EHD is a promising digital printing technology for going beyond the resolution limits of inkjet. Most examples showcase electronic or display related applications. However, in a recent TechBlick talk, as shown in slide 1, Dr Aart-Jan Hoeven showed an example in microfluidics where EHD could delvier value. Here, this technology could enable the electrode widths or pitches to be narrowed from 30-40um (possible with industrial inkjet) to perhaps 1-5um using EHD, thus saving space. This will support the miniaturization trend of microfluidics, making possible to even integrate them into the human body In slide 2 DoMicro BV 's laboratory-scale nano printer can be seen in more detail. It is able to deposit ultrafine features digitally! This DM50-ENP printer is generating significant interest and was developed as part of E-Nanoprint-Pro project Marcel Grooten Lars Wienholts #EHDjet #microfluidics #printedelectronics

Phosphors or QDs for color conversion in LCD and microLED? Which will win? This is an interesting and evolving technology space to watch. James E. Murphy et al from GE Research have developed best-in class narrowband red and green phosphors, and are now evolving the technology towards microLEDs and on-chip integration The red KSF phosphor is an excellent narrow band color converter for wide color gamut displays. It emits 5 peaks, each of which exhibits an ultra narrow 5-nm FWHM. The main peak is centred around 631nm. It is a stable material under high light flux and high temperature conditions. Indeed, it can be on-chip integrated as a direct replacement for existing yellow phosphors. It is a major commercial success with >19 licensees and >40 BILLION (and growing) KFS-containing LEDs sold worldwide into the display industry. As the slide below, presented at TechBlick July 2021, shows, the KFS technology is evolving. At first in 2014, the average particle size was a 25-30um. It is now down to 3-9um and evolving towards sub-micron and even nano-sized particles, enabling direct integration with microLEDs of today and tomorrow! This is an important technology trend because it brings the QD vs phosphor competition even to the microLED space (previously QDs were the only game in town due to their small size) Furthermore, GE's KSF can now be formulated into air-stable inks based on encapsulant-free phosphors suitable for inkjet printing without nozzle clogging. It means that it can be even printed as a color converter atop microLED, in particular allowing one to use efficient blue microLEDs to create red color and/or only transfer a blue microLED color. James E. Murphy offers also an interesting comparison of Cd-free InP QDs vs KSF for microLEDs. It argues that at very thin films (<10um), QDs are more efficient. However, as the layer is thickened, perhaps to prevent blue color leakage, self-abosrption effects can kick-in, reducing the EQE. Thus, it is argued that KSF clearly wins at >20um thickness given that it has no self absorption Finally, here is lack of ultra narrowband green phosphors leaving the space open to QDs. In particular, green perovskite QDs are very strong in this field. However, GE is advancing the development of its narrow-band GREEN phosphors. As shown below, these materials enable 100% DCI-P3. The performance is comparable to Beta Sialon but without cross talk with a KSF red emittesr. Furthermore, it offers 100% HTHH stability, enabling direct on-chip integration. Finally, it apepars to have QE levels approach >90%. Of course, just like KFS, it has a slow PL decay time on the order of 90-450um (QD is ns) To learn more about QDs and microLEDs join TechBlick's event on 30NOV-1Dec: www.TechBlick.com/microLEDs #microled #quantumdots #phosphors #displays #inkjet #miniled Rachel A. Cassidy, PhD, MBA, CLP

Introduction The Internet of things (IoT) relies on continuous data collection from a network of sensors over time. Whilst some sensors can be wired, some must be remote from a power network and should be able gather and transmit their data wirelessly. These wireless sensors need a reliable power source able to remain operational for extended periods of time, ideally for several years. Such a power source must be low-cost, compact, and able to fit into the form factor of the sensor. Power sources for thin wireless IoT sensors are typically based on bulky and non-rechargeable batteries or energy harvesting systems relying on intermittent energy sources such as light, pressure variation, or temperature variation. Rechargeable batteries combined with such an energy harvester would be very appealing in this context to compensate both the discharge of the battery over time and the irregular nature of the energy harvester. Printed batteries offer several advantages including mechanical flexibility, compact dimensions, and low production costs. In the past, several companies have been producing and selling printed batteries, but no rechargeable printed battery solution has been commercialized until now. In this article, we present a novel printed battery solution that directly addresses this challenge. We will discuss its structure, function, specifications, and the multiple possible applications we foresee for rechargeable printed batteries. Printed batteries Printed electronics is an innovative production method