Printed Circuit Boards (PCBs) form the backbone of all major electronics. These miraculous inventions pop up in nearly all computational electronics, including simpler devices like digital clocks, calculators etc. For the uninitiated, through electronics, which satisfies the device’s electrical and mechanical circuit requirements. In short, PCBs tell the electricity where to go, bringing your electronics to life.
Before PCB design, circuit designers are recommended to get a tour of a PC board shop and communicate with fabricators face to face over their PCB manufacturing demands. It helps prevent designers making any unnecessary errors from getting transmitted during the design stage.
However, as more companies outsource Best PCB manufacturer inquiries to overseas suppliers, this becomes unpractical. On this account, we present this article in order to provide a proper understanding of PCB board manufacturing process steps. Hopefully it gives circuit designers and those new to PCB Industry a clear view on how printed circuit boards are manufactured, and avoid making those unnecessary errors.
PCB Manufacturing Process Steps
Step 1: Design and Output
Circuit boards should be rigorously compatible with, a PCB layout created by the designer using PCB design software. Commonly-used PCB design software includes Altium Designer, OrCAD, Pads, KiCad, Eagle etc. NOTE: Before PCB fabrication, designers should inform their contract manufacturer about the PCB design software version used to design the circuit since it helps avoid issues caused by discrepancies.
Step 2: From File to Film
PCB printing begins after designers output the PCB schematic files and manufacturers conduct a DFM check. Manufacturers use a special printer called a plotter, which makes photo films of the PCBs, to print circuit boards. Manufacturers will use the films to image the PCBs. Although it’s a laser printer, it isn’t a standard laser jet printer. Plotters use incredibly precise printing technology to provide a highly detailed film of the PCB design.
Step 3: Printing the Inner layers: Where Will the Copper Go?
The creation of films in previous step aims to map out a figure of copper path. Now it’s time to print the figure on the film onto a copper foil.
This step in PCB manufacturing prepares to make actual PCB. The basic form of PCB comprises a laminate board whose core material is epoxy resin and glass fiber that are also called substrate material. Laminate serves as an ideal body for receiving the copper that structures the PCB. Substrate material provides a sturdy and dust-resistant starting point for the PCB. Copper is pre-bonded on both sides. The process involves whittling away the copper to reveal the design from the films.
Step 4: Removing the Unwanted Copper
With the photo resist removed and the hardened resist covering the copper we wish to keep, the board proceeds to the next stage: unwanted copper removal. Just as the alkaline solution removed the resist, a more powerful chemical preparation eats away the excess copper. The copper solvent solution bath removes all of the exposed copper. Meanwhile, the desired copper remains fully protected beneath the hardened layer of photo resist.
Step 5: Layer Alignment and Optical Inspection
With all the layers clean and ready, the layers require alignment punches to ensure they all line up. The registration holes align the inner layers to the outer ones. The technician places the layers into a machine called the optical punch, which permits an exact correspondence so the registration holes are accurately punched.
Step 6: Layer-up and Bond
In this stage, the circuit board takes shape. All the separate layers await their union. With the layers ready and confirmed, they simply need to fuse together. Outer layers must join with the substrate. The process happens in two steps: layer-up and bonding.
The outer layer material consists of sheets of fiber glass, pre-impregnated with epoxy resin. The shorthand for this is called prepreg. A thin copper foil also covers the top and bottom of the original substrate, which contains the copper trace etchings. Now, it’s time to sandwich them together.