nano-imprinting lithography technology - nano...

Micro/Nano fabrication process 2009-02

Nano-imprinting LithographyTechnology

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



Imprinting Technology



<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

Ref) 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

Ref) 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

Ref) 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 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



Ref) Resin micromachining by roller hot embossing, microsystem technology, 2007Ref) Subdivision Surfaces for procedural Design of Imprint Rolls, SPM, 2008

Schematic diagram of the mold fabrication process performed in Ref Paper

Roll NIL -Roll mold-



Ref) Large-Area Roll-to-Roll and Roll-to-Plate Nanoimprint Lithography: A Step towardHigh-Throughput Application of Continuous Nanoimprinting, 2008, ACSNANORef) Rigiflex Lithography nanostructure transfer, Advanced Material, 2005


Roll NIL -Flexible mold-


Ref) Roller nanoimprint lithography, America Vacuum Society, 1998Ref) Fabrication of organic light-emitting devices on flexible substrates usinga combined roller imprinting and photolithography-patterning Technique, American Vacuum Society, 2006


Roll NIL -Flat mold-


Roll to Roll Imprinting Technology



Roll-to-roll processing, also known as 'web' processing, reel-to-reel processing or R2R, is the process of creating electronic devices on a roll of flexible plastic or metal foil.Large circuits made with thin-film transistors and other devices can be easily patterned onto these large substrates, which can be up to a few metres wide and 50 km long.Roll-to-roll processing is a technology which is still in development. If semiconductor devices can be fabricated in this way on large substrates, many devices could be fabricated at a fraction of the cost of traditional semiconductor manufacturing methods. Applications could arise which take advantage of the flexible nature of the substrates, such as electronics embedded into clothing, large-area flexible displays, and roll-up portable displays.

Ref) http://www.gizmag.com/tag/oled/2/http://en.wikipedia.org/wiki/Roll-to-roll_processinghttp://www.geeky-gadgets.com/hp-develops-a-flexible-plastic-display/

<R2R Process for OLED(GE)> <R2R Process for Flexible display(HP)>

1. Introduction : Roll to roll process



Metal 증착 방법 - 진공공정

<Method 1> <Method 2>

P PP

2. Roll to roll micro lithography


AUnexposed polymer Removing

B Rinse

C Drying

D Metal etching

E Polymer Removing

Metal coated film feeding

Polymer Coating

UnexposedPhotopolymer removing

UV rollImprintingLithography

MetalEtching

Polymer Removing

Final patterns

System formation


3. Roll to roll micro printing


Ref) www.moazine.com

Micro/Nano fabrication process 2009-02Nano-fabrication & Micro-Optics LaboratoryYonsei University

Ref) www.nanoprinttech.com

3. Roll to roll micro printing : electronics printing


Ref) www.kosen21.org

3. Roll to roll micro printing : printing


… printing is a micro structuring technique ! but since hundreds of years, 99% of all printing applications are for visual usage, not for electronic functions.

Printing is expanded all manufacture process


Ref) www.electronics.ca

3. Roll to roll micro printing : limit of printing process


Ref) www.idtechex.com

3. Roll to roll micro printing : application


Good for flexible substrates, bad for glassWell suited for solvent-based organic semiconductors and thin filmsHigh throughputDemonstrated Flex OLED and TFT: DNP, Add-Vision, VTT, Berkeley

Line resolution > 50umHigh pattern setup costs

Cylinder pattern

Gravure is an intaglio printing process.The image carrier has the image cut or etched below the surface of the non-image area.On the gravure image carrier (usually a copper cylinder), all the images are screened,creating thousands of tiny cells.During printing, the image carrier is immersed in fluid ink. As the image carrier rotates,ink fills the tiny cells and covers the surface of the cylinder. The surface of the cylinder iswiped with a doctor blade, leaving the non-image area clean while the ink remains in therecessed cells.

Source: www.gaa.org

What is Gravure?

Summary of technology

Concerns


3. Roll to roll micro printing : gravure printing


Definition: With gravure printing an image is etched on the surface of a metal plate, the etched area is filled with ink, then the plate is rotated on a cylinder that transfers the image to the paper or other material

Ref) www.schur.com& International paper knowledge center

• High quality and expensive• Used for high quality photographic images • Opposite of relief printing plate created with engraved image creating cells of ink color• Ink is spirit based and dries immediately• Gravure printing is often used for high-volume printing of packaging, wallpaper, and gift wrap.

