multilayer interference coating, scattering, …attwood/srms/2007/07...professor david attwood univ....
Post on 08-Mar-2018
229 Views
Preview:
TRANSCRIPT
100 nm
10 eV 100 eVPhoton energy
(D. W
indt
, D. S
tear
ns, J
. Kor
trigh
t)
Wavelength
Nor
mal
inci
denc
e re
flect
ivity
Naturalcrystals
MgF2/Al
Si C
Pt,Au
1 KeV 10 KeV
10 nm 1 nm 0.1 nm
Multilayer mirrors ( )
1.0
0.5
0
mλ = 2d sin θ
Ch4_F00_Feb2007.ai
(W/C, T. Nguyen)
Multilayer Interference Coating,Scattering, Diffraction, Reflectivity
Professor David AttwoodUniv. California, Berkeley Multilayer Interference Coating, Scattering, Diffraction, Reflectivity, EE290F, 6 Feb. 2007
Scattering by Density VariationsWithin a Multilayer Coating
Ch04_F01_Feb2007.ai
(T. Nguyen, CXRO/LBNL)
Mo/Si
Professor David AttwoodUniv. California, Berkeley Multilayer Interference Coating, Scattering, Diffraction, Reflectivity, EE290F, 6 Feb. 2007
Scattering of Radiation by a Sinusoidal Density Distribution (Atoms or Electrons)
Ch04_F02VG.ai
na(z)
ki
ks
kd = zo2πd2θ
d
A
B
A
B
A
B
A
kiks
z
θ
Professor David AttwoodUniv. California, Berkeley Multilayer Interference Coating, Scattering, Diffraction, Reflectivity, EE290F, 6 Feb. 2007
ki
ks
kd = zo2πd2θ
Scattering from Density Variations
(4.1)
(4.2)
(4.3)
(4.4a)
(4.4b)
(4.5a)
(4.6a)or
(4.6b)
(4.5b)
Ch04_Eqs1_6VG.ai
In the long wavelength limit (λ >> a0)
Professor David AttwoodUniv. California, Berkeley Multilayer Interference Coating, Scattering, Diffraction, Reflectivity, EE290F, 6 Feb. 2007
Ch04_MltlyrMirBragg1.ai
d
neMoSiMoSiMo
MoSi
Si
λ
θ
mλ = 2d sinθ
For normal incidence, θ = π/2, first order (m = 1) reflection λ = 2d d = λ/2if the two layers are approximately equal ∆t λ/4a quarter-wave plate coating.
Multilayer Mirrors Satisfy the Bragg Condition
Professor David AttwoodUniv. California, Berkeley Multilayer Interference Coating, Scattering, Diffraction, Reflectivity, EE290F, 6 Feb. 2007
Ch04_MltlyrMirBragg2.ai
Multilayer Mirrors Satisfy the Bragg Condition
d
neMoSiMoSiMo
MoSi
Si
λ
θ
mλ = 2d sinθ (1 – )
For normal incidence, θ = π/2, first order (m = 1) reflection λ = 2d d = λ/2if the two layers are approximately equal ∆t λ/4a quarter-wave plate coating.
4δd2
m2 λ2
Professor David AttwoodUniv. California, Berkeley Multilayer Interference Coating, Scattering, Diffraction, Reflectivity, EE290F, 6 Feb. 2007
Professor David AttwoodUniv. California Berkeley Multilayer Interference Coating, Scattering, Diffraction, Reflectivity, EE290F, 6 Feb. 2007 Ch04_HiReflecMult.ppt
High Reflectivity Multilayer Coatings Require:
• Refractive index contrast at the interfaces• Minimal absorption in the low-Z material• Thin high-Z layer where possible Γ ; ΔτH /(ΔτH + ΔτL)• Interfaces which are chemically stable with time• Minimal interdiffusion at the interfaces• Minimal interfacial roughness (no crystallite formation
within the layers, no shadowing in the coating process,surface mobility)
• Thermal stability during illumination• Chemically stable vacuum interface
(e.g., Si02 or capping layer)• Uniform coating thickness
Ch04_HiOrdrReflc.ai
High Order Reflections from a Multilayer Coating
4
3
2
1
0
Distance from surface (in periods)10d
E2
100
10–1
10–2
10–3
10–4
10–5
10–710–6
0 2.5
(Courtesy of Y. Wu and J. Underwood.)
