Silver nanoparticle inks improve every year. These improvements are often incremental, but very important. One ever-present direction of development is towards inks which offer ever higher conductivity levels at a low curing temperature and a short curing time. This a critical figure of merit because it opens more substrate choices, saves time, and lowers energy consumption costs. Here, we highlight the progress by Agfa, who offers both solvent and water based, as well as screen and inkjet printed (IJ) Ag nanoparticle (NP) inks. The first slide below shows the progress in curing time and temperature of a solvent-based IJ printable Ag NP inks. The left picture is the zoomed up version of the right picture. The compares the properties of two different solvent based IJ Ag NP inks: SPS201 and SPS210 sintered at different temperatures (110C, 130C, and 150C). For a given sintering temperature, we can see that SPS210 reaches a lower resistivity level at a shorter time compared to SPS201, clearly demonstrating this incremental but important advancement of the Ag NP ink technology. As seen in the following slide, the SP2010 Ag NP IJ ink can achieve 3mOhm/sqr/mill when sintered at just 130C for 10min. These are excellent results. IJP Ag NP inks are beginning to find suitable applications. In the last slide, you can see printed Ag NP lines as narrow (70um) metallization line on a thin film photovoltaic technology (note: screen printed lines on Si PV are now 34um). Next to it, you can see a transparent heater application. Here, the application is a photochromic laminate for motor sport visors. The visor can change optical transmission to maintain good visibility in different outdoor light levels. One limitation of the photochromic laminate is that it can change its transparency state only slows. This can be a challenge when the driver enters, for example, a tunnel, transitioning from intense sun light into darkness quickly. To overcome this limitation, the laminate can be heated to accelerate the transition. To this end, a CNT or ITO solution is deployed. The result are ok however homogeneous heating can still take too long (40s or longer). To overcome this limitation, a metal mesh with linewidth of 70um and pitch of 2mm is inkjet printed using Ag NP inks (SPS211). As seen in the slide below, it reduces resistance to 11ohm, and achieves uniform heating in just 20s, which meets requirements.

Current substrate technologies impose severe limits on potential of stretchable or flexible hybrid electronics. This is because (a) they often limit curing temperature of conductive inks which limits conductivity levels far below bulk metal and (b) they rule out compatibility with standard SMT processes and materials such as solder reflow. The table below is a comparison of common flexible and stretchable substrates. The most common ‘flexible’ substrate is PET, which is low cost, resistant to chemicals, and offers a good surface energy for printing of inks. It however has poor heat resistance, generally making it incompatible with SMT processes and imposing temperature constraints on the curing of the ink, which can limit achieved conductivity levels. The most common ‘stretchable’ substrate is TPU which offers excellent stretching as well as a good surface for printing, but has very intolerant of heat and humidity, and imposes even more severe constrains on ink and solder/conductive adhesive processing temperatures than PET. Therefore, there is a need for a substrate that it flexible and stretchable and offers compatibility with SMD and higher temperature processes. Panasonic is developing such a product based on a novel patented fully cross-linked thermoset polymer system. Below you can film stretch comparison, showing how the new thermoset substrate survives 100% stretch cycle without deformation, unlike even TPU. In the next slide, it can be seen how this substrate survives a solder float operation (1m@260C) whilst PET and TPU are fully damaged. This clearly demonstrates more compatible with standard SMT processes. Next you can see the thermal stability of the film- it maintains its elongation and tensile properties even after 1000 thermal cycles (-55 C to 125C). To demonstrate some applications, they sintered Cu inks at 230C to form highly conducting copper inks. They also demonstrated a stretchable LED foil together with stretchable Ag inks. It is of course relatively early stage. Cost and volume questions will need to be addressed, paste makers may need to adjust paste formulations for good printing on this substrate, printers will need to learn how to process on this substrate. Nonetheless, this substrate is promising because it can enable more conductive pastes and SMT processes. It is not a solution looking for a problem, and clearly address a market need

