Dielectric thickness has a direct impact on the thermal resistance of an IMS PCB. This technical guide explains how dielectric thickness, thermal conductivity and heat-transfer area interact, including the effects of 50–75 μm, 75–100 μm, 100–150 μm and 160–220 μm dielectric layers. ChengYue also explains why higher W/m·K does not always mean lower thermal resistance and how engineers can balance thermal performance, electrical insulation, reliability and cost when selecting IMS materials.