Author: Aart-Jan Hoeven aj.hoeven@domicro.nl | DoMicro Advanced packaging of semiconductor-based sensors brings very specific interconnection requirements. These often are related to a very narrow pitch of the interconnections or the fragility of the sensor. Different interconnection methods may also be needed because of the orientation of the sensing area or the integration of the sensor in Flexible Hybrid Electronics. DoMicro has developed an interconnection process for micro assembly of semiconductor-based sensors. This interconnection process is described as inkjet printed wire bonding. This article highlights results from recent work on an application with complex sensors. Furthermore, it includes a perspective on the competitive advantages brought by inkjet printed wirebonds. Conventional interconnection methods Figure 1. Inkjet printed wire bonds for the interconnection of microprocessor bare die Join us at TechBlick's Future of Electronics RESHAPED conference & tradeshow in Berlin on 17-18 OCT 2023 - www.techblick.com/electronicsreshaped. Contact Aart-Jan Hoeven aj.hoeven@domicro.nl | DoMicro for your discounted attendee passes Figure 1 shows a sample with interconnections made with inkjet printed wire bonding. This printing method can be considered as 2.5D printing. Depending on the sensor and integration and processing challenges, the inkjet printed wire bond interconnection method brings advantages over conventional interconnection methods. Reduced heights: Thin integration of bare die sensors for flexible hybrid electronics can be done for BGA or QFN packages which are soldered to the PCB. These typically are made with wire-bond interconnections from the sensor die to a lead frame. This results in a relative thick package. Integration of the bare (and thinned) die directly on the flexible circuit reduces the total height. The inkjet printed wirebond interconnection method can be used to interconnect bare dies to the flexible circuit without adding extra height to the package. Configuration choices: Some optical sensor chips have their contact pads on the same plane as the sensor area. Interconnection with the (Flexible) PCB can therefore not be done using flip chip methods with anisotropic bonding. An advantage with inkjet printed wire bonds is that different configurations are possible. Solutions for heat limitations: The limitations of the processing conditions of some opto-semiconductor sensors do not allow wire bonding or flip chip bonding. The temperature, pressure or ultrasonic energy of these interconnection methods can damage those sensors. Inkjet-printed wire bonds uses less harsh processing conditions. This is a non-contact interconnection method where only limited heat is required. Inkjet printed interconnections enable new (ultra-thin) applications Using inkjet printing technology, DoMicro has developed a state-of-the-art approach for micro assembly of demonstrators for advanced applications with for example ICs, passive components, sensors and LEDs. In previous work, DoMicro has worked on the integration of thinned bare dies using the inkjet printed wire bond interconnection method. The technology for integrating dies is one of the key enablers for the realization of new applications in flexible hybrid electronics (FHE), e.g. in in-mould electronics or smart glass. This approach was developed for a wireless IoT demonstrator with a face-up thinned bare die. The die was interconnected on its bond pads. This demonstrator is shown in Figure 2. As it is impossible to inkjet print conductive tracks via a steep vertical surface, a dedicated ramp structure guides and supports the inkjet-printed silver conductors. This innovative approach of contacting avoids any regular and height consuming wire bond loops with glob top or as applied in advanced packaging, a redefinition layer or substrate (RDL) interface. The ‘die first’ approach is creating minimal height for assembling and mounting dies in systems. It is very suitable for sensor ICs for which the active side should be face up and it offers a compatibility of material surface interaction. The wireless IoT demonstrator includes touch sensors and a Bluetooth chip. With the integration of ultra-thin bare dies, the total height of the demonstrator could be kept below 0.5 mm. Using a flexible substrate of only 50µm thick and bare dies of 40µm thick, the passive components and crystals are now the thickest parts of this demonstrator. This thin form-factor enables smooth integration of functionality in various surfaces, labels, fabric etc. Figure 2. wireless IoT demonstrator Advanced sensor interconnections Based on the work as described above, DoMicro is currently working on an interconnection solution for advanced photoelectric sensors. These are opto-semiconductor line sensors with a high spatial resolution. The top electrode of the sensor is patterned and consists of more than 250 individual pixels at a fine pitch of 100µm. The pixels need to be interconnected with the read-out electronic device which is packaged as a flexible COF (Chip On Film). This semiconductor sensor cannot withstand high temperature and pressure so the interconnection processes have to be adapted to these constraints. The processing steps are defined: Bonding the COF module on the top electrode of the sensor using a non-conductive adhesive. Inkjet printing the ramp structure that allows for a smooth transition in Z-direction from the sensor pixels to the COF contacts. Inkjet printing the interconnection traces between the 250 sensor pixels and the COF contacts. Sintering of the silver nanoparticle ink: laser sintering allows for low heat impact on the sensor. Packaging the sensor assembly. Figure 3. Sensor (1) and the COF (2) on top. Right image shows the alignment of the sensor pixels with the COF contacts at 100µm pitch. Printing the silver interconnection traces is done using a Pixdro LP50 inkjet printer from SÜSS MicroTec. This versatile inkjet printing platform offers benefits like UV pinning, substrate heating, choice of many industrial printheads and high placement accuracy. Figure 4. Inkjet printing on substrate for Flexible Hybrid Electronics using SÜSS MicroTec LP50 advanced research inkjet printer Alignment of the printing and bonding steps is critical for this interconnection method. The positioning accuracy needs to be within 10µm. Furthermore, the wetting behaviour of the inks needs to be controlled in order to reach the required track gap accuracy. On top of this ramp the silver interconnection traces are printed using a silver nanoparticle ink. The traces are about 2mm long and 50µm wide. They connect each pixel of the sensor to a contact of the COF module. This is schematically shown in Figure 4. Images of the printed interconnections and its height profile are shown in Figure 5. Height profiles of samples were characterized using Keyence 3D Laserscanning microscope. Figure 4. Schematic representation of the printed interconnections between the sensor pixels and the COF contacts. 