Coatema Coating Machinery GmbH has demonstrated exciting developments, showing a pathway ultimately towards autonomous self-optimising coating and printing machines within the next decade or so. As can be seen below, Coatema develops multi-station printing and coating systems, inline integrating R2R slot die coating, inkjet printing, drying, laser processing, intense light sintering, winding/unwinding, etc. The example below is a machine installed at the OET - Organic Electronic Technologies P.C. in Greece. Of course, printing and coating are complex technologies with a large multi-parameter pace. Just some of the parameters are shown below. Therefore, product development and transition from lab-to- fab can be time consuming and challenging since finding as well as maintaining optimal printing, coating, drying, and sintering conditions across such as complex multi-step system can be a significant challenge, particularly for printing multi-layer devices or structures and for lab-to-fab transition. Coatema now integrates multiple measurement points inline within its machinery (see below). The result is millions of data points per minute as output, giving insights at every stage of the process. To make sense of all these data points, Coatema, together with partners Panda, is developing AI algorithms, which, for example, enable automatic identification of the location of the anomalies on the coated or printed surfaces. This automatic AI-based anomaly detection can be done in the time series as well, allowing one to identify the location as well as the time stamp of the anomalous coating or printing step. To identify such anomalies, as seen below, the algorithm is constantly analysing the data coming out of the multi-station fully-integrated printing and coating machines. These developments by Coatema demonstrate the future evolution of printing and coating machinery. This level of insight will enable accelerated product development , optimization and lab-to-fab transition, as well as excellent uniform quality maintenance over large production print runs. From the long-term perspective, it begins to lay the groundwork for autonomous self-optimising printing machines which find and maintain optimal print conditions with little human intervention.

Andy Behr, Technology Manager, Panasonic Electronic Materials andy.behr@us.panasonic.com North America website: https://na.industrial.panasonic.com/products/electronic-materials Visit our virtual booth The simple and direct answer is - because this is how we have always made them. And, for the last 80 years or so, this planar approach has served humanity pretty well. IC chips are flat and rectangular. Circuit boards are flat and rectangular. Displays are flat and rectangular. And we make these things by the millions! However, it’s challenging for designers to create alternative form-factor devices when all the primary functional components available are hard, flat, and rectangular. But, as Bob Dylan sang, the times they are a-changing. Creative companies have realized that there’s an enormous and emerging demand for new form factors across a wide variety of industry verticals. Advances in printed electronics, 3D printing, additive manufacturing, roll-to-roll processing and soft electronics are enabling new devices in sectors as diverse as medical/wellness/healthcare, automotive, aerospace, robotics, extended reality, sports, fashion and more. But there are significant challenges to be addressed. For example, conventional circuit board fabrication and assembly have had decades to optimize the entire manufacturing process and supply chain based on panel formats to create reliable circuit assemblies in a stream-lined and cost-effective manner. The materials used in these processes generally require a high degree of chemical and temperature resistance to survive manufacturing processes like copper etching, multilayer lamination and reflow soldering. It’s clear that, if new form-factor circuits will be manufactured using all or part of the established printed circuit board fabrication and assembly infrastructure, new classes of materials will be required. One way that Panasonic is contributing to this new form-factor evolution is through innovative materials development. Researchers at Panasonic Industrial division headquarters in Osaka, Japan have invented a truly novel polymer technology designed to drive the development of softer, more pliable, and even stretchable electronic circuits. Early work in this field had borrowed commercially available soft and stretchable polymers intended for other applications, primarily thermoplastic polyurethane (TPU) and silicone. While both materials are soft and stretchable, each has significant challenges for use in pliable circuit assemblies. For example, TPUs have generally very low-temperature online streamlined resistance (130°C or less) and suffer from hysteresis (the permanent deformation after strain, such as stretching.) Silicones generally don’t play nice with other electronic materials and addressing compatibility issues can be a headache for designers and fabricators. The proprietary polymer system from Panasonic Electronic Materials features some very attractive characteristics. It has very high-temperature resistance, with a thermal degradation temperature above 300°C. It has a high surface energy and is high-temperature compatible with a wide variety of inks, pastes, films, coatings, and adhesives. It is very soft (a modulus of less than 5 MPa), which makes it attractive for on-body applications or where conformity to complex geometries is required. It’s stretchable up to 200%, has ultra-low hysteresis, less than 0.1%, and can be stretched for thousands of cycles. Panasonic’s first-generation product based on this unique chemistry, branded BEYOLEX, is a transparent film designed for printed electronics applications. It is 100 microns of BEYOLEX film delivered on a PEN carrier with a PET top sheet. The high-temperature PEN functions as a mechanical stabilizer during processing and the PET protects the film during transportation. Packages containing five sheets of BEYOLEX part number MUAS13111AA can be purchased on-line from Digi-Key. More film products and delivery formats based on this polymer system are being developed by the Panasonic research team. At the same time, we continue working with customers and partners around the world on new products unconstrained by the flat and rectangular electronics paradigm. Panasonic Electronic Materials is committed to enabling the next generation of electronic devices that fit our world.

