| Structural Layer | Common Materials | Core Function |
|---|---|---|
| Circuit layer | Electrolytic copper foil ranging from 18 to 140μm | Make circuits and carry the welding of components |
| Insulating layer | Thermal conductive epoxy resin / ceramic filling adhesive | Insulation isolation + heat conduction (thermal conductivity 0.8–8W/m·K) |
| Metal base layer | Aluminum alloy (mainly 6061 / 5052) | The heat dissipation base quickly disperses the heat conducted by the insulation layer |
The heat dissipation pads need to be fully in contact with the aluminum plate: under the pads of high-power devices, "heat-conducting pads" should be designed and connected to the side of the aluminum plate through metallized vias (≥0.3mm) to enhance heat dissipation.
Line width adaptation current: Aluminum substrates are mostly used in high-current scenarios. The line width should be designed according to "1A current corresponding to 0.3mm line width (copper thickness 35μm)" to avoid heat generation.
Avoid burrs during aluminum plate cutting: Burrs on the edges of aluminum plates can easily puncture the insulation layer, so chamfering (≥0.5mm) treatment is required.
Insulation layer bonding: High-temperature and high-pressure (180℃ / 3MPa) bonding is required to ensure that the insulation layer is free of bubbles and the peel strength is ≥1.0N/mm.
Surface treatment: Tin plating / nickel-gold plating is preferred, and OSP (organic film has poor heat resistance) should be avoided.
Forming method: CNC milling is adopted (instead of die-cutting for ordinary PCBs) to ensure the flatness of the aluminum plate edges.