1: Sensor 2: Ramp 3: Read-out electronics COF Figure 5. Top left: 3D image of the printed interconnection. Top right: microscope image of the printed traces on the sensor, ramp and COF contacts. Bottom: height profile of the silver traces (average of the blue lines in the top right image) Alignment of both the ramp print and silver interconnection print with respect to the COF and sensor contacts is possible with the required accuracy. This printing strategy results in sufficient evaporation of solvents of the printed silver ink which is required to minimize ink wetting that could short-circuit the traces. It was found that the resistance for the printed interconnections was ~2 Ω/mm. Following these steps, packaging was done with a combination of potting and encapsulation. This protects the interconnections while providing strain relief for the COF module. Conclusions and outlook A 2.5D inkjet printing process was used for micro-assembly of advanced opto-semiconductor sensors with a large number of fine pitch pixel contacts that needed to be interconnected to an FPC. Using the contactless inkjet technique, it was possible to print interconnections at a 100 µm pitch. Laser sintering can be used for creating conductivity while limiting the heat load on fragile sensors. All individual process steps are shown to be feasible as functionality was shown with the demonstrator sensor assembly. Next steps will focus on maturing the process integration, repeatability and reliability aspects. The work demonstrates that inkjet-printed interconnections for advanced sensors are feasible. This alternative interconnection method can be used in situations where conventional wire-bonding packages or flip-chip bonding processes are not applicable. IMAGINE, CREATE, ACCOMPLISH DoMicro BV is a technology company providing innovative manufacturing technology, application solutions and micro assembly technology for flexible hybrid electronics (FHE) and micro devices. DoMicro develops cutting edge inkjet printing processes and technology for micro assembly and 3D packaging. At the forefront of innovation DoMicro offers state-of-the-art R&D services and exploration of new capabilities and applications for customers with manufacturability in mind. The company delivers R&D services, small series production, system architecture and project management. Typically for customers exploring new technologies for circuitry on flexible substrates like transparent conductive films, OPV electrodes, OLED, Lab-on-chip, wearables, in-mould electronics, IC and MEMS integrations. www.domicro.nl Join us at TechBlick's Future of Electronics RESHAPED conference & tradeshow in Berlin on 17-18 OCT 2023 - www.techblick.com/electronicsreshaped. Contact Aart-Jan Hoeven aj.hoeven@domicro.nl | DoMicro for your discounted attendee passes

The growing concern for the environment has led to a shift towards sustainable packaging and transportation solutions. This presentation will focus on the benefits of incorporating smart labels and low power technologies in transport packaging. We will discuss the various material choices available and how they impact the overall sustainability of the product. Additionally, we will provide a rough calculation of the total waste generated by traditional transportation methods and compare it to the waste generated by using printed electronics in smart labels and low power technologies to enhance logistics. Join us to learn how SODAQ's innovations and solutions can help reduce waste and promote a more sustainable future. SAVE THE DATE

The scalable slot-die coating methods adopted within TNO enable fabrication of efficient perovskite solar devices with intrinsic stability using various material and layer combinations. Furthermore, several different encapsulation strategies are investigated to define a low-cost route to guarantee long term stable modules. Demonstration of a stable semi-transparent bifacial flexible perovskite module is a step forward on various applications, such as building- and vehicle-integrated PV (BIPV & VIPV) and noise barriers on highways. In this talk, we will give an overview of our story towards realizing a stable, efficient, and bifacial perovskite processed via roll-to-roll slot-die coating technique. SAVE THE DATE

SAVE THE DATE

Ram Prasad Gandhiraman | Company: Space Foundry Inc SAVE THE DATE

Speaker: Georg Boedler Company: Inkatronic Inkatronic has over 25 years’ experience in inkjet technologies, and develops specialised industrial machines for mass production. Implementing an inkjet solution to industrial processes can create incredible advantages, as well as open up new opportunities for manufacturing. However, scaling up a solution from a proven laboratory method to a mass-manufacturing environment is surprisingly difficult. In our presentation, we will give a breakdown of some of the challenges that need to be overcome in order to achieve this successfully. SAVE THE DATE

Micro electronic pattern and flat cable core manufacturing process with electroforming by roll to roll equipments. This process can be applied to the development of flexible flat-cable, copper electrode of solar cell and flexible electonic components. The first advantage of this process is that relative long and wide scale metal pattern could be produced. SAVE THE DATE

By Mikael Boedler, INKATRONIC GmbH | mb@inkatronic.com Niederdorfstrasse 6, 4063 Hörsching Tel.: +43 7221 22298 In this article, we will discuss the different aspects of an effective ink delivery system. We will focus on a recirculating inkjet system as they are highly in demand in industry, especially where functional fluids come into play. Though recirculating printheads are mostly on the same price level as non-recirculating, gravity feed equivalents the ink supply system needed is much more intricate and as a result, significantly more challenging to implement (an example of a recirculating ink delivery system is shown in figure 1 below). The benefits of recirculating systems, however, are clearly outlined in the next section making it a worthy endeavour. Figure 1 - INKATRONIC Scalable Circulating Ink Supply. Advantages of Recirculating Inkjet Technology in Industry Improved Print Quality - Recirculating printheads maintain a consistent ink temperature and viscosity, resulting in more consistent droplet formation when jetting at various frequencies. This leads to a better print quality with sharper details and better lay-down accuracy. Reduced Nozzle failures - Continuous ink circulation helps prevent nozzle failures caused by ingesting air, ink drying out, or ink settling, ensuring uninterrupted printing. Faster Start-Up Times - most recirculating printheads can start printing immediately, whereas gravity-feed