This paper compares the thermal cycling performance of a quad flat no-lead (QFN) component and three different ball grid array (BGA) components assembled onto printed circuit board test vehicles of 4 different thicknesses from .040 to .125 inch thick that are otherwise identical for IPC 9701 test profiles of 0/100 ºC (TC1) and -40/125 ºC (TC3). Additionally, a limited comparison is provided for SnPb eutectic and SnAg3Cu0.5 (SAC305) Pb-free solders. The test results tend to support the improved reliability with thinner boards, but the correlation between PCB thickness and thermal cycling results are not always consistent or predictable. There are only a few cases where the reliability decreases monotonically with increasing board thickness as anticipated.

This Slide Show Utilizes the Cover Paper from the session.

This slide show discusses the use Power harvesting in conjunction with a typical battery and the efforts to manufacture this technology.  Many devices and sensors that would benefit from power harvesting are very small and located in harsh environments, such as inside the human body.  The Slides discuss some of the basics of how power harvesting can be achieved and calls for collaboration with the PCB industry.  

This slide show discusses inverters and power electronics for Heavy Machinery.  There is discussion of Wide Band Gap Powered Devices.  The purpose is increased efficiency gains.  A new material, silicone carbide, is discussed.  The capabilities of this material is presented.   

This Paper utilizes the introduction from the session as its paper then discusses Wide Bandgap Power Electronics 

All electronics products need a power source. Thereby power electronics has a fundamental impact on their design and integration, from materials and device up to systems and the applications they serve. They do this via a number of different paths, whether it be driving the bleeding edge of system size, weight, and power (a.k.a. – SWaP) specifications or determining the viability of battery-powered applications from autonomous vehicles to Internet of Things (IoT) little gadgets. The success of a system or product deployment is not only heavily dependent on the integration of intelligent power management (IPM) and shrinking size of its power supplies, but also how those power solutions interact with system loads and energy storage to optimize utilization for energy efficiency.

The session comprises three papers presenting a wide overview of the electronics market as seen through the lens of power electronics by focusing on three major areas of coverage, namely ‘power IoT’, energy storage and smart mobility, focusing primarily on IoT but the concepts and consideration being broadly applicable to a broad range of applications. Having a finger on the pulse of where power electronics industry stakeholders are headed is essential to maintaining a view on the horizon for what is technically achievable to form realistic expectations of application-driven marketing projections.

From automotive to semiconductor manufacturing, the bottlenecks for what is achievable are typically gated by power supply component size, form factor, and weight. From the perspective of power electronics, this mostly boils down to the power supply topology chosen, which can dictate switching frequency and therefore the minimum electrical/thermal requirements for key, passive components such as magnetics and capacitors. Given the broad range of skills, experience and expertise of the target audience, the technical details regarding things like topology selection and lower-level requirements will be abstracted into far simpler project requirements and drivers that directly impact passive component physical characteristics (e.g. – SWaP). The presentations attain to insight on how to translate seemingly complex power supply characteristics and bleeding-edge application needs into relatable information for their own area of focus, which can be brought back to teams and easily communicated to a broad range of stakeholders.

All electronics products need a power source. Thereby power electronics has a fundamental impact on their design and integration, from materials and device up to systems and the applications they serve. They do this via a number of different paths, whether it be driving the bleeding edge of system size, weight, and power (a.k.a. – SWaP) specifications or determining the viability of battery-powered applications from autonomous vehicles to Internet of Things (IoT) little gadgets. The success of a system or product deployment is not only heavily dependent on the integration of intelligent power management (IPM) and shrinking size of its power supplies, but also how those power solutions interact with system loads and energy storage to optimize utilization for energy efficiency.

The session comprises three papers presenting a wide overview of the electronics market as seen through the lens of power electronics by focusing on three major areas of coverage, namely ‘power IoT’, energy storage and smart mobility, focusing primarily on IoT but the concepts and consideration being broadly applicable to a broad range of applications. Having a finger on the pulse of where power electronics industry stakeholders are headed is essential to maintaining a view on the horizon for what is technically achievable to form realistic expectations of application-driven marketing projections.

From automotive to semiconductor manufacturing, the bottlenecks for what is achievable are typically gated by power supply component size, form factor, and weight. From the perspective of power electronics, this mostly boils down to the power supply topology chosen, which can dictate switching frequency and therefore the minimum electrical/thermal requirements for key, passive components such as magnetics and capacitors. Given the broad range of skills, experience and expertise of the target audience, the technical details regarding things like topology selection and lower-level requirements will be abstracted into far simpler project requirements and drivers that directly impact passive component physical characteristics (e.g. – SWaP). The presentations attain to insight on how to translate seemingly complex power supply characteristics and bleeding-edge application needs into relatable information for their own area of focus, which can be brought back to teams and easily communicated to a broad range of stakeholders.

Driven by the demand for advanced electronic devices where massive wireless data transfer is required, a new generation of communication system, so called 5G has been developed. This new technology isnow fully introduced to the market and will continue to rapidly expand due to very high demand. One of the key features in this technology is the capability of devices to transmit high volumes of data in high frequency bandwidth. Given the nature of the path of the electronic signal in highly conductive medium such as copper, as the signal frequency increases, the impact of the conductor roughness and the so called “skin effect” results in an increase of resistance. This brings a greater risk of compromising the signal integrity due to increased signal loss; in order to minimize the signal loss, it is highly desirable to keep the conductor profile as smooth as possible. This is considered as an absolute requirement. Therefore, the previous technique of creating adhesion between conductors and dielectrics by surface roughening is not suitable anymore. The ideal way to overcome this challenge would be to use a bonding enhancement system which does not require surface roughening. This study demonstrates the development of a novel surface treatment system for copper which can meet all of the challenges of electronic devices manufactured for high frequency applications. The surface treatment systems introduced here adopted the use of a subsequent treatment of organic coating, a so called “adhesion promoter” on top of pre-cleaned copper surface, to provide the strongest possible bonding strength. As a result,significant improvement of adhesion between copper conductor and lamination material can be obtained at very low surface roughness. This can be explained by the increased contribution of chemical bonding provided by the organic coating. Furthermore, superior thermal reliability can also be achieved. Since a minimal surface roughness has been created by the process, a significantly lower signal loss could also be obtained. The system introduced here offers the best approach for surface treatment process of high- speed IC substrate manufacturing.

