From Concept to Creation: The PCB Manufacturing Process Explained

June 7, 2024
From concept to creation: The PCB manufacturing process explained

In modern times, we have come to rely on electronics of all types and sizes in essentially every facet of our lives, from our cell phones and computers to our household appliances and medical devices. Increasingly, these electronics find themselves in our homes, workplaces, and public spaces as technological advances continue every year. 

Although the different uses of these devices are expansive, and their technology varies, one factor unifying the majority of them is that they contain printed circuit boards (PCBs) at their core.

PCBs provide the physical structure for components like microchips, capacitors, resistors, and connectors. Such devices depend on PCBs in order to route electrical signals between their various parts.

There are different types and styles of PCBs that exist (such as single, double, or multilayered), and they vary in design based on the kinds of devices they are used for and the functions they must serve. Regardless, all PCBs must undergo a thorough and complex manufacturing process that involves many steps. 

Generally, the more complex a PCB is, the more steps will be involved in its manufacturing process, with certain circuit boards requiring the completion of upwards of 20 steps.

However, for the most part, the essential steps during the development of a PCB always remain the same during the initial stages, no matter how complex the PCB is, and only begin to differ after the completion of the first layer.

What are the main steps of the PCB manufacturing process?

Before a PCB can be installed within an electronic device, it must first go through a complex fabrication process that involves several steps in sequence, each of which is as crucial as the last.

These steps require much time, planning, and consideration, needing machine-driven tools and computer guidance to guarantee accuracy, prevent short circuits or incomplete circuits, and ensure that the final product will perform exactly as intended.

The following are some of the most critical steps in the PCB manufacturing process, along with descriptions of the necessary requirements of each of these steps:

Creating the Design

The most critical step in the process is the PCB design stage, as this will allow you to plan out exactly how you are going to proceed.

During the design stage, it is necessary for a designer to formulate a blueprint for the PCB, which they must do with particular established requirements in mind. Generally, this blueprint is created with the help of design software, such as Altium Designer, OrCad, or Pads. 

One of the most widely used types of design software generating PCB designs is called Extended Gerber. With this software, it is possible to encode all the information required by the designer, such as the number of copper layers or solder masks needed. Once this information is collected, each of the design’s various components can be thoroughly analyzed to look for errors.

Design Review

Following the design stage, an engineer must review the established design, thoroughly examining every possible detail to ensure there are no parts missing and no structures that could be better placed or designed. 

During this inspection of the design, if the reviewer finds any errors, it may be necessary to return to the drawing board so that these issues can be corrected. However, if the engineer in charge of the review gives the design their stamp of approval, it can move on to the printing stage.


After the PCB manufacturer receives the schematic files containing the PCB’s design, they must then print the circuit board using a laser plotter printer that generates photo films with a high degree of detail.

This film marks the inner and outer parts of the PCB using black and clear ink, which can be used to indicate different things, such as the copper traces, circuits, and non-conductive parts for the inner elements and the copper pathways or the places where copper will be removed for the outer layers. 

Each layer of the PCB’s design gets a separate film sheet. Once they are all printed, registration holes are punched through them to make aligning them easier later on. 

Next, a copper foil layer is applied and pre-bonded to the laminate, serving as the PCB’s structure before being etched away to reveal the blueprint it covered up. 

The laminate panel is then covered with the resist, which is a photo-sensitive film containing chemicals that harden when exposed to UV light. When the PCB is blasted with UV light, it passes through the translucent parts of the film, hardening only these parts of the resist and indicating the locations of copper pathways while leaving the parts with black ink unhardened (these areas will be removed later on).

Finally, the leftover resist is removed with an alkaline solution, the PCB is pressure washed and left to dry.

Removing Unneeded Copper

After the PCB has dried and been reexamined by an engineer, a copper solvent solution bath must be used to remove the exposed excess copper. Following the removal of this copper, another solvent must be used to wash off the hardened resist, protecting the preferred copper. 

At this point in the manufacturing process, if your aim is to create a multilayer printed circuit board, there are a few additional necessary steps. These next steps essentially involve repeating the earlier steps, but for each layer of the circuit board.

Alignment and Inspection

In order to properly align the different layers of the PCB, it is necessary to use the holes punched through them after they were printed and place these layers on an optimal punch machine, which drives a pin through these holes.

Once all the layers are aligned, an AOI (automated optical inspection) machine must be used so that any defects on the board can be detected. To sufficiently check that no defects exist at this stage, the panels are compared to the original Gerber design.


