Microns
3
1
2
1.5
0.6
g-line
l=436nm
0.1
DUV
l=248nm
1
0.5
0.4
0.35
DUV
l=193nm
0.25
i-line
l=365nm
0.18
0.13
0.09
0.065
0.045
0.032
Pulling in feature size
0.01
1980
1990
2000
0.022
l =EUV 13.5 nm
0.016
2010
Year
A real big jump is needed to achieve higher resolution
R.Tiron
MIDI MINATEC
14 Mars 2014
© CEA. All rights reserved
|4
Self-assembly is a type of process in which a disordered system of pre-existing
components forms an organized structure or pattern as a consequence of specific, local
R.Tiron
MIDI MINATEC
14 Mars
2014 external direction. (wikipedia)| 5
interactions
among the components
themselves,
without
© CEA. All rights reserved
Self-assembly everywhere in the nature
R.Tiron
MIDI MINATEC
14 Mars 2014
© CEA. All rights reserved
|6
Phase separation governing self-assembly
Water- oil mixture
Block copolymers (BCP)
Self assemly based on phase separation: diff. morphologies accessible
R.Tiron
MIDI MINATEC
14 Mars 2014
© CEA. All rights reserved
|7
Block copolymers : definitions
Different morphologies function of molecular fractions fA
& fB
fA 
NA
N A  NB
L0
L0 : characteristic domain length scale
L0  aN 
a : statistical segment length
– Morphology  concentration
of each
phase
N : number of chain
segment
1/ 2the polymer
AB : Flory=
Huggins
parameters
Pitch
length
of the chain
2 = period 2of
 f Aa A  (1  f A )aB
= 2/3
in a1strong
segregation
– 1 polymer  1CD
pitch
(L0) range
f : molecular fraction
c
2
– For
CD/pitch = ct
 c1 constant morphology
T : temperature

–a
1/ 6
AB


T
c1, c2 : constants
N large => strong degree of phase separation
R.Tiron
MIDI MINATEC
14 Mars 2014
© CEA. All rights reserved
|8
Block copolymers : orientation control
Domains orientation controlled by surface
properties:
– Mandatory for lithographic applications
– Modified by chemical treatment,
exposure, statistic block copolymers
X.Chevalier, R.Tiron et al., Proc of SPIE 2011, 7970
R.Tiron
MIDI MINATEC
14 Mars 2014
© CEA. All rights reserved
|9
Pattern placement
Graphoepitaxy
Cheng et al, ACS Nano,VOL. 4, NO. 8, 4815–
4823, 2010, IBM Almaden Research Center
R.Tiron
MIDI MINATEC
Chemical epitaxy
Liu et al, JVST B. 28 (6),
2010, Univ. of Wisconsin
R.Ruiz et al, Science. 5891
(321), 2008, Hitachi
14 Mars 2014
© CEA. All rights reserved
| 10
Directed Self Assembly for Microelectronics
Block copolymers self assembly capabilities
–
–
–
–
Very high resolution
Low intrinsic Line Edge Roughness
Easy process
Low cost
C-MOS Lithography constraints
–
–
–
–
–
R.Tiron
Control the domain orientations (1D - 2D)
Alignment control with respect to a preview level
Integration capabilities
Low defectivity
Respect of design rules
MIDI MINATEC
14 Mars 2014
© CEA. All rights reserved
| 11
Outline
 Lithography: top-down or bottom-up
 CH shrink process implementation
 Perspectives
 High resolution materials
 Contact multiplication
 Summary
R.Tiron
MIDI MINATEC
14 Mars 2014
© CEA. All rights reserved
| 12
How to go from R&D to industrial ?
