The production processes that go into creating printed electronics

RISE

The first step when it comes to printed electronics is the idea, the concept – what is it that the engineer hopes to achieve? What end application does the engineer hope to revolutionise with a printed electronics device? Electronic Specifier’s editor, Daisy Stapley-Bunten, met with Björn Norberg, Sales Manager of Printed Electronics, RISE, to learn about the multiple disciplines that it was investing research into, and the innovations it had made so far.

RISE, the Research Institutes of Sweden, is Sweden’s research institute and innovation partner: ‘RISE is an independent state-owned research institute offering unique expertise and 100 test and demonstration environments for future-proof technologies, products and services.’ Norberg described RISE as an ‘integrator’, its research and innovation integrates multiple disciplines and focuses on large research areas, but at LOPEC 2018, RISE exhibited its printed electronic innovations. While RISE predominantly works to a client brief, it invests time and resources into its own projects, going further than just research and producing physical prototypes – it is only a matter of time before these devices progress into spin-off startups.

Norberg demonstrated the RISE innovations in printed electronics, but three devices in particular stood out as holding true potential to disrupt the market:

‘Transparent Intelligence’

RISE has created a hybrid electronic system which is integrated on glass, by combining printed and silicon electronic components, which enable novel multifunctional and intelligent products on transparent glass substrates: in other words ‘printing on glass’.

When asked whether he could envision this technology being used within automotive interiors and for infotainment systems, or for smart home products (e.g a wine fridge glass door with temperature sensor), Norberg explained: “RISE solves functional, not aesthetic, problems. We see this transparent intelligence platform being applied in security systems for glass cabinets, rather than cool futuristic screens.” No Tony Stark here.

This technology demonstrates the integration of the following:

• Printed circuits
• Printed electrochromic display
• Sensors (printed humidity sensor)
• Hybrid printed energy harvesting
• Data transmission module (NFC)

Ion Man

Electronics concentrate on the movement of electrons, but the printed iontronic devices from RISE focus on ions – a bio-inspired process. Fittingly, these devices are intended for medtech applications.

‘These devices allow localised and on-demand delivery of charged biomolecules. The ability of conductive polymers to conduct both ionic and electronic charges enables the translation of electronic signals into precise and fast delivery of biologically relevant ions,’ according to RISE.

Key aspects:

PEDOT:PSS as an electronic and iontronic material, printable ion exchange membrane to allow permselective delivery of desired ions (e.g. drug, neurotransmitter), printable hydrogels and encapsulation for drugs/ion storage. These devices have the potential to be deployed into the human body to sense and react, e.g. to sense whether a biochemical level is low and administer a drug accordingly, such as in the case of glucose and insulin levels for people with diabetes.

Modular hybrid-printed systems for sensing

‘Combining organic printed electronic, silicon technology and physical/chemical/biochemical sensing to provide novel possibilities for in-situ real time sensing.’ – RISE

RISE provided a concept prototype of how this technology could be applied, in the form of a temperature logger, but Norberg explained that the potential for this device is huge. It could be used to detect humidity levels inside the walls of structures – which is a topical concern in countries with a cold climate that suffer with mold – this device would provide a cheap and effective solution to assure a prospective buyer, or even just the current owner, of the property’s condition, without need for physical exploration.

In addition to this type of application, the device can be used for more serious situations – such as diagnostic purposes. With time constraints on healthcare professionals, the triage process could be magnified in its efficacy, patients could have biochemical tests with immediate results – less sophisticated results with this device – however it would provide enough data, faster, for a healthcare professional to make a decision about which direction a patient should be sent.

Key aspects:

Cost effective in situ and real time measurements, local data elaboration, visual presentation of data, transmission of data to smart devices for advanced handling and adaptability to different sensors and form factors.’

Other research areas at RISE:

Printed chemo-bio sensors, Silicon-Organic hybrid autarkic Systems (SiOS), a paper supercapacitor and the monolithic integration of electrochemical energy storage modules. RISE is also investing research into the actual printing process of printed electronics, using grafted metal, to address environmental concerns.

RISE presented its research and innovations to showcase the potential applications for printed electronics. The companies below, presented solutions to make the printed electronics process itself, more efficient.

EXAKT

Elina Landa, Sales and Technical Manager, Three Roll Mills/Cutting and Grinding Systems presented EXAKT’s machines which are used to create the pastes and inks for printed electronics. EXAKT is an OEM based in Hamburg and is the only company in Europe to provide these machines for small-scale production.

The ‘three-roll’ process uses the sheer force of the rollers to create the pastes and inks. On display at LOPEC 2018, EXAKT featured the E-Line EXAKT 80E PLUS: ‘The next industry gold standard of Three Roll Mill technology, based on a high precision and rock solid mechanical design with a digital electronics control system, it offers all-in-one dispersing and analysing functionalities.’

The new concept allows real time analysis of the dispersion process and immediate adjustment of machine settings to optimise results during the dispersion process in all gap setting modes.

saes group

Paolo Vacca, R&D Manager of Functional Chemicals Labs at saes group also presented printed electronics paste and ink solutions. These solutions are; the DryPaste-G dispensable dryer, DryPaste-EP dispensable dryer and AqvaDry ink.

The DryPaste solutions (one of which does not contain a silicon product which many companies in the Far East do not want as it interferes with the materials that they tend to use), can be applied to the back of printed electronics and work as ‘irreversible moisture getters’. They are specifically designed for printed electronics intended for use in waterproof products; such as fitness trackers and smart watches, and they can work for up to ten years.

