Conductive Inks: Power Electronics, EMI Shielding, In-Mold Electronics

Dr Khasha Ghaffarzadeh
Conductive Inks: Power Electronics, EMI Shielding, In-Mold Electronics
Every year IDTechEx Research publishes an article that reflects the latest trends in the conductive ink industry. These articles are based on IDTechEx Research's report Conductive Ink Markets 2019-2029: Forecasts, Technologies, Players, which is the result of ongoing research over the past eight years. This year IDTechEx will give an update on multiple less mature trends which offer high growth potential.

Power Electronics

A generational shift is taking place in power electronics. New semiconductor technologies such as SiC and GaN are enabling smaller and more integrated devices capable of handling higher power density levels. With these, the bottleneck against higher temperature operation is not the semiconductor device but the packaging material.
A critical packaging material is the die (and to a lesser extent substrate) attach. The push towards higher temperatures has, in some cases, already pushed solder, the incumbent, to or beyond its performance limit, creating the need for an alternative. The need to sustain the roadmap towards higher temperature will only aggravate the challenge.
Sintered metal pastes have emerged as a compelling proposition. They increase the thermal conductivity and the melting temperature, allowing devices to reliability operate at higher temperatures. This technology is already in commercial use after some seven years of development and its markets will expand as the shift towards new semiconductor technologies further accelerates.
Sintered metal paste technology is improving. The development targets are to achieve rapid low (or zero) pressure sintering of ever larger surface areas and to narrow the significant price differential versus SAC solder. There is innovation in the material system.
Ag is dominant but promising Cu alternatives have also emerged with friendlier sintering conditions. Nano or hybrid (nano + micron) are positioning themselves as alternatives to traditional solutions based on micron-sized particles. The short-term promise is to lower the sintering temperature whilst the long-term one is to eliminate it altogether. Suppliers are also diversifying the product form factor, moving beyond just screen or stencil printing, to make the product more of a drop-in replacement. Machines makers are now offering turn-key solutions, integrating the pick-and-place, the drying, the pressure sintering units. To learn more please visit Conductive Ink Markets 2019-2029: Forecasts, Technologies, Players this report provides a detailed analysis of this growing field. It offers a detailed review of need, the technology and its competitors, the application landscape, and the key global product developments. It provides a complete coverage of all the key existing and emerging players and their offerings worldwide. It develops short- and long-term forecasts for metal sintered die attach pastes in electric vehicles, which is a growing market.
Examples of various applications covered in this article. Sintering: top image shows an IGBT module for a list system utilising Ag sintering; 2nd from top image shows the SiC inverter used in Tesla which utilizes silver sintering; 3rd from top image shows cross-sections of various sintered joints, and 4th from top shows various form factors by which the sintering paste is being offered. Conformal metallization: top image shows spray coated packages with Ag metallization; 2nd from top shows cross-section of spray-coated metallization using three different particle morphologies; 3rd from top shows jetted solutions for in-package insolation; 4th and 5th from top shows two examples of aero top sol-metallized antennas and an automotive LED headlamp. Forming and Stretching: top set of images show various products and prototypes made using in-mold electronics for the automotive and consumer electronic industries, and the bottom set shows products and prototypes of e-textiles made using stretchable inks. Fine-feature printing: top images shows hybrid photopatterned approach to narrow line width; 2nd row shows hybrid embossed approach to narrow linewidth; 3rd row shows direct printing demonstrating <1um; and final line is using stencil printed bump metallization of low-T chip attach. Here the trend will be towards finer pitch together with fine pitch circuit metallization. IDTechEx have taken many of these photos at various conferences and tradeshows worldwide. Companies whose work is shown include Optomec, Ntrium, Henkel, DuPont, Danfoss, Tesla, Alpha Assembly, Toyobo, TaktoTek, Asahi Kasei, Komura-Tech, Toray, O-Film, Dowa, Bando Chemical, GIS, Fujikura Kasei, MNTech, ConnecTech, J.W. Speaker, Atra Plastics, and others. For more information on all these examples and many more examples across many applications areas please visit Conductive Ink Markets 2019-2029: Forecasts, Technologies, Players

