LITHO2006, Marseille June 2006 1

Plasma Treatment of NIL

polymers to enhance

anti-adhesion properties

Isabel Obieta (iobieta@inasmet.es)

LITHO2006, Marseille June 2006 2

INDEX -Objective- Plasma conditions- Characterization techniques - Materials- Results

*Contact angle: lifetime*AFM: Roughness and thickness modified*XPS: main functional groups and depth of modification

- Imprinting trials- Conclusions

LITHO2006, Marseille June 2006 3

Objective to enhance the anti-adhesion behavior via plasma functionalization of the polymer surface in order

to avoid the problems of adhesion between the stamp and the substrate during the de-moulding in

the NIL process.

A process for low pressure plasma treatment has been developed, including the nature of reactive gases and the configuration of the plasma reactor.

LITHO2006, Marseille June 2006 4

CVD-RF (ASM) at 13,56MHz:a) tubular reactor, low pressure and

capacitive-coupled plasma.b) Power: 25-150 Wc) Time: 1-5 mind) Flow of reactive gases: 25-225 sccm

MW plasma (Iplas) at 2,45GHz:a) Remote cold plasmab) Distance to plasma: 8 to 20cmc) Power: 1500-3000 Wd) Time: 3-20 mine) Flow of reactive gases: 50-225 sccm

SF6 + ArCF4 + Ar

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Characterization

- Contact Angle: verification of stability and lifetime oftreatments

- AFM: roughness and thickness modification

- XPS: chemical composition and in-depth profile

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MATERIALS

- mr-I 9030 (allyl from mrt) ⇒ 300nm thickness

- PDAP (allyl from mrt) ⇒ 280 nm thickness

- mr-I 8030 (acrylate from mrt) ⇒ 300 nm thickness

- mr-I 7030 (acrylate from mrt) ⇒ 300 nm thickness

- PMMA (acrylate from mrt) ⇒ 500 nm thickness

LITHO2006, Marseille June 2006 7

mrI-9000: RF plasma

84889296

100104108

9000 Sample1 Sample2 Sample3

C.A

. Day1

Day4

Day8

Sample1 Time=2min Power=100W SF6=37,5 Ar =150Sample2 Time=2min Power=25W SF6=50 Ar =200Sample3 Time=2min Power=100W SF6=200 Ar =0

LITHO2006, Marseille June 2006 8

AFM (mr-I 9000)Before treatment:

CA=86ºAfter treatment

CA=105,9 ± 1,2º º

RF PLASMA Time =2min Power =25W SF6= 50sccm Ar =200sccm • Before treatment: thickness = 287,86nm; roughness = 0,62nm• After treatment: thickness = 248,84nm; roughness = 0,353nm

LITHO2006, Marseille June 2006 9

PDAP: MW plasma

• PDAP (IVb_3) MW 2500W 15min 200SF6 50Ar• PDAP (IVb_4) MW 2500W 5min 200SF6 50Ar• PDAP (IVb_5) MW 2000W 5min 200SF6 50Ar

No modification in the thickness, slight increase of the roughness

0

20

40

60

80

100

120

PDAP (IVb_3) PDAP (IVb_4) PDAP (IVb_5)

Sample

CA CA Untreated

CA (+0 days)

CA (+1 days)

CA (+3 days)

CA (+5 days)

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Sample1 Time=2min Power=100W SF6=37,5 Ar =150 Sample4 Time=1min Power=125W SF6=37,5 Ar= 100Sample2 Time=2min Power=25W SF6=50 Ar =200 Sample5 Time=1min Power=125W SF6=175 Ar=25Sample3 Time=2min Power=100W SF6=200 Ar =0 Sample6 Time=1min Power=125W SF6=225 Ar= 25

90

95

100

105

110

115

8000 Sample1

Sample2

Sample3

Con

tact

Ang

le

Day1

Day4

Day8

90

95

100

105

110

115

8000

Sample

4Sam

ple5

Sample

6

Con

tact

Ang

le

Day1

Day5

mrI-8000: RF plasma

LITHO2006, Marseille June 2006 11

mrI-8000: MW plasma

86889092949698

100102104106

8000 Sample 1 Sample 2

C.A

.

