Introduction In the 1990's, with the advent of surface mounting of semiconductor packages, multilayer printed circuit boards and multilayer substrates for Ball Grid Array packages were introduced. In order to create electrical interconnections between the different metal layers, vias are fabricated [1]. In most cases vias are hollow cylinders of copper, created by plating a … [Read more...]
Modeling Heat Conduction in Printed Circuit Boards Using Finite Element Analysis
Introduction Heat transfer in and around a printed circuit board (PCB) is generally very complex. Some of the heat generated in components is conducted away through the multiple conducting (trace) layers, vias, and dielectric layers of the board; and some is dissipated by convection and radiation from the exposed surfaces. There has long been a focus on characterizing the … [Read more...]
The 45° Heat Spreading Angle – An Urban Legend?
Ever hear about the 45° heat spreading angle? Most of us have. However, no one I've talked to seems to know where it came from. Is it an urban legend, such as alligators in the sewers of Manhattan, or is it an eternal truth deposited into the collective subconscious of the thermal engineering community? However fascinating it might be to explore the historical origins of this … [Read more...]
Thermomechanical stress modeling in microelectronics and photonics
Thermomechanical stresses and deformations are the major contributors to malfunctions of, and failures in, microelectronics and photonics devices, packages and systems. In microelectronics, the most serious consequences of the elevated thermal stresses are usually associated with mechanical (structural) failures (e.g., ductile rupture, brittle fracture, failures due to fatigue, … [Read more...]
High accuracy thermal interface resistance measurement using a transient method
Heat dissipation of active devices has become one of the limiting factors in further miniaturization. While component manufacturers succeed in decreasing the overall thermal resistance of their packages, the thermal interface resistance to the board becomes the next limiting factor. Therefore, understanding interface and contact resistances becomes increasingly important for … [Read more...]