offering numerous advantages. It is simple, cost-effective, and environmentally friendly. Components are printed using organic inks made from soluble polymers and particle dispersions. Printing processes such as inkjet or screen printing enable high-volume production at low costs. Different materials such as metals, semiconductors, or dielectrics can be chosen and formulated as printable inks, enabling a variety of different functions to be achieved. These inks can be printed on a large scale, deposited on a variety of flexible or rigid substrates at relatively low temperatures, and subsequently integrated into many industrial or consumer products. Printed electronics is a technology ideally suited for the manufacturing of sensors on flexible substrates. This enables them to be used to great effect in situations lacking the space for conventional sensors. The same printing technology can be applied for battery production. However, it has only recently become possible to print rechargeable batteries. This innovative printable battery technology was developed by Evonik in partnership with InnovationLab. The technology is called TAeTTOOz and has now been acquired by InnovationLab for upscaling and mass production. How it works This state-of-the-art rechargeable printed battery technology is based on redox-active polymers and conventional printing methods can be used to produce thin, flexible batteries that can store electrical energy without requiring metals or metallic compounds in their storage system. Importantly, battery cells produced using TAeTTOOz technology do not require a liquid electrolyte to function, which inherently eliminates the risk of leakage and subsequent hazards. In conventional Li-ion batteries (Figure 1, left), only the small Li+ cations move in and out of the electrodes on either side of the battery in a process known as 'intercalation'. A polymer-based battery works differently (Figure 1, right). Here, both anions and cations move within the electrolyte during cycling. Figure 1: Comparison of the working principles of conventional Li-ion batteries (left) and TAeTTOOz batteries (right). The polymer battery technology relies on redox-active organic molecules (polymers) whose redox states can be reversibly changed during the charging and discharging phases. Essentially this means that the redox polymer can undergo both a loss of electrons (oxidation) and a gain of electrons (reduction), with both processes being reversible. TAeTTOOz batteries have two polymer-based conductive materials that are used as cathode and anode inside the battery, and a third ionic material that functions as a solid-state electrolyte (Figure 2). The cathode and anode materials are optimized to chemically store electric charges supplied from an external power source. This is achieved by a change of their redox state under a given loading voltage during the charging process. Figure 2: Example of 3D structure of a printed rechargeable battery. When a discharge voltage is applied, the initial redox state is reversibly restored, and power can be drawn from the battery. The solid-state electrolyte ensures electrical charge compensation in the battery by means of ionic mobility. Production The inks are water-based and can be formulated to meet customers' specific needs, and do not require the use of toxic or CMR (carcinogenic, mutagenic, or toxic for reproduction) solvents. Due to the non-toxic nature of these organic inks, the printed products are compatible with common waste: Rechargeable batteries that are disposable! To match specific printing needs, these inks are characterized in terms of their particle size, stability and rheology (i.e. flow characteristics). Combining these inks with printed conductive traces on a substrate allows both the batteries and the associated charging and discharging circuitry to be printed in a relatively small number of printing steps. Flexible substrates that can be used include foils made from polyimide (PI), polyesters (PET, PEN) or thermoplastic polyurethanes (TPU). Due to the interesting fact that the battery does not actually hold any voltage prior to its first charge, subsequent production processes such as picking and placing of components are possible without any risk of overvoltage damage. These batteries can be printed from "start-to-finish" on standard screen-printing presses either in a full roll-to-roll continuous production mode or in sheet-to-sheet mode. The lateral dimensions of printed batteries typically range from 1 to 20 cm, and the overall thickness does not exceed 0.5 mm. These batteries can, of course, also be stacked, folded, or rolled to design 3D objects for integration into existing systems. The use of universal printing techniques enables customized batteries in different sizes to be fabricated. The size of printed batteries can vary from a few cm² to several m² with certain performance limitations in the case of extreme sizes. Applications and customization One of the major applications for the TAeTTOOz battery technology is its combination with a sensor or sensor array coupled with one of various energy harvesting components to create a fully autonomous, self-powered unit for IoT applications. The same principle can be utilized in signage or other similar devices. Several 