overview of euv lithography
TRANSCRIPT
Overview ofEUV Lithography
David Attwood
University of California, Berkeley
(http://www.coe.berkeley.edu/AST/sxr2009)
07 Overview of EUV Lithography / Spring 2009
Extreme Ultraviolet (EUV) LithographyBased on Multilayer Coated Optics
Reflectivemask
Absorberpattern
Multilayermirror
Wafer to record 30 nm features or smaller, overcm2 dimensions
4:1reductionoptics,aspheric,multilayercoated
λ = 13 nm
6.7 nmperiod
MoSi
Ch10_08_June08.ai
CU_Jan12_04.pptD. Attwood 9
EUV Lithography Will Use aStep and Scan Ring Field System
Ch10_F05_modif.ai
International Technology Roadmapfor Semiconductors†
†Semiconductor Industry Association (SIA), December 2004 update. *Possible 2-year cycle for leading edge companies.
2005* 2007* 2011*2003*
SIA_RdmpTbl_Sept2008.ai
First year of volume production 2004 2007 2010 2013 2016
Technology Generation 90 nm 65 nm 45 nm 32 nm 22 nm(half pitch, 1:1, printed in resist)
Isolated Lines (in resist) 53 nm 35 nm 25 nm 18 nm 13 nm[Physical gate, metalized] [37 nm] [25 nm] [18 nm] [13 nm] [9 nm]
Chip Frequency 2.5 GHz 4.9 GHz 9.5 GHz 19 GHz 36 GHz Transistors per chip (HV) 190 M 390 M 770 M 1.5 B 3.1 B (3 × for HP ; 5 × for ASICs)
DRAM Memory 1.1 G 2.2 G 4.3 G 8.6 G 34 G(bits per chip)
Field Size (mm × mm) 22 × 32 22 × 32 22 × 32 22 × 32 22 × 32
Wafer Size (diameter) 300 mm 300 mm 300 mm 450 mm 450 mm
2009*
CU_Jan12_04.pptD. Attwood 8
The Engineering Test Stand (ETS):A Pre-manufacturing EUV Stepper
Maskstage
Projectionoptics
Waferstage
Collectionoptic
EUV Plasmasource
Condenseroptics
Courtesy of R. Stulen / Sandia
SPIE 2004 Santa Clara, CA / Intro to EUV Lithography 2Attwood/SRI_2006_Korea.ppt
Courtesy of Dr. Hans Meiling, ASML
Professor David AttwoodAST 210/EECS 213Univ. California Berkeley Ch10_powrpt.ppt
Full-field Images Printed on ETS
Using Shipley EUV-11A resist,scan time is ~15 minutes.
32.5 mm
24 mm
200 mm wafer
Courtesy of G. Kubiak, D. Tichenor, and B. Replogle, Sandia National Laboratories.
Professor David AttwoodAST 210/EECS 213Univ. California Berkeley
Diffraction Limited Aspherical Optics AreCritical to the Success of EUV Lithography
Courtesy of John Taylor, LLNL.
• λλλλeuv /50 figure
• Low flare
• Ultrasmooth finish
• 10 µm departure from a sphere
Tinsley Sample CZerodur-M
150 mm diameter
Ch10_DiffrLtdAsph.ppt
Ch10A_2004.ppt
Prof. David AttwoodAST 210/EECS 213Univ. California, Berkeley
N = 40D = 6.7 nm
(Courtesy of Sasa Bajt, LLNL)ˇ
A High Quality Mo/Si Multilayer Mirror
CU_Jan12_04.pptD. Attwood 15
High Reflectivity, Thermally and Environmentally RobustMultilayers Coatings for High Throughput EUV Lithography
Courtesy of Sasa Bajt / LLNLˇ
Professor David AttwoodAST 210/EECS 213Univ. California Berkeley Ch10_powrpt.ppt
An Example of a 0.25 N.A. 6-MirrorEUV System
NA = 0.25
RFW = 2.0 mm
Dist. < 1 nm
RMS = 0.025λ(λ = 13.4)
1390.0 mm
M1
M2
M3
M4
M5
Mask
Wafer
M6
Courtesy of R. Hudyma and D. Sweeney, LLNL.
