PCBs or Printed circuit boards are electronic devices that are used to support various components soldered into holes that have been drilled onto the surface of the board. Alternately, copper pads are also used to attach these components in a surface mounted board.
The Printed circuit board joins all the leads electrically. This is done using using copper passages on the board. These copper passages are conductive where the board itself is non-conductive. Initially, when the PCBs were first invented, they were single sided. The copper engravings were present only on one side of the board. However, modern PCBs have copper engravings on both sides of the board allowing them to hold more components while taking less space. Currently, multi-layered PCBs are also in production.
The Copper etchings on the board's surface are part of the production process of the PCB. The multi-layered circuit boards that are currently being produced consist of many layers of dielectric material soaked in adhesives. These are used to separate the copper engravings. When all these layers have been aligned, they are bound into a single structure. Printed circuit boards with more than 48 layers, are being commercially manufactured.
There are many companies that are manufacturing printed circuit boards for commercial purposes. These companies have modern state-of-the-art facilities for producing PCBs. There are many variations and innovation in the preparation and production of printed circuit boards. However, the core procedure for manufacturing
PCBs consists of following steps:
The first step is called the initial setup. During this process the materials to be used and specific processes to be employed for production are decided upon. Specific requirements of a customer are also determined with the help of the Gerber files that are received with the purchase order.
The Gerber file data is used to make a film that can be positioned on the copper layer.
This is the most important process in which the film-protected copper along with the rest of the unprotected areas, is exposed to a chemical that eliminates the unprotected copper. When the process is finished, the copper tracks and the pads that were protected remain in their place while the rest of it is washed away. Modern etching techniques have been introduced that utilize plasma laser. In such cases, chemicals are not used for the purpose of removing copper, allowing for much more defined conductive lines.
The next step is to drill holes into the board. These holes will be used to attach plate-through applications. The information concerning the precise locations of these holes on the board as well as their sizes is presented in the drill drawing file.
In the next step, bare copper tracings are applied with protective material so that they remain protected from environmental damage. This also helps in insulating the etchings.
A thin solder layer is used for coating pad areas so that the PCB is readied for wave or re-flow soldering process that will start once the components are placed in their proper places.
When the printed circuit board has been completed, a thorough visual inspection of the same is carried out to ensure its quality. By applying voltage at different points, the flow of current through the board is also ascertained.