Although less common, gravure printing may also be used for printing magazines, greeting cards, and high-volume advertising.

Gravure printingNano-fabrication & Micro-Optics LaboratoryYonsei University


http://www.schur.com/skabeloner/skabelon2/?id=80&setlanguage=2�


Sheet-fed

Wed-fed

Concept of offset printing


Press Types: sheet-fed and web-fed



Blanket, ink paste, transferDemonstrated 20 ~ 30μm line widthAccuracy: 2.5μm / 400mm,Repeatability: <2.5 μm

Line resolution > 50umHigh pattern setup costs

Ref) Stanford University

Feeding system: The feeding system is the device that feeds the paper into the press.Printing system: The printing system for offset presses contain 3 major components: the plate cylinder, blanket cylinder, and the impression cylinderInking system:The inking system on offset presses consists of a fountain which holds the ink and a set of rollers, known as the roller train, which distribute the ink and carry it to the printing plate.Dampening system:Delivery system:


Press components

Summary of technology

Concerns



Gravure-offset printing

In gravure-offset printing, the ink (or paste) is first doctored into the grooves of a gravures plate. An offset pad or-roller, made of a rubber or silicone polymer, picks up the ink from the gravure grooves by pressing against it. Then the pad or roller transfers the ink to the substrate by pressing or rotating over it. After that, the conductor inks for ceramics are dried and fired at 600–900 C.

Printed substrate (below) and ink left on blanket (above)Flow of roller type gravure offset printing.


Ref) Marko Pudas, Juha Hagberg, Seppo Leppa¨ vuori, ”Printing parameters and ink components affecting ultra-fine-line gravure-offset printing for electronics applications” Journal of the European Ceramic Society 24 (2004) 2943–2950

3. Roll to roll micro printing : gravure-offset printing


Gravure-offset printing

300 and 20 um wide dried lines 37.5 and 50 um wide dried lines printed with ink

50 mm wide Au conductors on a PZT layer in a pressure sensor structure.

100 mm wide Ag conductors printed over a 90o

corner of a ceramic substrate.


Ref) M. Lahti , S. Leppa¨vuori, V. Lantto, ”Gravure-offset-printing technique for the fabrication of solid films” Applied Surface Science 142 1999. 367–370

3. Roll to roll micro printing : gravure-offset printing


• Non contact – Low impact to object

• Low cost – Lithography and developing process unneeded

• Scalability – It can be set up to produce very small quantities and size to very large quantities and size

• Efficient material use– Ink jet is direct write, effectively no waste

Ink jettechnology

Drop-on-Demand

Thermal Piezoelectric

Continuous

4. Roll to roll ink-jet printing technology


Why ink-jet?


Thermal ink jet process

Piezoelectric ink jet process


Continuous ink-jet

Drop on demand ink-jet

4. Roll to roll ink-jet printing technology


4. Roll to roll ink-jet printing technology : application


Imprinting system



■ History

• 1980 – Foundation of Electronic Visions• 1985 – Creation of the world’s first double-side mask aligner• 1992 – Development of the first performance wafer bonding systems• 1997 – Entered the nanotechnology market with the development of the first nanoimprinting system• 1998 – Development of the revolutionary cavity coating technology

• 2000 – Introduction of Fully-automated and integrated production systems • 2001 – Design & Installation of the first 300mm automated SOI production bonder• 2006 – Release of bond cluster module for SOI market• 2008 – Release of production wafer bonder for 3D applications

EVG

Ref) www.gvgroup.comNano-fabrication & Micro-Optics LaboratoryYonsei University


■ Products

• Lithography – Mask aligner SystemsResist Processing SystemsLithography Track SystemsNanoimprint Lithography Systems (UV-NIL, μCP, HE)Inspection Systems

• Bonding – Wafer Bonding SystemsBond Alignment SystemsIntegrated Bonding SystemsSOI Bonding Systems Temporary Bonding and Debonding SystemsInspection Systems

EVG



■ EVG 620 Bond Aligner

• Features

- bond alignment of 2~3 wafer stacks up 150nm wafer sizes

- Manual or motorized alignment stage

- Fully motorized high resolution bottom side microscopes

- Quick tool change between different wafer sizes and bonding

- Easy to use Windows based operation

• Technical Data

- Alignment methods

>Backside alignment : ± 2μm >Transparent alignment : ± 1μm >IR alignment : option