Process for High Energy Li-ion Batteries Speaker: Nicolo Brambilla | Company: Nanoramic Laboratories | Date: 9-10 Feb 2022 | Full Presentation Nanoramic’s Neocarbonix™ at the Core technology enables Tier-I battery companies and automotive OEMs to achieve next-gen battery performance using existing equipment and manufacturing processes. Neocarbonix™ at the Core uses PVDF-free cathode electrodes manufactured with an NMP-free coating process, resulting in environmentally friendly, lower-cost, high-power and energy-dense batteries that are compatible with any cathode chemistry. Neocarbonix™ at the Core is also an enabler of Si-dominant anodes, using a water-based coating process and inexpensive forms of Si. Join TechBlick on an annual pass to join all live online conference or online version of onsite conference access library of on-demand talks (600 talks + PDFs) portfolio of expert led masterclass year-round platform https://www.techblick.com/ Our next battery-related event will take place on 15-16 FEB 2023, covering 1) Solid-State Batteries: Innovations, Promising Start-Ups, & Future Roadmap 2) Battery Materials: Next-Generation & Beyond Lithium Ion The speakers include: General Motors, Graphenix Development, Brookhaven National Laboratory, Fraunhofer IKTS, RWTH Aachen University, Lawrence Livermore National Laboratories, Meta Materials Inc, Skeleton Technologies, Solid State Battery Inc, Argonne National Laboratories, OneD Battery Sciences, VTT, Leyden Jar Technologies B.V., b-Science, Rho Motion, Wevo-Chemie, LiNA Energy, CNM Technologies, Ionblox, Empa, Zinc8 Energy Solutions, Avicenne Energy, Echiontech, South8 Technologies, Basquevolt, NanoXplore, Chasm, Li Metal, Sila Nanotechnologies, Quantumscape (tentative), Fraunhofer ISI, etc https://www.techblick.com/

Silicon photovoltaics (PV) are one of the most important markets globally for printed electronics. This is because each wafer carriers a small of fired screen printed silver paste. Indeed, this could be the largest market worldwide. The chart below- from the indistry roadmap ITRPV 2022- shows the amount of Ag metallization utilized per wafer (both front and back metallization) per watt depending on the type of silicon photovoltaic (monofacial p-type, TOPCon n-type, HJT n-type, etc). It shows that today something around 25-30 tonnes is used per GW of solar for HJT n-type PV and around 12-14 tonnes for monofacial and bifacial types. Considering the size of the PV market, this translates into a 100+ tpa market! As shown in the charts below, screen printing remains the prevelant technology for metallization, despite long-term attempts by other technologies to make even a small dent into this space. In the long term future, other technologies such as plating on seed layer or stencil printing are expected to obtain a small foothold, although we have heard this story too many times already. There are various screen printing techniques. Single print and dual print (finger and bus bar printed seperately in two seperate steps) are the most common techniques. Double printing (print a second layer on an already screen printed already for better aspect ratio) is also popular. The advantage of dual print is that different paste types could be used for fingers and bus bars, giving optimal results. There is of course always a trend to narrow the linewidht of the screen printed lines, whilst maintaing high aspect ratio, excellent ohmic contact, and high conductivity. This has been the direction of development for years. Today, the state of practice in production is a screen printed linewidth of around 34-35um. The industry expects this to evolve to a linewidth of 20um, which is very narrow for screen printing and would represents a real advancement of the art. In the slide below, you can see an example from Fraunhofer ISE (2019) demonstrating a screen printed finger with a linewidth and height of 19um and 18um, respectively. This is, in my view, the state of the art, and requires close collaboration of all those involved from stainless mesh makers, to paste and particle manufacturers, to emulsion makers, and so on. This is an incredibly important market for the printed electronics industry. Outside China, the main particle makers remain Dowa, Ames Goldsmith, Metalor, and Technic. There are many paste makers including Heraeus, DuPont, etc. Of course, given that the market is in China, the supply chain has also been moving there with Chinese suppliers rising in terms of market share as well as technology capabilities. Indeed, their powders and pastes are no longer significantly inferior to the state of the art. To protect market share, others must evolve their particle/powder and paste technology so that it can sustain the roadmap towards ever narrow printed linewidths without a loss in efficiency. This is one of the guiding principles directing technology development. Finally, Fraunhofer ISE publishes an excellent and very detailed annual report on the state of the global photovoltaic industry. As seen below, global production is already a staggering 140+ GW/year with 82% being produced in Asia. To support the scale of this industry, any metallization technology requires to have excellent throughput. The ITRPV 2022 roadmap also outlines the throughput step for the backend steps. It shows that screen printing machines today handle something around 7000 wafers per hour (180 x 182 mm2). This is expected to rise to over 9000 wafers per hour in a decade. This is included here to show the scale of the challenge faced by alternative processes including non-contact technologies such as inkjet.

