Issue link: https://iconnect007.uberflip.com/i/913789
December 2017 • The PCB Magazine 35 THERMAL MANAGEMENT CONSIDERATIONS AT THE BARE BOARD LEVEL 2-oz. plane layers under the outer layers, mak- ing it a 10-layer design. This simple fix reduced the heat by 10X and gave them a major perfor- mance improvement in the optics capabilities. There are some design considerations. How- ever, when using these thick copper planes, as backfill becomes a possible concern. One must also consider the resin fill of the areas without the copper, as to which materials are used. Too much resin can seriously affect movement in the Z-axis. So once again careful consideration must be given, when using heavy copper inner- layers, to balance the thermal conductivity with fill requirements and trace widths. As an alter- native to heavy copper-clad materials one can consider the use of the internal heatsink. Figure 2: Comparison of materials vs. heat capacitance. Figure 3: Details of material comparisons.