direct writing technology

Direct Writing Technology Advances and Developments

K K B Hon*, L Li** and A Malshe***University of Liverpool*University of Manchester**University of Arkansas***

STC ‘E’ 2008 Keynote Paper

What is Direct Writing?

• Direct Write covers a range of technologies, possibly in reconfigurable short production runs, of two or three dimensional functional structures using processes that are compatible with being carried out directly onto potentially large complex shapes.

PA, 2004

• Any techniques or process capable of depositing, dispensing or processing different types of materials over various surfaces following a preset pattern or layout.

A Pique & D B Chrisey, 2002


• The intent is to address combinations of:• Functional structures

• Vast range of substrates (materials/shapes)

• High precision in form or function

• Multi length scale

• Reconfigurable

• Direct fabrication

• Robust final product


• Digital deposition of functional materials onto a substrate surface.

Layout of Paper - 1

1.0 Introduction

Background and overview

2.0 Direct Writing Technologies

Classifications of DW technologies based on materials transfer processes and length-scale

Relationship with conventional RP technology (FDM, LENS, 3DP)

Layout of Paper - 2

3.0 Laser-based processesTechnology description, process principles, key characteristics, process performance.

4.0 Inkjet-based processes

5.0 Syringe-based Processes

Layout of Paper - 3

6.0 Emerging Processes6.1 Focussed ion and electron beam6.2 Nano-printing6.3 Scanning probe approaches6.4 Other methods (thermal spray, electrostatic,

electrophoretic, etc)

7.0 Industrial Applications of DW7.1 Materials and substrates: organic, inorganic

and biological7.2 Electronic and devices

Layout of Paper - 4

8.0 Conclusions

9.0 Acknowledgements

10.0 References

Types of DW Technologies

DW Addition

Direct Control Interim Tools

Nozzle Technique

Laser Techniques

Focus Spraying

Screen Printing

Soft Litho

Ink Jet Displacement Pumps

Droplet control

Optimisation for:

- low shear

- pastes/slurries

- sintering/curing

- etc

DMD LCVD LENS

Maskless Mesoscale Material Deposition- M3D

Flexible Maskless approach

direct from CAD

Mesoscale Feature Sizes

<10 to >>100+ µm

Low-Temperature Substrates

High Aspect Ratios

Conformal

Non-Contact (Stand-Off)

Wide Range of Materials

Reduced chemical usageOptomec

M3D Electronics Samples

Wide Range of Materials1-1000 cP source materialCommercial and Custom

ConductorsMetals: Cu, Ag, Pt, Au, Pt/Rh, PdConductive Polymers

Insulators Adhesives Wide Variety of Substrates

Rigid and FlexKapton, FR4, Si, Plastics, Metals

Smart Card Inductor on Flex

GPS AntennaRedistribution

500 µm TrenchResistor Pads

Characteristics of Syringe-based DW

• Conformal and non-contact.

• 25 µm feature size.• Wide materials range from

5 to 106 cP.• Laser surface mapping..• In-situ laser sintering.

• Mesoscale geometries.

• Complex patterns from CAD.

• 25 µm feature size.

Capabilities of Syringe-based DW system

K H Church

Line Dynamics and Stability

Use of Rayleigh-Taylor Criterion for Instability analysis.

K H Church

Production of Passive RLC Components

15nH two-turn inductorKapton substrate, 0.005”0.150” diameter

Resistor array on microscope slide

1pF Microstrip Interdigitated capacitor, 0.005” Kapton Film Substrate

25pF Multi-leaded RF bypass capacitor

LC network designed for shunt LC resonance at 1.1GHz K H Church

Droplet Formation

Drops form at high acoustic frequencies

10 kHz formation rate gives fluid shear rates in the region of 104 s-1

Each drop is identical and travels at velocities 2 – 4 ms-1

B Derby

Detail of Tracks Produced by Inkjet DW

Droplet control and optimisation is essential.