Rolling nanolithography can take the linewith resolution of R2R lighography even below 1um. This technology, by Meta Inc (Meta Materials Inc) includes a roller around which a mask is wraped and within which a UV light sits. The wrap-aroud mask itself it manufactured using electron beam lithography, giving it very fine features. Therefore, the mask can support, like nanoimprint technology, nano-meter scale features. However, the UV exposure itself may limit feature size to 500nm or 1um range. The current web size is 300mm although Meta is developing technology to scale this to 1200mm webwidths. Here, a step-and-repeat process can be used to create larger rolling masks (note: there might be some 100um wide discontinuities and thus may not be fully seamless, although they are workarounds for this). To achieve single-layer ultrafine line metallizaiton, first a photoresist is deposted and then patterned using the rolling UV mask. Next, a thin metal layer is R2R evaporated (AI or Ag, for example) before creating the final pattern in a R2R lift-off process. Ultra fine features with excellent aspect ratio (300nm/100nm) can be achieved. This is a wide web industrial R2R or R2S process that can print few micron or even sub-micron features on 1.2m wide webs at lenghts of 6 km and at print speeds around 2-10 m/min speeds. The embedded slides show examples of products. On slide 2, you can see the examples of fine feature sizes achieved, putting the technology in the same feature size range as silver nanowires. In slide 3, you can see the demonstration of Al and Ag metal mesh with L/S of 500nm/30um achieving 3.5-5 ohm/sqr at 96% transparency. The bechmarking chart shows that this nanoweb technology can outperform all the other options in terms of its low sheet resistance and high transparency.

(AME/PE) Speaker: Chris Booher | Company: ChemCubed | Date: 10-11 March 2021 | Full Presentation ChemCubed, a U.S. based manufacturer of materials and printing solutions for 3D printing / Additive Manufacturing, will present their ElectroJet brand solutions for AME/PE covering the offerings of materials (silver conductive and dielectric insulating inks), equipment (electroUV3D inkjet printer for electronics), and processes. The multi-faceted portfolio will be highlighted for differentiation in performance, economics, flexibility, compatibility and benefits to key applications and market segments. ChemCubed will also present examples of the ElectroJet brand’s resulting solutions to date by application, further understandings of unmet needs within the industry and emerging technology to address the needs in the future developments of materials and equipment. Christopher Booher Chief Marketing Officer @ ChemCubed Bio Chris Booher holds a BBA in marketing with over 25 years of business experience in the packaging and materials industry and is committed to growing ChemCubed’s leading technologies position in the 3D printing materials market. He has worked with multiple companies from privately owned expansions to Fortune 500s headquartered in the USA and Europe. His experience ranges from full P&L general management, sales and business development for application-specific technologies in paper, films, adhesives, specialty coatings and printing inks. Chris is focused on partnering with customers to fully embrace target driven solutions tailored to each company’s unique end-use applications and needs. Join TechBlick on an annual pass to join all live online conference or online version of onsite conference access library of on-demand talks (600 talks + PDFs) portfolio of expert led masterclass year-round platform https://www.techblick.com/ And do NOT miss our flagship event in Berlin on 17-18 OCT 2023 focused on Reshaping the Future of Electronics. This event attracts 550-600 participants from all the world and offers a superb ambience and dynamic exhibition floor. To learn more visit https://www.techblick.com/electronicsreshaped To see feedback about previous event see https://www.techblick.com/events-agenda

A major challenge in printed electronics is the inability to solder directly on Ag paste (the most common ink and paste material) because no intermetallic layer is formed. With Cu, this can be different. Here, Copprint is showing results, demonstrating that one can directly solder onto their Cu pastes with good shear test results, even if sometimes the wetting is not the best. It also shows how a strong intermetallic layer is formed during the solder, for example, with the standard SAC305 solder on an FR4 substrate. This is an important advancement of the art because it makes printed electronics more compatible with standard SMT processes. Furthermore, the Cu ink is compatible with low-T solders too, enabling one to solder components directly onto a PET substrate with printed Cu lines. In general, Cu inks have had issues in the past. The conductivity has not been high enough, meaning more material is needed thereby eroding their $/Kg advantage vs. Ag. They have also required novel sintering steps with a new learning curve and with new equipment. The data from Copprint suggests that their ink can be sintered very fast and achieve conductivity levels outperforming those of classic Ag suppliers.

