theories and applications of chem. eng., 2004, vol. 10, no. 2 2922 · 2004-11-08 ·...

화학공학의 이론과 응용 제10권 제2호 2004년

Theories and Applications of Chem. Eng., 2004, Vol. 10, No. 2 2922

김 상 태동우화인켐

반도체용 포토레지스트의 연구 개발 동향반도체용 포토레지스트의 연구 개발 동향



- Photopolymer

- Microelectronics Fabrication Process- Development Trend of Lithography and Resist- Classification of photoresist- Typical of Photoresist

TypicalTypical i, gi, g--line & LCD resist (365 nm)line & LCD resist (365 nm)

Typical Typical KrFKrF resist (248 nm)resist (248 nm)

Typical Typical ArFArF resist (193 nm)resist (193 nm)

Immersion LithographyImmersion LithographyBasic F2 resist (157 nm)Basic F2 resist (157 nm)

ContentsContents



감광성 고분자의 용도

•인쇄제판

- 평판 PS판- 감광성 凸판- 감광성 flexo판- 스크린 인쇄판- Off-press color proof

• Photoresists (PR) for Microlithography- G/I-line PR- Deep UV, Excimer laser resists- 전자선, 감광성 polyimide resists- Laser direct writing (LDW)

•인쇄회로기판(PCB)용 PR

- 감광성 dry film PR (DFR)- Photo solder mask (resist) - 납땜- Photoetching ink (스크린 잉크) - 식각, 도금- 전착성 PR

•인쇄제판

- 평판 PS판- 감광성 凸판- 감광성 flexo판- 스크린 인쇄판- Off-press color proof

• Photoresists (PR) for Microlithography- G/I-line PR- Deep UV, Excimer laser resists- 전자선, 감광성 polyimide resists- Laser direct writing (LDW)

•인쇄회로기판(PCB)용 PR

- 감광성 dry film PR (DFR)- Photo solder mask (resist) - 납땜- Photoetching ink (스크린 잉크) - 식각, 도금- 전착성 PR

화상형성 분야 (Photoimaging)화상형성 분야 (Photoimaging)

•광가공 (Photofabrication) : Photoetching (광식각)

- 고정밀 전자, 기계부품- TV shadow mask, IC lead frame- Micromachine

•전자 표시장치 (Display)

- TV 형광면 (RGB color 화상)- TFT LCD (flat panel) color filter- Video camera 고체촬상소자

•광가공 (Photofabrication) : Photoetching (광식각)

- 고정밀 전자, 기계부품- TV shadow mask, IC lead frame- Micromachine

•전자 표시장치 (Display)

- TV 형광면 (RGB color 화상)- TFT LCD (flat panel) color filter- Video camera 고체촬상소자



/diffusion

CrystalGrowth

Microelectronics Fabrication ProcessMicroelectronics Fabrication Process



반도체 전공정 재료비 구성반도체 전공정 재료비 구성

Silicon wafer45 %

Photomask18 %

Gas16 %

Photoresist10 %

Chemical5 %

Target3 %

Etc.3 %



1. Top coat on ArF resist2. Water attack free resin

193nm 134nmArFArF immersionimmersion

Material issues157nm 115nmFF22 immersion immersion

Material issues157nmF2

Deep UV

Acrylate, Novolac, Polystyrene5-15ÅX-ray

Acrylate, Novolac, Polystyrene0.1ÅE-beam

Material issues10-14nmEUV

Acrylate193nmArF

PVP248nmKrF

Novolac365nmi-line

Novolac436nmg-lineNear UV

ResinSource

Classification of photoresistClassification of photoresist



Res

olut

ion

(㎛)

10

1.0

0.1

‘75 ‘85 ‘95 ‘00

Contactprinter

Cyclized RubberBisazide

DNQ-Novolak

First Turning Point

Chemical Amplification

Second Turning Point

Year

Development trend of lithography and resistDevelopment trend of lithography and resist

‘05

0.05

G-linestepper

I-linestepper

KrF ArFscanner

EUVE-Beam

Immersion Litho.

ArF F2 Immersion system



Positive PR Negative PR

SubstratePR

SubstratePRCoating

Substrate Substrate

Light (Exposure) Light (Exposure)

Development

Developed PatternSubstrate Substrate

Positive & Negative photoresistPositive & Negative photoresist



General ComponentsGeneral Components

i-line Photoresist DUV DUV PhotoresitPhotoresit ((KrFKrF))

Novolak Resin Protected Poly-vinyl-Phenol Resin

PAG(Photo Acid Generator)

PAC(Photo Active compound)

Additive

Additive

SolventSolvent

Quencher



i-line Positive Photoresist Compositioni-line Positive Photoresist Composition

OH

R

H2C

O

SO3R'

N2

SO3R'

CO

SO3R'

COOH

Novolak Resin

+ PAC (Alkali)

Unexposed partAzocoupling

ProductsInsoluble

Photo Active Compound

Exposed partH2O

Solvent2-Heptanone

+ N2

Soluble

+

O

SO3R'

N2

OH

R

H2C

O

SO3R'

N N

ONa

CH2

NaOHdeveloping

Coupling Effect



SubstrateSubstrate

Metal Metal DepositioDepositionn

Resist Resist CoatingCoating

Exposure Exposure & P.E.B.& P.E.B.

