김 상 태 동우화인켐

김 상 태

동우화인켐

반도체용 포토레지스트의 연구 개발 동향

반도체용 포토레지스트의 연구 개발 동향

- Photopolymer

- Microelectronics Fabrication Process

- Development Trend of Lithography and Resist - Classification of photoresist

- Typical of Photoresist Typical

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

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

Typical ArF ArF resist (193 nm) resist (193 nm) Immersion Lithography Immersion Lithography Basic F2 resist (157 nm) Basic F2 resist (157 nm)

Contents

Contents

감광성 고분자의 용도

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

• Photoresists (PR) for Microlithography

- 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

- 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

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l Growt h

Microelectronics Fabrication Process

Microelectronics Fabrication Process

반도체 전공정 재료비 구성 반도체 전공정 재료비 구성

Silicon wafer 45 %

Photomask 18 % Gas

16 % Photoresist

10 %

Chemical 5 %

Target 3 %

Etc.

3 %

1. Top coat on ArF resist 2. Water attack free resin 193nm Æ 134nm

ArF ArF immersion immersion

Material issues 157nm Æ 115nm

F

F

immersion immersion

Material issues 157nm

F

Deep UV

Acrylate, Novolac, Polystyrene 5-15Å

X-ray

Acrylate, Novolac, Polystyrene 0.1Å

E-beam

Material issues 10-14nm

EUV

Acrylate 193nm

ArF

PVP 248nm

KrF

Novolac 365nm

i-line

Novolac 436nm

g-line Near UV

Resin Source

Classification of photoresist

Classification of photoresist

R es ol ut io n (㎛ ) 10

1.0

0.1

‘75 ‘85 ‘95 ‘00

Contact printer

Cyclized Rubber Bisazide

DNQ-Novolak First Turning Point

Chemical Amplification Second Turning Point

Year

Development trend of lithography and resist Development trend of lithography and resist

‘05 0.05

G-line stepper

I-line stepper

KrF ArF scanner

EUV E-Beam

Immersion Litho.

ArF F

Immersion system

Positive PR Negative PR

Substrate PR

Substrate Coating PR

Substrate Substrate

Light (Exposure) Light (Exposure)

Development Developed Pattern

Substrate Substrate

Positive & Negative photoresist

Positive & Negative photoresist

General Components General Components

i-line Photoresist DUV DUV Photoresit Photoresit (KrF ( KrF) )

Novolak Resin Protected Poly-vinyl-Phenol Resin

PAG

(Photo Acid Generator) PAC

(Photo Active compound)

Additive

Additive Solvent

Solvent

Quencher

i-line Positive Photoresist Composition i-line Positive Photoresist Composition

OH

R H2 C

O

SO3R' N2

SO3R' C

O

SO3R'

COOH

Novolak Resin

+ PAC (Alkali) Unexposed part

Azocoupling Products

Insoluble

Photo Active Compound

Exposed part

H

O

Solvent 2-Heptanone

+ N

Soluble

+

O

SO3R' N2

OH

R H2 C

O

SO3R'

N N

ONa CH2

NaOH

developing

Coupling Effect

Substrate Substrate

Metal Metal Depositio Depositio n

n Resist Resist Coating Coating

Exposure Exposure

& P.E.B.

& P.E.B.

Development

Development Dry Etching Dry Etching

PHOTORESIST (PR)

PHOTORESIST (PR)

Chemical amplification concept Chemical amplification concept

Ph3S SbF ₆ ^hv

H

OH

n

O O

O C CH

CH

CH

C CH

CH

CH

+ CO

+

[ ] H PAG

PBOCSt Tert-butyloxycarbonyl

(t-BOC)

PHOSt

H₂C C CH₃ CH3

+ H SbF ₆

Amplification Exposed

part

CH2 CH

OH

Alkali soluble

CH₂ CH

O C O C

CH₃ CH₃ C H₃ O

CH₂ CH

O Si

CH₃ CH₃ C H₃

CH₂ CH

O CH

O

CH₃ CH₂CH₃

CH₂ CH SO₂

O C O

C CH₃

CH₃ CH₃ O

CH₂ CH

O CH

O

CH₃

O CH₂ CH

O

H H

H H

H

H

H H

H H

H H

Various mechanism in chemical amplified resists

Various mechanism in chemical amplified resists

KrF Resin Structure Design KrF Resin Structure Design

O O

OH

O O R

CN

y z x

n

Adhesion Promotion Unit Aqueous Development unit Acid Catalyzed Deprotection unit