CU_Jan12_04.pptD. Attwood 10
EUV Source Candidates for Clean, Collectable13-14 nm Wavelength Radiation
Laser Produced Plasma Source Electrical Discharge Plasma Source
Courtesy of Neil Fornaciariand Glenn Kubiak, Sandia.
EUV
Rearelectrode
Frontelectrode
Capillary
Hot, EUVemittingplasma
Xe(1 Torr)
Highvoltage
Ch10A_2004.ppt
Prof. David AttwoodAST 210/EECS 213Univ. California, Berkeley
Multilayer Mirror Parameters:40 bilayers, σ = 0.5 nm rms, Γ = 0.44, FWHM of curve centered at 13.5nm
0
0.005
0.01
0.015
0.02
0.025
0.03
0.035
0.04
0.045
0.05
8 9 10 11 12 13 14 15 16 17 18 19
Wa ve le ngth (nm )
Ref
lect
ivit
y, In
ten
sity
(au
)
EUV Spectrum of Capillary Discharge Plasmawith Nine Mirror Optical System
(Courtesy of Jason Dimkoff, Sandia)
Measured Xe dischargeplasma spectrum 2.2% spectral bandpass for a
9-mirror, 70% reflectivity, Mo/SiEUV multilayer mirror system
Jason Dimkoff AST 213
Typical EUV spectrum from a Xenon plasmain a capillary electrical discharge
References:Blackburn J, Carroll P, Costello J and O’Sullivan G 1983 J. Opt. Soc. Am. 73 1325Gayasov R and Joshi Y 1998 J. Phys. B 31 L705Kaufman V and Sugar J 1984 J. Opt. Soc. Am. B 1 38Kaufman V, Sugar J, and Tech J 1983 J. Opt. Soc. Am. 73 691Sugar J and Kaufman V 1982 Physica Scripta 26 419O’Sullivan G 1982 J. Phys. B 15 L765
Ch06_Xe_Sn_Spectra.ai
Professor David AttwoodAST 210/EECS 213Univ. California, Berkeley
Comparative Spectra: Xe and Sn
80 0
1
2
3
4
5
0.5
1.5
1
2.5
2
3.5
3
9 10 11 12 13
4p54d9 → 4p64d8
5p → 4d
4p64d7(4f+5p) → 4p64d8
Xe+10
Xenon
• Debris is the issue
Tin
Sn+10
Rel
ativ
e in
tens
ity
14 15 16 17 18 12 13 14 15 16 1817 19 20nmnm
Courtesy of G. O’Sullivan (Univ. College Dublin) R. Faulkner (UCD Ph.D, 1999) A. Cummings (Nahond Univ. Ireland)
Absorberpattern Buffer layer
Capping layer
Substrate:Low thermal expansion material (LTEM)(6" square × 1/4" thick)
Multilayer Coating
Typically
Mo/Si multilayer (d = 6.7 nm)with 30 nm SiO2 capping layer
Cr or TaN absorber (~70 nm)with 50 nm Ru Buffer layer
LTEM substrate(Ti-doped fused silica)ULE (Corning), orZerodur (Schott)
Ch10_ReflecMask.ai
Reflective Mask for EUV Lithography
Professor David AttwoodAST 210/EECS 213Univ. California, Berkeley
Ch10A_2004.ppt
Prof. David AttwoodAST 210/EECS 213Univ. California, Berkeley
Amplitude Defect Phase Defect
Mask Blank Defects Can Be On the SubstrateOr Within the Stack
Ch10A_2004.ppt
Prof. David AttwoodAST 210/EECS 213Univ. California, Berkeley
EUV Scatter
•
••
•
•
•
•
•
•
•
•
86 nm equiv. defect
100 µm 2797bf.msk
SEM
AFM
Defect mapof mask blank
1µm
Defect Map Allows Correlation of Defects to Other Tools
Ch10_D_powrpt.ppt
Professor David AttwoodAST 210/EECS 213Univ. California Berkeley
At-Wavelength Mask Blank Defect Inspection
• At-wavelength response to phase and opaque defects
• Correlation with conventional inspection tools
50 µm
Dark Field
Courtesy of Moonsuk Yi (LBL) and J. Bokor (UCB/LBL).
