Selecting the right metal-base thickness is critical for high-power IMS PCB thermal management, mechanical stability, and overall system reliability. This article explains how metal-base thickness affects heat spreading and thermal performance, compares common thickness options from 0.4 mm to 6.0 mm, and provides practical guidance for choosing aluminum or copper bases. Based on ChengYue’s IMS manufacturing capabilities, the guide helps PCB engineers balance thermal performance, weight, rigidity, cost, and application requirements for high-power electronics.