Track width depends on surface wetting characteristics but typical size and separation of around 100 μm is possible.

B Derby

Applicability of DW Technology

Direct Write products

Bulk structures

Sacrificial parts for tooling

Products

Mould tools

Functional materials

Passive structures

Active devices

Optical waveguide

Electronic circuitry

Switch, batterySwitch,

OLEDinterconnect, antenna, filter

resistor, capacitor, filter, etc

Active

λ filter, delay, attenuator,etc

structures

Coatings

Passive

Drug, diagnostics,

assays, sensors

Labels, filters, thermal

conductors etc

Magnetics

Solar cells

Prototypes

M Humphries & J Townsend

Direct Writing Applications in Defence

Graded materials eg

thermal barrier coatings

High strain actuators

Advanced piezoelectric transducers

Porous cathode

Porous anode

Catalyst layerFuel cells

D Burgess

Process Comparisons

J W Sears

Frequency Selective Surface Produced by DW

-25

-20

-15

-10

-5

0

8 9 10 11 12 13

Frequency (GHz)

Att

enu

atio

n (

db

)

Flat Panel

Curved Panel

Performance of the FSS

• Broader peak• Lower attenuation

Summary of Progress

Structure of paper.Database with over 200 references.IS&T Conference on Digital Fabrication first launched in 2005.Multi-scale nature of DW technology.Application domains and case studies.Scientific principles of DW processes.Background materials of DW systems.Issues on common RP processes and DW processes overlap.

Contributions from CIRP Members

Please send your comments and contributions to:

[email protected]

CIRP E K/N 2008

Could direct writing make some of these components ?

• Layer deposition techniques

• Molecular beam epitaxy

• Vapour phase epitaxy etc.

• Sculpture techniques

• Chemical, mechanical, etching

Transistor

MEMS

Controllable RAM

Environmental transducers

Conclusions:

• Nanotechnology will be crucial for MoD in many areas

• But MoD does not buy technology

• MoD will not be aware of the manufacturing technique

• Materials Domain keen to see direct writing used

• Funding possibilities

• Developments of Defence - specific technology

• Demonstration of sub-systems using direct writing techniques

• Aim is demonstration not technology development

DIRECT SCOPING STUDY – PART 1

• Definitions

• Technologies and Processes

• Benefits

• Limitations

• UK Activities

• Application Areas and Sectors

• Timescales and Supply Chain

• Barriers

Direct write has significant potential

• Direct Write has the potential for major direct and indirect impact on:

– markets of importance to the UK

– exploiting valuable capabilities in the UK

• The onus is on end users, through consultation and collaboration, to identify where Direct Write may best be applied

Contributions Received

Prof. T Pfeifer

Prof. G Chryssolouris

One another.

DIRECT WRITE SCOPING STUDY – PART 1…


•The term Direct Write is used is used here to describe a range of technologies, possibly in reconfigurable short production runs, of two or three dimensional functional structures using processes that are compatible with being carried out directly onto potentially large complex shapes

DIRECT WRITE SCOPING STUDY – PART 1…What are the Direct Write Technologies and Processes?

DW

Add material

Modify material

Broad, unrestrained addition

Localised addition

Interim process tool (mould,

mask)

Functional Active / Passive structure

Localised processing

PC/CAD control


mask)

PC/CAD control

DW

Add material

Modify material

Broad, unrestrained addition

Localised addition


mask)

Functional Active / Passive structure

Localised processing

PC/CAD control


mask)

PC/CAD control


Technology hierarchies and maturity

Processes

Components

Subsystems

Materials

Design rulesCAD Measurement

ScanningDispensing Handling Etc.

Nozzles PumpsFluidics Control systems Software

Materials Formulation Scaled up materials processing Dispensate Structures

Processes

Components

Subsystems

Materials

Design rulesCAD Measurement

ScanningDispensing Handling Etc.

