How Is a Print Circuit Board Made?

 printed circuit board assembly

Computers, pagers, radios and radar systems all have printed circuit board assembly, also known as PCBs. The circuit boards inside these devices have electronic components that are responsible for connecting components and connectors to one another. Signals and power are relayed throughout the devices using the PCB. While the circuit board looks complicated, it's not nearly as difficult for companies to make, especially when compared to many years ago.

 printed circuit board assembly

Circuit boards in different devices are different. Each one has its own function, so it's built differently. The person who designs the board uses a computer-assisted design system that has a special software used to create the layout of the circuit pattern. Even the holes for component leads are designated a position during this time. The spaces in between the paths tend to be ,04 inches or less. All this information is inputted in a numerical controlled drilling machine. It may also be inputted into an automatic solder paster during the manufacturing process. After the pattern is laid out, a negative of it is produced and printed out on a clear plastic sheet that's the same size as what the actual circuit board will be.

Usually, fiberglass is used to make the circuit board. Copper foil is then bonded to one side or both sides. Sometimes, paper reinforced phenolic resin with copper foil is used because it's less expensive. Resistors, transistors, integrated circuit chips, diodes and capacitors are all needed to create the board.

How It's Made

 printed circuit board assembly

The process must occur in a very clean area. The first step is to make the substrate. The material then goes through an oven to get semicured. The material is then made into large panels and stacked into layers with the alternating layers adhering to the copper foil. The stacks goes into a hot press that pushes down a great deal of pressure. It's then full cured and bonded. Holes are then drilled based on the pre-determined pattern.  printed circuit board assembly

The inside of the hole design is then plated with copper. Any holes not met for conductivity are plugged. An additive and substractive process I sused to create the desired pattern. Copper os added on the substrate pattern while the areas that don't need copper are etched away after all the surface is plated.

The foil is then degreased while the panels go through a press. The mask is taken away while the panels are sprayed with an alkaline developer. Copper is used to electroplate the panels. A solvent is used to strip the photoresist from the board. The contact fingers are then attached. The tin-lead coating is then fused to the surface of the circuit pattern. The panels are then sealed, stenciled and cut. Electronic components are then mounted.