Development of Under Layer material for EUV...

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NISSAN CHEMICAL INDUSTRIES, LTD. Electronic Materials Research Laboratories.

SEMATECH IEUVI resist TWG, 2011-02-27

Challenging and Solution by xChallenging and Solution by x--layerlayer

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Development of Under Layer material for EUV Lithography

Nissan Chemical Industries, LTD.

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Reflectivity control is the key factor.BARC material is necessary for Optical Lithography.

Substrate

BARC

PR

Fitting optical phase

Optical LithographyOptical Lithography(with g(with g--line, iline, i--line, KrF, ArF)line, KrF, ArF)

Substrate

Under-layer

PR

No reflection with EUV

EUV LithographyEUV Lithography(with 13.5nm)(with 13.5nm)

Because EUV light is absorbed or path the layers, it does not need the reflectivity control . However, UL is used as adhesion and LWR reduction purpose.

Opt. Lithography and EUV Lithography

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RLS trade off

LER

Sensitivity

Resolution

LER

Sensitivity

Resolution

Sub.U.L.

PR

To apply the functional UnderTo apply the functional Under--Layer(ULLayer(UL) to minimize the trade off RLS) to minimize the trade off RLS

R: ResolutionL: Line-Edge-Roughness

S: Sensitivity

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<HM+UL>

PR (FT: ~50nm?)

UL (FT: ~20nm)

HM-1 (CVD)

Substrate-1

Org.-UL

Requirements for EUV Under-layer・High adhesion with PR・Block the contamination from substrate (Barrier film) ・Good performance with thin film (~20nm) ・Good etch performance with fast etch rate or thin FTK.・No out-gassing・・resolution enhancementresolution enhancement (pattern collapse)(pattern collapse)・・Reduce LWR, LERReduce LWR, LER-- Enhance Enhance SensitivitySensitivity

Under-layer

Substrate

P.R.

Stack structure;

Org.-HM

Inorg.-UL

Substrate-1

<Tri-layer>

PR (FT: ~50nm?)

Requirement for EUV UL materialRequirement for EUV UL material

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Pattern Collapse

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20

25

30

35

40

45

B C D E F G

Lin

e W

idth

[nm

]

on Si

Conv. KrF-BARC (narrow collapse margin)

Optimized UL for EUV-PR

Optimized UL had capability for below 30nm HP.

PR: SSR-3HP: 32nm

Minimum standing line width

SPIE 2009, 7273-113, Selete, D. Kawamura, et al.

Pattern Collapse

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Silicon

HM-layerNCX (U.L.)

PR

OH

OO

OO

OO

SO O-

OR2 S+

R2

R2

OR1

EUV-PR resin

Introducing High adhesion unit into basePolymer of UL.

High density unit High polarity unit

Pattern Collapse

UL could help resist to increase Pattern Collapse window

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36.9nm 30.4nm 26.7nm

32.6nm 31.1nm 26.4nm 22.3nm

35.7nm 30.5nm 26.2nm

8.4nm 6.0nm 5.6nm

5.7nm 6.9nm 6.7nm 6.0nm

7.5nm 6.0nm 6.4nm

24.3nm 22.8nm5.9nm 5.9nm

13.45 mJ12.45 mJ11.45 mJ10.45 mJ

15.45 mJ14.45 mJ13.45 mJ12.45 mJ11.45 mJ10.45 mJ

21.7nm 19.9nm4.9nm 5.6nm

14.35 mJ13.4 mJ12.45 mJ11.5 mJ10.55 mJ

UL-A（Polar unit）

Ref.

UL-B（Polar unit）

Exp：MET, EUV-PR

Achieved ~20nm size Pattern at over dose condition.

The comparison of pattern collapse margin.

Pattern Collapse

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Line-Edge-Roughness

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UL improves the LWR

On X-Layer

On ULSeleteEUV symposium @ Barcelona

Line-Edge-Roughness

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Material Concept for profile controlMaterial Concept for profile control

H + H +

H +H +H +

H +

base - Base - Base -

NCX (Barrier/Buffer property)

ConceptConcept--11High film density (Physically barrier)

ConceptConcept--22Enhancement of Acid generation efficiency at interface between UL and PR.