Promotion of Photospeed in Exposure Area Control Resolution

Main Backbone Deep UV transmission

Thermal stability & Dry etch resistance

-Large Hydrophobicity in Unexposed Area

-Large Hydrophilicity in Exposed Area

OH O R₁ O R₂

Acetal

OH C O O

Annealing

OH O

O O OH O

R1 O R2

Hybrid

Low Activation Energy Good Resolution

Good CD-Bias Low PEB Sensitivity

Out Gassing

High Activation Energy Themally Stable

Less LER Good Etch Performance

High PEB Sensitivity

Good Etch Performance High Resolution Environmental Stability

Wide Process Margin

Typical KrF resist (248nm)

Typical KrF resist (248nm)

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

R₁ S C N₂

S O

O O

O

R₂

S+

R

R

Better resolution and DoF Higher transparency

Higher sensitivity Thermally Stable Lower transparency

Onium Type Diazo Type

Combination of two Combination of two PAGs PAGs. .

High resolution with high

High resolution with high photospeed photospeed

레지스트 설계 목표

Pivotal Point control DOF margin 확대 1. +Defocus (Thinning )

2. –Defocus（Scum）、Pattern (Lifting)

（ Resist 의 공통 과제 ）

－Defocus Lifting

Best Defocus ＋ Defocus Thinning

Resist 의 개발

Resist 의 개발

O O O O OH

O O O O

O O O OH

O O

O O

COOR COOH

O O

O O

COOR COOH

O O

OH O

O O

O O

O O

O O

O O O

O O

O

O O

O O

O O

O O O O

O O O OH

O O

O O O

O OH O

IBM TOSHIBA

FUJITSU

NEC

IBM

: Low Etch resistance Poor adhesion

: High etch resistance

High Resolution Conventional developer

: High etch resistance

Poor adhesion Special developer

Matacrylate type ArF resist (193 nm)

Matacrylate type ArF resist (193 nm)

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

NA=

NA=nSin nSinθ θ Resolution = k1

Resolution = k1 λ λ / NA / NA Æ

Æ Improvement of Resolution Improvement of Resolution DOF = k2 n

DOF = k2 n λ λ / NA / NA Æ

Æ Improvement of DOF Improvement of DOF

Reference : Nikon, Tokyo Electron Reference : Nikon, Tokyo Electron

Development of Top Coat Development of Top Coat

Not dissolve resist film during coating.

Not dissolve resist film during coating.

Æ

Æ Need appropriate Need appropriate solvent solvent Not dissolved to water but

Not dissolved to water but dissolved to alkaline dissolved to alkaline Higher

Higher hydrophobic surface hydrophobic surface of the film for speedy scanning of the film for speedy scanning Prevent

Prevent PAG PAG and and quencher quencher from from dissolving dissolving to water to water Optical characteristics : appropriate optical

Optical characteristics : appropriate optical constant

constant n n should be 1.333 should be 1.333 ( n ( n of water) of water)

Issue to Realize Immersion Lithography Issue to Realize Immersion Lithography

Existing

Existing ArF ArF scanner scanner is not compatible with immersion lithograph. is not compatible with immersion lithograph.

Æ

Æ Excess capital investment in new Fab Excess capital investment in new Fab. .

Scanner lens contamination by dissolved

Scanner lens contamination by dissolved photoresist photoresist component component Immersion water attack

Immersion water attack photoresist photoresist top surface. top surface.

Requirement of material development for new resin system Requirement of material development for new resin system Adjustment PR transparency for different wavelength (134nm) Adjustment PR transparency for different wavelength (134nm)

Solution :

Solution : Top coat Top coat

Solution : Development of new

Solution : Development of new ArF ArF resist resist