1 12&13/05/2005 review meeting more moore_sp3-wp consortium confidential ltm contribution to...

112&13/05/2005 Review Meeting More Moore_SP3-WP CONSORTIUM CONFIDENTIAL

LTM contribution to SP3-WP6

Two tasks:

1. Thermal characterization of ultra thin resist films (D 3.6.1.3.1)

2. Spin Coating and bake modeling for Ultra thin resist films (M 3.6.1.5)


Thermal characterization of ultra thin resist films (D 3.6.1.3.1)

• Thermal expansion of thin films followed by ellipsometry

• Simple homopolymer studied : 1. Polystyrene (PS)2. PMMA3. Poly Hydroxystyrene (soluble part of CAR)

• Studies of Clariant resist :1. MMC2 (copolymer)2. MMC3 (CAR)3. MMC4 (terpolymer)


Simple polymer 1 : PS(4000 g/mol, Tg ~ 80°C)

20 40 60 80 100 1200

2

4

6

8

10

12

14

16

18

20 nm 45 nm 75 nm 100 nm

Def

orm

atio

n (%

)

Temperature (°C)20 40 60 80 100

0,0

5,0x10-4

1,0x10-3

1,5x10-3

2,0x10-3

melt glassy

a (K

-1)

Thickness (nm)• No variation of Tg

• Increase of the coefficients of thermal expansion for thickness below 50 nm


Simple polymer 2 : PMMA(950 000 g/mol, Tg ~ 120°C)

20 40 60 80 100 120 140 160 180 2000

20

40

60

80

100

16 nm 27 nm 47 nm 95 nm 142 nm 315 nm

Def

orm

atio

n (%

)

Temperature (°C)

40 60 80 100 120 140 160 180 2000

2

4

6

8

10

12

Si Si + plasma O

2

Si + HMDS

Def

orm

atio

n (%

)

Temperature (°C)

•Si/PMMA interactions :•Tg variations and a are not significative•To be continued for thinnest films…

• No variation of Tg

• Influence of the interface effects?

47 nm


Simple polymer 3 : PHS (8000 g/mol, Tg ~ 170°C)

40 60 80 100 120 140 160 180 200

312

314

316

318

320

322

324

326

328

330

cycle 1 cycle 2 cycle 3

Thic

knes

s (n

m)

Temperature (°C)

Diminution of the thickness during successive cycles :

Degradation or relaxation of PHS chains? Mechanism?

Solvent evaporation

1. Kinetic measurements shows compaction even for long time

2. Degradation or chemical modification of PHS with light


Clariant Resist 1 : MMC2 copolymer hydroxystyrene – butoxystyrene

(no PAG) Tg ~ 155°C

40 60 80 100 120 140 160 1800,0

0,5

1,0

1,5

2,0

2,5

3,0

3,5

4,0

45 nm 60 nm 130 nm 240 nm

Def

orm

atio

n (%

)

Temperature (°C)

40 60 80 100 120 140 160 180 200 220 240140

142

144

146

148

150

152

154

T g (°C

)

Thickness (nm)

40 60 80 100 120 140 160 180 200 220 240

1,0x10-4

1,5x10-4

2,0x10-4

2,5x10-4

3,0x10-4

3,5x10-4

4,0x10-4

4,5x10-4

5,0x10-4

5,5x10-4

melt glassy

a

Thickness (nm)

1. Diminution of Tg for thickness below 50 nm (significative?)

2. Diminution of the thermal expansion

Contradictory results ?


Clariant Resist 2 : MMC3 2-methyl-2-adamantol methacrylate (MAdMA)/

Mevalonic lactone methacrylate(contains PAG)

20 40 60 80 100 120 140 160-20

-15

-10

-5

0

5

40 nm 90 nm 140 nm

Def

orm

atio

n (%

)

Temperature (°C)

•Presence of PAG : photo activation of the resist with the spot ligth above Tg

Thermal compaction of the film above Tg

Compaction


Clariant Resist 3 : MMC4Terpolymer hydroxystyrene – styrene-butylmethacrylate

(no PAG) Tg ~ 160°C

40 60 80 100 120 140 160162,0

162,5

163,0

163,5

164,0

164,5

165,0

165,5

166,0

166,5

167,0

cycle 1 cycle 2

Thic

knes

s (°

C)

Temperature (°C)

Diminution of the thickness of the filmsduring successive cycles :

Photo degradation

40 60 80 100 120 140 160

0,0

0,2

0,4

0,6

0,8

1,0

1,2

1,4

46 nm 165 nm

Def

orm

atio

n (%

)

Temperature (°C)

Cycle 2 for 46 nm and 165 nm films :Tg is not detectable


Thermal properties of Ultra thin resists films

• results:

1. No obvious Tg changes with thickness

2. Strong influence of the thickness on thermal expansion of the film

3. Thin layer properties for material if e<100 nm for all materials

Important recommendationLigth filtering to avoid photo degradation


Spin-Coating modeling

Four steps while Spin-coating:

1: Resist deposition

2 : Film generation

3 : Matter ejection predominant for film thinning

4 : Solvant evaporation predominant

Compositionunchanged


Film thinning

Evaporation at the free surface concentration gradient and diffusion

0 50 100 150 200 250 300 350 400 450 5001,0x10-15

1,5x10-15

2,0x10-15

2,5x10-15

3,0x10-15

3,5x10-15

4,0x10-15

4,5x10-15

5,0x10-15

Fric

tion

para

met

er

x (nm)

Hypothesis: wall slows the intermolecular mobility, hence

increases the friction parameter between macromolecules


Spin-Coating Simulation

0,0 0,2 0,4 0,6 0,8 1,0 1,2 1,4 1,6 1,8 2,00,0

0,2

0,4

0,6

0,8

1,0

Sol

vent

vol

ume

fract

ion

x (µm)

t=0s t=2s t=4s t=6s t=7s t=8s t=9s t=10s t=15s Free Surface

0 2 4 6 8 10 12 14 160,0

0,2

0,4

0,6

0,8

1,0

1,2

1,4

1,6

1,8

2,0

Film

thic

knes

s (µ

m)

Spinning time (s)

e

Exemple of the coating of a wafer with a resist


Post Applied Bake

0 20 40 60 80 100 120 140 160 180 2000,00

0,05

0,10

0,15

0,20

0,25

0,30

0,35

0,40

1 2 3 4 56

Sol

vent

vol

ume

fract

ion

x (nm)

t=0s t=1s t=2s t=3s t=4s t=5s t=6s t=7s t=8s t=9s t=10s t=15s t=20s t=30,2s t=40,4s t=50s

1 t=60s Free surface

No wall influenceOn film

homogeneity


Accuracy of the model

• Without wall effects: the model predicts accurately the spin curves and film compaction while heating

• With wall effects: No significant differences after Post Applied Bake on the film structure Friction parameter accurate?

Conclusion: Further studies are needed to properly simulate wall effects

1 12&13/05/2005 review meeting more moore_sp3-wp consortium confidential ltm contribution to...

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