45 nm45 nm 40 nm40 nm 35 nm35 nm
35 nm35 nm
Major support and collaborators include Sematech, Intel, AMD, IBM, Samsung and others.
Mask
Wafer
Two-bounce, 0.3 NA, METat ALS Beamline 12.0
Programmable illumination
Annular
Significant issue forEUV lithography
When will EUV resists beavailable with combinedhigh spatial resolution(20 nm), high sensitivity(10 mj/cm2), and low lineedge roughness (LER,1.2 nm)?
22 nm lines and spaces
10mJ/cm2
Courtesy of Patrick Naulleau, CXRO/LBNL.
Addressing critical EUV lithography issues for Sematechat the ALS: testing state-of-the-art EUV resists
Intel EUV MET InstallationIntel EUV MET Installation
Courtesy of Jeanette Roberts, Intel
J. Phys. D: Appl. Phys. (London) 37, 3207(2004)
Ch10_thruputModls_June08.ai
EUV Source Power Requirementsare Set by Wafer Throughput Models
Professor David AttwoodAST 210/EECS 213Univ. California, Berkeley
Original courtesy of Jos Benschopand Vadim Banine, ASML.
J. Benschop et al., SPIE 3997, 34 (2000),V. Banine and R. Moors, SPIE 4343, 203 (2002).
CollectableEUV power
60 W
Updated EUVpower and waferthroughput:
5 mj/cm2 resist300 mm wafers89 fields/wafer
Collectable, in-band,“clean” (no debris,no out-of-band)
EUV Power@ reticle
3.5 W
Power@ wafer140 mW
Illum. timeper field0.26 s
Illum. timeper wafer
23 s
Raw waferthroughput80 wafers/hr
120 W250 W
10
120 wafers/hr
Ch06_IonizaEnergXenon.ai
Professor David AttwoodAST 210/EECS 213Univ. California, Berkeley
Ionization Energies for Xenon
...
. . .
Xenon (J. Gillaspy, NIST) +11 +10 +9 +8 +7 +6 43 44 45 46 47 48 e–s 259 232 206 180 107 93 eV
Xe + 10 4f → 4d linesare strong near 13.5 nm
Ch06_Xe_Sn_Spectra.ai
Professor David AttwoodAST 210/EECS 213Univ. California, Berkeley
Comparative Spectra: Xe and Sn
80 0
1
2
3
4
5
0.5
1.5
1
2.5
2
3.5
3
9 10 11 12 13
4p54d9 → 4p64d8
5p → 4d
4p64d7(4f+5p) → 4p64d8
Xe+10
Xenon
• Debris is the issue
Tin
Sn+10
Rel
ativ
e in
tens
ity
14 15 16 17 18 12 13 14 15 16 1817 19 20nmnm
Courtesy of G. O’Sullivan (Univ. College Dublin) R. Faulkner (UCD Ph.D, 1999) A. Cummings (Nahond Univ. Ireland)
Laser Plasma Laboratory College of Optics & Photonics: CREOL & FPCE at UCF
The UCF tinThe UCF tin--doped droplet sourcedoped droplet source
Martin RichardsonK. Takenoshita, C-S Koay, S. George, T. Schmid, S. Teerawattansook R. Bernath, C. Brown
Laser Plasma LaboratoryCollege of Optics and Photonics & CREOL, UCF
