EUV-initiated surface changes in polymers A. Bartnik, H. Fiedorowicz, R. Jarocki, J. Kostecki, M....
-
Upload
gloria-wood -
Category
Documents
-
view
219 -
download
0
Transcript of EUV-initiated surface changes in polymers A. Bartnik, H. Fiedorowicz, R. Jarocki, J. Kostecki, M....
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
Chamber for irradiation,Options:•High vacuum for mass spectrometry,•Reactive gas under low pressure• possible use for micromachining
EUVbeam
EUV source for surface processing
View of the EUV source for surface modification
Source section, low vacuum
Schematic view of the double stream gas puff target
Gas puff target area
Gas valve
Orifice for differential pumping
lenslaser
beam
low-Z gas(hydrogen, helium)
krypton
outer nozzle inner nozzle
LaserNd:YAG
0.8 J, 4 ns, 10 Hz
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
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 spectra of Kr, Kr+Xe, Xe plasmas (reflected)
2,0 1,5 1,0 0,5 0,0 0,5 1,0
0
10
20
30
40
fluen
ce (
mJ/
cm2 )
distance from axis (mm)
Intensity distribution close to 10nm in the focal plane of the EUV collector
Intensity distribution in the wide wavelength range in the focal plane of the EUV collector
2 1 0 1 20
10
20
30
40
50
60
70
fluen
ce (
mJ/
cm2 )
distance (mm)
EUV fluence in the focal plane for Kr plasma
Poly (methyl methacrylate) PMMA 5 EUV pulsesa)no further treatmentb)soaked in PMMA developer (methyl isobutyl ketone + isopropyl alcohol)
Polyamide 6 (Nylon) 5 EUV pulsesa)no further treatmentb)soaked in isopropyl alcohol)
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
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.
EUV induced structures on PET surface
Measurements of chemical changes
500 1000 1500 2000
0,0
0,2
0,4
0,6
0,8
1,0
1,2
1,4
1,6
not - irradiated EUV - irradiated
inte
nsity
(ar
b. u
nits
)
wave number (cm-1)
•Raman scattering
•Infrared spectroscopy
•X-ray photoelectron spectroscopy
500 1000 1500 2000
EUV - irradiated not - irradiated
inte
nsity
wavenumber (cm-1)
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.
XPS spectra of PEN
1400 1200 1000 800 600 400 200 00
1x105
2x105
3x105
4x105 b)a)
C KL1
O KL1
C 1sO 1s
C KL1
O KL1C 1s
O 1s
inte
nsity
(ar
b. u
nits
)
binding energy (eV)
1400 1200 1000 800 600 400 200 00
1x105
2x105
3x105
4x105
binding energy (eV) in
tens
ity (
arb.
uni
ts)
290 288 286 284 2820
1x104
2x104
3x104
4x104
5x104
290 288 286 284 2820.0
2.0x104
4.0x104
6.0x104
C2
C3
C1
c)
a)
d)
b)
inte
nsity
(ar
b. u
nits
)
binding energy (eV)536 534 532 530 528
1x104
2x104
3x104
4x104
5x104
O1
O2
int
ensi
ty (
arb.
uni
ts)
binding energy (eV)
C1C
2C
3
inte
nsity
(ar
b. u
nits
)
binding energy (eV)536 534 532 530 528
1x104
2x104
3x104
4x104
O1
O2
inte
nsity
(ar
b. u
nits
)
binding energy (eV)
• Concentration of C2 and C3 remarkably decreased, • Concentration of oxygen decreased • O1/O2 ratio remained almost unchanged
• Broadening of the peaks• Shift of maxima of the peaks
oxygen is being removed as a whole O‑C=O functional group
each peak comes from more than one unique specie
XPS spectra of PET, PEN and PI
• Carbon enrichment in the near surface layer in all cases
• Concentration of O and N decreased
Changes in ablation and surface modification
thresholds
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
40 30 20 10 0 -10
PEN not-irradiated PEN EUV-irradiated
inte
nsity
binding energy (eV)
40 30 20 10 0 -10
PI not-irradiated PI EUV-irradiated
inte
nsity
binding energy (eV)
30 20 10 0 -10
-C=C-(benzene)
O=C-O
C-CC=OC-O
PET not-irradiated
inte
nsity
binding energy (eV)
30 20 10 0 -10
PET EUV-irradiated
inte
nsity
binding energy (eV)
PET – valence XPS
not-irradiated
EUVirradiated
not-irradiated
EUV rradiated
not-irradiated
EUV irradiated
PEN – valence XPS
PI – valence XPS
XPS spectra of PET, PEN and PI
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