5
Ref
lect
ivity
Scattering angle 2θ (°)7.5 10 12.5
m = 1
23
45
W/C multilayer22 layer-pairsd = 36.1 Åλ = 1.54 Å
MeasuredCalculated internal interferenceof incoming and outgoing waves
Professor David AttwoodUniv. California, Berkeley Multilayer Interference Coating, Scattering, Diffraction, Reflectivity, EE290F, 6 Feb. 2007
Ch04_SpillerBook.ai
SOFT X-RAY OPTICSEberhard Spiller
SPIE (1994)Professor David AttwoodUniv. California, Berkeley Multilayer Interference Coating, Scattering, Diffraction, Reflectivity, EE290F, 6 Feb. 2007
Professor David AttwoodUniv. California Berkeley Multilayer Interference Coating, Scattering, Diffraction, Reflectivity, EE290F, 6 Feb. 2007 Ch04_AngulrScan.ppt
An Angular Scan of a Multilayer Mirror Performs a Fourier-Transform of the Density Profile
Ch04_MultlyrIntrfMir.ai
Multilayer Interface MirrorsComputational Model
With refractive index n:
www.cxro.LBL.gov
(Courtesy ofJ. Underwood)
1(Vacuum)E1
zx
θ∆tA
∆tB
Ej–1
Ej
En
E2
RE1
RE2
REj–1
REj
Layer pair N
Layer pair l
2 (Material A)
3 (Material B)
j – i
j
j + 1
n – 2 (A)
n – 1 (B)n substrate
n = 1 – δ + iβ = 1 – (f1 – if2)na re λ2
2π0 0
Professor David AttwoodUniv. California, Berkeley Multilayer Interference Coating, Scattering, Diffraction, Reflectivity, EE290F, 6 Feb. 2007
Atomic Scattering Factorsfor Silicon (Z = 14)
(Henke and Gullikson; www-cxro.LBL.gov)
Ch02ApC_Tb1F07_Sept05.ai
Energy (eV) f1 f2 µ(cm2/g) 30 3.799 3.734E–01 1.865E+04 70 2.448 5.701E–01 1.220E+04 100 –5.657 4.580E+00 6.862E+04 300 12.00 6.439E+00 3.216E+04 700 13.31 1.951E+00 4.175E+03 1000 13.00 1.070E+00 1.602E+03 3000 14.23 1.961E+00 9.792E+02 7000 14.33 4.240E–01 9.075E+01 10000 14.28 2.135E–01 3.199E+01 30000 14.02 2.285E–02 1.141E+00
15
10
5
0
–5
–10
101
100
10–1
10–2
f1
f2
µ(cm
2 /g)
10 100 1000E (eV)
10000
10 100 1000 10000
10 100 1000E (eV)
10000
107
105
103
101
10–1
σa(barns/atom) = µ(cm2/g) × 46.64E(keV)µ(cm2/g) = f2 × 1498.220
0 0
0
0
Silicon (Si)Z = 14
Atomic weight = 28.086
K 1838.9 eV L1 149.7 eV L2 99.8 eV L3 99.2 eV
Edge Energies:
Professor David AttwoodUniv. California, Berkeley Multilayer Interference Coating, Scattering, Diffraction, Reflectivity, EE290F, 6 Feb. 2007
Atomic Scattering Factors forMolybdenum (Z = 42)
(Henke and Gullikson; www-cxro.LBL.gov)
Ch02ApC_Tb1F12_June2008.ai
Energy (eV) f1 f2 µ(cm2/g)
30 1.071 5.292E+00 7.736E+04 70 19.38 4.732E+00 2.965E+04 100 14.02 1.124E+00 4.931E+03 300 4.609 1.568E+01 2.292E+04 700 31.41 1.819E+01 1.140E+04 1000 35.15 1.188E+01 5.210E+03 3000 35.88 1.366E+01 1.997E+03 7000 42.11 3.493E+00 2.189E+02 10000 41.67 1.881E+00 8.248E+01 30000 42.04 1.894E+00 2.769E+01
µ(c
m2 /g
)
10 100 1000E (eV)
10000
10 100 1000 10000
10 100 1000E (eV)
10000
σa(barns/atom) = µ(cm2/g) × 159.31E(keV)µ(cm2/g) = f2 × 438.590
0 0
Edge Energies:
40
50
60
20
30
10
0
101
100
f1
f2
106
104
105
102
100
101
103
0
0
K 19999.5 eV L1 2865.5 eV M1 506.3 eV N1 63.2 eV L2 2625.1 eV M2 411.6 eV N2 37.6 eV L3 2520.2 eV M3 394.0 eV N3 35.5 eV M4 231.1 eV M5 227.9 eV
Molybdenum (Mo)Z = 42
Atomic weight = 95.940
Professor David AttwoodAST 210/EECS 213Univ. California, Berkeley
Ch04_OptomizReflcty.ai
Optimized Reflectivity with Thin “High-Z” Layers
• Sharp interfaces needed for scattering• Thin high-Z layer to minimize absorption• Low-Z layer best as a “spacer”
(Vinogradov and Zeldovich, 1977)(also see Borrmann, 1941)
(4.7)
(4.8)
high-Zlow-Z
high-Zlow-Z
high-Z
high-Zlow-Z
Professor David AttwoodUniv. California, Berkeley Multilayer Interference Coating, Scattering, Diffraction, Reflectivity, EE290F, 6 Feb. 2007
Ch04_ComputdReflec.ai
Computed Reflectivity of aW/C X-Ray Multilayer Mirror
1.0
0.8
0.6
0.4
0.2
00
(Courtesy of J. Underwood and D. Solina)
2
λ = 8.34 Åd = 22.5 ÅN = 100Γ = 1/3
4 6Glancing angle (°)
Ref
lect
ivity
8 10 12
W/C
Professor David AttwoodUniv. California, Berkeley Multilayer Interference Coating, Scattering, Diffraction, Reflectivity, EE290F, 6 Feb. 2007
Professor David AttwoodUniv. California Berkeley Multilayer Interference Coating, Scattering, Diffraction, Reflectivity, EE290F, 6 Feb. 2007 Ch04_MultilyrIntrCtg.ppt
Molybdenum as the “scattering layer”Silicon as the non-absorbing “spacing layer”
Actually an exaggeration, the complex refractive indexof each material plays a role in the reflection process
The absorption edge Si-L3 = 99.2 eV (12.5 nm)Higher photon energies are absorbed in Si,lower photon energies (longer wavelengths) are not.Typically λ = 13.4 nm or more.
