Printed circuit board (PCB) fabrication turns design data into a reliable, production-ready board through a tightly controlled sequence of steps—DFM checks, imaging and etching, multilayer lamination, drilling and copper plating, solder mask and legend, surface finishes, profiling, and 100% electrical test. This guide walks you through the PCB fabrication process step by step and shows where tools like a Gerber viewer and DFM analysis fit in, so you can hand off clean final artwork (Gerber files), avoid rework, and get boards built faster with consistent quality.
Note:in this guide, “PCB fabrication” means producing the bare board (as governed by IPC-6012/IPC-A-600), while “PCB manufacturing” refers to the broader, end-to-end flow that also includes assembly into a functional PCBA (accepted under IPC-A-610/J-STD-001).
Printed circuit board (PCB) fabrication is a process of fabricating real-life electronic printed circuit boards. The PCB fabrication follows a complex procedure that involves several steps that work together to make sure that the PCB functions well. Mainly the PCB is divided into two categories single or double layers and multilayers. The fabrication process for single-layer and double-layer PCBs is similar and simple. However, the fabrication process of multilayer PCBs is a bit complex and requires special knowledge and experience to design and fabricate. Hence, complex multilayer PCBs may involve up to 20 steps for fabrication. Modern PCB design often starts with powerful tools like KiCad, Autodesk Fusion 360 or Altium Designer, streamlining the transition from concept to production.
Each step in the PCB fabrication process is critical and requires skilled hands to execute. Minor negligence in the fabrication stage can negatively affect the performance of the PCB. Due to the accuracy needed for the fabrication process and the importance of proper handling, it is crucial to select an experienced PCB manufacturer that provides a wide range of services like NextPCB. At Next PCB, we perform multiple quality checks on our manufactured PCBs to ensure the delivery of a well-functioning circuit board.
To aid your understanding of the PCBfabrication process, NextPCB has provided a flowchart that visually describes the stages of the process.
As mentioned, the PCBfabrication process involves several stages depending on the complexity and unique features of the circuit design. Understanding the fabrication process helps designers develop a deep knowledge of how PCB fabrication impacts the performance of the circuit board.
An understanding of the PCB fabrication process and its impacts on the output enables PCB designers to utilize such techniques that go well with the fabrication process. So, now that we know the importance of being familiar with the procedure of PCB production. Let's get its in-depth knowledge.
Schematic design is the first stage of PCB production. In schematic design, the engineer outlines the building blocks of the various circuits integrated on a PCB. A schematic design narrates from where an electrical signal begins, where it connects with other components, and where it ends. The schematic uses symbols to represent electronic components, which help layout designers draw the blueprint of the printed circuit board. This initial phase demands top-tier schematic design software to ensure clarity and functionality.
After the completion of schematic drawings, PCB designing begins. PCB designing starts with complete planning and appropriate know-how of the functions of the circuit board, as the design parameters of a circuit board affect its electrical properties. The designer starts drawing a layout design by following the schematic drawings. The layout is the second stage of PCB production; it begins with outlining and declaring the board size and involves component placement on the board.
During component placement, the designer ensures that all the components are arranged in a way that avoids signal crossing. After placing the component, the designer creates a netlist by assigning each pad its dedicated net. A netlist may describe logic, connections between components, and hierarchical relationships. Further, the netlist helps in structuring the circuit board.
After the placement of components and generation of the netlist, it's time to route the signal traces. Now at this stage, the designers have two options for routing the PCB. Number one is auto-routing, which is possible due to netlist, and offered by the PCB layout software; the other one is manual routing which a designer does by himself to meet specific design parameters.During routing, engineers commonly employ trace analysis tools like the trace width current calculator to optimize copper trace dimensions for current handling, ensuring reliability.
To lay out the PCB blueprint, the designers have a wide range of PCB designing software, for example, Altium, Altium 365, Extended Gerber and Fusion 360.
Once the routing of the PCB is complete, the designer checks it against the schematic and all other aspects of PCB designing.This step ensures that there are no errors, as it's nearly impossible to modify the design after PCB fabrication starts. Any mistakes in this stage can affect the final output. Hence, the designers check them in different ways to find and eliminate the error, if any.
As soon as the testing gets ends, the Gerber file of the circuit design is sent to the PCB manufacturer, where the actual fabrication begins. When the PCB design file arrives at the fabrication house, the manufacturer first checks the file for the Design for Manufacturing (DFM)test to ensure the design meets the minimum fabrication requirements for the circuit board or not.
NextPCB's Gerber Viewer is an essential tool that allows PCB designers and engineers to view and analyze Gerber files, ensuring the accuracy and correctness before fabrication. This free online tool offers convenience and confidence in the PCB fabrication process.
