nano-imprinting lithography technology Іnanomolding.yonsei.ac.kr/lecture/02_nanoimprinting.pdf ·...

Micro/Nano fabrication process 2009-02

Nano-imprinting LithographyTechnology І

Nano-fabrication & Micro-Optics LaboratoryYonsei University


Limitation of photolithograph

Agenda

- Remind of photolithography technology

- What is diffraction

- Diffraction limit

Concept of nano-imprinting lithography

Basic process of nano-imprinting lithography technology



Photoresist process for lithography

Clean substrate

Remind of photolithography technology

Development

Post Baking

Etching

Remove PR

Soft Baking

PR Spin Coating

UV Exposure

Apply Adhesion Promoter(HMDS)

Limitation of photolithography



UV Exposure

UV Exposure

Real case of photolithography(ultra small pattern size)

Mask

Ideal case of photolithography

Diffraction effect

회절로인해같은조건의촬영시위와같은상이한결과를초래

(Image blur 현상발생)

Photolithography process and limitation



What is diffraction ?

Basic assumption : Light is wave

Diffraction is the process by which light waves traveling through a small hole, slit or around a boundary will spread out



What is diffraction ?

Diffraction causes the loss of resolving power

Image blur 현상은각종수차에의해영향을받지만공기중의 particle에의한 diffraction으로인해같은조건의촬영시위와같은상이한결과를초래한다



Diffraction limit

Example – Diffraction of circular aperture

is a Bessel function of the first kind



Diffraction limit

D θ

The radius of the Airy disk



Nano-imprinting LithographyTechnology II



<금속활자본>

현존하는가장오래된금속활자본직지심체요절

• 정식명칭: 백운화상초록불조직지심체요절

• 1377년(고려우왕 3) 7월청주흥덕사간행

• 세계에서가장 오래된금속활자본

• 1372년쓰여진책을 77년금속, 78년목판으로간행

• 금속활자본은현재 프랑스국립도서관에소장

• 2001년유네스코세계기록유산등재

<목판본>

<금속활자본표지>

Imprinting

자료출처: http://www.jikjiworld.netNano-fabrication & Micro-Optics LaboratoryYonsei University


직지심체요절금속활자제작및 인쇄과정

< 글자본선정> < 자본붙이기> < 어미자만들기> < 주형틀만들기>

< 쇳물붓기> < 활자떼어내기> < 조판> < 인쇄>

Imprinting

자료출처: http://www.jikjiworld.netNano-fabrication & Micro-Optics LaboratoryYonsei University


2. Press mold

3. Remove mold

1. Mold fabricaion step- Using E-beam lithography, FIB, etc.

2. Imprinting step- Nano mold with nano-scale pattern

is pressed into a resist

Mold

ResistSubstrate

Mold

ResistSubstrate

Mold

1. Mold fabrication

< Mold >

< Resist pattern >

Nano-imprinting process



Nano-imprinting 기술의종류



Basic process of nano-imprinting lithography technology

Procedure of nanoimprinting lithography : 2 basic step

1. Pressing mold

2. Remove mold

3. Pattern transfer (RIE)

resistsubstrate

resistmold

resistsubstrate

resistmold

resistsubstrate

1. Imprint step- Nano mold with nano-scale pattern

is pressed into a resist

2. Pattern transfer step- Pattern transfer to substrate by RIE

(Reactive Ion Etching)

- RIE is used to remove the residual resist in the compressed area

자료출처: Proc. SPIE 4349, (2001), p. 82

< Mold >

< Resist pattern >



Heating of Substrate and Mold

to above Tg

Application ofMolding Pressure

Cooling of Substrate and Mold

to below Tg

Demolding

Procedures

1. Press mold with heat

2. Remove mold

Mold

ResistSubstrate

Mold

ResistSubstrate

< Mold >

< Imprinted resist >

Thermal nano-imprinting lithography technology

자료출처: http://www.obducat.com/Default.aspx?ID=187Nano-fabrication & Micro-Optics LaboratoryYonsei University


UV nano-imprinting• Material: UV-curable photopolymer• Processing condition: room temp. & low pressure• No fluidity problem

Procedures <Pyramid pattern><Lattice pattern>

Photopolymer dispensationon substrate

Covering the mold Aligning

Releasing the mold

PhotopolymerSubstrate

UV-transparent mold

UV-light

Pressure

UV nano-imprinting lithography technology

자료출처: http://www.obducat.com/Default.aspx?ID=187 JJAP, vol. 44, No. 7B, pp. 5600, 2005Nano-fabrication & Micro-Optics LaboratoryYonsei University


Design and construction of continuous UV nano imprinting systemContinuous UV nano-imprinting system

For flexible substrate

For rigid substrate

1. Can replicate nano patterns of large area with high precision

2. Can replace conventional lithography process

Fabrication results

Continuous UV nano-imprinting lithography technology



Imprinting system



EVG 社

• Precise wafer/substrate alignment for wafer bonding applications

• High-resolution bottom side splitfield microscope

• 1 µm alignment accuracy

• Easy to use Windows based operation

EVG 620 bond aligner



SUSS 社

NPS 300 (Nano patterning stepper)

..

