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...]
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...]
Calculations for Thermal Interface Materials
It's no news to any of the readers of this publication that the increased power dissipation of integrated circuits has led to continuous refinement of package designs and component materials. This trend has increased the importance of thermal interface materials (TIMs) as a key factor in determining the thermal performance of packages intended for high-power applications. This … [Read more...]
Thermal Calculations for Multi-chip Modules
Due to the flexible manufacturing processes for producing BGA packages, there has been an explosion of new package designs, many of which contain more than one integrated circuit chip [1]. Existing industry standards for IC package thermal characterization apply only to single-chip packages. This Calculation Corner will present some techniques for calculating the junction … [Read more...]
Simplified Transient Model for IC Packages
Previous installments of this column have all dealt with situations in which the die temperature was assumed to be at a constant temperature after the system had achieved the steady state. However, there are many times in which it is useful to know how rapidly the temperature of the chip changes when the applied power changes abruptly. This month's column presents a simple … [Read more...]