Molybdenum has relatively good scattering properties in thisphoton energy (wavelength) region, with limited absorption.
Mo/Si Multilayer Interference Coating
Ch04_HiQualtyMoSi.ai
A High Quality Mo/Si Multilayer Mirror
N = 40d = 6.7 nm
Courtesy of Sasa Bajt (LLNL)ˇ
Professor David AttwoodUniv. California, Berkeley Multilayer Interference Coating, Scattering, Diffraction, Reflectivity, EE290F, 6 Feb. 2007
Professor David AttwoodUniv. California Berkeley Multilayer Interference Coating, Scattering, Diffraction, Reflectivity, EE290F, 6 Feb. 2007 Ch04_MoSi_ctngs.1.02.ppt
High Reflectivity, Thermally and Environmentally RobustMultilayers Coatings for High Throughput EUV Lithography
12.0 12.5 13.0 13.5 14.0 14.50.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8R
efle
ctiv
ity
Wavelength (nm)
Mo/B4C/Si70% at 13.5 nm
FWHM = 0.55 nm50 bilayers
Courtesy of Sasa Bajt (LLNL)ˇ
Ch04_ReflectCurv70.ai
Multilayer Mirrors HaveAchieved a Reflectivity of 70%
Professor David AttwoodUniv. California, Berkeley Multilayer Interference Coating, Scattering, Diffraction, Reflectivity, EE290F, 6 Feb. 2007
Ch04_SputtrdDepo.ai
Sputtered Deposition of a Multilayer Coating
Table rotation
Target forhigh-Z material
Target forlow-Z material
Erosionarea
Shadow mask
Magnetic flux linesconfining plasma
Target housing(negative cathode)
Mirrorsubstrate
Tablegrounded
Planetary rotation
Rotating tableMirror substrate
Target material (cathode)
Magnetron
S
NS S
Mirrorsubstrate
Mirrorsubstrate
Deposited thin film
Target housing
Targeterosionarea
Plasma ions moving towards cathode (target material)
Plasma containingmagnetic flux lines
Sputtered atoms(target material)moving toward
table
Shadowmask
SputteredSputteredparticlesparticles
Sputteredparticles
Professor David AttwoodUniv. California, Berkeley Multilayer Interference Coating, Scattering, Diffraction, Reflectivity, EE290F, 6 Feb. 2007
Ch04_DCmagntrn.ai
(Courtesy of Jim Folta, LLNL)
DC Magnetron Sputtering is Used to ReliablyDeposit Multilayer Coatings of Predictable
Center Wavelength and Excellent Uniformity
Extreme Ultraviolet Lithography
Vacuum chamber
Substrate platter
Substrate
Spinnermotorassembly
SiMo Magnetronsources
Substrates mounted on a rotating platterare swept across each sputter sourcesequentially to form the multilayer.Modulating the platter velocity providesprecision control of radial thickness distribution and absolute film thickness.The substrate is also spun fast aboutits own axis for azimuthal uniformity.