'self-powered autonomous sensor unit' projects are ongoing with our customers and partners, both from industry and academia, in which a printed rechargeable battery is combined with a temperature or moisture sensor is combined with a solar cell, a printed RF-harvesting antenna or a piezoelectric material. This technological concept has already been successfully applied and proven with the use of printed organic photovoltaic (OPV) solar cells. The batteries technical specifications are defined by the chosen layout. Battery capacities from 0.1 to 0.2 mAh/cm² at an operating voltage of 1.2 V are typically achieved. The mentioned capacity and voltage determine the target applications. Obviously, they are too low to drive bright LEDs or heaters but optimal for low-power applications such as the powering of sensors in smart labels and patches. Due to the screen-printing process, there is full freedom of cell design (Figure 3), with vertical or coplanar designs entirely possible. To achieve higher voltages, the printing technology enables several cells to be connected in series (Figure 3, right). For example, connecting two cells in series provides 2.4 V. The number of printing steps remains constant for a coplanar layout and increases in vertically stacked designs. Figure 3: Freedom of design offered by screen printing illustrated by a Peano fractal design (left), and a dual-cell battery design (right) in which two battery cells are connected in series. Reliability and general characteristics Until now, these batteries have been primarily used in demonstration setups and for R&D purposes. The batteries have now been fully characterized in terms of their performance under various loading conditions, with self-discharge and cyclical measurements recorded. The achieved battery capacity is approaching the theoretical maximum achievable with the materials used – currently, it sits at about 70 % to 80 % with printed batteries. The performance and reliability of printed batteries depends on a multitude of factors, including the printing geometry, the printing machine used, the resulting printed layer thickness and reliability, battery configuration, substrate, encapsulation, etc. The cycling stability of the anode and cathode materials exceeds 500 cycles for above 80 % capacity retention, when used as individual materials in button cell batteries. Long term stability crucially depends on the utilized encapsulation technology. InnovationLab will be providing more information shortly, following the full completion of the technology transfer from Evonik. Conclusion Printed batteries are thin, lightweight, and flexible. They can provide a cost-effective solution for industrial wireless sensors and other IoT applications. The new TAeTTOOz technology enables flexible, rechargeable solid-state batteries to be printed on industrial scale, with Heidelberg Printed Electronics as InnovationLabs manufacturing partner. These printed batteries are also notably safer and environmentally friendlier than traditional metal-based batteries. Soon, InnovationLab will supply both the printing materials and the know-how for the design, printing, and characterization of printed batteries. The company will also produce and sell its proprietary range of printed batteries to its customers, enabling the design-in and use of printed rechargeable batteries across industry. About us InnovationLab is the expert for printed and organic electronics with a focus on flexible printed pressure sensors. We provide tailored print solutions for our customers' R&D challenges. Our expertise relies on a solid understanding of materials, processes and printing technologies which are essential for the development of flexible and hybrid electronic systems. Together with our partners from academia and industry, such as BASF SE, SAP SE, Heidelberger Druckmaschinen AG, Karlsruhe Institute of Technology, and Heidelberg University, we continuously expand our portfolio in printed electronics. Our cluster management team coordinates the agile community, consisting of partners on-site and in the extended network. We offer services in the field of research & development, pilot and industrial production as well as consulting and facility management. Here, the main focus is on accompanying customers from their first idea to the industrial production of their product - from LAB-2-FAB. We are able to take over at any stage of development and will lead our customers' products to success in compliance with their individual needs. For industrial production, we have a strong partner on our side in Heidelberger Druckmaschinen AG, which prints sensors in 3-shift operation at its production site

Speaker: Franz Vollman | Company: Heraeus | Date: 10-11 March 2021 | Full Presentation Electromagnetic interference (EMI) is increasingly becoming a problem in design of electronic devices – especially in 5G mobile phones. Higher frequencies, reduced height and real estate in the phone and increasingly dense packaging of sensitive components causes interferences and requires new solutions. To meet this challenge Heraeus now offers an innovative digital system solution based on a particle-free Ag-ink and inkjet printing technology. This provides excellent shielding performance, high thru-put on mass manufacturing equipment, the possibility to apply selective shielding without the need for any masking and thus the most cost effective EMI shielding solution. 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