Moza Al-RabbanQatar University
Howard ScottLawrence Livermore National Laboratory
Vivek BakshiSEMATECH
Funded by SEMATECH, SRC Intel and the State of Florida
Laser Plasma Laboratory College of Optics & Photonics: CREOL & FPCE at UCF
The tinThe tin--doped droplet laser plasma EUV sourcedoped droplet laser plasma EUV source
Multi-component 30 -35 um diameter target at 30 kHz -- Location precision 3 um
Modest laser intensities I ~ 1011 W/cm2
Mass-limited targets
Target contains only 1013 tin atoms
Recently demonstrated 30 kHz laser droplet irradiation with intelligent feedback beam and target control – continuous operation for 8 hours
Laser Plasma Laboratory College of Optics & Photonics: CREOL & FPCE at UCF
High CE demonstrated with Droplet TargetHigh CE demonstrated with Droplet Target
CE = 2% at 13.5 nm for tin-doped droplet target source
0.0
0.5
1.0
1.5
2.0
0 5 10 15 20 25 30
Co
nv
ers
ion
Eff
icie
ncy
Laser Intensity (x1010 Wcm-2)
0.0
0.5
1.0
1.5
2.0
0 5 10 15 20 25 30
Co
nv
ers
ion
Eff
icie
ncy
Laser Intensity (x1010 Wcm-2)
0.E+00
2.E+04
4.E+04
6.E+04
12.5 13.0 13.5 14.0 14.5
-0.1
0.1
0.3
0.5
0.7
Mirro
r Refle
ctivityPh
oto
n C
ou
nts
(A.U
)
spectrum Mirror R
at 13.5nm, CE = 2% at 13.6nm, CE = 2.25%
Wavelength (nm)
0.E+00
2.E+04
4.E+04
6.E+04
12.5 13.0 13.5 14.0 14.5
-0.1
0.1
0.3
0.5
0.7
Mirro
r Refle
ctivityPh
oto
n C
ou
nts
(A.U
)
spectrum Mirror R
at 13.5nm, CE = 2% at 13.6nm, CE = 2.25%
0.E+00
2.E+04
4.E+04
6.E+04
12.5 13.0 13.5 14.0 14.5
-0.1
0.1
0.3
0.5
0.7
Mirro
r Refle
ctivityPh
oto
n C
ou
nts
(A.U
)
spectrum Mirror R
0.E+00
2.E+04
4.E+04
6.E+04
12.5 13.0 13.5 14.0 14.5
-0.1
0.1
0.3
0.5
0.7
Mirro
r Refle
ctivityPh
oto
n C
ou
nts
(A.U
)
spectrum Mirror R
0.E+00
2.E+04
4.E+04
6.E+04
12.5 13.0 13.5 14.0 14.5
-0.1
0.1
0.3
0.5
0.7
Mirro
r Refle
ctivityPh
oto
n C
ou
nts
(A.U
)
spectrum Mirror R
at 13.5nm, CE = 2% at 13.6nm, CE = 2.25%
Wavelength (nm)
0.0
1.0
2.0
3.0
4.0
5.0
6.0
1.00E+10 1.00E+11 1.00E+12
Intensity (W/cm^2)
CE
(%
in 2
%B
W in
2P
I sr)
70 mJ60 mJ
CE = 5.5 % with solid tin!
CE = 3% achievable with droplet source--- for 30 kHz, 140 mJ laser
120 W / 2π
FOM FC2 teamF. Bijkerk S.A. vd Westen C. Bruineman
yrotarobaL amsalP resaL FCU ta ECPF & LOERC :scinotohP & scitpO fo egelloC
murtceps noissime ATU eht etalupinam won nac eW murtceps noissime ATU eht etalupinam won nac eWal
ized
Pho
ton
Cou
nt(A
.U.)