DevelopmentDevelopmentDry EtchingDry Etching

PHOTORESIST (PR)PHOTORESIST (PR)



Chemical amplification conceptChemical amplification concept

Ph3S SbF6hv

HOH

n

O O

O

C

CH3

CH3CH3

n

C

CH3

CH3CH3

+ CO2 +

H[ ]

PAG

PBOCSt

Tert-butyloxycarbonyl(t-BOC)

PHOSt

H2C CCH3

CH3

+

H SbF6

Amplification

Exposed part



CH2 CH

OH

Alkali soluble

CH2 CH

OC

OC

CH3

CH3CH3O

CH2 CH

O

SiCH3

CH3CH3

CH2 CH

OCH

O

CH3

CH2CH3

CH2 CH SO2

OC

O

C

CH3CH3

CH3O

CH2 CH

OCH

O

CH3

O

CH2 CH

O

HH++

HH++

HH++HH++

HH++

HH++

Various mechanism in chemical amplified resistsVarious mechanism in chemical amplified resists



KrF Resin Structure Design KrF Resin Structure Design

OO

OH

O

ORCN

zyx

n

Adhesion Promotion UnitAqueous Development unit

Acid Catalyzed Deprotection unitPromotion of Photospeed in Exposure AreaControl Resolution

Main BackboneDeep UV transmission Thermal stability & Dry etch resistance

Acid Catalyzed Deprotection Unit :High Contrast Provider

-Large Hydrophobicity in Unexposed Area-Large Hydrophilicity in Exposed Area



OH O

R1 O R2

Acetal

OH

CO

O

Annealing

OH O

OO

OH O

R1 O R2

Hybrid

Low Activation

Energy

Good Resolution

Good CD-Bias

Low PEB Sensitivity

Line Edge Roughness

Out Gassing

High Activation

Energy

Themally Stable

Less LER

Good Etch

Performance

Relatively Low Margin

High PEB Sensitivity

Good Etch Performance

High Resolution

Environmental Stability

Wide Process Margin

Polymer synthesis

Typical KrF resist (248nm)Typical KrF resist (248nm)



Selection of Diazo PAG & Onium PAGSelection of Diazo PAG & Onium PAG

R1 S C

N2

S

O

O O

O

R2 S+R1

R2-

Better resolution and DoFHigher transparency

Higher sensitivityThermally Stable

Lower transparency

Onium TypeDiazo Type

Combination of two Combination of two PAGsPAGs..

High resolution with high High resolution with high photospeedphotospeed



레지스트 설계 목표

Pivotal Point control DOF margin확대1. +Defocus (Thinning )2. –Defocus（Scum）、Pattern (Lifting)

（Resist의 공통 과제）

－DefocusLifting

Best Defocus ＋DefocusThinning

Resist의 개발Resist의 개발



O OO O OH

O O O OO O O OH

O OO O

COOR COOH

O OO O

COOHCOOR

OO

OH

OOO

O

O

O

OOO

O O

OOO

O

O

OOO

OO

O O O OO O O OH

OO

O O OO OH O

IBM TOSHIBA

FUJITSU

NEC

IBM : Low Etch resistancePoor adhesion

FUJITSU : High etch resistanceHigh ResolutionConventional developer

NEC : High etch resistancePoor adhesionSpecial developer

Matacrylate type ArF resist (193 nm)Matacrylate type ArF resist (193 nm)



Immersion Scanner (193nm)Immersion Scanner (193nm)

NA=NA=nSinnSinθθ

Resolution = k1 Resolution = k1 λλ / NA/ NAImprovement of ResolutionImprovement of Resolution

DOF = k2 n DOF = k2 n λλ / NA/ NAImprovement of DOFImprovement of DOF

Reference : Nikon, Tokyo ElectronReference : Nikon, Tokyo Electron



Development of Top CoatDevelopment of Top Coat

Not dissolve resist film during coating. Not dissolve resist film during coating. Need appropriate Need appropriate solventsolvent

Not dissolved to water but Not dissolved to water but dissolved to alkalinedissolved to alkaline

Higher Higher hydrophobic surfacehydrophobic surface of the film for speedy scanningof the film for speedy scanning

Prevent Prevent PAGPAG andand quencherquencher fromfrom dissolvingdissolving to waterto water

Optical characteristics : appropriate optical Optical characteristics : appropriate optical constant constant nn should be should be 1.3331.333 ( ( nn of water)of water)



Issue to Realize Immersion LithographyIssue to Realize Immersion Lithography

Existing Existing ArFArF scannerscanner is not compatible with immersion lithograph.is not compatible with immersion lithograph.Excess capital investment in new Excess capital investment in new FabFab..

Scanner lens contamination by dissolved Scanner lens contamination by dissolved photoresistphotoresist componentcomponent

Immersion water attack Immersion water attack photoresistphotoresist top surface. top surface.

Requirement of material development for new resin systemRequirement of material development for new resin system

Adjustment PR transparency for different wavelength (134nm)Adjustment PR transparency for different wavelength (134nm)

Solution : Solution : Top coatTop coat

Solution : Development of new Solution : Development of new ArFArF resistresist

theories and applications of chem. eng., 2004, vol. 10, no. 2 2922 · 2004-11-08 ·...

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