Next, the layers must be fused together, and the outer layers must join with the substrate in a lamination process. At this point, the outer layer is made up of sheets of fibreglass pre-impregnated with epoxy resin, while the original substrate containing the copper trace etchings is covered both on its top and bottom with thin copper foil.

Pins attached to a heavy steel table are used to secure the board’s layers. A prepreg layer is placed over the alignment basin, followed by the substrate layer, the copper sheet, further sheets of prepreg, and an aluminum foil and copper press plate. 

Using a bonding press computer, this stack is heated up and pressure is applied to certain points to ensure that the epoxy melts and the layers fuse together. Then, the stack is allowed to cool at a controlled rate. Once it has cooled, the restraining pins are removed and the top pressure plate can be discarded.

Drilling and Plating

Guiding holes are drilled into the stack board, followed by exact holes formed with a computer-powered drill with air-driven spindles that turn at 150,000 rpm. An X-ray locator ensures the accuracy of these holes. After these holes have been drilled, any additional copper lining the edges of the production panel must be filed off with a profiling tool.

After this copper is removed, a chemical is used to fuse the PCB’s layers together. Then, the board is cleaned and bathed in a series of different chemicals. In part, these chemicals coat the panel in a very thin copper layer that covers the walls of the previously drilled holes.

Outer Layer Imaging and Etching

Next, it is necessary to apply yet another layer of resist to the outer layers of the PCB. Then, these outer layers must be plated using the same strategy used on the inner layers earlier.

However, a tin layer is added this time to help guard the copper of these layers. Using the same solvent from earlier, any unwanted copper is then removed from the outer layer, and the remaining resist coating is removed as well.

Following this, just as we did with the inner layer, an automated optical inspection (AOI) must be performed to make sure that this layer also meets the design’s requirements and to verify that all of the excess copper has been sufficiently removed.

Applying Solder Masks, Silkscreens, and Surface Finishing

Once they are thoroughly cleaned, the surface of each panel is then covered with an ink epoxy and solder mask film, and a UV light is used to indicate which parts of the solder mask must be removed. After these parts are removed, the rest of the mask is cured in an oven.

Once the PCB comes out of the oven, essential data, such as company ID numbers, warning labels, manufacturer marks or logos, part numbers, and pin locators are all printed directly on the PCB’s surface with an inkjet printer and a surface finish is applied. 

To finish the PCB, it is necessary for plating to take place with various materials, such as immersion silver, hard gold, lead-free HASL, and immersion tin (ISn). These finishes allow for the mounting of electronic components.

Electrical Reliability Testing

As a final precaution, it is necessary to apply multiple electrical functionality tests to various parts of the PCB to assess their functionality and conformity to the original design. 

It is possible to locate any disconnections or shorts by performing circuit continuity and isolation tests. All of these tests also ensure that the PCB is in compliance with IPC-9252 standards.

Profiling, Routing Out, and Final Inspection

During the final stage, it is necessary to cut different boards from the original panel, which can be done with a CNC router or a V-groove.

It is important for fabrication engineers to identify the shape and size of the PCB and program where cuts/scores must be made along the edges so that it is possible to separate the boards from each other easily. After programming these details, the machine takes care of the rest.

This is typically followed by one final inspection that involves verifying several aspects of the board, such as hole sizes, board dimensions, and cleanliness, among other factors.

How Circuits Central Can Help You Manufacture PCBs

As outlined above, the PCB manufacturing process can be quite lengthy and can include many steps, each of which is complex and requires extreme precision and attention to detail. 

For this reason, it can be rather challenging to handle this process independently without sufficient experience, expertise, and the right specialized tools and equipment, as without these things, it is easy to make mistakes along the way. 

Fortunately, Circuits Central can help you take care of all of your PCB manufacturing needs. Our team of PCB experts has plenty of experience with PCB design, PCB prototyping, PCB assembly, and post-manufacturing testing and development

No matter how complex your PCBs are, we can handle their development and manufacturing thanks to our in-depth knowledge and reliable production facility. We have helped clients from a diverse range of industries design and manufacture top-quality PCBs for different applications. 

We always ensure that everything is done to the highest possible standard. The best part is that you will not have to lift a finger during this process, as we will handle everything for you.

For more information about our approach to the PCB manufacturing process or to learn more about our other PCB assembly and manufacturing services, call Circuits Central at 1 (888) 602-7264 or contact us here.

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