microLED display technology requires massive parallel transfer technology. This is a complex technology as it is and will grow even more complex as displays with smaller dies and high PPIs are considered. This has been one of the frontiers of development in the uLED industry. Many parallel transfer approaches have been proposed. Most are based on a type of stamp which picks up the microLED dies from the growth substrate and transfers them onto the target substrates, placing them at the right spot. A critical challenge is how to overcome inevitable height and dimensional variations of uLEDs using standard elastomer-based microLED technology, which, if not managed properly, can adversely impact that all-important figure-of-merit: yield! LuxNour Technologies Inc. is proposing a novel approach based on electromagnetic stamps which can - as shown in slide 1- tolerate tens of σ in uLED variation! This increases yield and eases the pressure on exact control of the microLED dimensions during the growth. Join the specialist TechBlick conference on microLEDs on 30-Nov and 1-Dec to learn morewww.TechBlick.com/microLEDs Makarem Hussein in slide one shows the structure of such an electromagnetic head, containing a bulk electromagnetic at the back, a non-magnetic dielectric element in between, and a pattern of high permeability materials (e.g., Ni) and openings. The high permeability areas shield the bulk magnetic, preventing its flux from protruding out. In contrast, the openings represent discontinuities in the shield, allowing the EM force to penetrate out. Slide 2 shows a close up of the structure as well as the resultant magnetic flux In this approach, the microLEDs will also require a layer of metallization with a ferroelectric material. As shown in slide 2, when the magnetic field is on, the microLEDs - regardless of height variations - are picked up by EM force at the location of openings/discontinuities. When the field is off, the dies are released (or placed). Slide 3 shows an example of a100mx100mm stamp on a 150mm Si wafer. Here, the high-permeability material is nickel. This stamp can handle 15um microLED dies with spacing of just 7.5um. This is a very interesting technology with excellent potential. Of course, there is significant know-how and expertise and technology in EM stamp/head development (see patent: ). Furthermore, the microLED wafer manufacturers must adopt their metallization step to depost a ferrous material. Makarem Hussein will join speakers from Samsung, Sharp, AUO, ST, Coherent and many others to discuss the present and future of microLED technology on 30 NOV - 2 Dec - see agenda here www.TechBlick.com/microLEDs

Written by: Tessa Reder and Kate Laing | Voltera Experimenting in the world of Flexible Hybrid Electronics (FHE) comes with a variety of hurdles. Printing technologies are vastly different in terms of materials compatibility and have pros and cons that make them suitable for particular applications. Choosing materials that match the printing technology you intend to use is the most important decision you’re going to make. NOVA, Voltera’s new direct-ink write (DIW), precision dispensing, and 3D printing platform for printed electronics, changes the landscape on which the field of FHE is built. Providing the opportunity to experiment with any screen printable material, and customize and re-design patterns on the fly, NOVA allows a materials flexibility that has never been experienced before. “Additive manufacturing is transforming what electronics are, as well as their role in the world around us. If you want to print on a thermoplastic stretchable elastomer, like a rubbery material, with NOVA — you can do that. And all of a sudden you have an electronic device that has the mechanical properties of the skin. This is something that was never possible before with traditional electronics,” said Matt Ewertowski, Product Manager at Voltera, during a Made in Ontario podcast interview with Professor Gerd Grau, Director of the E-AM lab at York University. As additive electronics technology evolves, researchers like Professor Grau and his group are pushing the boundaries of how the additive manufacturing process can revolutionize the design of products in industries across the board. Professor Grau and Master’s student Yoland El-hajj began exploring the potential of extrusion printing, also known as direct-write technology, to fabricate tattoo electrodes. Existing sensor technology used in the medical industry can be cumbersome, heavy, and uncomfortable for patients — especially when it needs to be worn for long periods of time. Research in printed biomedical tattoos has previously relied on traditional fabrication methods, which are costly and complex, and the majority of the electrode tattoos use organic materials with low conductivity. After identifying this gap in the microfabrication of printed medical electrodes, El-hajj sought to explore the potential for more accessible and efficient microfabrication processes — specifically, extrusion printing. Inkjet and Extrusion Printed Silver Biomedical