Download Slajd 1 - microbeam.eu

EUV-initiated surface changes in polymers
A. Bartnik, H. Fiedorowicz, R. Jarocki, J. Kostecki, M. Szczurek
Institute of Optoelectronics, Military University of Technology,
Kaliskiego 2 ,00-908 Warsaw, Poland
A. Biliński, O. Chernyayeva, J.W. Sobczak
Institute of Physical Chemistry Polish Academy of Sciences, 44-52
Kasprzaka Street, 01-224 Warsaw, Poland
Outline
• motivations
• laser - plasma EUV source for surface
modification
- the source description
- EUV parameters
• interaction with selected polymers
- surface morphology - SEM measurements
- chemical changes - XPS measurements
• summary
Motivations
• Surface processing- what for?
Change of some surface properties: wettability, roughness, optical
and adhesive properties, biocompatibility
• How can be obtained?
Changing surface morphology and chemical structure
• Physical methods:
plasma treatment, ion implantation, UV irradiation
• Why EUV irradiation?
Additional method, very small penetration depth, applicable for any
polymer
EUV source for surface processing
Laser-plasma
EUV source,
Gas-puff target,
Low vacuum
EUV collector,
Efficient turbo pump,
Differential pumping
EUV
beam
Chamber for irradiation,
Options:
•High vacuum for mass
spectrometry,
•Reactive gas under low
pressure
• possible use for
micromachining
EUV source for surface processing
Laser
Nd:YAG
0.8 J, 4 ns,
10 Hz
View of the EUV source for
surface modification
krypton
low-Z gas
(hydrogen, helium)
laser
Source section, low
vacuum
Orifice for
differential
pumping
lens
beam
outer nozzle
inner nozzle
Schematic view of the double
stream gas puff target
Gas valve
Gas puff target area
EUV spectra of Kr, Kr+Xe, Xe plasmas
Spectra of Xe, Kr, Kr+10%Xe EUV direct radiation measured using a spectrograph with
transmission grating TG 5000 lines/mm (high resolution) and 250 lines/mm (low resolution)
EUV spectra of Kr, Kr+Xe, Xe plasmas (reflected)
High resolution spectra of Xe, Kr, Kr+10%Xe EUV reflected from Au plated ellipsoidal collector,
measured using a spectrograph with transmission grating TG 5000 lines/mm
EUV spectra of Kr, Kr+Xe, Xe plasmas (reflected)
Low resolution spectra of Xe, Kr, Kr+10%Xe EUV reflected from Au plated ellipsoidal collector,
measured using a spectrograph with 250 lines/mm transmission grating
EUV fluence in the focal plane for Kr plasma
70
60
2
fluence (mJ/cm )
2
fluence (mJ/cm )
40
30
20
10
50
40
30
20
10
0
2,0
1,5
1,0
0,5
0,0
0,5
1,0
distance from axis (mm)
Intensity distribution close to 10nm in
the focal plane of the EUV collector
0
2
1
0
1
2
distance (mm)
Intensity distribution in the wide
wavelength range in the focal plane
of the EUV collector
EUV induced structures on PMMA and PA surfaces
Two opposite processes are possible: crosslinking and fragmentation
of polymer chains.
Evidences of fragmentation shown here and in next slides
Poly (methyl methacrylate) PMMA
5 EUV pulses
a) no further treatment
b) soaked in PMMA developer
(methyl isobutyl ketone +
isopropyl alcohol)
Polyamide 6 (Nylon) 5 EUV pulses
a) no further treatment
b) soaked in isopropyl alcohol)
EUV induced structures on PET surface
SEM images of the microstructures formed under EUV irradiation with the fluence
close to maximum, well above the ablation threshold, followed by acetone rinsing
Surface morphology of PET foil irradiated
with different number of EUV pulses
with further acetone treatment:
a) 10 pulses,
b) 25 pulses,
without acetone treatment:
c) 10 pulses
d) 250 pulses
The acetone rinsing removes the light
fractions revealing the nanostructures
having the form of grains with the size of
the order of tens nanometers. The general
form of surface microstructures remains
unchanged.