In Mold Electronics

This remains a highly promising technology. The production learning curve is still challenging and the concept-to-mass production flow is not yet routine and well-established. Yet, a wave of products is arriving in the market, e.g., curved defrosters for automotive LED lighting, wearable patches, etc. IDTechEx Research analysts continue to monitor this space closely and feel that the market is not far off its inflection point (estimated as 2021-2022).
Indeed, at IME-enabled product level, IDTechEx estimate that the market will exceed $250M by 2024. This translates into opportunities for paste markets. Some suppliers have engaged strongly with this trend, putting themselves in leading positions in terms of customer relationships and feedback, product qualification advances, and product performance and customization ability. There is still however room for innovation. The general direction of improvement remains towards better stretchability, kinder and faster curing conditions, stronger adhesion, and is an excellent match with all the other stack materials such as dielectrics or graphics inks. The report from IDTechEx Research Conductive Ink Markets 2019-2029: Forecasts, Technologies, Players provides a full analysis of the IME landscape, identifying latest prototypes and products, covering latest players around the world, assessing key technical and commercial challenges, and offering short and long term market projections at the level of IME product and conductive inks.

Conformal conductive coating

This is a diverse and promising space. In one manifestation, spray-on inks are targeting package-level EMI shielding. Here, they hope to displace sputtering, the incumbent, which benefits from sunk CapEx and lower material consumption costs. They offer low CapEx production in atmospheric conditions and better conformal coverage. Others are developing inkjet printing solutions, highlighting the ability to control thickness uniformity and to deposit only on required areas. Jetted or dispensed inks are also being proposed for in-package EMI isolation between individual dies in a multi-die package especially for high-frequency devices. These are hot growth potential in which the decisions are being made today. In particular, the expected rise of multi-IC packages with embedded antennas targeting 5G will fuel demand for package-level shielding. Indeed, the transition from board- to package-level shielding is a megatrend that will stay.
Suppliers are differentiating on multiple fronts. First is performance. Here they experiment with different ink types. Some propose micron-sized, prioritising cost and maturity. Flat flakes offer higher conductivity if aligned well. Others develop nano or even particle-free inks, offering to offer the thinnest solution with the best adhesion and shielding properties. Most offer a hybrid solution, sitting somewhere between full nano to full micro and full spherical to full flake type.
This may not be enough. Suppliers are taking steps to make it as easy as possible to adopt the product. Some position as possible full solution providers, integrating their inks with curing units to minimise customers' learning curve and adoption barriers. Some go even further, proposing mechanisms to fine-tune layer thickness post-deposition to locally boost performance in EMI hotspots. In general, this continues to be a dynamic and rapidly evolving area.
There are further manifestations of conformal printing. Aerosol has had some success in the past, but some products have reached their end of life. Here we are seeing new inks emerge which offer ultra-low temperature curing with strong adhesion making more substrate materials compatible with aerosol metallization. To learn more please see IDTechEx's Report Conductive Ink Markets 2019-2029: Forecasts, Technologies, Players it provides a detailed analysis of conductive inks related developments in EMI shielding and other conformal printing techniques, identifying and covering players worldwide, examining latest application and adoption trends, offering insights about challenges and future opportunities, and providing market forecasts.

Fine feature printing

This is a general development trend that has enabled many applications. This trend will continue. In one example, fine feature printing allowed conductive inks to stay relevant in the touch screen edge electrode business as bezels narrowed. Here, hybrid (additive + subtractive) techniques were deployed. In a similar area, fine feature printing is enabling invisible metal mesh touch film printing. Here, direct printing methods have shown as technology demonstrators ultranarrow features below <1um. These techniques will target application beyond touch films including security printing, fine TFT electrode printing, and so on.
In parallel, hybrid flexible electronics (FHE) is becoming viable. By FHE we mean integrating rigid electronics with and/or on flexible parts. It is becoming viable (a) because ultrathin and flexible packaged complex ICs with high I/O pin count are becoming available, and (b) because ultralow temperature solder compatible with low-temperature substrates are being introduced. This trend will require fine-feature printing to metallize the circuit pattern on the flexible substrate whilst maintaining compatibility with the I/O pin spacing of complex IC packages.
There are other aspects of fine-feature printing. To learn more please see IDTechEx Research report Conductive Ink Markets 2019-2029: Forecasts, Technologies, Players. It provides a comprehensive global review of all the player developing various direct or hybrid approach to fine-feature printing for a variety of applications.
This report is based upon eight years of truly global research. It provides the most comprehensive and authoritative view of the conductive inks and pastes market, giving detailed ten-year market forecasts segmented by application and material type. The market forecasts are given in tonnage and value at the ink level. It also provides a detailed assessment of more than 25 application sectors, including all the key emerging applications sectors. For more information please look at Conductive Ink Markets 2019-2029: Forecasts, Technologies, Players.
Top image: Henkel