printheads may require cleaning cycles to recover missing nozzles. Enhanced Printhead Longevity - The reduced risk of nozzle clogs and more stable operating conditions can extend the lifespan of recirculating printheads when compared to gravity feed systems. Improved Jetting Consistency - The stability in ink properties provided by recirculating printheads helps maintain consistent output across multiple print jobs, making them suitable for high-volume and continuous printing applications. Reduced Maintenance - Gravity feed printheads may require more frequent cleaning, purging, and maintenance, while recirculating printheads need less attention, leading to lower downtime and operating costs. Join us at TechBlick's Future of Electronics RESHAPED conference & tradeshow in Berlin on 17-18 OCT 2023 - www.techblick.com/electronicsreshaped. For your special attendee discounts please contact us. Basic Principles of a Recirculating Ink Delivery System In theory, a recirculating ink supply is simple. By creating a pressure difference between the “in” and “out” ports of a printhead a flow of ink is generated (see Figure 2). At the same time, the correct pressure difference must be maintained to generate a slightly negative meniscus pressure at the nozzles. Achieving such a state initially is relatively easy, the hard part is maintaining it while the printhead starts jetting, recirculating pumps run and ink is refilled to compensate for the rate of ink leaving the system. Figure 2 - A simple diagram showing two ink tanks with different pressures connected to a printhead. Pin is higher than Pout causing ink flow through the printhead. The overall pressure at the printhead will determine if a meniscus is held at the printhead nozzles. Figure 3 - INKATRONIC Single Head Circulating Ink Supply. What are the Requirements for a Recirculating Ink Delivery System Pressure Control A meniscus pressure operating window is around ±2 mbar. Though changes within this range are unlikely to affect jetting stability, drop properties will always be affected by the smallest changes causing shifts in printed densities. For this reason, keeping the meniscus pressure within an optimal range is essential. Ink Pumps A reliable ink pump is essential for circulating ink through the system. Diaphragm pumps are commonly used for inkjet applications due to their accuracy and low maintenance requirements, though they must offer good speed control. Sharp start/stop operations are undesired and low pulsation is essential. Peristaltic pumps have their advantages but they need more frequent maintenance with their tubes, while gear pumps should be avoided due to their high shear rates which can affect an ink’s properties in circulating loops. For good chemical resistance, in the case of diaphragm pumps, they should contain FFKM valves and seals. Teflon is the recommended material for membranes. Join us at TechBlick's Future of Electronics RESHAPED conference & tradeshow in Berlin on 17-18 OCT 2023 - www.techblick.com/electronicsreshaped. For your special attendee discounts please contact us at mb@inkatronic.com. Valves As a general rule, valves should be avoided where possible. If needed they have to be compact, with FFKM elastomers, large orifices, and low power consumption. This combination is often not available as standard and a partnership with a manufacturer is required to develop such valves. Pressure Spikes Pumps and valves create varying pulses of pressure, each of them, or in combination, can lead to undesired spikes in pressure. Pressure spikes can cause an immediate loss of nozzles. A positive spike can float a nozzle causing nozzle plate wetting (as shown in figure 3) and a cleaning stop. A negative pressure spike can lead to nozzle drop-outs by the ingestion of air (as shown in figure 4). In the case of a momentary ingestion of air, this is less consequential as the circulating flow of ink will quickly recover the nozzles. An acceptable range for pressure spikes can be +5 to -10 mbar, noting that the “in” pressure is most sensitive to this. It should also be noted that in some cases when large amounts of nozzles are started/stopped simultaneously they themselves can cause pressure spikes at the inlet side of the printhead. Figure 4 - Shows a printhead nozzle plate wetting. This is due to a positive pressure at the nozzle plate. Figure 5 - Shows a printhead nozzle ingesting air. This is due to too high negative pressure at the nozzle plate. Tubing and Connectors Appropriate fittings and tubing should be used that are compatible with the inks chosen for the printing application. Long-term testing should be conducted to observe shrinking, swelling, and sweating. All tubes should be kept as short as possible and with multiple heads they have to be exactly equal in the length. High-quality connectors are recommended as a leaking inkjet system can cause lots of trouble to fix, not to mention the mess. More critical though, is the ingestion of air at any point of the negative pressure side of the system, such a leak is almost impossible to identify. This causes Ink foaming which provokes large jetting dropouts and the level control system to give false readings, which can cause an ink overflow. Materials for Manifolds and Tanks The material chosen for an ink tank should be compatible with the ink chemistry, preventing any chemical reactions or contamination. Common materials for ink tanks are stainless steel, high-density polyethylene (HDPE), polypropylene (PP) and aluminium. In the case of aluminium, it should never be used with water-based inks. Sedimentation and Draining of the system Sedimentation can occur in only a few hours which leads to unstable jetting and nozzle clogging. To avoid sedimentation of high-density inks they need constant motion or stirring. Ink should be kept circulating through the entire ink supply system and extended idle times should be avoided. For a weekend shutdown, it is recommended to implement an automatic draining process to remove the ink from the system and keep it agitated in the main ink reservoir. Temperature Control Ink temperature should be maintained precisely at the optimal value, deviating only ±1°C. This has to be controlled at the tanks and at each printhead. The tank heaters have to be well distributed, local overheating of ink must be avoided. Flow-through heaters in the ink recirculation lines can be used in addition, if needed. Experiments have to be conducted in order to determine an ink’s sensitivity to temperature. Printheads with integrated heaters should reach the target ink temperature with the heater switched off, otherwise the temperature reading by the head thermistor may not be representative of the ink temperature at the “in” and “out” ports. Printhead heaters should be used for fine-tuning the ink temperature, raising it by not more than 2°C. Degassing, Air Bubble Removal