Nozzles PumpsFluidics Control systems Software

Materials Formulation Scaled up materials processing Dispensate Structures

DIRECT SCOPING STUDY – PART 2

• Definitions

• Technologies and Processes

• Benefits

• Limitations

• UK Activities

• Application Areas and Sectors

• Timescales and Supply Chain

• Barriers

DIRECT WRITE SCOPING STUDY – PART 2…Direct Writing enables a diverse range of benefits

• Rapid and cost effective prototyping– using diverse functional materials

• Mass customisation– high volume one-offs

• Creation of new products– novel features

• Advanced manufacturing– disrupting the Supply Chain


Recognise that there are limitations

• Cost associated with flexibility

• Constraints on material selection

• Resolution achievable

• Yield impact late in manufacturing process

Applications must be selected where the benefits underpin marketdriven needs


UK capability and benchmarks

Keyword in Grant

“Inkjet”

EPSRC NSF

“Direct writ*” α

“Soft lithography”

20 (£4,115434)

17 (£2,172,937)

3 (£10,591,879)

26

37

17

“functional coat*” 15 (£2,543,708) 3

“Nano pattern*” 11 (£11,478,310) 8

“Screen print*” 20 (£3,605,555) 10

0%

5%

10%

15%

20%

25%

30%

35%

40%

45%

50%

55%

60%

65%

USA Europe A s ia UK

% p

ub

licat

ion

s

Publications 2000-2003 inclu. laser with (direct

writ*)

0%

5%

10%

15%

20%

25%

30%

35%

40%

45%

50%

55%

USA Europe China Singapore UK Other Asia

% p

ub

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tio

ns

Publications 2000-2003 inclu. in soft lithography

* indicates a truncated term

α this group may include vacuum processes not relevant to this study

0 %

5 %

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15 %

20 %

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35 %

USA UK

Japa

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The N

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Franc

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% p

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Publications 2000-2003 inclu. inkjet with polymer

electronics or (direct writ*)

DIRECT WRITE SCOPING STUDY – PART 2…UK is active in researching materials through to process

University of Arizona (bio microjets)

Materials - ‘inks’Understands

underlying physics; Develops new

chemistries

Process –‘Printhead’

Develops and optimises delivery

elements

Production –handling

Develops systems and bulk handling

techniques for production

UMIST (printing systems)

University of Cambridge (plastic electronics, displays)

UK research

ROW research

Fraunhofer ResearchNaval Research Labs (printable batteries)

Anglia Polytechnic University (relief maps)

University of Illinois –(thermopen ceramics

micro fluidics)

University of California, (plastic electronics,

displays, metal droplet)

University of Virginia (inkjet, self assembled monolayers)

Imperial College, London (polymer semiconductors)

National Renewable Energy Lab (direct metallization for solar

cells)

École Supérieure, Limoges (3D

piezoceramics)

MIT (ceramics, nanosensor structures)

Linköping University (plastic electronics, inkjet)

Queen Mary , University of London (atomisation

printing)

Chemnitz University of Technology (polymer

printing)

University of Nottingham (Cold Gas Dynamic

Spraying)

Carbon Based Electronics consortium activities in

polymers include Bangor, Cambridge, Imperial,

Kings College & University College,London

State University, New York (thermal spray)

US funding through DARPA’sMICE, made widely reported

process developments but interviewees report development

has slowed since programme completion

University of Liverpool (polymers, Cold Gas Dynamic Spraying)

DIRECT WRITE SCOPING STUDY – PART 2…UK is active across supply chain’s for inkjet technology

Philips

EPSON

Motorola

Du Pont

Dow

Flint Inks

Spectra

Litrex

RolltronicsSuperior micropowders

Seiko Epson

ROW commercia

l

Xaar

Patterning Technologies Ltd

RTC circuits

Gwent Electronic Materials L:td

Plastic Logic

Avecia

Xerox

Optomec Design

QMP –Qinetiq Metal Printing

Microfab Inc.

