THE MANUFACTURING PROCESS OF HIGH QUALITY PRINTED CIRCUIT BOARDS
Nearly all electronics products today contain printed circuit boards (PCBs). High quality printed circuit board manufacturing technology has allowed electronic items to become increasingly smaller and more complex; key to today’s dynamic and rapidly-progressing electronic innovations. While the PCB manufacturing process can vary, the main elements involved remain the same.
Here is a quick summary of the steps involved in the manufacture of high quality printed circuit boards.
Our experienced circuit board designers at PCB Solutions use industry-leading computer-aided design software to lay out the custom circuit pattern on the circuit board. The substrate most often used to manufacture printed circuit boards is a type of fiberglass-reinforced epoxy laminate known as FR4. (Flexible printed circuit boards use a flexible plastic such as polyamide.) The epoxy resin has a copper foil bonded to one or both sides. The copper is etched away from the substrate surface to create the desired pattern. Printed circuit board manufacturers typically use an etching process employing the chemical ferric chloride.
PCB Solutions adheres to a long-standing commitment of using only top-quality materials, in each of these important phases. Ensuring that the final output leaves nothing to chance.
After the foil surface of the substrate is degreased, the panels pass through a vacuum chamber where the bare printed circuit boards have a thin layer of photoresist material pressed onto the surface of the foil. The vacuum chamber keeps air bubbles from being trapped between the foil and the photoresist.
Quality assurance is key at this phase and not to be overlooked. At PCB Solutions we can’t imagine hiring an ‘cheap’ manufacturer who does not adhere to such quality measures resulting in a final output that does not meet our strict standards.
The printed circuit pattern mask is laid on top of the photoresist and the panels are exposed to ultraviolet light. Photoresist becomes more soluble when exposed to ultraviolet light and only those areas of the board where tracks are desired are covered in the resist. When the mask is removed, an alkaline developer is sprayed on to dissolve the irradiated photoresist in the printed circuit pattern and the copper foil is left exposed on the substrate.
Steps and terminologies used at these phases sound complex to the lay-person and are best left to a high-quality PCB manufacturer who understands and adheres to the latest quality manufacturing processes.
The printed circuit panels are electroplated with copper except for areas still covered with photoresist. A protective coating is plated on the copper plating to prevent oxidation and protect the printed circuit pattern. The photoresist is then stripped from the circuit boards with a solvent and an acid solution applied to remove the copper foil. Contact fingers are then attached and plated with tin-lead, nickel, and gold.
The protective coating is fused on the surface of the copper printed circuit pattern and each panel is sealed with epoxy. The panels are then cut into individual boards and the electronic components are placed in the circuit by a series of machines. Components are soldered to the circuits, the flux residue is cleaned off, and the printed circuit boards are ready for packaging and shipping to their next destination.
While many electronic manufacturers have their own proprietary processes for manufacturing printed circuit boards including customizations to match the intended output, the steps laid out above are a general outline of how a printed circuit board is manufactured.