Role of Copper in PCB Board Fabrication
Copper is a key component in printed circuit boards (PCBs). These boards are essentially pathways that channel electric charges from one point to another. While dozens of materials can carry these charges, copper is the most common choice for PCBs because it is highly conductive. This allows the signals carried by a circuit to travel easily from one end of a PCB to the other without losing energy. It also has a number of other desirable properties, including resistance to corrosion and mechanical flexibility.
To make a PCB, the designer first prints the circuit design on a piece of laminate material, then affixes a layer of copper foil to it. This foil is patterned, with translucent and black areas that indicate which parts of the circuit should be kept as pathways and which should be left unpattered. The copper clad is then etched, which reveals the blueprint beneath. Next, the layers of a pcb board fabrication are assembled and soldered to each other. This process is aided by the fact that copper has high thermal conductivity, allowing it to dissipate heat generated by the components on a board and transfer it away from them.
When it comes to etching copper, the thickness of the material plays a crucial role. A higher copper weight provides lower electrical resistance and better current-carrying capacity than thinner foils. However, the extra expense of using thicker copper must be balanced against the added time and cost associated with processing it.
The Role of Copper in PCB Board Fabrication
The etching process is accelerated by the use of a chemical solution called a solvent. The acid in this chemical dissolves the hardened photoresists that cover the portions of the copper intended for use as pathways. The resulting copper solvent is then washed off the exposed copper, leaving only the traces that were planned to be part of the circuit. This step is critical to the quality of the finished product.
Once the unwanted copper is removed, the remaining traces are covered with a preventing coating to protect them from damage during the finishing process. Then, the stack of layered copper, laminate, and a prepeg are taken to the manufacturing press. A pair of heated plates apply both heat and pressure to the stack. This fuses the epoxy to the laminate and etching residue, as well as firmly fixes the layers together.
During this phase, the manufacturer will also inspect and clean the resulting circuit board for any defects. This includes checking the copper for proper thickness, patterning, and alignment. The manufacturer will also look for any areas that need balancing with dummy or fill copper. This balancing technique compensates for differences in the copper distribution on each side of the board, ensuring that both sides are etched at an equal rate and avoiding any interference with signal paths.
