Multilayer PCB Manufacturing Process 5 - Inner Layer Process - How to achieve interlayer circuit conduction?

? After the creation of the inner layer board circuits and the press fit of the multilayer boards, the multilayer circuit boards are now laminated together. Now, each layer has its own circuitry, and the next step is to figure out how to realize interlayer circuit conduction. Multilayer PCBs take such two processes: drilling, hole plating. Drill holes in the board first, drilling out the line between the layer and the layer connected to the conduction holes, and then, the non-conductor part of the holes using chemical plating to make the holes conduction, and plating way, in the hole of the inner wall and the surface layer plated with a layer of copper to increase the thickness of the copper layer, to avoid the conductor is too fragile. In this way, there is a reliable electrical connection between the layers.

? Deposited copper, also known as vias (hole metallization <PTH>), in order to make the hole wall of the resin or fiberglass surface to generate conductivity, so that double-sided or multi-layer PCB interlayer conductor connectivity, the use of chemical deposition method in the hole after drilling the hole wall deposited on a thin layer of (1 to 2 micron thick) chemical copper, for the subsequent plating of the copper to provide electrical conductivity.

? The copper immersion reaction can be found at /view/9d84e1000166f5335a8102d276a20029bd6463da.html

? After drilling and through-hole plating, the inner and outer layers have been connected, and the next step is to create the outer layer of the PCB.