At this stage, the manufacturer starts by printing the Gerber files onto laminates. But before getting printed onto the laminates, the Gerber files are printed onto a transparent sheet and make "films" known as the photo negatives of the PCB design or photo tools.These tools are printed using a plotter, which uses clear and black inks to differentiate the conductive paths and non-conductive spaces on the PCB. This step is foundational to the pcb production workflow.
Clear Ink:The plotter use clear ink to print the conductive paths of the printed circuit board.
Black Ink:The area printed with black ink refers to the non-conductive space of the PCB.
Note:For some reason, the functionality of ink is inversed for the outer layers of the PCB. This means that for outer layers, the clear ink denotes the area required to remove, while the black ink denotes the conducting paths of the circuit.
The number of films required for a PCB depends on its layer count. However, for the printing of the solder mask, the solder mask needs its "films." So, for a two-layer PCB, we need to print four films, and for a 4-layer PCB, we need to print six films.
Once the printing of films is complete, the manufacturer aligns all the photo tools and punches some holes through them, known as registration holes. Later these holes help align the photo tools with the laminate and fibreglass sheets.
Lamination is a stage in PCB production at which the manufacturer stacks the copper layers, prepreg and laminates together and aligns them between two thick plates of steel and screws that plates together to generate pressure. Then the ready stack rests in a high-heat oven for curing, which is a process that melts the prepreg, so it works as an adhesive to bind the cores and copper layers together.
But before lamination, the laminates undergo a lengthy procedure consisting of several processes. So, let's have a look at them.
So, once the photo tools are printed, they are ready to get converted onto the laminates. Before the conversion of photo tools onto the laminates, the laminates are pressure washed to eliminate any dust or dirt to avoid issues like short circuits and open circuits. Then a coat of photo-sensitive material known as photoresist is applied to the laminate.
Now, to convert photo tools onto laminate, the manufacturer uses a UV printer. The UV printer has pins on its surface that works as a guide to align the photo tools with the laminate, as the laminate and photo tools have holes punched into it previously. Now, on the printer surface, the operator sandwiches a laminate between two photo tools and then lid down the printer. Then the printer starts its operation, and the area of photo tools printed with black, which represents the non-conducting parts of the circuit, absorbs the UV light and remains un-harden. Whereas the conducting surface of the circuit board, which is printed with clear ink, lets the UV light pass through it and gets polymerized or hard.
At the stage of image development, the UV-exposed laminates are pressure washed with an alkaline solution that removes the unharden layer of photoresist material from the laminates.
After removing the unharden layer of resist, the laminates are again pressure washed with an alkaline solution that etches the exposed copper from the laminates. Now at this stage, we get the exact same circuit design printed onto the laminates as we lay out in the software.
After the etching, the dry film is chemically removed from all over the laminate, which leaves the whole circuit exposed.
Before processing the finished laminate for drilling, it is significant to confirm that there are no errors in the laminates because, later, it is almost impossible to make changes in the inner layers of the PCB. To eliminate human errors, the manufacturer uses Automatic Optical Inspection(AOI). The AOI uses data provided by the Gerber files to check for errors. If any error is found, it is immediately shared with the concerned department to correct the mistake. Otherwise, the process of PCB fabricationcarries on without any disturbance.
If the PCB is a multi-layer printed circuit board, after the Automated Optical Inspection and prior to the lamination, the inner laminates are chemically treated to make the surface of the laminates a little rough to aid the adhesion of the laminates during the curing process and increase laminate bond strength. At NextPCB, we use organic chemistry to oxide the laminates, which leaves the copper a dark brown in colour. However, there are other methods available too, that provide different colours.
The Aims behind Brown Oxide.
(1) Roughening the copper surface to increase the surface area in contact with the resin.
(2) Increase the wettability of the copper surface to the flowing resin.
(3) Make the copper surface passivated to avoid an adverse reaction.
The lamination is the process of binding cores, prepreg and copper foil together under high heat and high pressure. At this stage, the high heat melts the prepreg, and pressure helps the laminates to bond together and make a strong bond. After the lamination, we get a perfectly stacked board.
After the lamination, the panel is ready for drilling vias and holes for through-hole components. Before drilling the holes, an X-Ray machine is used to locate and mark the spots where holes have to drill. Once the marking is complete, the laminates go for drilling. To avoid errors, the drilling of holes is a computerized process.
The normal-size holes are drilled with the standard machinery, but drilling tiny vias and holes requires special machinery.This accuracy is key in pcb board fabrication, especially for multi-layer units.
The drilling process causes some uneven raised in the edges of the metal. Burr represents the same elevated copper. Whereas the deburr is the mechanical process of smoothing the elevated copper area. This process also clears the holes from the burr and provides smooth holes for electroplating.
Desmear is a process of removing a thin layer of resin that usually appears on the inner copper layers due to heat and drilling. The desmear only applies to multi-layer circuit boards and enhances the electrical connectivity of the signal traces.
A more comprehensive answer to why we should execute desmear is that it exposes the copper rings that need to be interconnected in each layer. Further, the bulking age
