HXPCB provides aluminum PCB manufacturing services

Material Selection
The first step is to select the appropriate aluminum metal substrate material, which is chosen for its excellent thermal conductivity. The dielectric layer is usually made of a thermally conductive resin, such as polyimide, to provide electrical insulation while facilitating heat dissipation. The copper layer responsible for the circuit’s conductive path is also selected based on the design specifications.

Copper Cladding
The aluminum substrate is first covered with a thin copper foil, usually using a lamination process. This copper layer forms the circuit path, and the thickness of the copper foil is selected based on the current-carrying requirements of the final product. In some cases, copper deposition can be performed using electroplating methods to achieve more precise thickness control.

Drilling
After copper plating, the board is drilled according to the design specifications. Drilling is used to make through-holes (for heat dissipation and inter-layer connections) and to mount components. The drilling process must be carefully controlled to avoid damaging the aluminum substrate or the copper layer. When using precision drills, care must be taken to remove any burrs or debris generated during the drilling process to prevent short circuits.

Etching
The next step is the etching process, which removes excess copper from the surface, leaving the desired circuit pattern. This is usually done using a chemical etching process using an acidic or alkaline solution. The etching process must be carefully monitored to ensure that the copper paths are accurate and etched evenly, especially in areas with complex circuit designs.

Dielectric Lamination
Next a dielectric layer is applied to provide electrical insulation between the copper and aluminum layers. This layer is typically made of a thermally conductive material, such as polyimide or other engineering resins, which is laminated to the copper layer under controlled conditions of heat and pressure, ensuring a strong bond without damaging the delicate copper traces.

Surface Finishing
Surface finishes such as electroplating or gold plating are used to improve the solderability and conductivity of the board. This process is critical to ensuring PCB reliability, especially for high-power applications where high currents flow through the board.

Solder Mask Application
Solder mask is used to protect the copper circuits from oxidation and ensure that components are only soldered to the correct pads. Solder mask also prevents shorts between tracks with larger spacing.

Component Mounting and Assembly
Once basic PCB fabrication is complete, components are mounted on the board using either surface mount technology (SMT) or through-hole mounting techniques, depending on the design. Components are soldered to the board using either reflow or wave soldering processes.

Testing and Inspection
After assembly, the PCBs undergo rigorous testing and inspection. This includes electrical testing to check for shorts, opens, and proper operation, as well as visual inspection (including automated optical inspection, or AOI) to ensure that solder joints are correct and free of manufacturing defects.

Final Quality Control
Finally, the PCBs undergo a final quality control inspection, including an X-ray inspection of internal vias and layer junctions, to ensure that the board meets all design specifications and quality standards.