Lucent

STMicroelectroincs

Microfab Technologies Inc

Materials - ‘inks’Understands

underlying physics; Develops new

chemistries

Process –‘Printhead

Develops and optimises delivery

elements

Production –handling

Develops systems and bulk handling

techniques for production

New Polymer Electronics programme EU Framework - PolyApply, (extension of PolyScene) announced 2003. Designed to link with EU companies outside traditional electronics or plastics and to

exploit advanced in polymer materials

Sciperio

Conductive Inkjet Technology Ltd (Xennia Technology Ltd, Carclo plc)

Imaging Technology International

OhmcraftHitachi

UK commercia

l

Inca


Sector overview ICT BiotechnologyAdvanced

manufacturingAdvanced materials

Energy & Environment

Example end use

Large area, distributed sensors e.g. RFID tags, integrated sensors e.g. vehicle monitoring Displays – consumer goods, automotive

Bioscaffolds , in vivo repair- bone, tooth or other tissue

Biochips – custom test arrays

Diverse markets –e.g. packaging & other industrial processes -Pharmaceutical process improvement

Diverse markets –biotechnology,electronics etc. Nanotechnology sector may be better enabled

Instrumentation, fuel cells, solar cells, batteries etc.

Threats and issues

Benefits already identified

Rapid prototyping

Mass customisation Conformal shapes

Large areas

Lightweight

Rapid prototyping

Mass customisation

Conformal shapes

Distributed large areas

Other more mature processes have have considerably more investment driven momentum

Immature supply chain, systems etc with limited qualification

Rapid prototyping

Mass customisation

Cost reduction by supply chain rationalisation

Process sensitive to materials & target accuracy

Process ‘sensitive’ to materials properties, e.g. cells

Smaller scale enabled e.g. monolayers

Potential energy saving impact energy savings

The technologies are considered applicable to many sectors


been predicted across a range of sectors from Automotive to Pharmaceuticals/Healthcare

• Automotive– lightweight conformal currently

– sensors and instrumentation

– custom designs

– rapid prototyping of functional structures

• Pharma/Healthcare– processes for accurately dispensing actives

– diagnostic tools for drug discovery and genomics

– cell handling for diagnostics, bioscaffold repair, prosthetics

DIRECT WRITE SCOPING STUDY – PART 2…Applications will emerge in different timescales

• Rapid prototyping– PCB’s

– Biochips

• Mass customisation– custom chemistry

– parallel chemistry

– ceramic goods

– electronic tags

• Novel products– electronic

functionality on personal equipment

– automotive structures

– displays

– sensor arrays

– batteries

• Advanced manufacturing

– PCB

– repair of high value goods

And some are being developed now…

DIRECT WRITE SCOPING STUDY – PART 2…Direct and indirect benefits may impact some segments of the supply chain preferentially

DIRECT WRITE SCOPING STUDY – PART 2…Although considerable benefit to UK is expected, a number of barriers need to be overcome

• Low awareness and infrastructure– potential benefits, ability to test, development

support, design rules

• Potentially incomplete Supply Chain

• Legacy and investment in other technologies

• Perception of high investment cost

DIRECT WRITE SCOPING STUDY – PART 2…Numerous benefits arise from Direct Write capability

•The challenge for adopters is to identify where the benefits underpin market driven needs to enhance business performance

Agenda

DIRECT WRITE SCOPING STUDY – WORKSHOP…

Objectives

• Within each sector group, identify:• Relevance of Direct Write and its application

• Key benefits and how they will be delivered

• What needs to be in place for exploitation

• How specific barriers will be overcome

DIRECT WRITE SCOPING STUDY – WORKSHOP…

Process

• Split into sector teams

• Appoint scribe and presenter

• Address the specific questions

• Summarise discussions

• Feedback to the group

• Logistics– timings

– groups

– locations

Layout of Paper - 2

3.0 Laser-based DW processes3.1 Evolution of measures3.2 Measures for manufacturing systems

Classification of measuresBasic measures

direct writing technology

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