Tattoo Electrodes is a preprint of El-hajj’s final thesis paper, due to be submitted for publication in a journal later this summer. It examines the quality of biomedical tattoo electrodes fabricated using NOVA and DIW technology in comparison with those made via a more traditional route, like inkjet technology. The two print methods were optimized to print silver-based conductive inks on tattoo paper and the resulting tattoo electrodes were compared by their sheet resistance, impedance, and mechanical performance in terms of bending strain. El-hajj and her team used silver-based inks due to their high conductivity, mechanical robustness, biocompatibility, and cost. Figure 1: Extrusion printed silver tattoo electrode (top) and conventional snap electrode (bottom) The results of El-hajj et al’s research indicates that traces printed using DIW technology have improved sheet resistance and impedance when compared to traces printed using inkjet technology. The proposed mechanism for these differences is because the viscosity of DIW conductive inks is significantly higher than inks used in inkjet technology which are low viscosity and have a relatively high proportion of solvent. DIW inks are therefore not absorbed as readily by the tattoo paper used as the substrate, which allows for more robust electrical traces and improved conductivity in comparison to inkjet inks. “There is a large potential for the fabrication of medical electrodes using printing methods, and with the use of more robust materials. Printing-based techniques can provide numerous benefits for medical sensors, such as flexibility in the materials and patterns and personalization of the sensor structure. In addition, more electrically and mechanically robust materials can be implemented using flexible materials,” says El-hajj. Advancements in additive electronics manufacturing processes are enabling scientists, researchers, and product developers to push the boundaries of electronics innovation, due in part to the variety of materials you can print with and print on. Through experimentation with different materials and applications, NOVA users — including Professor Grau’s research team — are studying and developing additive manufacturing techniques to create a new generation of electronics with transformative potential.

Speaker: Andreas Friedrich | Company: Geely | Date: 10-11 March 2021 | Full Presentation Printed Electronics is one of the game changing technologies that will be a design enabler for future lightweight and smart solutions in many areas of Automotive. In this presentation we look at some of those, with the viewing angle of a designer and see what opportunities they might bring us and what challenges are still left to be solved. Andreas Friedrich Chief Designer @ Geely Design Bio Andreas Friedrich has a long track record in the automotive industry. He has worked with various customers, amongst others 8 years with Volvo Interior design during his 20 years with Consultancy company Semcon. Since 2013 he is part of Lynk & Co Design in Sweden where they design the Lynk & Co cars. There he has been working with Interior Design of the first car and was employed in 2016 as Chief Designer for Advanced Interior. Now he is Chief Designer for New Tech & Innovation and supports the whole GeelyDesign community of brands. As a trained Architect and Industrial Designer he has always had a big interest in New Technologies and how that can be used to enhance the user experience. 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

This is an interesting development in the world of printed electronics introduced by Prof.Ana Claudia Arias from University of California Berkeley at the ePrint Swiss conference which took place a few weeks ago in Buchs, Switzerland. This technology is now being commercialized by InkSpace Imaging As shown in slide one, the basis of this technology are coils composed of a loop of wires (inductance) and four capacitors, two of which are used to match RF power of MRI and two are used to tune for skin frequency. The current non-printed incumbent manufacturing process for commercial coils is based on high-quality electronic components such as porcelain capacitors, thick copper traces (75um or so) and low-loss substrate (e.g., 75-μm-thick Pyralux AP low-loss substrate) The challenge with the current technology is that the current coil arrays are made for adults, as shown in slide two. As such, they do not fit well to the contours of the pediatric body. The misfit adds to discomfort for babies who may have to be subjected to MRI once a week because MRI is the safe option since it does not exposure patient to ionization radiation. Furthermore, the poor physical fit also means a poor signal-to-noise ratio, meaning that long scan times (e.g., 2 hours) will be needed to obtain images with sufficient resolution (note: typical exposure times are 20-30min for adults). This makes it very difficult for pediatric patients in particular who may need to be sedated to prevent motion artefacts These coil structures can be printed on flexible substrates, enabling the coil array to closely follow the contours of the body of the pediatric patient. Slide three also shows how this could be achieved. In one design, the structure consisted of screen-printed