C.A (+1 day)

C.A. (+6 days)C.A. (+8 days)

8000: UntreatedSample 1: Ar:200 sccm SF6: 50 sccm Pow er: 2000W Time: 15 minSample 2: Ar:50 sccm SF6: 200 sccm Pow er: 2000W Time: 10 min

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Before treatment:CA=92º

After RF treatmentCA=101,8 ± 1,6º

RF PLASMA Time= 1min Power= 125W CF4= 175sccm Ar= 25sccmMW PLASMA Time= 10min Power= 2000W SF6= 200sccm Ar= 50sccm Before treatment: thickness = 385-400nm ; roughness = 2-3nmAfter RF treatment : thickness =373,69nm; roughness = 0,3-0,4 nmAfter MW treatment : thickness =379,14nm; roughness = 1-3 nm

After MW treatmentCA=104,5 ± 2,1º

AFM (mr-I 8000)

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Lifetime of the treatment

100

105

110

115

120

125

130

2000W 15min 200SF6 50Ar

CA

Day 0Day 14Day 15Day 29

mrI-7000: 2000W 15min 200:50, SF6:Ar

mrI-7000: MW plasma

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Before treatment: CA=80,7º

After treatmentCA=126,9º

AFM (mr-I 7000)

MW PLASMA Time =10min Power =2000W SF6= 200sccm Ar =50sccm • Before treatment: thickness = 326,89nm ; roughness = 0,265nm• After treatment: thickness = 303,68nm; roughness = 6,399nm

LITHO2006, Marseille June 2006 15

PMMA

PMMA2_8 RF 125W 1min 175SF6 25ArPMMA2_11 RF 25W 2min 50SF6 200ArPMMA6_1 MW 2000W 5min 200SF6 50Ar

Basically no modification in the thickness and roughness after MW plasma, higher after RF treatment

0

20

40

60

80

100

120

140

PMMA2_8 PMMA2_11 PMMA6_1

Samples

CA

CA untreated

CA (+1)

CA (+5)

LITHO2006, Marseille June 2006 16

XPS results (In-depth profile)

02004006008001000

Energía de enlace (eV.).

F 1s

C 1sO 1s

F KLL

F 2s

O 2s

02004006008001000200

Energía de enlace (eV.).

F 1s

C 1sO 1s

F KLL

F 2s

O 2s

BulkSurface

02004006008001000

Energía de enlace (eV.).

C 1s

O 1sO 2s

0102030405060708090

100

0 100 200 300 400 500

nm.

% a

t FCSi

mr-I 8000

mr-I 7000

mr-I 8000

mr-I 7000

MW

PLA

SMA

∅63,296F

96,63933,36C

3,3613,344O

BulkSurfaceElement

6nm deep

•In-depth spectra show no fluorine groups after few nanometers (~6nm)

LITHO2006, Marseille June 2006 17

280285290295

Energía de enlace (eV.).

293.2

286.7285.0

289.2

291.4

276281286291296301

Energía de enlace (eV.).

293.2 286.7

285.0

289.2

291.4

Surface

mr-I 8000

Bulk

280285290295300

Energía de enlace (eV.).

286.7

284.4

289.2

mr-I 7000

mr-I 8000

• CF2 (291,4eV) and CF3 (293,2eV) are themain groups responsible for the anti-adhesion.

• The spectrum of mr-I 7000 has more intensity in this region. (Higher CA)

XPS results (Functional groups)

C pe

ak

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Stamp Plasma Power (W) Time (min) SF6 Ar Contact Angle Silane (2 PDMS) Untreated --- --- --- --- aprox.81º Si (1 PDMS) MW 3000 10 200 50 128,11º Si (2 PDMS) MW 3000 10 200 50 129,66º Si (1 PDMS) RF 25 2 50 200 116,59º

Si

MW

3000

10

200

50

Aprox. 127º

All the tests were made under the same imprint conditions that were optimized previously by Tekniker:

- Temperature of 140ºC- Force of 50000N (≈63 bar)- Embossing time of 5 minutes (total time of each imprint aprox. 20min).

Imprinting trials (I)

LITHO2006, Marseille June 2006 19

• The colour pattern of the residual layer shows no differences.

• Characteristics well defined and good filling of the patterns.

INASMET

INASMET

TEKNIKER

TEKNIKER

Imprinting trials (II)

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TEKNIKER

INASMET

• Treated samples do not adhere at all during demoulding, although someresist sticks on the walls of the stamp after several imprints.

•The process was correct: filling correct, details well defined, …

•The treated polymer has the same etch rate as the untreted one.

• More regular pattern obtained with the Inasmet sample.

Imprinting trials (III)

LITHO2006, Marseille June 2006 21

A short process for low pressure plasma treatment has been developed, which improves the pattern transfer and eliminates the manual de-

moulding needed after NIL processing

-This has been proved on several polymers

-A complete characterization of the surface of the different polymershas been performed

Conclusions

LITHO2006, Marseille June 2006 22

Thank you for yourattention

The partial support of the EC-funded project NaPa(Contract no.NMP4-CT-2003-500120) is gratefully acknowledged