Ink formulations can contain dissolved gases or air bubbles, which can disrupt the flow of a fluid within the printhead. A degasser removes these entrapped gases from the ink, resulting in more stable and reliable jetting. This is especially recommended for water-based inks, while UV and solvent-based inks will always show improvements from this. The Parameters for Setting up an Inkjet System For each specific ink and printhead, a different set of parameters will need to be determined. These parameters include: Temperature. “In” and “out” pressures. Flow rate. Head voltage. Waveform. These parameters must be determined experimentally by setting up an ink supply system, with a chosen printhead, the printhead electronics and the ink of choice. When testing a new ink the starting point should be to set the recommended temperature/viscosity set-points provided by the ink manufacturer in accordance with the printhead requirements. With the right temperature settings the “in” and “out” pressures are set in the range which prevents the printhead from dripping or sucking in air. The resulting flow rates are in a range of 10 to 200 ml/min depending on the printhead and have to be measured and maintained. At this point, the jetting performance can be analysed using a dropwatcher. The “in”/”out” pressures can now be adjusted with each jetting trial to find the region within which we achieve the best jetting performance. A flow rate that becomes too low can cause jetting instability and a delay/complete loss of nozzle recovery. A flow rate that is too high can affect the jetting straightness. The next parameter to test is the temperature. Temperature changes during the operation of a system should not fluctuate more than ±1°C. Any changes in temperature during jetting can affect drop size, jetting speed,as and jetting stability. As with pressure, temperature should be adjusted between jetting tests under the dropwatcher in increments of 0.5°C, while keeping other parameters constant. This should also produce a profile showing the ideal range in jetting performance, this time, relative to temperature. If the ideal temperature is different to the temperature set at the start of the procedure, the pressure range test can be repeated to see if the optimal pressure range changes with the new temperature value. Both pressure and temperature range tests would need to be repeated until the optimal pressure and temperature ranges stay constant. This entire procedure has to be repeated for each different ink chemistry, though it is a more complex procedure to swap out a printhead to test with the same ink. It is recommended to select as few printheads as early as possible in the development stages of a printing solution to avoid uneconomically lengthy development times. Functional fluids often have a high amount of solids in their chemistry and as such require frequent/constant agitation to prevent sedimentation, mentioned earlier. For chemists, it’s a challenge to design such fluids within the low viscosity requirements of piezo printheads, somewhere between 4 to 20 mPa s. Testing is recommended to avoid unpleasant surprises in the form of damaged printheads. Other parameters such as head voltage and waveform can also be analysed, however, they are outside of the scope of this article. A dedicated apparatus for complex inkjet development is the INKATRONIC Test Bench, with Dropwatcher shown in Figure, 6 below. With such equipment it is possible to gain productivity and have all the necessary tools at your side to effectively achieve your targets. Figure 6 - Shows the INKATRONIC Test Bench which includes a Meteor dropwatcher for analysing ink jetting in microscopic detail as well as a vacuum table for test prints. Join us at TechBlick's Future of Electronics RESHAPED conference & tradeshow in Berlin on 17-18 OCT 2023 - www.techblick.com/electronicsreshaped.For your special attendee discounts please contact us at mb@inkatronic.com.

Surface Lighting has the ability to change the world of design and change how we interact with products around us. It is a game changer for the printed electronics industry, since light and visual interfaces are becoming a part of any product. We are becoming completely depended on light as a indicator and design element, that communicates ambience, emotions, and statuses. Today Visual Interfaces have to be assembled through the hybrid electronics approach. LEDs are picked and placed and covered with light guides to achieve the target shape and form. Technologies like this maybe cheap to manufacture in mass, but they are hard to setup and to incorporate and any adjustment in shape requires additional setup costs and time. Surface lighting is paper-thin and thus has no space requirements. Affordable Surface Lighting technologies so far have been also accompanied with draw-backs of complex driving electronics, large size or lack of brightness. A technology that can meet all of this is OLED. OLED are made in process that are similar to the chip manufacturing industry. This makes them expensive in unit cost and even more in setup. Thus the dream of Light Everywhere, OLED Everywhere vanishes quickly on hard economical reality. Inuru has simplified the way OLEDs are manufactured by not taking the material into vacuum to to evaporate them, but taking the molecules and printing them. We are utilizing state of the art ink-jet technology used for color printing today. The infrastructure we use for an output of 8M panels require a fracture of the space than conventional evaporation processes. The additive manufacturing of ink-jet allows us to save materials, reduce cost and print any shape in real time, on demand like color. We are 3D printing lighting on a nano-meter precision. This technology will revolutionize the electronics manufacturing and will open printed electronics industry to a wider audience. SAVE THE DATE