Ag paste with micron-sized particles, dielectric (UV curable resin + BaTiO3), Ag paste (30um screen printed) atop a 75-um PET substrate. Here In an improved novel design which simplified the manufacturing process, the PET substrate is replaced with a 75-um PEEK with itself acts as the dielectric. Thus, two Ag pastes are printed on each side. Here, the ere is no need to print and cure (UV +heat) the dielectric layer (UV curable resin + BaTiO3 ink) In all cases screen printing is deployed because thick layers with high conductivity must be printed over large areas at low cost. Now the question is how does this printed coil system perform? The Q-factor is an important figure-of-merit. The Q-factor for the standard technology however is at first glance much higher than the printed version (400 vs 25?). However, in reality, when the non-printed coil comes into contact with the body, the coupling causes a huge loss of the Q-factor, reducing the gap between the printed and non-printed versions Furthermore, now the key advantage of printed solutions comes into play: flexibility. This means that it can sit much closer to the body of the baby. As shown in slide 4 the relative SNR (signal to noise ratio) drops as the distance to the body increases! This means that the solution sitting closer to the body- even when it has a lower Q-factor- can offer a superior performance!! This is a wonderful and clever solution, solving a real problem with the key benefits and unique value propositions of printed flexible electronics The results of this study were published here https://www.nature.com/articles/ncomms10839

Printed electronics and power electronics? There is a direct link via die attach materials. Indeed, this is a success story but as with many other such stories in printed electronics, it gets called something else once it reaches the market. So what is this story? Many die attach systems in power electronics (IGBT Mosfets, SiC, GaN, LEDs, etc) continue to use solder. Thanks to wide band semiconductors *WBS), the trend is towards ever higher areal power densities which translates into higher junction temperature. Indeed this shift to WBS means that the semiconductor is no longer the limiting factor, but the packaging materials. One such material that falls short is lead-free solder. At operating temperatures like 175C (target is 200C and beyond), the max temperature of the solder should be 265C if the homologous temperature is to be 50% or less. The first slide below shows that lead-free solders do not have a high enough melting temperature. The common SAC solder falls clearly short. AuSn or SnAgSb might be options, but even they are forced to operate near their limit. To solve this shortcoming, sintered metal die attach materials (Ag and Cu) offer a good alternative. The table in slide 2 table shows that sintered Ag (also Cu) has a bulk-like melting temperature, enabling very high operating/junction temperatures. The thermal conductivity – depending on the sintering- can be very high, even much higher than AuSn. The technology is already commercial for many years in places like Tesla cars (Ag sintered die attach on SiC power electronics). It is a market that will grow as electrification of the vehicles continue apace. It will also be boosted further as GaN power amplifiers gain a foothold in 5G communication infrastructure. The sintered metal can be applied in different ways. In the printed case, the die attach paste (containing Ag or Cu particles) can be stencil printed or screen printed or dispensed. For ‘pressured’ versions, the most common approach is to screen print the paste, pre-dry it, position the die and pre-heat the substrate, and sinter under pressure. The target is to form a strong adhesion and to form a bondline free of voids and as much solid-like as possible. This is why sometimes external pressure is applied to squeeze out all the voids and form a compact solid-like bondline. In another technique a dry film can laminated onto a wafer. The dies are therefore picked with the die attach already applied. Alternatively, one can using a dry film This technology has come a long way. There are now many pressure-less versions with also rapid sintering. Both nano and micorn sized particles are used. The technology also now gives good bond strength even on non-matching surfaces (e.g., applying Ag die attach on a Cu surface). Nonetheless, it is still not a full replacement for lead solder The chart in the final slide is an excellent study recently published by a DA% Consortium offering a real benchmarking based on tested results. Thus, the technology wins when lead can not be used, the costs can be tolerated, and lead-free solder falls short. However, it still has room for improvement to match the best in class of lead-based solder Join www.TechBlick.com to learn more