f::g:h
x 1.1 01 21:ix 6.8 01 11x 8.3 01 11x 4.1 01 11 /W mc 2
1x5.0 0 31
1x0.1 0 31
08 09 01 0 11 0 21 0 031 41 0 51 0 61 0Wa ev le ( htgn Å)
1x5.0 0 31
1x0.1 0 31
1x5.1 0 31
1x0.2 0 31
08 09 01 0 11 0 21 0 31 0 41 0 051 061 71 0 81 0 91 0 002Wa ev le ( htgn Å)
1x5.0 0 31
1x0.1 0 31
1x5.1 0 31
1x0.2 0 31
1x5.2 0 31
1x0.3 0 31
08 09 01 0 11 0 21 0 31 0 41 0 051 061 71 0 81 0 91 0 002
nS 9+
-bN Like t inAg ces( 1- )
aW velength ( Å)
nS 9+
0
21 .5 31 .0 13.5 14.0 14.5 51 .0 51 .5
Waveleng ht n( )m
Nor
mal
ized
Pho
ton
Co
a
b
c
d
.0 01x5 31
.1 01x0 31
.1 01x5 31
.2 01x0 31
.2 01x5 31
.3 01x0 31
08 09 001 011 021 031 041 51
nS 11+
-Y -Like t inAg (sec 1- )
Wa lev tgne h
.0 5x 01 31
.1 0x 01 31
.1 5x 01 31
.2 0x 01 31
.2 5x 01 31
.3 0x 01 31
08 09 01 0 011 21 0 31 0 041 51 0 61 0 071 81 0 91 0 002
Z L-r ki e t in( Ag s ce 1- )
Wave el ng ht Å( )
nS 1+ 0 nS 1+ 0
1x0.2 0 31
1x5.2 0 31
1x0.3 0 31
nS 9+
-bN Like t inAg ces( 1- )
nS 9+
0
02
04
06
08
001
021
041
061
1.0 0.1 01 01 00
02
04
06
08
001
021
041
061
1.0 0.1 01 01 0ytisnetnI resaL 01 x( 11 mc.W 2- )
Te, m
ax (e
V)0 01 001
eT pm re ruta e ( eV )
9.0
8.0
7.0
6.0
5.0
4.0
3.0
2.0
1.0
nS 1+
nS 2+
nS 3+
nS 4+
nS 5+
nS 6+
nS 7+
nS
nS 1+ 0
nS 8+nS 21+
nS 31+
nS 41+
nS 51+
Frac
tiona
l pop
ulat
ion
1 01 001eT pm re ruta e ( eV )
9.0
8.0
7.0
6.0
5.0
4.0
3.0
2.0
1.0
nS 1+
nS 2+
nS 3+
nS 4+
nS 5+
nS 6+
nS 7+
9+
nS
1+0
nS 1+ 1nS 8+
nS 21+nS 31+
nS 41+
nS 51+
Frac
tiona
l pop
ulat
ion
0
02
04
06
08
001
021
041
061
081
1.0 0.1 01 01 00
02
04
06
08
001
021
041
061
081
1.0 0.1 01 01 0ytisnetnI resaL 01 x( 11 mc.W 2- )
Te, m
ax (e
V)
0 01 001eT pm re ruta e ( eV )
0.1
9.0
8.0
7.0
6.0
5.0
4.0
3.0
2.0
1.0
nS 1+
nS 2+
nS 3+
nS 4+
nS 5+
nS 6+
nS 7+
nS
nS 1+ 0
nS 8+nS 21+
nS 31+
nS 41+
nS 51+
Frac
tiona
l pop
ulat
ion
1 01 001eT pm re ruta e ( eV )
0.1
9.0
8.0
7.0
6.0
5.0
4.0
3.0
2.0
1.0
nS 1+
nS 2+
nS 3+
nS 4+
nS 5+
nS 6+
nS 7+
9+
nS
1+0
nS 1+ 1nS 8+
nS 21+nS 31+
nS 41+
nS 51+
Frac
tiona
l pop
ulat
ion
Laser Plasma Laboratory College of Optics & Photonics: CREOL & FPCE at UCF
Hydrodynamic Modeling: Effects of Laser WavelengthConversion efficiency Conversion efficiency -- Tin with other laser wavelengthsTin with other laser wavelengths
Condition: Tin-doped droplet, 35 µm dia, 10ns pulse, I = 1.0 x 1011 W/cm2
0.35µm: Te - Higher laser intensities required
1.0E+16
1.0E+18
1.0E+20
1.0E+22
1.0E+24
0 50 100 150 200
0
20
40
60Ne
Te
R(≅m)
0nsλ = 0.35 µm
Te
ne
Tcrit
1016
1018
1020
1022
1024
20
0
40
60
ne
(cm
-3) T
e (eV)
1.0E+16
1.0E+18
1.0E+20
1.0E+22
1.0E+24
0 100 200
0
20
40
60Ne
Te0nsλ = 1.0 µm
1016
1018
1020
1022
1024
20
0
40
60
ne
(cm
-3)
Te (eV
)
Tcrit
ne
Te
1.0E+16
1.0E+18
1.0E+20
1.0E+22
1.0E+24
0 100 200 300
0
20
40
60Ne
Te0nsλ = 10 µm
1016
1018
1020
1022
1024
ne
(cm
-3)
20
0
40
60T
e (eV)Tcrit
ne
Te
10µm: -Emission comes from lower ne region
