XPS characterisation of POSS resist before etching · Background analysis: Photelectrons suffer...

157-Crispies Bruxelles oct. 03 1

XPS characterisation of POSS resist before etching

IMN contribution to WP1:Prototype photoresist material development


Outline

• Identification of chemical environments

• 2 methods to study POSS surface segregation– ARXPS– Background analysis

• POSS depth distribution

• Other experiments

• Work continuing


POSS-acrylates XPS data

C5O1

0

500

1000

1500

2000

2500

3000

529531533535537Binding energy (eV)

Inte

nsi

ty (

CP

S)

O5

O2 O1

O 1s

0

500

1000

1500

2000

282284286288290292294Binding energy (eV)

Inte

nsi

ty (C

PS

)

C1

C2

C3C4C5

C7

C 1s

C1

C2

C7C2C3


Methods to investigatePOSS surface segregation

Background analysis:

Photelectrons suffer inelastic collisions during travelBackground function of

inelastic scattering cross sectionlocation of electron emission

Angular resolved XPS:

Probed depth varies with TRequires high resolution

high s/n spectraspectra at various T

depth

T

Kinetic energy


020040060080010001200

Sp. "atomique"

0

Energie de liaison (eV)

Background data processing

020040060080010001200

spectre émis

0


020040060080010001200

Sp. expérimental

0


détecteur

hv

sample

Experimental

Corrected from T(E)

Corrected from background


Angular XPS: POSS surface segregation

8

10

12

14

16

18

20

22

0.2 0.4 0.6 0.8 1 1.2

increasing take off angle

60-40-0100-0-040-60-020-80-0

% S

i

normalised probed depth

18.6

10.3

6.6

3.2

197%93%64%5%

20/8040/6060/40100/0

deviation of % Si / nominal

0

1

2

3

4

5

6

7

0.2 0.4 0.6 0.8 1 1.2


60-40-0100-0-040-60-020-80-0

%C

Car

boxy

licnormalised probed depth


Background signal analysis:POSS depth distribution (1)

0

50

100

150

200

250

1000 1020 1040 1060 1080 1100 1120 1140 1160Kinetic energy (eV)

Inte

nsi

ty (

CP

S)

Si 2s Si 2p

Generated

20%

0.66

0.20

L = 1.6 nm

0

100

200

300

400

500

600

700

1000 1020 1040 1060 1080 1100 1120 1140 1160

Kinetic energy (eV)

Inte

nsity

(CPS

)

Si 2s Si 2p

20%

40%

100% 60%

Background decreases

0

100

200

300

400

500

600

700

800

900

1000

760 780 800 820 840 860 880 900 920 940 960 980Kinetic energy (eV)

Inte

nsi

ty (

CP

S)

C 1s

20%40%

100%60%

Background increases

Confirms difference between copolymers

0

50

100

150

200

250

1000 1020 1040 1060 1080 1100 1120 1140 1160Photoelectron kinetic energy (eV)

Inte

nsi

ty (

CP

S)

Si 2s Si 2p

Generated

20%

POSS material

0.365

10 nm

Island model:not suitable

Exponentialgradient:suitable


Background signal analysis:POSS depth distribution (2)

0

50

100

150

200

250


Inte

nsi

ty (C

PS

)

Si 2s Si 2p

Generated

20%

0.66

0.20

L = 1.6 nm

0

50

100

150

200

250

300

350

400


Inte

nsi

ty (

CP

S)

Si 2s Si 2p

Generated60%

0.55

0.5

L = 1.5 nm

0

20

40

60

80

100

120

140

160

180

200


Inte

nsi

ty (

CP

S)

Si 2s Si 2p

Generated30%

0.30

0.25

L = 1.5 nm

0

50

100

150

200

250

300

350


Inte

nsi

ty (

CP

S)

Si 2s Si 2p

Generated40%

0.62

0.42

L = 1.4 nm

1 POSS-rich layer at surface

Si bulk concentration vs nominal

1.5 nm

POSS surface concentration

0.920.900.76120/8040/6060/40100/0

0.4

30/MA20

Decay length ~ POSS size

0,140,290,430,720,200,420,50,72


POSS segregation – Development issues

0

100

200

300

400

500

600

700

1000 1020 1040 1060 1080 1100 1120 1140 1160Photoelectron kinetic energy (eV)

Inte

nsity

(CP

S)

Si 2s Si 2p

40%

60%

30% MA20

and 30% MA10IA20

30% POSS:

§ Identical spectra withX = MA20 or X = MA10IA20

§ Between 40% and 60% copolymers è less surface segregation

§ MA20 and IA20 show development difficulties, MA10IA20 do not.

è Correlation of segregation with development difficulties is not totally performed


Other experiments

• TEM: failure

• XPS at various T: measurements at 50°C, 175°C, 20°C

polymer

Si

polymer

adhésive

0

10

20

30

40

50

60

70

50 175 20

OCSi

atom

ic %

Temperature


Work continuing: new materials (1)Ethyl-POSS versus Cyclopentyl-POSS

0

5

10

15

20

25

0.2 0.4 0.6 0.8 1 1.2


60-40-0100-0-040-60-020-80-0

% S

i


18.610.3

6.6

3.2

0

5

10

15

20

25

0.2 0.4 0.6 0.8 1 1.2


100-0-040-60-020-80-0

% S

i


12.5

2.3 4.6

Cyclopentyl-POSS copolymers show less surface segregation


Work continuing: new materials (2)

0

5

10

15

20

25

0.2 0.4 0.6 0.8 1 1.2


40-60-0

40-60-0 + PFOS

% S

i


PAG has no effect on POSS segregation

PAG is ‘normally’ distributed

0

5

10

15

20

25

0.2 0.4 0.6 0.8 1 1.2


40-40TBFA-20MA

40-60TBMA%

Si

normalised probed depthTBFA seems to reduce segregation

XPS characterisation of POSS resist before etching · Background analysis: Photelectrons suffer...

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