A production-oriented consortium
– Defectivity
– Design compatibility
Pre-industrial
reactor
Lab. scale
R.Tiron
First 300 mm demonstration
– Process development
– Etch, Strip, …
Process capability
Samples:
– Material compatibility
– Material properties
MIDI MINATEC
– Throughput
– Patterning capability
Maturity II
Process development
Industrialization
300 mm INTEGRATION
Industrial
scalability
Maturity III
Integration
Maturity I
Scale-up material qualification
DSA Materials
14 Mars 2014
© CEA. All rights reserved
| 13
DSA program in LETI
 Push material platforms to maturity
 From lab scale to industry
 Evaluate advanced copolymer platform
 Develop 300mm patterning solutions
 Certify material compatibility with clean room standard
 Screen DSA material performances
 Verify transfer capabilities
 Scale-up DSA processes to production level
 Compatibility with design rules
 Respect of ITRS standard : defectivity, throughput…
R.Tiron
MIDI MINATEC
14 Mars 2014
© CEA. All rights reserved
| 14
DSA 300 mm process implementation
BCP self-assembly
by graphoepitaxy
 No metallic contamination in polymers
 POR using cylindrical BCPs PS-b-PMMA from
Arkema
 Spin casting solvent : PGMEA
 Brush bake: 250C / 2min
 Non grafted brush removal : using PGMEA
Contact shrink
 DSA bake: 250C / 2min
 PMMA remove wet and/or dry processes
 Two DSA dedicated tracks in Leti: SOKUDO DUO
and TEL LITHIUS
“Pattern density multiplication by direct self-assembly of BCP: towards
300mm CMOS requirements” R. Tiron et al,) - 8324-23, SPIE2012
R.Tiron
MIDI MINATEC
14 Mars 2014
© CEA. All rights reserved
| 15
PMMA removal: wet treatment
Missing
contacts
CD-SEM
AFM
wet dev.
Wet by acetic acid
200nm
h + wet dev.
– Only wet : missing contacts
– Need to depolymerize PMMA before wetting by different exposure
treatments (ebeam, 193nm, implantation, etc)
R.Tiron
MIDI MINATEC
14 Mars 2014
© CEA. All rights reserved
| 16
DSA LETI’s 300 mm pilot line
193nm or e-beam
litho pattern
CD ~ 120nm
BCP self-assembly
M.Argoud et al. Proc of
SPIE 2014 9049-81
BCP pattern
transfer
CD ~ 15nm
CD ~ 15nm
100nm
DSA Process of reference (lithographie and etch) available on
300 mm pilot line in Leti
R.Tiron
MIDI MINATEC
14 Mars 2014
© CEA. All rights reserved
| 17
Defectivity and CDU
POR on SOKUDO DUO Track using C35 from Arkema
Defectivity by CD-SEM
image analysys:
– 154 contacts/field
– 3 images/chip
– 58 chips/wafer
Low defectivity
 26796 measured points
 0 missing contacts
 100 % hole open yield
Spec: ±4%
Good CD control after DSA
CDBCP = 25.5 nm
3(CDU wafer) = 1.2 nm
3 (local CDU) = 1.09 nm
(CDguide = 55.2nm / 3 = 4.3nm)
Arkema first generation PS-b-PMMA materials (L0 = 35nm) deliver good
performances on 300 mm pilot line (SOKUDO track )
R.Tiron
MIDI MINATEC
14 Mars 2014
© CEA. All rights reserved
| 18
BCP etching optimization
P.Pimenta Barros et al. Proc of
SPIE 2014 9054-15
SiARC
SOC
Si
PROCESS 2
PROCESS 1
DSA after acetic acid
treatment
1. Brush opening
3. SIARC etching
4. SOC etching
Profile after SOC etching
SiARC
SOC
Si
CD ~13nm
CD ~18nm
CD ~16nm
CD ~24nm
SiARC
SOC
Si
CD ~13nm
CD ~15nm
CD ~11nm
CD ~14nm
PS-PMMA transfer in typical 193 hard-mask is demonstrated
R.Tiron
MIDI MINATEC
14 Mars 2014
© CEA. All rights reserved
| 19
Outline
 Lithography: top-down or bottom-up
 CH shrink process implementation
 Perspectives
 High resolution materials
 Contact multiplication
 Summary
R.Tiron
MIDI MINATEC
14 Mars 2014
© CEA. All rights reserved
| 20
PS-PMMA material (BCP and brush)
 Extendibility (determine high and low
resolution limit)
 Material maturity (35nm < L0 < 46nm)
Batch to batch repeatability
Contamination control
Life time
Evaluate the impact of physical-chemical
polymer properties on patterning process
window
High  materials
 Identification of chemical platform
 Achieve Maturity 1 on Q4-2013
High  BCP




PS-b-PMMA BCP
Work axis on materials
CD = 7nm
CD = 7nm
G.Fleury et al., Proc of SPIE 2014 9049-77
100 nm
R.Tiron
MIDI MINATEC
200 nm
14 Mars 2014
© CEA. All rights reserved
| 21
Broad range of PS-b-PMMA
L0 = 22 nm
L0 = 38 nm
500 nm
L0 = 51 nm
500 nm
L0 = 28 nm
X.Chevalier et al, SPIE 2013 8680-5
500 nm
L0 = 38 nm
L0 > 60nm
CD  10nm
CD  20nm
100nm
100nm
CD  35nm
100nm
Customizable PS-b-PMMA polymers with various pitch demonstrated
R.Tiron
MIDI MINATEC
14 Mars 2014
© CEA. All rights reserved
| 22
Where integrate DSA?
