» PCB & ASSEMBLY Despite the effects of the filler, the thermal conductivity of glass-reinforced materials is limited by the nature of the glass. For highest thermal conductivity, the dielectric may simply be a layer of unreinforced resin. This demands critical control in manufacture to maintain a consistent dielectric thickness, whereas the glass fabric provides a natural mechanical spacer. Note that whatever the proportion of ceramic filler, and with or without glass reinforcement, the resin must retain its ability to reliably bond the baseplate and circuit foil and withstand potentially Zusammenfassung Ein entsprechendes Wärmemanagement ist erforderlich, um die Zuverlässigkeit von Komponenten zu gewährleisten, die eine erhebliche Eigenerwärmung aufweisen wie z.B. LEDs in Beleuchtungsanwendungen sowie IGBTs und FETs in Stromversorgungen, Umrichtern und Motorantrieben. Im ersten Artikel einer zweiteiligen Serie wird untersucht, wie IMS dazu beitragen kann, die Wärme in Baugruppen mit Leistungshalbleitern und LEDs zu kontrollieren und abzuführen. Résumé Une gestion thermique appropriée est nécessaire pour garantir la fiabilité des composants qui présentent un auto-échauffement important, comme par exemple les LED dans les applications d’éclairage, ainsi que les IGBT et les FET dans les alimentations électriques, les convertisseurs statiques et les entraînements à moteur. Le premier article d’une série en deux parties examine comment l’IMS peut contribuer à contrôler et à dissiper la chaleur dans les sous-ensembles comprenant des semiconducteurs de puissance et des LED. Резюме Чтобы гарантировать надежность компонентов, подверженных значительному самонагреванию, например, светодиодов в осветительных системах, биполярных транзисторов с изолированным затвором и полевых транзисторов в источниках питания, инверторах и электроприводах, требуется соответствующее регулирование теплообмена. В первой статье серии из двух частей рассматривается вопрос, как изолированная металлическая подложка может помочь в контроле и отводе тепла в компонентах с силовыми полупроводниками и светодиодами. severe thermal cycling conditions. In general, the reinforced dielectrics have lower thermal conductivity and higher breakdown voltage. Another basic difference between reinforced and non-reinforced dielectrics is in their mechanical bendability, which allows post-forming of the substrate into three-dimensional shapes. This can help in applications such as automotive LED lighting, giving the opportunity to combine several elements into a single fitting while also simplifying the design and final assembly. Choosing optimal IMS properties By managing these variables – resin composition, glass reinforcement, dielectric layer thickness, baseplate material, and baseplate thickness – IMS manufacturers can present a portfolio of materials that offer various combinations of properties; particularly thermal performance, reliability, and cost. The image BILD2 compares the specifications of Ventec’s ‘tecthermal’ family of thermally enhanced substrates. They cover thermal conductivity values ranging from 2.2W/m.K to 7.0W/m.K, which compares with 0.3W/m.K for standard FR4 material. The diagram includes the non-IMS substrate VT-5A2, which has thermal conductivity eight times better than FR4 and is aimed at cost-sensitive applications. Typical maximum operating temperatures for insulated metal substrate laminates are about 130°C. Certain glass-reinforced grades can be as low as 90°C. High-Tg thin laminates and prepregs are available, capable of operation up to 150°C. A simple and effective solution An IMS can be a simple and effective solution to thermal management challenges, particularly in systems containing power semiconductors and LEDs. The opportunity to dissipate large quantities of heat energy through the substrate helps ensure reliability while at the same time permitting a space-saving solution. Depending on the application and operating conditions, IMS also helps design without components like heatsinks and other cooling devices such as a fan. Various combinations of dielectric composition, baseplate material, dimensions, and circuit foil give IMS products a wide range of thermal – as well as electrical and mechanical – properties. These give designers a broad scope to optimize the characteristics to suit their application. http://www.venteclaminatescom 30 EPP Europe » 04 | 2023
Product Updates « PCB & ASSEMBLY New oven minimizes maintenance in high solder paste reflow applications Vitronics Soltec introduces reflow oven upgrade Vitronics Soltec, brand of ITW EAE, has released a new reflow soldering oven that it says addresses the unique challenges facing high solder paste customers. The Centurion+ is an upgrade of the Centurion with features that further minimize maintenance and keep the process chamber cleaner. “In applications that require a high amount of solder paste, the amount of maintenance required increases,” the manufacturer explained. “To address this challenge, the new system features greater accessibility to components that require maintenance. Easily removable blow boxes with removable side plates make cleaning easier in the cooling area. Easily removable baffle boxes on infeed and outfeed reduces downtime for cleaning.” The machine can be configured with Ultra Cathox to handle more than 50 kg of solder paste per week. This reduces maintenance requirements while keeping a clean process environment. It is very effective in removing volatile compounds from the process tunnel during reflow. In thermal oxidation, or- ganic vapors are converted to hydrocarbons, which are captured by a filter. The design also ensures that when maintenance is required, users have easy access and can do the maintenance job with few tools required. “We designed the Centurion+ with considerable input from our customers to make sure we were addressing all of their needs,” said Coco Zhang, ITW EAE Reflow Business Manager. “We have a strong relationship with the world’s leading manufacturers and work directly with them to identify areas that need further innovation.” With the best heat transfer in the industry, the Centurion is able to run any profile at the lowest set point possible, which minimizes the thermal differences over the product and uses less energy. www.itweae.com The company says the new oven offers easily removable blow boxes with removable side plates make cleaning easier in the cooling area Source: ITW EAE Quick-turn soldering processes Mechnano develops ESD high-temp 3D-printable resin Arizona-based manufacturer of parts with discrete carbon nanotubes using vat photopolymerization system Mechnano, has announced it has developed a new high-temperature, rigid ESD material in partnership with Tethon3D. The resin can be processed on a variety of vat photopolymerization systems (SLA, DLP, LCD). The vat photopolymerization process allows for Quick-Turn part fabrication with ultra-high accuracy, Nano- Uniform ESD and exceptional surface finish, while taking advantage of custom 3D-printable design freedom. The electronics industry can be more agile when handling bespoke customer requests by using additive manufacturing (AM), commonly known as 3D printing, to fabricate ESD parts to support the reflow process. Arizona-based Mechnano uses AM to help electronic manufacturing service (EMS) providers reduce cycle time, increase throughput, and ensure Nano- Uniform ESD protection. The resin can be processed on a variety of vat photopolymerization systems (SLA, DLP, LCD) Agility is essential for customer-specific applications that require a variety of nonstandard components for low-volume production runs. Customers often request custom carriers/pallets to hold printed wiring assemblies during the reflow process. These carriers must protect today’s micro-electronic components from electrostatic discharge and withstand multiple cycles of a high-temperature wave soldering process (245°C). Source: Mechnano Using traditional manufacturing technologies for fabrication of these components can slow down production and increase cost, while using the traditional carbon fiber filled materials in these components does not protect today’s electronics. The challenge is quickly fabricating custom Nano-Uniform ESD components that would withstand numerous thermal cycles. Mechnano, in partnership with Tethon3D, has developed a new high-temperature, rigid ESD material to meet this challenge. The resin can be processed on a variety of vat photopolymerization systems (SLA, DLP, LCD). The vat photopolymerization process allows for Quick-Turn part fabrication with ultra-high accuracy, Nano- Uniform ESD and exceptional surface finish, while taking advantage of custom 3D-printable design freedom. mechnano.com EPP Europe » 04 | 2023 31
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