PCB Technical - How design affects the PCB manufacturing process

PCB design is a complicated process. It must be carefully considered down to the smallest details. All design choices affect one or more stages of the PCB manufacturing process. This includes everything from shape and size to the type of drilling technique used. When returning to the drawing board for redesign, it may take several weeks to complete without paying attention to how the design will affect the PCB manufacturing process. In order to make everything go smoothly, it is very important to truly understand the PCB manufacturing process from start to finish, so that the best design choices can be made from the beginning.

PCB manufacturing process

Understanding the PCB manufacturing process means understanding all the steps that go into it. This is divided into two stages; PCB manufacturing process and PCB assembly. Both are equally important, and design choices will determine the success of each stage.

PCB manufacturing process

The PCB manufacturing process starts with the creation of the circuit board itself. It must be compatible with the PCB layout specified by the design. It all started with the use of lasers to image the schematic on the circuit board.

From there, the excess copper is removed from the board by etching. In the case of multi-layer boards, they will be constructed by heating and pressing the layers at this time.

Next, drill the mounting holes, and then do more copper etching. At this point, the circuit board is about half completed.

As the circuit board manufacturing process continues, electroplating begins. The panel goes through a series of chemical baths to deposit a very thin conductive copper layer on the surface of the panel, including in the recently drilled hole.

Next, add a thin solder mask to the surface to separate any conductive elements and help prevent oxidation.

Once completed, the PCB design is silk-screened onto the board. This includes all positions of the pins and other important information such as part numbers.

Finally, it's done. The surface is chemically coated to prevent oxidation and other environmental risks. Depending on the environment and circuit board components, many types of surface treatments can be used. Surface treatment options can include gold, silver, lead, and tin.

PCB assembly

PCB assembly starts from the bare board. The first step is to apply solder paste on the circuit board to prepare for component mounting.

The assembly moves to the placement machine. This automated equipment places surface mount components on the circuit board.

Next is reflow soldering. The components need to stay in place, so the solder paste is heated to adhere the components to the circuit board.

Any unsafe connections after this step need to be re-soldered manually.

If the circuit board requires through-hole technology, then these components will be installed next. Then wave soldering will be used to fix the through-hole mounted components.

After inspecting any components that are not firmly adhered to the circuit board, another round of final soldering will be performed.

Finally, thoroughly clean your circuit board with a solvent to remove any excess resin or other contaminants. The circuit board is now ready to be packaged and shipped out.

Design for Manufacturability

Design for Manufacturability (DFM) analysis can do many things to ensure that the design is optimized before the PCB manufacturing process begins. The DFM performed by ECM will determine whether the design meets the requirements of the actual PCB manufacturing process. DFM can detect designs that may cause manufacturing problems.