Key words High frequency, skin effect, adhesion promotor, signal integrity, IC substrate

The electronic packaging industry is undergoing a revolutionary convergence between the printed circuit board segment and the semiconductor packaging segment. New, streamlined and hybrid package architectures are emerging to meet future product requirements – particularly for mobile electronics and infrastructure to support industry megatrends like 5G. There are new challenges for forming electrical interconnections between different types of package elements while maintaining high volume manufacturability and reliability.

In particular, the use of high speed and high frequency dielectric materials complicates the PCB fabrication process. Generally, these low loss and low Dk materials are not amenable to multiple lamination cycles due to the nature of their chemistry; however, conventional PCB fabrication techniques that circumvent this problem by using plated-through-holes introduce undesirable resonance structures and consume precious real estate that could otherwise be used for routing.

Transient liquid phase sintering (TLPS) paste vias can be used to either augment or replace sequentially formed plated microvia interconnects, which necessitate multiple lamination cycles, as well as plated-through-holes (PTH) with their attendant loss of routing density and lossy stubs. TLPS-filled z-axis interconnect layers can be fabricated in parallel with individual x-y trace layers or PCB subconstructions of multiple layers with PTH, interleaved, and laminated in a single cycle. The circuit layers thus electrically joined through the z-axis can be of the same or different materials, complexity and native construction. The adhesive surrounding the TLPS interconnects and mechanically joining the circuit layers can be prepreg or film adhesive and be selected for its adhesive, dielectric and mechanical characteristics. With an appropriate adhesive layer, the TLPS z-axis interconnect concept is extendable to applications outside of PCB construction including area array assembly and thermal transfer.

TLPS pastes, which metallurgically bond to circuit pads, offer both high performance and versatility of installation that is conducive to high manufacturing volumes. Because sintering pastes can be formulated with a variety of particle sizes and flow behavior this technology can provide a spectrum solution to applications from filled microvias in either a printed circuit board or semiconductor package scale, to printed bumps for interconnection of subassemblies, to thermal interfaces with embedded heat sinks.

This paper will present the two most common implementation flows for the installation of the TLPS paste z-axis interconnects in mixed mode PCB constructions.

In many aerospace and defense systems, there are increasing demands for multi-functional adhesive solutions that not only fulfill the traditional role of component and assembly bonding, but also offer additional features to address electrical and thermal requirements to improve device reliability. Developing robust adhesives that encompass all these characteristics can be quite challenging.

Broad adoption of wide-bandgap (WBG) semiconductors (i.e. gallium nitride (GaN), silicon carbide (SiC), etc.) combined with diverse accessible heterogeneous integration (DAHI) technologies are transforming power electronics system design and assembly processes. The power requirements of these systems -- especially military electronic systems such as surveillance, airborne multifunction radars, communication systems, directed energy systems, etc. are increasing dramatically. Consequently, the necessary heat dissipation of such electronic devices has already reached several thousand watts/cm2 at chip level and is projected to grow exponentially. While already a critical element of system design, heat management has become even more important as power densities rise.

This paper presents a multi-functional solution for assembling high power density electronic devices that can manage heat, provide electrical isolation, tolerate large surface topography nuances up to 5 mil (the rest of the paper uses metric units – change?), and improve solvent and moisture resistance. Data will be presented highlighting these various properties along with details regarding reliability improvements.

Power electronics based on silicon devices must operate below 125 C and IGBTs under 150 C - WBG devices could extend this to 200 C. Thermal management of power electronics, whether power supplies or power components, requires interfacing the package to a heat sink using a thermal interface material (TIM). Traditionally used thermal greases provide good end of line performance but they can degrade. TIMs come in a wide variety of properties, physical formats and automation readiness to suit the wide variety of applications. Additionally, TIMs may be tasked with insulation reliability, adhesion and encapsulation. We will discuss thermally conductive solutions including greases/gels, liquid and solid gap fillers as well as metal core PCBs and their use in cooling power electronics – with reference to performance, reliability and manufacturing.

For many years, metals have been used as thermal interface materials (TIMs) in the electronics industry. With high reliability and high thermal conductivity, metals have been a great solution, especially for challenging applications. Thermal properties of any TIM are defined by their thermal conductivity and interface resistance. The biggest obstacle for metal TIMs to overcome is interface resistance. Because most metals are very stiff, a certain amount of pressure needs to be applied to form a close connection between the materials, thus lowering interface resistance. As electronic devices are continually getting smaller, consuming more power, and producing more heat, finding the right TIM becomes one of the top priorities in any application. Solid liquid hybrids (SLHs) are the next generation of metal TIMs. SLHs are a combination of metals that are solidus at room temperature with ones that are liquidus at room temperature. With low thermal resistance and low bondline thickness, SLHs are the perfect solution for certain high-end applications. This paper will discuss the possible applications where SLHs can be used, as well as challenges and obstacles that still need to be overcome to encourage adoption across the industry.