March 2, 2005 5751-26 Emerging Lithographic Technologies IX, Microlithography 2005, San Jose, California
EUV Source System Development Update: Advancing Along the Path
to HVM
I.V. Fomenkov, D.W. Myers, B.A. Hansson, D.C. Brandt, A. Ershov, B. Klene
7March 2, 2005 5751-26 Emerging Lithographic Technologies IX, Microlithography 2005, San Jose, California
Development of a Laser Produce Plasma EUV Source has Significant Challenges
Laser
Cost/CoOExtraction Efficiency
Rep-ratePulse Width
Beam QualityPointing Stability
Beam Transport System
Coating LifetimePointing Stability
Drive laser multiplexing
Source Material/DeliveryCE
Droplet stabilityMaterial purityServiceability
Laser Window Protection
Lifetime
CollectorLifetime/Cost
ManufacturabilityDebris Mitigation
MLM Average ReflectivityMLM Stability
Other
Compliance RequirementsAlignmentMetrology
System complexity
11March 2, 2005 5751-26 Emerging Lithographic Technologies IX, Microlithography 2005, San Jose, California
Liquid Metal Droplet Generator Developed
Heated Reservoir
Droplet Generator
Vacuum Vessel
Lens
Plasma
Camera
h Continuous stimulated droplet generation of liquid metals (Li and Sn) at temperatures up to 250°C
h Droplets diameter ≤100 µmh Droplet rates up to 48 kHzh Working distance of 50mm
100 µm Sn droplets at 36 kHz, captured using strobe lighting
Ref: Poster #5751-108, Algots, Cymer
Philips’s EUV Source:
Update and Issues
J. Pankert, EUV Source Workshop San Jose 2005
Philips Extreme UV
Schematics of the source
+
laser
tin supply
excess tinremoval
cooling channel
Philips Extreme UV
Summary of the properties• Electrodes
– Rotating: scalability to very high powers– Regenerative electrodes:
• Liquid tin surface• Erosion problem fundamentally solved
• General properties– CE 2%– Pinch size < 1mm– 5 kHz demonstrated– 120 W continuous operation– 260 W short term (limited by vacuum vessel)
EUV Sources for Lithography (SPIE, November 2005)Vivek Bakshi, Editor
This comprehensive volume, edited by a senior technical staff member at SEMATECH, is the authoritative reference book on EUV source technology. The volume contains 38 chapters contributed by leading researchers and suppliers in the EUV source field. Topics range from a state-of-the-art overview and in-depth explanation of EUV source requirements, to fundamental atomic data and theoretical models of EUV sources based on discharge-produced plasmas (DPPs) and laser-produced plasmas (LPPs), to a description of prominent DPP and LPP designs and other technologies for producing EUV radiation. Addi-tional topics include EUV source metrology and components (collectors, electrodes), debris mitigation, and mechanisms of compo-nent erosion in EUV sources. The volume is intended to meet the needs of both practitioners of the technology and readers seeking an introduc-tion to the subject.
Prices: $127 / $150 (SPIE Member/List)(Available November 2005)