Advanced Thermal Management Solutions on PCBs for High Power Applications

Abstract

AbstractÀWith increasing power loss of electrical components, thermal performance of an assembled device becomes one of the most important quality factors in electronic packaging. Due to rapid advances in semiconductor technology, particularly in the field of high-power components, the temperature distribution inside of a component is a critical parameter of long-term reliability and must be carefully considered during the design phase.Two main drivers in the electronics industry are miniaturization and reliability. Whereas there is a continuous improvement concerning miniaturization of conductor tracks (i.e., lines and spaces have been reduced continuously over the past years), miniaturization of the circuit carrier itself, however, has mostly been limited to decreased layer counts and base material thickness. This can lead to significant component temperature increase and thence to accelerated system degradation. Enhancement of the system reliability is directly connected to an efficient thermal management on the PCB level. There are several approaches that can be used to address this issue: optimization of the board design, use of base materials with advanced thermal performance, and use of innovative buildup concepts.The paper provides a short overview about standard thermal solutions such as thick copper, thermal vias, plugged vias, or metal core based PCBs. Furthermore, attention will be focused on the development of copper filled thermal vias in thin board construction. In another approach, advanced thermal management solutions are presented at the board level, exploring different buildup concepts (e.g., cavities). Advantages of cavity solutions in the board are shown that not only decrease the thermal path leading from the high power component through the board to the heat sink, but also have an impact concerning the mechanical miniaturization of the entire system (reduction of z axis). Such buildups serve as a favorable packaging solution with promising thermal performance. Moreover, using thermal simulations different setups are compared and a deeper insight into the thermally relevant geometry and material parameters is provided, allowing production efforts to be reduced and to offering optimized designs and board buildups.

Via-Hole-Type Flip-Chip Packaging to Improve the Thermal Characteristics and Reliability of Blue Light Emitting Diodes

“…Our findings are in good agreement with previously reported results. 14,27,28 It is reported that FCLED samples exhibit much better thermal dissipation characteristics than lateral LEDs. 27,28 It is also found that the thermal conductivity of PCB, MCPCB, Si, ceramic and AlN substrates can be increased by using electroplated-copper-filled thermal vias (TVs), since the thermal path from the LED chip toward heat sink is shortened.…”

“…14,27,28 It is reported that FCLED samples exhibit much better thermal dissipation characteristics than lateral LEDs. 27,28 It is also found that the thermal conductivity of PCB, MCPCB, Si, ceramic and AlN substrates can be increased by using electroplated-copper-filled thermal vias (TVs), since the thermal path from the LED chip toward heat sink is shortened. 28,29 To characterise the reliability of the packaged samples in sulfur ambient, the samples are loaded into a chamber, where humidity and temperature are set to be 75% and 25°C, respectively, with H 2 S gas (a concentration of 15 ppm).…”

“…For this, thermal vias (TVs) are employed to increase the thermal conductivity of PCB, MCPCB, Si, ceramic and AlN substrates, where holes are filled with a highly conductive material; the most common filling material is electroplated copper. 14,[25][26][27][28] Two different types of TVs have been positioned in LED packages, namely, underside and lateral side of the LED die, and these TVs are shown to be very effective in improving heat dissipation. In this study, in order to enhance device reliability by improving heat dissipation and suppressing crack formation, a via-hole structure is also introduced in the lead frame.…”

Thermal Metamaterials for Heat Flow Control in Electronics

“…Regarding thermal management for PCB-based electronics, the existing macroscale approaches to controlling heat transport include the use of through-hole thermal vias in communication with large-area thick metal planes or cores [24], creating a cavity in the PCB to further reduce through-plane thermal resistance to a heat sink [24], using high thermal conductivity metal/graphite inlays [25], or novel PCB-based heat pipes [26]. Basic printed circuit board copper (Cu) plane layout for anisotropic thermal conductivity has also been exploited as a design strategy.…”

Thermal Design of LED by DOE

“…The LED technology is developing rapidly and more powerful LED devices placed in smaller packaging appear on the market, which must effectively dissipate large amounts of heat. [1] Heat negatively affects the performance and is a prerequisite for the emergence of failure, so proper thermal management is essential for the design of each LED device or system [2].…”