Thermally conductive solder masks.

摘要

Electronic devices mounted on top of a Printed Circuit Board (PCB), must dissipate power resulting in high temperature. PCBs are made of FR-4, a thermally insulating material, and so do not dissipate power efficiently. There are three methods which can be used to eliminate the problem of poor power dissipation. The first method uses heat sinks on the PCB as heat spreaders to dissipate heat. The second method adds materials such as C-SiC and CVD diamond onto the PCB. The third embeds materials like AlSiC and C-SiC into IC packages. Adding material to the PCB is the method further described in this paper. The approach used was to deposit SiC on the PCB by pulsed laser deposition. SiC was chosen because of its high thermal conductivity, excellent electrical insulation, and relatively low cost. After making deposits, samples were measured to determine the effectiveness of the approach. After noting that a PCB with solder mask could not be deposited with SiC, work proceeded on different configurations of SiC depositions. First, adding SiC to the PCB always reduced the temperature, thus confirming the hypothesis. Second, the preferred configuration was the expected one, that of depositing SiC as a top layer of the PCB and then placing SMD on top of it. Further study is needed to determine the optimum thickness of SiC.