euv interference lithography workshop/oral 42 resist-10 solak.pdf · euv interference lithography....
TRANSCRIPT
H. Solak, 16.7.09, Honolulu
EUV Interference Lithography
Harun H. Solak, V. Auzelyte, A. Langner, S. S. Sarkar, A. Weber,H. Pruchova, M. Kropf, Y. Ekinci, C. David, J. Gobrecht
Laboratory for Micro and Nanotechnology,Paul Scherrer Institute
Switzerland
H. Solak, 16.7.09, Honolulu
Outline
EUV Interference scheme
Beam for EUV-IL
Masks for EUV-IL
EUV-IL results and understanding resist behavior
Future of PSI EUV-IL tool
H. Solak, 16.7.09, Honolulu
EUV-IL at the Swiss Light Source:
a nanofabrication facility for academic and industrial useIn operation since 2003
Available to users through proposals or for a fee
EUV photoresist characterization – 300+ resists tested
Major upgrade in 2009 - focus on below 20 nm patterning
H. Solak, 16.7.09, Honolulu
EUV Interference Scheme
Line/space pattern
2-beam interference
• Frequency multiplication: Factor depending on
the diffraction orders chosen
• Good match to undulator radiation
• Achromatic (no temporal coherence needed)
• Requires spatial coherence
H. Solak, 16.7.09, Honolulu
EUV Interference Scheme4-beam interference
• Frequency multiplication
• Grating phases determine the pattern
• Profile not sinusoidal
Simulated intensity
H. Solak, 16.7.09, Honolulu
EUV beam for Interference Lithography• Spatial coherence:
• Undulator radiation
• Spatial filtering (pinhole)
• Nothing in the beam after pinhole (no optics, filters, windows etc)
• Uniform illumination
• Stable beam: SLS and beamline
• Bandwidth (interferometer dependent)
• Grating interferometer (achromatic)
H. Solak, 16.7.09, Honolulu
EUV beam for Interference Lithography
H. Solak, 16.7.09, Honolulu
Electron Beam Lithography + dry etching
Grating Masks
35 nm to 2000 nm pitches
Many pitches and patterns on one mask
100 nm (42% transmission)
10-40 nmGrating period
100 nm h/p 40 nm h/p 20 nm h/p
H. Solak, 16.7.09, Honolulu
800
• 0.8 mm lines - easy cross section – multiple period, multiple dose
• 20-50 nm h/p
• dose for EUV resist: 30-40 mJ/cm2
M390
Line/space Masks
H. Solak, 16.7.09, Honolulu
• Lines and contact holes on one mask
• 20-50 nm h/p contact holes
• 15-35 nm h/p lines
• dose for EUV resist: 40-80 mJ/cm2
M394
Contact Hole Masks1 mm
H. Solak, 16.7.09, Honolulu
High efficiency Mo Masks
100 nm
+1st order
-1st order
0th orderEUV
Grating
EUV-CCD Camera
80 85 90 95 1000
1
2
3
4
2.0 2.5 3.0 3.5 4.0
90 nm-thick Mo and 40% duty cycle grating were used for the calculated efficiency
Measured efficiency Calculated efficiency
1st /0th o
rder
rela
tive
effic
ienc
y
Undulator energy (eV)
1st order
Energy = 92.5 eV
1st order
0th order
Intensity (a.u)* M. Saidani et al, MNE 08
150 nm-pitch Mo gratingThickness: 90 nm
H. Solak, 16.7.09, Honolulu
Zero-zeroth-order PMMA grating
600 nm-pitch PMMA gratingThickness: 240 nm
1st order
0th order
Frame: EUV transmitted by membrane around square grating
H. Solak, 16.7.09, Honolulu
Line/space Patterns in PMMA
50 nm half pitch 45 nm 40 nm
35 nm 30 nm
H. Solak, 16.7.09, Honolulu
20 nm
Calixarene resist
12.5 nm
TEBN-1 from Tokuyama, Japan
H. Solak, 16.7.09, Honolulu
30 nm
Hydrogen silsesquioxane (HSQ)
20 nm
Fox-12, Dow Corning
H. Solak, 16.7.09, Honolulu
Beyond the roadmap
Resist: Fox12 (Dow Corning)Thickness: 20 nm
11 nm h/p
No FUNDAMENTAL limit down to 11 nm !
H. Solak, 16.7.09, Honolulu
50 nm h/p 42.5 nm h/p 32 nm h/p
25 nm h/p 21.5 nm h/p 19.5 nm h/p
FOX12 – HSQ - Hydrogen silsesquioxane
Testing resist performance
H. Solak, 16.7.09, Honolulu
19.9 mJ/cm2
31.0 mJ/cm2
h/p 50 nm 35 nm 30 nm 25 nm 20 nm
EUV resists
H. Solak, 16.7.09, Honolulu
EUV resists
50 nm42.5 nm
32 nm
25 nm21 nm
18 nmthinner resist
More than 300 resists were tested!
H. Solak, 16.7.09, Honolulu
Effect of substrate electrons
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0
dose [mJ/cm²]
heig
ht [n
m]
Cr
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0
dose [mJ/cm²]
heig
ht [n
m]
CrSi
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0
dose [mJ/cm²]
heig
ht [n
m]
CrSiAuNi
Absorption length (nm)
Si 585
Cr 28
Au 21
Ni 15
H. Solak, 16.7.09, Honolulu
Contrast curves
0
10
20
30
40
50
60
70
80
0 0.5 1 1.5 2 2.5Dose (mJ)
Thic
knes
s (n
m)
after PEBafter develop
2% dose steps
H. Solak, 16.7.09, Honolulu
Resist contrast loss
0
10
20
30
40
50
60
70
200 300 400 500 600 700Dose to mask (mJ/cm2)
Line
wid
th (n
m)
HP 50HP 45HP 40
Half-pitch NILS EL/NILS50 3.14 0.8045 3.14 0.7440 3.14 0.80
EL analysis by
H. Solak, 16.7.09, Honolulu
Recent and Ongoing UpgradesFull time facility
From 15% to 100% operationDedicated undulator
Sample preparation/developmentat the beamline
WHEN:fall of 2009
NEW electron beam writer VISTEC
EBPG5000plus ES100keV
for mask preparation
H. Solak, 16.7.09, Honolulu
Sample processing:
Spin coating and development in class 100Exposures in class 1000PEB right after each exposure
– amine filtered env.
Stable flux, 10-50 mW/cm2Throughput ~ 1 wafer/hourSample stage for 4’’, 6’’, 8’’ wafersStage travel size 80×80 mm2
Software controlled exposure
EUV IL at PSI
Performance• Area: 1-4 mm2 area
• Exposure time:1-30 sec
• 11 nm … 1000 nm half-pitch