H +

H +e-/acid

LWR / LER

Footing / Scumming

Top downX section

Line-Edge-Roughness

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Si-Sub./HMDS Acrylate HighHigh--densitydensity

HP 45

HP 35

HP 32

Taper/Footing profile Taper/Footing profile Vertical profileVertical profile

SPIE 2009, 7273-113, Selete, D. Kawamura, et al.

High Density UL material

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Photo-sensitivity

Keep the performance of Pattern Collapse & LER,

but enhance the photo-sensitivity of EUV resist

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PR

UL

EUV

H+ H+

e- e-

Acid Generation MechanismAcid Generation Mechanism

2nd e-

e・+

e- Activation

EUV

Polymer matrix of U.L.

PAGàH+

Polymer matrix of PR

PAGàH+

2nd e-

e・+

e- Activation

EUV

Polymer matrix of U.L.

PAGàH+

Polymer matrix of PR

PAGàH+

Sensitivity

X HX H

RH : ResinMX : PAGRH : Radical cation of resinR : Radical of resinRH(H) : Protonated resinM : decomposition of PAGX- : Counter anion of PAG

・+

+

・

prof. Tagawa, Kozawa, et al

ee

MXMX

M

+

XX-

- +H

RHRH

EUV

RHRH ・+ RH(H)RH(H)+

RHRH

RR・・

-

Acid Generation Acid Generation

Electron Electron GenerationGeneration

Resin

PAG

Resin

Radical

Anion

ProtonationProtonation

Proton Proton tranfertranfer

X HX H

RH : ResinMX : PAGRH : Radical cation of resinR : Radical of resinRH(H) : Protonated resinM : decomposition of PAGX- : Counter anion of PAG

・+

+

・

prof. Tagawa, Kozawa, et al

ee

MXMX

M

+

XX-

- +H

RHRH

EUV

RHRH ・+ RH(H)RH(H)+

RHRH

RR・・

-

Acid Generation Acid Generation

Electron Electron GenerationGeneration

Resin

PAG

Resin

Radical

Anion

ProtonationProtonation

Proton Proton tranfertranfer

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Si-Sub. (O.D.=1.7)(w/ HMDS)

UL-H (O.D= 13.3um-1)(w/ Chromophore)

11.68mJ/cm212.53mJ/cm2

12.25mJ/cm213.21mJ/cm2

11.98mJ/cm212.96mJ/cm2

Sensitivity enhanced~10% by Underlayer

2nd electron concept can enhance photospeed and also make pattern profileMore vertical!

1010.5

1111.5

1212.5

1313.5

1414.5

15

25 35 45 55Hp (nm)

Dose

to

size

(mJ/

cm2) HMDS

NCX- B

Sensitivity

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0.015

0.02

0.025

0.03

0.035

0.04

8 9 10 11 12 13 14 15 16Dose (mJ/ cm2)

CD (u

m)

Type BType A Type A

Type BIncrease sensitivityIncrease sensitivity

Tool: METTarget CD: hp30nm

EUV Litho Evaluation ~Dose to CD hp 30nm~

Type B resin used UL can improve sensitivity,and pattern space area is more clear than type A resin from top view.

⇒⇒ Type B resin generated more Type B resin generated more electronelectron by EUV.by EUV.UL can control PR sensitivity and litho profile by control 2UL can control PR sensitivity and litho profile by control 2ndnd electron gen..electron gen..

Sensitivity

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Conclusion

１．The key parameter for EUV-UL development are Outgassing control, strong adhesion with PR and LWR control and less LER.

2. The pattern collapse margin was improved by introducing polar unit into basepolymer of UL.

3．High density UL could make resist profile more vertical and less LER.

4．The result of acid generation efficiency at UL surface was roughly correlated withactual PR photo-speed. (But need to confirm some other resist platform)

Development of Under Layer material for EUV...

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