Author: Jesus Zozaya | CEO of Voltera | jesus@voltera.io Goal: Design and print a high-performance ultra-high frequency (UHF) RFID tag using precision dispensing of nano copper ink on a paper substrate. Promising Technology: Radio Frequency Identification (known as RFID) is a technology that leverages wireless communication over radio waves to communicate with and locate objects. RFID tags are small label-like objects that are placed on an item which can be tracked and communicated with using an RFID reader — a handheld device that scans RFID-equipped items. UHF RFID tags are passive, meaning they don’t require a battery or power source. UHF RFID has many applications, being well-suited to use cases where non-contact data transfer and item localization can prove beneficial. For example, tracking inventory in a warehouse or manufacturing plant, acting as a high-speed point-of-sale scanner in consumer stores, enabling non-contact cashless payments, and even tracking donated blood bags in healthcare settings. While it seems like RFID tags are just fancy barcodes, they provide many benefits compared to traditional optical barcodes. RFID tags do not require a line-of-sight and are therefore resistant to bad lighting conditions and other environmental factors. You can quickly scan a room full of thousands of RFID tags without having to identify each individual tag (tags can even be scanned if they’re behind a wall!). RFID tags also integrate a user-writable memory space, enabling item identification, the ability to update information in the tag when it is scanned, and tracking the condition or state of the item. Perhaps most useful of all, RFID tags can be used to identify a location in a space, so a smart warehouse will always know where items are located in inventory. What’s the catch? Current RFID tag manufacturing methods, such as etched aluminum or screen-printed silver RFID tags require the use of hazardous chemicals and result in tags that are resistant to biodegradation and are not recyclable due to their laminate structure. With billions of RFID tags manufactured each year, this presents a substantial environmental impact. Join us at TechBlick's Future of Electroncis RESHAPED conference & tradeshow in Berlin on 17-18 OCT 2023 - www.techblick.com/electronicsreshaped Quantum Leap: A novel approach using printed nano copper inks on a paper substrate offers the potential of more cost effective, better performing, biodegradable RFID tags for the industry of tomorrow. The most common manufacturing method for RFID tags is etched aluminum, where powerful solvents are used to subtract material from an aluminum foil and PET laminate, creating the antenna pattern. As mentioned above, these chemicals are hazardous, the manufacturing process is water-intensive, and the produced RFID tags cannot be recycled or composted. Using nano copper inks in the same application enables the production of biodegradable RFID tags using an additive printing process. This means less material is used, there are no hazardous etchants, and less water is wasted. Providing equivalent electrical performance to the highest performing printed silver inks, these eco-friendly nano copper RFID tags also result in a significant cost reduction compared to both etched aluminum and printed silver RFID tags. Creating the RFID Tag We set out to create a high-performance RFID tag using our own custom antenna design, printed with Copprint’s LF-301 ink, an ink specifically formulated for use on paper substrates. Using Voltera NOVA’s high-speed prototyping capability, combined with industry-leading design software, we designed a tag in-house that could perform just as well, if not better than industry standard tags. Step 1: Design the Tag Using Autodesk Eagle™ we laid out the pattern for the antenna using the meander half-dipole antenna topology, commonly used in RFID. This design prioritizes all-around performance by emphasizing both near-field and far-field performance, while reducing space requirements and providing a lot of tuning possibilities. Once the preliminary design was complete, gerber files were exported for the next steps. Step 2: Simulate the Tag Since it can be challenging to properly characterize performance of an RF system, we first performed simulations of our design to determine its expected performance. Using MATLAB® Antenna Toolbox™, the preliminary antenna design was simulated and iterated upon. To obtain the desired performance characteristics including antenna sensitivity and directionality, the geometry of the antenna was fine-tuned. The finalized design had a minimum self-reflection coefficient (S11) of -29.42 dB at 922.50 MHz, passing the required maximum of -10 dB. This is also known as the resonant frequency where the tag will function best, which is well within the 902 MHz and 928 MHz frequency bandwidth for North American RFID tags. Step 3: Print the Tag After iterating, the design was finalized. We imported our files into NOVA’s software, then calibrated the Copprint LF-301 nano copper ink using NOVA’s integrated workflow to generate the appropriate ink settings. After experimenting with multiple nozzle geometries on the Smart Dispenser, best performance was obtained using a Nordson EFD 0.004” Optimum Chamfered Tip nozzle with a custom ink profile generated with NOVA’s calibration workflow. Once the ink was calibrated, a cardstock paper substrate was secured on the Vacuum Table Module. The design was then printed using NOVA, with each RFID tag taking less than 15 minutes to print. Step 4: Prepare the Tag After printing, we completed post-processing of the tag in order to properly unlock the potential of this ink. Copprint provided guidelines for this on their website. First, the RFID tag has to be dried in order to prepare it for further processing. It was placed in a blast dry oven for five minutes at 80°C. Next, the print must be sintered. Sintering is the process of chemically bonding the different microscopic sections of copper together to form one continuous conductor. This process is essential to unlock the full performance of nano copper inks. For Copprint, sintering was achieved by placing our print in our hot-press for 15 seconds at 270°C. Once this process is complete, we burnish the surface to prepare it for soldering. Step 5: Solder the Tag Upon completion of post-production, we attached the RFID controller IC to the antenna to complete the RFID tag. In production, a special adhesive known as anisotropic conductive adhesive (ACA) is often used to attach RFID IC’s to the antenna. However, since Copprint LF-301 behaves like copper, the IC could be soldered after sintering of the antenna was complete. Using solder paste and an air reflow station, the transceiver IC was bonded to the printed antenna. Results In the end, the RFID tag performance exceeded that of off-the-shelf RFID tags bought from market leaders. When tested side by side, we see the potential of nano copper ink RFID tags; while the commercial tags we acquired were made of a non-recyclable laminate, our RFID tag was composed simply of paper and copper ink, which made it compostable. In addition, our tag would be more cost effective to produce at scale. See how we made the RFID Tags Using NOVA enabled us to produce this RFID tag in-house with no upfront capital costs such as screen-printing screens. We only required the purchase of Copprint’s LF-301 ink. Additionally, by leveraging NOVA’s modular Smart Dispenser and built-in ink calibration workflow, we were able to get up and running with a new material very quickly. All of this resulted in a print time of 15 minutes per tag, enabling many design iterations each day rather than one iteration per week. Join us and the global community in Berlin on 17-18 OCT 2023 and let us together RESHAPE the Future of Electronics, making it Additive, Sustainable, Hybrid, Wearable, or 3D.

