Presentation to DuPont - Altium · Silvers •Silver/Silver Chloride –DuPont 5880, DuPont 5876, DuPont 5874 . Polyimide Ink -Printed heater on FR4 DuPont KA801 . Wearable Printed

Printed Electronics

Overview of Inks, Substrates, Processes and Applications

Insulectro

Two Broad Categories

Fired On Polymer Thick Film

• Very High Temperature Processing. – Ceramic substrates

– Screening and “Tape” application of conductors and dielectrics.

– Furnace sintering @ 850°C

• Applications – RF circuits, O2 sensors,

very high temp environments.

• Polymer binder with conductive filler. – Wide range of substrates. – Flexible. – Operating temps from 50 to

260°C depending on ink and substrate.

– Very wide range of applications. • Wearables

– Printable chemical sensors.

Polymer Thick Film (PTF) Circuitry

Truly “additive” printed circuitry, where conductive material is printed onto various substrates, PET, polycarbonate, polyimide ,

fluoropolymers, and paper.

Exposed conductor Dielectric

Printed Electronics 1. Substrate acts a printing base

2. Conductors are printed

3. Dielectrics are overprinted twice

4. Conductors may be applied again

5. Dielectrics printed again as a

coverlay

• Through holes are drilled in the substrate and the right ink can make the connection.

• Conductive adhesive is used for component assembly.

Materials of Printed Electronics

Conductors & Dielectrics (Inks) Substrates

• Polyimides

• Epoxies

• Acrylics

• Thermoplastics

• Kapton (Polyimide)

• Paper

• PEEK

• PEN

• Heat Stabilized PET

• Polycarbonate

• PVC

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Thermoplastic Acrylic

• Fast drying

• Flexible

• High adhesion

• Low Temp

• Long shelf life

• Can be soldered

• Flexible

• High adhesion

• Medium Temp

• Long shelf life

Binder System Groups

Epoxy Polyimide

• High Strength

• Can be plated

• Can be soldered

• Cold limited Storage

• Flexible

• Fast drying

• Can be plated

• Can be soldered

• Long shelf life

Binder System Impacts

• Thermal Performance – Operating Temperature • Adhesion • Flexibility • Drying/cure Time and Temperature • Storage Requirements – Shelf Life • Function

Overview of Ink Families • Standard inks

• Low temperature dry/cure

• Stretchable – Wearables

– In-mold

• High operating temperature

• High conductivity

• Sensors

• Fired/sintered

Examples of DuPont Thermoplastic Inks

• Carbons – DuPont 7102, DuPont 7105, DuPont 8144

• Silvers – DuPont 5025, DuPont 5028, DuPont 5065

Silvers

• Silver/Silver Chloride – DuPont 5880, DuPont 5876, DuPont 5874

Polyimide Ink -Printed heater on FR4

DuPont KA801

Wearable Printed Sensors & Interconnects

• Fabric

• Thermoplastic Polyurethane (INTEXAR™)

• Stretchable Conductor (PE872, PE873)

• Stretchable Sensor (PE971)

• Encapsulant Overprint (PE773)

How do Conductive inks work?

• For inks that are not sintered, (thermoplastic, thermoset, UV cured) – Close inter-particle contact is necessary – This is done as the binder (polymer) shrinks

• Resistance can be increased by barrier coatings (oxides) on the particles of the conductive filler. – This is why silver is the most popular conductive particle, silver oxide is

very conductive.

As Applied Processed

SEM of Dried Ink

Thermoplastic Screenprintable Ink (Ag loading 89%)

Very dense packed Ag structure

SEM Highly Filled Silver Ink

Super dense-packed Ag particle/network

Photonically Sintered Copper

Printed Cu Antenna on FR-4 Effect of photonic sintering

• Photonically heated copper ink overcomes the challenge of copper oxidation.

• Ink is heated much faster than the substrate.

• Ink is heated much faster than the substrate.

Ink Compatibility

• Need to consider compatibility. Extremely Important, wrong product selection can lead to issues! – With Conductors, dielectrics, and substrates

– With graphic inks, and conductive adhesives

– The materials must work together.

• No re-softening (dielectric over ink)

• No change in resistance

• No adhesion issues

• No flexibility issues

Application of conductive inks

• Screen printing (most common) • Flexographic printing • Rotogravure printing • Ink Jet (New)

Rotary screen Flat-bed screen Flexography Rotogravure

Printing speed and typical tooling cost

High Speed Printing

Performance and Testing

– Resistivity measurements – Flexibility/Creasibility – Environmental performance – Adhesion/Cohesion

Application of conductive inks

• Screen printing • Flexographic printing • Rotogravure printing

Rotary screen Flat-bed screen Flexography Rotogravure

Printing speed

High Speed Printing

Screenprinting

Example: Screen Recommendations

• DuPont 5025, thermoplastic Silver, Thermally dried – 255/48 PE mesh, 5-7µm EOM, 25 Newtons, ~22° angle, use up to

50% of frame ID for image area. This will provide a dry film thickness ~ 10 microns or 0.4 mils.

• DuPont 5018, UV cured – 255/40 PE mesh, 5-7µm EOM, 25 Newtons, ~22° angle, use up to

50% of frame ID for image area. This will provide a dry film thickness ~ 19 microns or 0.75 mils, per pass, two passes are recommended

Mesh size controls print (wet) thickness

Screening is capable of fine lines

38% Ag 80% Ag

65% Ag

10 mil Line/Space

5 mil Line/Space

5 and 5 with standard screening, below with special processing

Silver content does not necessarily determine

fine line capability.

Conveyor drier

Static oven

Processing: Drying and Curing

UV-curing unit

IR Dryer

Many inks dry @ 300F

Low temp inks dry @ 200F

Sensor Inks: Ag / AgCl • Inks based on silver/silver chloride can be used for onboard

electrochemical sensors. • They can matched with chemistries to sense and measure many

different ions/compounds.

Printed Electrodes for Solution Analysis

Markets for Printed Electronic Inks

• Circuit Materials

• Medical Applications/Sensors

• High Speed Printed Electronics

• RFID Applications

• Automotive

• Display, Lighting, Windows

Markets for Printed Electronic Inks

• Printed Sensors – Homeland security applications – Blood glucose, urine, cumidin analysis

• Printed heaters – Automotive seat heaters – Printed heaters for floors and ceilings – Printed heaters for modular or integrated systems

• Solar Cell applications – Rigid – Flexible

• Many applications – Electronics everywhere (Internet of things)

• New materials/processes are continually being developed

• Many Inks that meet that meet the following needs • High conductivity

• Flexible

• High operating temperature

• Low temp processing

• Solderable

Printed Electronics

Useful Links

• Insulectro

• DuPont Microcircuit Materials

– Printed Electronics

– Wearables

– In-Mold

– Fired On (Hybrid)

– Biomedical