Measurements of chemical changes
•Raman scattering
•Infrared spectroscopy
•X-ray photoelectron spectroscopy
intensity
intensity (arb. units)
EUV - irradiated
not - irradiated
500
1000
1500
-1
wavenumber (cm )
2000
1,6
1,4
1,2
1,0
0,8
0,6
0,4
0,2
0,0
not - irradiated
EUV - irradiated
500
1000
1500
-1
wave number (cm )
2000
Raman spectra
Infrared spectra
Signals come mainly from bulk with a very small contribution from the
modified near surface layer. Hence the spectra before and after
irradiation are almost identical.
5
intensity (arb. units)
a)
b)
4x10
5
3x10
O 1s
C KL1
O KL1
C 1s
5
2x10
5
1x10
0
1400 1200 1000 800 600 400 200
intensity (arb. units)
XPS spectra of PEN
0
5
4x10
5
3x10
5
1x10
0
1400 1200 1000 800 600 400 200
4x10
4
4
C3
C2
C1
4
1x10
0
290
288
286
284
binding energy (eV)
282
d)
4
6.0x10
4
4.0x10
4
2.0x10
0.0
intensity (arb. units)
b)
4
C3
290
C2
C1
288
286
284
binding energy (eV)
282
intensity (arb. units)
intensity (arb. units)
intensity (arb. units)
c)
4
2x10
0
binding energy (eV)
5x10
3x10
O 1s
O KL1
5
2x10
binding energy (eV)
a)
C 1s
C KL1
• Concentration of C2 and C3
remarkably decreased,
• Concentration of oxygen
decreased
• O1/O2 ratio remained almost
unchanged
4
5x10
4
4x10
O2
4
3x10
oxygen is being removed as a
whole O-C=O functional group
O1
4
2x10
4
1x10
536
534
532
530
binding energy (eV)
528
• Broadening of the peaks
• Shift of maxima of the peaks
4
4x10
4
3x10
O2
4
O1
2x10
4
1x10
536
534
532
530
binding energy (eV)
528
each peak comes from more
than one unique specie
XPS spectra of PET, PEN and PI
polymer
PET
PEN
PI
component
C1s
O1s
C1s
O1s
C1s
O1s
N1s
non-treated
72,07
27,94
70,67
26,92
75,9
17,51
6,58
irradiated
80,23
19,77
82,16
17,85
82,92
12,31
4,77
• Carbon enrichment in the near surface
layer in all cases
• Concentration of O and N decreased
Changes in ablation and
surface modification
thresholds
XPS spectra of PET, PEN and PI
PET – valence XPS
PEN – valence XPS
PEN not-irradiated
PEN EUV-irradiated
C=O
C-O
notirradiated
C-C
not-irradiated
intensity
intensity
PET not-irradiated
EUV rradiated
O=C-O
-C=C(benzene)
30
20
10
0
40
-10
30
binding energy (eV)
20
10
0
-10
binding energy (eV)
PI – valence XPS
PET EUV-irradiated
PI not-irradiated
PI EUV-irradiated
not-irradiated
intensity
intensity
EUV
irradiated
30
20
10
0
EUV irradiated
-10
binding energy (eV)
40
30
20
10
binding energy (eV)
0
-10
Conclusions
• EUV source for surface modification was presented
• Parameters of the EUV source were measured
• morphology changes in selected polymers were
presented
• chemical changes were proved
• results and interpretation of XPS measurements were
presented
Acknowledgements
The research was partially performed in the frame of
the EUREKA project E! 3892 ModPolEUV
and under COST Action MP0601,
funded by the Ministry of Science and Higher Education
(decision Nr 120/EUR/2007/02)