Professor David AttwoodUniv. California, Berkeley Multilayer Interference Coating, Scattering, Diffraction, Reflectivity, EE290F, 6 Feb. 2007
320 fg/µm2
1.4 mm
1.0 mm
Fe contaminatedsolar cell
Scanningstage
xy
Sample Focalspot
Fluorescentx-rays
Solid stateSi (Li) detector
M1
M2
Multilayer coatedelliptically bent
mirrors
e–
SynchrotronSource (white
radiation)
Aperture
1 µmD
focal spot
Buried, Trace Amounts of Ironin a Defective Silicon Solar Cell
Ch04_F14VG.ai
(Courtesy of A. Thompson and J. Underwood, LBNL;and R. Holm, Miles Lab)
Professor David AttwoodUniv. California, Berkeley Multilayer Interference Coating, Scattering, Diffraction, Reflectivity, EE290F, 6 Feb. 2007
Ch04_F15VG.ai
Microprobe Analysisof Contaminated Soil
pg/µm2
1 mm
1 mm
Ca
2.4
Cr Fe
ZnNi Cu
1.0
0.1 pg/µm2
0.2 pg/µm2
0.3 pg/µm2
10
(Courtesy of T. Tokunaga; and A. Thompson, LBNL)
Professor David AttwoodUniv. California, Berkeley Multilayer Interference Coating, Scattering, Diffraction, Reflectivity, EE290F, 6 Feb. 2007
Ch04_F16aVG.ai
High Resolution X-Ray DiffractionUnder High Pressure Using
Multilayer Coated Focusing Optics
Multilayercoated mirrors
10–16 keVx-rays
Film
2θDiamondanvil cell
Diamond anvil cell
e–Synchrotronradiation
Aperture Focusedx-rays
Sample under pressure(0–300 GPa)
Gasket
Pressure medium
Scatteredx-rays
H.K. Mao et al., Science 277, 1220 (29 Aug. 1997)Nature 396, 741 (24 Dec. 1998)
Professor David AttwoodUniv. California, Berkeley Multilayer Interference Coating, Scattering, Diffraction, Reflectivity, EE290F, 6 Feb. 2007
Ch04_ElasticyRheolgy.ai
NATURE 396, 741(24/31 DECEMBER 1998) www.nature.com
Professor David AttwoodUniv. California, Berkeley Multilayer Interference Coating, Scattering, Diffraction, Reflectivity, EE290F, 6 Feb. 2007
Recent Progress in Multilayer Mirrors
RecentProgMultiilyrMir.ai
80
70
60
50
40
30
20
10
01 10
Wavelength (nm)
Near-Normal Incidence Multilayer Mirrors
Peakreflectance
(%)
H2Owindow
VTi
Si
Au
CSc
Professor David AttwoodUniv. California, Berkeley Multilayer Interference Coating, Scattering, Diffraction, Reflectivity, EE290F, 6 Feb. 2007
Ch04_CassegrainTele.ai
The Cassegrain Telescope
Filmor CCDConcave
primarymirror
Convexsecondary
mirror
Sun
Professor David AttwoodUniv. California, Berkeley Multilayer Interference Coating, Scattering, Diffraction, Reflectivity, EE290F, 6 Feb. 2007
EUV Image of the Solar CoronaShowing Loops Near the Solar Limb
(Courtesy of L.Golub, Harvard-Smithsonian and T. Barbee, LLNL)
Ch04_F10VG_Sept05.ai
http://vestige.Imsal.com/TRACE
λ = 17.3 nm(71.7 eV)
Professor David AttwoodUniv. California, Berkeley Multilayer Interference Coating, Scattering, Diffraction, Reflectivity, EE290F, 6 Feb. 2007
Ch04_DynamicsSolar.ai
Dynamics of the Solar Corona
(Courtesy of L. Golub, Harvard-Smithsonian)
Professor David AttwoodUniv. California, Berkeley Multilayer Interference Coating, Scattering, Diffraction, Reflectivity, EE290F, 6 Feb. 2007
4:1reductionoptics,aspheric,multilayer
coated
Reflectivemask
Absorberpattern
Multilayermirror
Wafer to record 50 nm or smallerfeatures, over cm2 dimensions
λ = 13 nm
Extreme Ultraviolet (EUV) Lithography
Ch04_F11VG.ai
50 60 70
Extreme Ultraviolet Lithography
Professor David AttwoodUniv. California, Berkeley Multilayer Interference Coating, Scattering, Diffraction, Reflectivity, EE290F, 6 Feb. 2007
Ch04_PolarizStudies.ai
Polarization Studies of Magnetic Materials
NdFeBmagnets
Laterallygraded W/B4Cmultilayer mirror
H
DDetector(a)
(d)(c)
(b)
Fe/Crtransmissionsample
Ι0
Substrate
A
A
A
A
AB
B
B
B
H parallel kH anti-parallel k
6
4
2
0
–2
–4
–6680 690 700 710 720 730
ω (eV)ω (eV)
Rot
atio
n (d
egre
es)
6600.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7–22 mm +22 mmCenter
680 700 720 740
Ref
lect
ance
(arb
. uni
ts)
(Courtesy of J. Kortright and M. Rice, LBNL; and R. Carr, Stanford)
Professor David AttwoodUniv. California, Berkeley Multilayer Interference Coating, Scattering, Diffraction, Reflectivity, EE290F, 6 Feb. 2007
top related