Aluminum PCB Advanced Circuits Specification Aluminum Printed Circuit Boards Contain a Thin Layer of Thermally Conductive Dielectric Material that Transfers Heat. There are many names for these products; Aluminum clad, aluminum base, Metal clad printed Circuit Board (MCPCB), Insulated Metal Substrate(IMS or IMPCB), Thermally conductive PCBs, etcâ?¦ but they all mean the same thing and perform the same way. How Are Aluminum PCBs Made? A thin layer of thermally conductive but electrically insulating dielectric is laminated between a metal base and a copper foil. The copper foil is etched into the desired circuit pattern and the metal base draws heat away from this circuit through the thin dielectric. Operating theory: The power device surface mounting on circuit layer, it is ideally suited for the mounting of high power light emitting diodes (LEDs) easily dissipating the heat generated by power devices.