EVG



■ History

• 1949 – Foundation of Karl Suess KG in Munich• 1963 – Development of first aligner for the production of transistors• 1974 – Release of first mask aligner for full production processes• 1989 – Development of first wafer bonder• 1998 – Launch of world’s first 300mm probing system

• 2001 – Renaming of Karl SUSS group in SUSS MicroTec• 2004 – Development of first mask aligner for sub-micron processes• 2006 – Release of bond cluster module for SOI market• 2008 – Release of production wafer bonder for 3D applications

SUSS

Ref) www.suss.comNano-fabrication & Micro-Optics LaboratoryYonsei University


■ Products

• Lithography – Mask AlignerLithography ClustersPhotomask DesignAlignment VerificationWet ProcessingNanoimprint LithographySpin & Spray Coaters

• Wafer Bonder – Automated Bond ClusterSemi-Automated Wafer BondersManual Wafer BondersStand-Alone Related Tools

• Micro-optics – Refractive microlens arraysDiffractive Optics, DOE1D and 2D Diffuser

SUSS



■ NPS 300 (Nano patterning stepper)

• Features

- NIL tool combining hot embossing and UV-NIL on wafer

- Possibility to add inert gas for faster print

- High accuracy and low volume fluid dispense

- Automatic stamp pick-up

- Manual or automated wafer loading / unloading

- Long-term stability and reliability

• Technical Data

- Imprinting Resolution : Sub-20nm- Alignment Accuracy : 100nm- Overlay Accuracy : 250nm

SUSS



■About MII• Molecular Imprints, Inc. (MII) was founded in Austin, Texas in 2001, spun out of the University of Texas.

• Drop Pattern Generation System is the heart of Molecular Imprint’s advanced nanopatterning technology

• Precise placement of photoresist

• Uniform and consistent nanopatterning

• Low cost, down to 10nm feature

• Can be applied to HDD industry to take 1TB/in2

• Can be also economically extend the semiconductor industry’s Moore’s Law to the sub 30nm regime

Molecular Imprint

Ref) www.molecularimprints.comNano-fabrication & Micro-Optics LaboratoryYonsei University


■ Product• Imprio HD2200

Resolution: Sub-20nm, half-pitch for discrete track and bit patterned media

Throughput (double-sided): >150 disks per hour

Alignment: <10 microns (relative to disk spindle hole)

Disk Automation: Fully automated cassette-to-cassette and template loading

• Imprio HD1100

Resolution: Sub-50nm, half-pitch

Alignment: Not available

Flexibility: Can be configured to accept 25mm to 76mm substrates

Automation: Automated wafer and template loading

Molecular Imprint



■ Product

• Perfecta TR1100

Resolution: Sub-50nm

Alignment: <10um (template to substrate)

Flexibility: Designed for 150mm synthetic quartz substrates

Automation: Automated wafer and template loading

• Imprio HD300

Resolution: Sub-32nm half pitch

Alignment: < 10nm, 3σ (single point, X,Y)

Automation: Fully automated wafer and mask loading

Flexibility: 200mm and 300mm substrates (SEMI standard)

Field size: 26mm x 32mm (step-and-scan compatible)

Throughput: Four wafers per hour

Molecular Imprint



■ History• 2003 – NND established, NANOSISTM launch• 2004 – 30nm patterning with a silicon stamp• 2005/02 – Supplied NANOSIS 410 to ISRC in Seooul National University• 2005/06– Supplied NANOSIS 620 to Sogang University• 2005/08– Exhibition and operation at Nano Korea 2005

• 2005/10– Supplied NANOSIS 620 to LG Chem• 2005/11– Supplied NANOSIS 610 to Korea University• 2006/10– Supplied NANOSIS 420 to GIST• 2007/10– Supplied NANOSIS 830 to KOPTI• 2008/05– Supply over 10 sets NIL system in domestic market

Nano & Device

Ref) www.nanodevice.comNano-fabrication & Micro-Optics LaboratoryYonsei University


■ Product

• Nanosis 620

Economic price

Universal imprinter : UV curing, hot embossing

Near zero residual layer

Minimized footprint through a compact design

Excellent pattern uniformity

• Nanosis 820

Economic price

Universal imprinter : UV curing, hot embossing

Powerful alignment system

Near zero residual layer

Excellent pattern uniformity

Reduced process time

Nano & Device

Ref) www.nanodevice.comNano-fabrication & Micro-Optics LaboratoryYonsei University


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



Thickness of residual layer



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 - nano...

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