Authors Wim Christiaens | Quand Industries | Wim.Christiaens@quad-ind.com Textiles are tactile, sensorial and visual. Qualities can be modified or even expanded when technology is added, transforming passive textiles into active and interactive devices, monitoring and detecting bodily functions due to their constant contact with our skin. Printed electronics are also more durable than traditional electronics and can withstand multiple washing cycles, crinkling, friction and sweating. The lower production costs and easy scalability of printed electronics also stimulate the development of new (IoT) applications and a larger adoption of e-garments and smart fabrics in general, which can promote a healthier lifestyle and reduce the risk of disease, accidents and injuries in many industries. Their integration is straightforward. After printing the sensors on TPU they can be transferred onto the textile material via hot press lamination. Both are well-established techniques. Join us at TechBlick's Future of Electronics RESHAPED conference & tradeshow in Berlin on 17-18 OCT 2023 - www.techblick.com/electronicsreshaped. For special discounts on attendee passes please contact Wim.Christiaens@quad-ind.com Compared to traditional electronics manufacturing, printed electronics are easily scalable and low cost. They are durable, precise, efficient and comfortable to wear. They have excellent interconnectability. The PCB’s can be positioned in a remote spot, are small and don’t need much power to work. Applications that change our lifestyle Athletic monitoring: Train smarter, not harder A wide range of smart sportswear (e.g. shirts, insoles, sports bras) track vital signs (via printed ECG or EMG sensors), core temperature, and biomechanics both during training and in the recovery phase. It helps athletes to enhance performance, ensure a healthy athletic growth, help reduce stress and prevent different types of injuries. Alleviating the healthcare and medical sector Smart textiles serve as a functional and comfortable ‘wearable computer’ that help health care professionals by monitoring and communicating a patient's condition by detecting, storing, analysing, and transmitting physiological signals. Join us at TechBlick's Future of Electronics RESHAPED conference & tradeshow in Berlin on 17-18 OCT 2023 - www.techblick.com/electronicsreshaped. For special discounts on attendee passes please contact Wim.Christiaens@quad-ind.com Automotive and aerospace In the aerospace industry and in vehicle engineering, current applications focus on smart sensors integrated in interior fabrics and biometric monitoring for safety purposes. Information can provide insight into the driver's physical condition and level of fatigue, triggering haptic feedback through the steering wheel or warning alerts in the car's cockpit. Active workwear The monitoring of vital signs of workers in demanding environments and high-risk industries has been made easier. In regulated industries where safety rules restrict workers from wearing devices, smart workwear can give insightful information about the condition of workers or machine operators that can be used to optimize their well-being, performance and productivity. Thermal workwear to dynamically regulate body temperature of workers in cold climates is another huge application domain. Textile-integrated flexible heaters There is a steep rise of interest is heating technology for garments. Stretchable printed electronics heaters make it easy to incorporate heat into comfortable, elegant, flexible, lightweight clothing. The high precision that can be achieved with screen-printed circuitry also makes it simpler to provide warmth exactly where required and avoid areas of the body which don’t need any additional heat. Join us at TechBlick's Future of Electronics RESHAPED conference & tradeshow in Berlin on 17-18 OCT 2023 - www.techblick.com/electronicsreshaped. For special discounts on attendee passes please contact Wim.Christiaens@quad-ind.com

Stephan Harkema and Corné Rentrop | TNO at Holst Centre | stephan.harkema@tno.nl A growing desire for continuous data collection, real-time information, and connectivity has resulted in increased demand for electronic functionalities that are fully integrated in everyday objects. Consumer electronics, healthcare, wearable electronics, IoT, and smart packaging are examples of market segments that follow this trend. Printed circuit boards (PCBs) are state-of-the-art when it comes to creating electronic functions, but pose challenges with respect to sustainability. These highly integrated electronic products, where plastics, metals and semiconductor components are seamlessly combined, are a challenge to recycle. The only suitable end-of-life scenario is still limited to shredding and incineration. With increasing electrification, digitization, broad wireless integration (IoT) and welfare, the amount of waste from electronics and electronic devices increases drastically. An estimated 1.2 Mtons of Printed Circuit Boards (PCBs) end up in the total amount of annual e-waste[1]. Only a third is recycled in environmentally sound facilities. This means that around 800 million kilograms may be traded, recycled in a non-compliant and polluting manner or may end up on a landfill. There is a more eco-friendly alternative to PCBs: Hybrid and Printed Electronics (HPE). This technology is a big step forward compared to PCBs, but much more is needed to achieve circular production of next-generation electronics. Despite their name, printed circuit boards (PCBs) are not actually printed. They consist of multiple layers of electroplated copper on glass-fiber epoxy substrates onto which electrical components, so-called surface-mounted devices (SMDs) are assembled. The copper layers are etched with hazardous chemicals to create the circuitry. At end-of-life, the encapsulated copper and unrecyclable epoxy carrier make PCBs a recycling challenge. Transitioning from PCBs to HPE (Hybrid and Printed Electronicprovides immediate opportunities to achieve ecological benefits: reduced device thickness, lower weight, printed sensors, and additive instead of deductive manufacturing of the circuitry. Printed electronics is a disruptive technology that is on the verge of breakthrough in the automotive, lighting, and medical domains. Each use case represents a slimmer, lighter, more appealing, more practical, and less polluting alternative to the conventional device based on printed circuit boards (PCBs). However, in both types of electronics, PCBs, and HPE, the circuitry and SMDs contain potentially critical, high-impact metals embedded in plastics to protect them from