Contact shrink
Contact shrink: good test case to improve materials and processes
To implement DSA (ex. cuts), need to combine resolution and density
R.Tiron
MIDI MINATEC
14 Mars 2014
© CEA. All rights reserved
| 23
Contact doubling
Guiding template
BCP DSA
BCP etching
Cylindrical BCP (L0= 38nm)
in guiding templates
elliptical
“eggs box”
– Contact doubling demonstrated with
DSA
– Pitch sizing possible with contact
doubling approach
A.Gharbi et al. Proc of SPIE 2014 9049-58
100nm
R.Tiron
MIDI MINATEC
14 Mars 2014
© CEA. All rights reserved
| 24
What’s next: Exotic configurations
 15 nm
100 nm
100nm
100nm
Complex structures available for contact multiplication by DSA to
address design rules (hexagonal symmetry may be broken)
R.Tiron
MIDI MINATEC
14 Mars 2014
© CEA. All rights reserved
| 25
Pattern prediction and simulation
Complex structures available for contact multiplication by DSA to
address design rules
R.Tiron
MIDI MINATEC
14 Mars 2014
© CEA. All rights reserved
| 26
DSA physical modeling
Model based on spinodal decomposition and the CahnHilliard equation
Guidings
Simulation
Experimental
Cortosy to S.Moulis, J.Belledent
Physical modeling will be used to calibrate a compact model
R.Tiron
Bottom-up Approaches for Nanotechnologies
May 29th 2013, Orleans
© CEA. All rights reserved
| 27
Predicting polymer structures: compact model
Design
Calculated CH
placement
BF BD SZ0
BF BD+2% SZ+0.5
BF BD-2% SZ-0.5
Simulation contour
Contour variation w.r.t. dose, focus and mask CD error variations
Experimental validation
+ Extracted Contour
+
Calculated CH
position
CH position on
wafer
Pattern multiplication: process available and simulation tools under
development
R.Tiron
Bottom-up Approaches for Nanotechnologies
May 29th 2013, Orleans
© CEA. All rights reserved
| 28
Summary
 DSA is a complementary lithography technique
– In a first step by using PS-b-PMMA like materials (lowest CD
after etching 10nm); In a second step by using high  materials
 A credible alternative for contact and via patterning
– CDU is improved by using DSA 3 < 2nm
– Defectivity 5 defects per wafer (99.97% of good contacts): need
to move to automatic measurements
– Etching capabilities demonstrated
– Metrology DSA is in film order: need to implement hybrid
approach
 What’s next: 2D structures
– Physical and compact models have to be implemented in order
to predict order
R.Tiron
MIDI MINATEC
14 Mars 2014
© CEA. All rights reserved
| 29
Next generation lithography:Probably both
Top-down or bottom-up?
together
Top-down: externally controlled tools are used to cut, mill, and shape
materials into the desired shape and order. (ex. conventional lithography)
Bottom-up: Assemble nano objects out of smaller units
(ex. Block Copolymers)
These terms were first applied to the field of nanotechnology by the Foresight Institute in 1989
LITHOGRAPHY REQUIERMENTS
TOP-DOWN
BOTTOM-UP
RESOLUTION: minimum linewidth or space that may be
printed
–
+
REGISTRATION: degree to which the pattern can be aligned to
previously printed features.
+
–
REPRODUCIBILITY: Ability to produce the same feature size
across an entire wafer
+
–
THROUGHPUT: The time to complete a print
+
+
R.Tiron
MIDI MINATEC
14 Mars 2014
© CEA. All rights reserved
| 30
All this is possible thanks to:
A.Gharbi, P.Pimenta-Baross, K Jullian, I.Servin,
S.Barnola, S.Bos, J.Belledent, G.Chamiot Maitral,
M.Argoud, S.Bouanani, R.Tiron LETI
X.Chevalier, C.Nicolet, C.Navarro Arkema
PhD and internship position available in our team
To joint us please contact me [email protected]
R.Tiron
MIDI MINATEC
14 Mars 2014
© CEA. All rights reserved
| 31
R.Tiron
MIDI MINATEC
14 Mars 2014
© CEA. All rights reserved
| 32

Download Report