• 250 nm overlay accuracy

• Unmatched sub-20 nm embossing capability

• Submicron Stamp-to-Wafer alignment with state-of-the-art pattern recognition system



Molecular Imprint 社

Imprio 250

• Resolution: Sub-50 nm

• Alignment: < 10 nm

• Flexibility: 200 mm and 300mm substrates with automated loading

• Field size: 26 x 32 mm active print area.



Nano & Device 社

Nanosis 610

• No align option

• Near zero residual layer

• UV curing & hot embossing (universal)

• Good pattern uniformity

• 6 inch direct imprinting



Issues of nanoimprinting

Thickness of residual layer

Large area patterning

Demolding

Imprinting material

Mass productivity and system itself

Fabrication of nano master / mold



Nano Imprinting LithographyTechnology III



Agenda

- Large area patterning

- Mass productivity


Mass productivity and system itself



What is residual layer?

UV-transparent mold

Imprinting material (photopolymer)

Pressure

UV- curing

This is the residual layer !

After the residual layer etching



Importance of thickness of residual layer

Purpose of the nano imprinting lithography

• Use the pattern itself

- AR Surface- Optical nano grating- Wave guider- Nano structure for optoelectronic devices

• Use the pattern as a barrier for after process

- Replace the photolithography process



AR coating on mold

AR coating (Anti reflection coating)

Optical substrate has about 4% reflection in general

UV

Reflection of UV

Mold without AR coating

PHotopolymer

AR coating on mold surface is very important




Nano structure for optoelectronic devices (MLA on VCSEL)

Rn1

VCSEL Micro-Lens Fiber

VCSEL array

Emitting area

Bonding padRn1

Rn1

We must control the residual layer for designed focal length




Use the pattern as a barrier for after process (critical reason)

UV-transparent mold

photopolymer

Preparation Mold lamination andAppling pressure

UV curing

UV

Demolding

Remove the residual layer

Etch the substrate Remove the photopolymer

이때 pattern의크기에비해너무두꺼운 residual layer가남아있다면이를제거할때 pattern은모두손실되고만다



Zero residual layer process

Conventional imprint Zero residual imprint



Application of nano-imprinting technology I



연꽃잎

Super hydrophobic surface

자료출처: http://blog.empas.com/hl1vgt/, Manhui Sun, Langmuir, Vol.21, pp.8978, 2005 L. Feng, Advanced Material,Vol.14, pp.1857, 2002Alexander Otten, Langmuir, Vol.20, pp.2405, 2004



매미날개의모사

연꽃잎의모사 응용분야

<자동차>

<유리창>

Super hydrophobic surface

자료출처: Manhui Sun et at al.,langmuir, vol.21, pp.8978, 2005Woo Lee et at al., Langmuir, Vol.20, pp.7665, 2004http://www.dumitrup.com/blog/



나방의눈

Anti-reflective surface

자료출처: http://www.motheye.com/, http://blog.empas.com/squirrel1226/1Nano-fabrication & Micro-Optics LaboratoryYonsei University


무반사면의응용나방눈의모사패턴

Anti-reflective surface

자료출처: http://www.motheye.com/, http://www.nature.go.kr/insect/insectGuide/MNE’06 Micro- and Nano- EngineeringKenji Sogo, Journal of Photopolymer Science Technology, Vol.19, pp.647, 2006



상어의피부

Drag reduction of surface


자료출처: http://news.softpedia.com/news/The-Shark-Coating-42520.shtmlD. W. Bechert, Naturwissenschaften, Vol. 87, pp.157, 2004


<Speedo Fastskin II><Drag reduction of surface>

10% 감소효과

상어피부 상어피부형상의응용 -수영복

Drag reduction of surface


자료출처: http://www.speedo.com D. W. Bechert, Naturwissenschaften, Vol. 87, pp.157, 2004


Application of nano-imprinting technology II



Imprinting of bio chip

Bio chip fabrication using nano-imprinting


자료출처 : http://bmc.ub.uni-potsdam.de, http://www. macrogen.co.kr


Bio chip fabrication using nano-imprinting



LOC with microfluidic channels

Lab-on-a-chip fabrication using nano-imprinting


자료출처 : http://www.biodent.com, http://pubs.rsc.org

nano-imprinting lithography technology Іnanomolding.yonsei.ac.kr/lecture/02_nanoimprinting.pdf ·...

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