external influences, such as mechanical damage and moisture. As opposed to PCBs, the environmental impact of HPE can be further reduced by using recyclable, bio-based, and renewable or compostable materials. Figure 1: roadmap to sustainable electronics Roadmap to sustainable printed electronics Most, if not all, products are mass produced. A first primary focus lies with a successful market entry which is often achieved by innovative functionalities in an aesthetic product design at competitive price levels. Manufacturing of such products is often not immediately optimized for low material usage, low power usage, and a minimal carbon footprint. Instead, single use and low recyclability are often accepted at this stage to achieve commercial success, which may be essential for the survival probability of the company. Petrochemical materials offer a high degree of reliability, low cost and supply security and are therefore ideally suited for high volume production in this first stage of the roadmap, as shown in Figure 1. A first step towards increasing a product’s sustainability is to address, and preferably extend, its end-of-life by enabling repairability, for instance by a modular design with repairable or replaceable components, or by enabling upgrades. Such steps do not immediately improve recyclability or reduce the environmental impact of production and the materials, but they do provide a significant improvement to the environmental impact by the simple fact that the product does not need to be replaced by a new one. Also energy consumption during the use phase may be addressed. For some examples, such as devices containing highpower elements (e.g. lighting), optimization of power usage may be an effective means of lowering the overall environmental impact. Join us at TechBlick's Future of Electronics RESHAPED conference & tradeshow in Berlin on 17-18 OCT 2023 - www.techblick.com/electronicsreshaped. For your spercial attendee discounts please contact us: stephan.harkema@tno.nl ] Following this second stage, a third step may be taken in which a product undergoes a simplification of its design with a reduction of coatings to limit material usage, production steps and overall energy consumption. Printed electronics technology offers an increasingly credible alternative to PCBs and perfectly matches this stage in the roadmap: 1) lower thickness, 2) printed functionalities instead of discrete SMD components that have a higher footprint, 3) recyclable thermoplastic polymers and 4) additive manufacturing as opposed to deductive etching of copper. Nonetheless, challenges still remain in terms of costs and reliability in comparison to the PCB. Circular use of materials, as depicted in the fourth stage in Figure 1, requires more drastic changes, especially to enable other choices at end-of-life. When end-of-life is reached, the product needs to be dismantled into its chemical building blocks. Here, printed electronics also provides opportunities, as many of the starting materials are meltable and therefore relatively easy to dismantle. The favoured cradle-to-cradle recycling approach is a possibility to further reduce the environmental impact. However, seamlessly integrated electronic products manufactured to survive rigorous testing in harsh environments cannot be disassembled so easily, which leaves shredding and incineration of these products as the only option at end-of-life. The plastics serve as energy carriers for metallurgic processes. While metallurgic processing at an industrial scale may be very efficient for metal recovery, the plastics are lost entirely. Recuperation of the plastics faces the challenge of achieving a high enough purity level to reach the material properties of the initial plastic. When combining plastics with coatings or metals or other plastics, purity levels plummet and only secondary use is realistic. Recycling of integrated electronics to yield metals, components and plastics separately and in a pure and circularly usable form therefore requires a method of disassembly prior to recycling. Not only does this allow circular use of all components and materials, it also enables higher recycling rates. It is therefore vital for electronics production in a circular economy to include design-for-recycling principles. In the before-last stage, bio-based materials may be introduced as a replacement for generally used fossil-based polymers. In the final stage, biodegradability is an option for specific use cases where disposal into the environment is likely or a more effective approach to recycling. Devices applied to the human body with a limited lifetime of days to weeks are well-suited to go this far in their sustainable developments, while others intended for long-term use are less likely to benefit from biodegradability. Materials from bio-based origins are considered to be environmentally friendly, but large volume production may put additional strain on food supplies and animal feed (1st generation feedstock) or land use for non-food biomass (2nd generation)[2]. Algae are a promising candidate for third-generation bio-mass due to a very high growth rate (5-10x terrestrial plants)[3]. Moreover, cultivation of algae do not strain food supplies and available cultivated farmland. Achievable lower environmental impacts Quantification of the environmental impact typically proceeds through a life-cycle assessment. Guidelines to achieve a lower environmental footprint for printed electronics were provided by Prenzel et al.[4]. Copper has a significantly lower global warming potential than silver, possibly up to a factor of 70[5]. While this choice for a different metal would lead to a more than 95% lower contribution to the GWP, it is limited to the printed circuitry alone, if processing remains otherwise identical. Similar values are possible for the plastic carrier if e.g. paper is a suitable alternative. However, reliability would then be at stake due to a high sensitivity to moisture/water, revealing the potential, but also the intricacies related to developing sustainable electronic products. At a higher integration level, ultra-thin organic photovoltaic solar cells were reported to demonstrate a 10-85% reduction in carbon footprint by a combination of a different substrate, less silver and a modified design[6]. For printed electronics devices closer to industrialisation, a recent life-cycle assessment by Tactotek indicated that, compared to PCBs, in-mould structural electronics (IMSE) enabled a reduction of the carbon footprint by 34-62%, depending on the application and its details[7]. The reductions in carbon footprint for these printed electronics