• ‘DryPaste-EP: A high capacity, solventless dispersion of a modified chemical dryer in an epoxy matrix, designed for use in OLEDs and organic electronics applications. Due to its viscosity it can be applied by screen printing, blading or syringe.’
• ‘DryPaste-G: a high capacity, solventless, thermally curable, dispensable dryer designed for use in OLEDs and organic electronics applications. Due to its viscosity it can be applied by screen printing, blading or syringe.’
• AqvaDry – Ink transparent dispensable dryer: ‘a transparent UV curable dispensable transparent dryer, designed to be used in OLEDs and organic electronics applications. Available as in ink-jettable formulation, to be typically used as a filler or film, to improve the performance of Thin FIlm Encapsulation (TFE).

Optomec

Mike O’Reilly, Director of Aerosol Jet Products spoke about Optomec’s Aersosol Jet, a new generation of in-line digitally driven dispense systems for advanced packaging and assembly.

Optomec, a leading global supplier of production grade Additive Manufacturing (AM) systems has announced the Aerosol Jet HD System designed to address the most demanding electronics packaging challenges – increasing density of electronic components. The Aerosol Jet HD System is a compact, configurable production platform that can dispense a wide range of electronic materials with features as small as 20 microns. The system can also produce larger features, from 100’s of microns to millimetres, and print wide-area conformal coatings from 100nm to 10’s of microns in thickness.

The Aerosol Jet HD System is based on Optomec’s patented Aerosol Jet technology, a fine-feature material deposition solution used to directly print functional electronic circuitry and components onto low-temperature, non-planar substrates, without the need for masks, screens or subtractive post-processing. Based on the next-generation of Optomec’s production-proven Aerosol Jet print engine, coupled with in-line automation, the HD System can handle a variety of substrate sizes and compositions, providing high-resolution printed electronics for today;s most demanding advanced packaging applications such as 3D interconnects, conformal RF/EMI shielding, and precision micro-dispense of insulators and adhesives.

“The demand for miniaturisation of electronic systems, especially in mobile device, medical and mil-aero applications, has exposed a technology gap in advanced electronics packaging that current dispense solutions cannot address. With this announcement, Otomec offers a practical, seamless and cost-effective solution that can deliver an order of magnitude improvement in dispense resolution, addressing the advanced packaging needs of today and providing a pathway far into the future,” said Dave Rahahi, CEO of Optomec.

The compact, modular design of the Aerosol Jet HD System enables it to easily plug into almost any existing manufacturing environment to fill production gaps and provide new capabilities. The solution provides a turn-key approach to advanced electronics packaging with the Aerosol Jet Print Engine and tool path generation software integrated into a standard dispense automation platform. In addition, production-ready recipes for a range of conductive, dielectric, adhesive and other materials, capable of extended runtimes and high yields are available with the initial product release.

Optomec 3D printing technology can co-exist with current manufacturing processes because it is based on an open systems approach and delivered in a module format. This enables Optomec to bring value to customers while enabling them to leverage existing capital assets or acquire like systems without disrupting their manufacturing processes.

Merck Group

Dr. Giles Lloyd, Senior Manager of Global Marketing and Project Management at Merck Group, Germany, talked about its solutions for ‘Printing the future: materials for the next generation of printed electronics’.

‘The Merck Group work on the optimisation of materials for the printing process. They are working on an initiative for new materials for the automotive future – with OLED lighting, for example. Printed electronics has enabled freedom with design and the Merck Group lisicon portfolio enables the ability to easily fabricate organic electronic devices with high performance by employing the specially developed and matched sets of materials for the complete device stack.

Merck is a leading supplier of printable organic semiconductor and dielectric materials for organic electronics. The lisicon portfolio offers materials and formulations for the manufacture of innovative applications such as flexible displays, printed electronic circuitry and components. The product range covers not only high performance semiconductors and dielectrics, but also injection layers, passive materials and surface treatment chemicals.

Merck’s lisicon concepts are designed individually for specific requirements and enable mass production using a variety of conventional fabrication techniques, such as spin-coating and inkjet, gravure and flexographic printing.

Electronics are ubiquitous in our modern lives and are normally based on high temperature, vacuum processed silicon devices that necessitate fabrication on silicon wafers or glass panels in the case of displays. This results in rigid, fragile and expensive devices. Printed electronics using Merck’s lisicon products are different. They allow low temperature printing of electronic devices such as Organic Thin Film Transistors (OTFT) and Organic Photo Detectors (OPD) using specially developed materials. These materials can be printed at high throughput on plastic substrates thereby revolutionising manufacturing techniques in the electronics industry. Such printed electronics will help to drive the Internet of Things (IoT) by enabling the ultra-high volume requirements that realise the ultimate promise of ubiquitous connectivity and ambient intelligence.

For this next revolution in semiconductor technology, low cost and ultra-high throughput are the critical parameters enabled by printed electronics. In addition to high volume manufacturing, printed electronics involved fabrications methodologies allowing freedom of size, form factor and application architecture. Large-area electronics such as display backplanes can significantly benefit from this.

They can be produced using these techniques and materials to realise the potential of flexible and robust displays manufactured on plastic substrates. Possible used of this include electronic paper that can be rolled up and put in your pocket. These new product opportunities are being explored by highly innovative new companies through to existing major players in the displays markets and developments show considerable promise for the future.’ – Merck Group.