Impulse Printing- unveiled and presented recently at TechBlick- seems to be an exciting technology. The technology details are not yet fully disclosed, and the development is still at a laboratory stage, but the disclosed results and claimed performance levels are incredible. As you can see below, the technology can digitally print tracks with resolutions as low as 2um and as high as one millimeter. It can print materials with an extremely wide viscousity range, from 0.1 to 10,000 Pa.S, meaning that it can print copper and silver inks as well as solder and epoxy(!) based conductive adhesives! The technique prints over 3D surfaces, able to print over gaps as short as 1um and as tall as 10mm. This digital printing technique can print sequential as well as simultaneous patterns at high speeds. The diversity in all paramters (resolution, print gap, viscosity of ink or pastes, etc) is very unique for any digital pritning process. Indeed, as shown in the chart belows, each technology occupies a given position in terms of resolution/feature size, viscosity, print gap, etc). Perhaps, as this technology inches towards scale-up, trade-offs will become clear, and not all the reported performance benefits will be satisfied at the same time. The technology is still young and in development. Today, the print area is a small (1x10mm2) but there is a roadmap to scale the tool to be able to print first at 20x20mm2 and then 96x96mm2. Watch this space as the technology will soon be spun out into a start up!

To scale up microLED displays to large areas, smaller displays can be titled. Because microLEDs can be truely edge-less devices, the tiling can function, yielding a seemless look. Each title should house the microLEDs, backplane, as well as driver electrodes. The microLEDs and the backplane sit on the front side of the glass substrate whilst the driver electrodes are tucked away at the back. Interconnects are needed to connect the two. Wrap-around electrodes (interconnects wraping around the edge to connect front and back) is an elegent solution which bypasses the need for a drilled and filled through-glass via. The wrap around electrodes can be printed or PVD deposited (both prefer chamfered glass) . The latter can yield better feature sizes and thin and conductive lines, whilst the former can increase productivity. The below images demonstrate various technologies. Screen printing is a robust solution with low TACT time. Applied Materials has demonstrated that it can screen print very narrow (30um) linewidths over narrow spacings (50um). These are excellent results. Note, by way of reference, that state-of-the-practice/production and state-of-the-art in screen printing of conductive paste on silicon solar PVs are 35um and 20um, respectively. In the process, first the top and botton electrodes are printed before the substrate is rotated (with excellent alignment) to print the electrodes over the edge. This technologies requires excellent machines. Applied Materials has launched a machine able to handle 230x230mm substrate with +/- 6um repeatability and a throughput of 1000pph. Note that optimization of the past and print process are critical. In general, a paste with very high conductivity (20% bulk Ag) with 5B adhesion onto glass will be needed. The target final printed thickness is 3-5um. The screen printing process should yield smooth surface with no peaks near the edge. Aerosol jet is also being proposed for additive deposition of wrap-around electrodes. The advantage of aerosol is that it can print over 3D surfaces and that it can in general deposit fine features than screen printing. To achieve wrap-around electrodes, two half-wrap electrodes must be printed (see below). In between the steps, the glass will need to be rotated. Optomec claims to achieve 18k full-wrap interconencts per hour (excluding the time it takes to rotate the glass). Note that the example below shows L/S 50um although, in princible, aerosol jet can go from down. In general, this is an interesting solution for the microLED market

Flexible Hybrid Electronics (FHE) brings together the best of printed and flexible electronics with rigid Si-based electronics. A critical and often limiting bottleneck is the interconnect between printed (often wide) and Si ICs (often narrow pitches). Normal solder can not easily be used because (1) substrate such as TPU (stretchable electronics) and PET (flexible electrodes) impose severe temperature limitation, often even below bismuth-based low-T solders, and (2) some inks, specially Ag inks, dissolve in solder. Furthermore, these interconnects need not only support the pitch sizes of the ICs, but also survive flexibling as well as stretching, and be compatible with standard industry processes. One option is to deploy particle filled (often Ag particle) epoxies to form the interconnects. Here, unless it is anisotrophic, then the pitch sizes will be limited. Furthermore, particle loadings are often high to achieve high conductivity, adding to cost. Sunray has developed a novel solution: they disperse ferromagnetic particles within a two-part epoxy system. Under an external magnetic field, the particle align vertically, forming z-axis conductive paths. Here, the pitch can be down to 100um. The curing temperature can be as low as 80C, making compatible with TPU and PET. The material can sustain extreme repeated stretching. Furthermore, the process is, as shown below, compatible with standard SMT process. The material can be stencil printed or dispensed. Once the component is pick and placed, a magnetic pallet is used to align the particles before sending the film through a curing step (batch over, reflow, vertical oven) This is an interesting process. It of course lacks the self alignment properties of solder. The ptich is also currenly limited to 100um, which is too wide for many ICs.