examples are very hopeful and do not stand alone. More examples are available in the literature. Join us at TechBlick's Future of Electronics RESHAPED conference & tradeshow in Berlin on 17-18 OCT 2023 - www.techblick.com/electronicsreshaped. For your spercial attendee discounts please contact us: stephan.harkema@tno.nl ] Design-for-recycling (DfR) The benefits of the application of a design-for-recyclability would further enhance these values as a DfR enables the recovery of the materials. When comparing automated shredding and sorting of PCBs containing electronic waste to manual extraction of the PCB for recycling, higher recovery rates were obtained for the latter (95-99% vs 12-60%)[8]. Another study indicated that extensive dismantling and high-quality recycling would lead to the highest reduction of the product’s global warming potential[9]. Norgren et al. applied design-for-recycling to several use cases and examined the role of a DfR in a circular economy[10]. As described, design-for-recycling holds the potential to increase the quantity and value of materials recovered and reused from products that have reached their end-of-life. Important to realize is that improved recyclability provides a balance between reliability and recyclability: a part is typically designed to withstand rigorous testing (peel tests, pull-out tests, bending tests, stretching, ..), sometimes in combination with harsh environmental exposure (climate chamber set at elevated temperature and humidity, thermal shock tests, aging test at high T and/or with UV exposure). The specs and standards that must be met are often based on conventional PCB electronics and warrant re-evaluation of their applicability in a circular economy. The additional trade-off of recyclability versus costs may come in next, as additional measures or specialistic materials may be necessary to reach the DfR. The question is then when the gains in environmental impact exceed the potential loss in reliability and or potential increase in costs and which methods for quantification are accepted by the industry and policy makers. TNO at Holst Centre has developed a DfR approach that can be applied to various printed electronics devices, including in-mould structural electronics, flexible lighting, flexible sensors, and (medical) health patches. In this design, the encapsulant of the printed electronics and discrete semiconductor components can be removed at end-of-life. First demonstrations of the principles on in-mould structural electronics (IMSE) in the EU Treasure project led to successful device disassembly[11]. Upon removal of the polycarbonate encapsulant, that had been applied by injection moulding to a polycarbonate substrate with printed silver circuitry, the printed silver circuitry was exposed. Subsequent hydro-metallurgic processes by Treasure partner Univaq (University of L’Aquila) could target the printed silver directly and specifically without the need to chemically remove the PC beforehand[12]. A full life-cycle assessment, including the comparison of a recycling end-of-life scenario compared to shredding and incineration, is underway. Figure 2: schematic representation of a design-for-recycling with a) an electronic device encapsulated in plastic, b) first stage of dismantling with the removal of the plastic encapsulant, c) & d) second stage of dismantling that targets SMDs and (printed) circuitry and e) plastic substrate with any leftover (graphic) layers. Figure courtesy of Amires. Figure 3: a) forced mechanical disassembly of an IMSE device without DfR leading to rupture of the substrate, b) disassembly of an IMSE device with DfR; c,d) Flexible lighting device with DfR in on-state and off-state during peel tests Join us at TechBlick's Future of Electronics RESHAPED conference & tradeshow in Berlin on 17-18 OCT 2023 - www.techblick.com/electronicsreshaped. For your spercial attendee discounts please contact us: stephan.harkema@tno.nl ] Acknowledgements Holst Centre is a research and innovation partner specialized in health technologies, flexible and wireless electronics, powered by the shared expertise of imec and TNO. This research has been funded by the Dutch Ministry of Economic Affairs, and the European Union’s Horizon 2020 research and innovation programme under grant agreement No 101003587 (EU Treasure project), No 101070167 (EU Ecotron project). Original electrical and injection-mould design were realized in the Flexlines project that received funding from Interreg Vlaanderen-Nederland. The authors would like to gratefully acknowledge the exceptional contributions from Peter Rensing, Pit Teunissen, Jan van Delft, Jeroen Schram, Gerwin Kircher, Adri van der Waal and dr. Margreet de Kok from TNO at Holst Centre, and Sanne Domensino and Joris Vermeijlen from Fontys University of Applied Sciences. We also gratefully acknowledge the wonderful support provided by Rick Leuven and Yibo Su from Brightlands Material Center for injection moulding with the Flexlines mould. References: [1] Baldé, C.P., D’Angelo, E., Luda, V., Deubzer, O., and Keuhr, R. Global Transboundary E-waste Flows Monitor – 2022, United Nations Institute for Training and Research (2022) [2] Coma M., Martinez-Hernandez E., Abeln, F., Raikova, S., Donnelly, J., Arnot, T.C., Allen, M.J., Hong, D.D., Chuck, C.J.Faraday Discuss., 202, 175 (2017) [3] Maliha A., Abu-Hijleh, B., Energy Systems (2022) doi:10.1007/s12667-022-00514-7 [4] Prenzel T.M., Gehring, F., Fuhs, F., Albrecht, S. Matériaux & Techniques 109, 506 (2021) doi: doi.org/10.1051/mattech/2022016 [5] Nuss P, Eckelman MJ (2014) PLoS ONE 9(7): e101298. doi:10.1371/journal.pone.0101298 (2014) [6] Välimäki, M.K., Sokka, L.I., Peltola, H.B. Int J Adv Manuf Technol 111, 325–339 (2020). doi:10.1007/s00170-020-06029-8 [7] Tactotek webinar “Environmental Performance of IMSE®”, 2022, https://www.tactotek.com/resources/webinar-environmentalperformance-of-imse [8] Ardente F., Mathieux, F., Recchioni, M. Resources, Conservation and Recycling 92, 158-171 (2014) doi:10.1016/j.resconrec.2014.09.005 [9] Alston, S., Arnold, J. Environ. Sci. Technol. 45, 21, 9386–9392 (2011) doi:10.1021/es2016654 [10] Norgren A., Carpenter A., Heath, G. Journal of Sustainable Metallurgy 6:761–774 (2020). doi: 10.1007/s40831-020-00313-3 [11] Harkema, S., Rensing, P., Domensino S., Verweijlen J., Godoi-Bizarro, D. submitted for publication [12] Ippolito, N.M.*, Romano, P., Passadoro, M., Pellei, G., Vegliò, F. Treasure Project H2020 - Recycling of automotive waste for the recovery of precious and critical metals: pilot plant tests. The 16th International Conference on Chemical and Process Engineering, Naples, May 21-24, 2023