microLEDs can be directly integrated with CMOS drivers (instead of usual TFT backplane) enabling high-PPI displays suited to AR/MR glasses, metaverse, and even in some cases large-area displays. The key technological challenge for this is the hybridization and/or monolithic integration of GaN microleds and CMOS. This is no easy feat as it involves heterogenous hybridization or integration of two different material systems: GaN and Si. Over the years, several technologies have been proposed by companies and institutions to hybridize the two parts. They are ranging from hybridization techniques to full monolithic 3D integration. These options – explored from over the last decade from 2011 to 2022- are depicted in the slide below, which offers a clear categorization of the techniques, e.g., hybridization vs monolithic integration, direct vs indirect bonding, align vs non-aligned, etc. In this presentation, François Templier from CEA-Leti will review these techniques and explain challenges for their fabrication at TechBlick's specialist event on microLEDs on 30NOV-1Dec www.TechBlick.com/microLEDs . Some examples of solutions will be given, such as microtube technology and recent results with hybrid bonding. More info www.TechBlick.com/microLEDs

Manufacturing in particular mass transfer and repair remain the biggest challenges in realization of microLED displays. To simplify the process, many propose to transfer only the blue (or even a UV) LED and achieve RGB by depositing color converters such as quantum dots. This requires an additional deposition step. But what if one could achieve chip-scale monolithic integration of QDs and GaN microLED chips? Indeed, Saphlux proposes just this and will present this on 30Nov-1Dec 2022 at TechBlick's microLED and QD event www.TechBlick.com/microLEDs Saphlux has taken this approach one step further. Instead of post-transfer deposition of QDs, their technology enables chip-scale integration of quantum dots and microLEDs. In this technique, a nano-porous structure is directly formed inside LEDs to serve as a natural vessel for in-situ QD integration. The effective light path can be extended by nano-porous structure to boost the overall efficiency due to the strong scattering effect. The reliability of quantum dots is - it is claimed- also improved greatly because of the high thermal conductivity of gallium nitride material. Importantly, this technology claims to be able to integrate red, green, and blue pixels monolithically into a single chip to greatly reduce the complexity and cost of Micro-LED display manufacturing. In this technique, nanopores in LEDs can be created by dipping the material in an acidic solution and applying a bias voltage, which drives electro-chemical etching of n-type GaN. By adjusting the etching voltage, one can change both the porosity and the size of the nanopores. Then the blue LED are bonded with exposed nanopores GaN to a current-driver panel and red/green QDs are selectively loaded to achieve Micro-LED full-color conversion. Saphlux will present this on 30Nov-1Dec 2022 at TechBlick's microLED and QD event www.TechBlick.com/microLEDs

Holst has developed and advanced the so-called LIFT technology to enable even the laser transfer or laser printing of microcomponents such as microLEDs with high 1-um precision. In the first slide you can see a comparison of the classical Laser Induced Forward Transfer (LIFT) vs the technique developed at Holst which is Volume-Controlled Laser Printing (VCLP). In LIFT, the laser illumination causes a jetting of low to medium viscosity inks onto the acceptor or target substrate. This is not a young technology and some consider it the digitization of screen printing. In the example here you can see 200um dots of conductive paste printed with the LIFT process. The VCLP is different. Here, the laser releases fine droplets onto the target/acceptor substrate. Given the volume control, better resolution is accessible. The example herein shows 40um dots of highly viscous solder paste printed using VCLP technology. Note that here the high-throughput deposition of ultrafine interconnects, such as conductive adhesives and solder pastes, is from a structured carrier plate covered with a proprietary permanent release coating An important feature of the VCLP technique is the control of heat flux. Without this the laser printing can result in blurred or poor definition. To manage the heat flux, Holst has developed a proprietary “permanent” stack for clean, fine interconnect printing. In the second slide, you can see the positive impact of this layer in achieving well defined high resolution laser printing What is amazing is that not only inks and pastes (also adhesive and solders) can be printed, but also microcomponents such as microLED dies. In the schematic in slide 3, you can see the concepts. Here, the microLEDs sit on the proprietary “permanent” stack and are then laser released across the print gap onto the acceptor/target substrate. The dies can be <10um with a <5um dicing street. This technique can reach >10M UPH (units per hour) with 1um assembly accuracy The final slide shows examples of mini as well as microLED transferred using this technique. The mini LEads are 125x125x80 um3 and the microLEDs are 60x60x10 um3 This are incredible results and points towards a new high throughput laser printing technique able to print finelines of inks as well as highly viscous pastes, and mini and micro components To learn more you can either join us onsite at the High Tech Campus where the Holst Centre is also located on 12-13 OCT 2022 and join our microLED event online on 30NOV-1Dec where this technology will be presented https://www.techblick.com/electronicsreshaped www.TechBlick.com/microLEDs