A complete Guide on PCB Board Manufacturing in 20202020-05-25
PCB Board Manufacturing: A Step by Step Guide to PCB Manufacturing
Since Printed Circuit Boards are an important part of electronics today, therefore, it is important to connect with a reliable PCB board manufacturing company. If you have the basic knowledge regarding the manufacturing of Printed Circuit Board, you will be able to make a more efficient and reliable decision.
In lame man terms, we can say that Printed Circuit Boards are those small green boards that we often have seen in electronics. These boards are responsible for electronics’ functionality. The main objective of a Printed Circuit Board is to form a connection among the components inside the machine. Thus, allowing the electronics to perform as desired.
Despite the fact that PCB is extremely small in size, but its manufacturing requires effort and extensive attention. One wrong hole, incorrect etching, or anything else would lead to the failure of the Printed Circuit Board. That then would affect the performance of your electronics.
So, in this article, we are going to provide you with a concise introduction to the manufacturing process of Printed Circuit Boards. Without any further delay, let us get straight to point.
The Manufacturing Process of Printed Circuit Board
Several steps are imperative for the development of a Printed Circuit Board. You would have to focus on these steps, even if you yourself are the manufacturer, or you are reaching out to a skilled PCB board manufacturing company.
Generally, PCB board manufacturers use copper as the basic material for a Printed Circuit Board. However, this does vary as the consumer’s needs. Nonetheless, it is important for the PCB to have all its layers aligned and properly bounded to perform efficiently.
See the manufacturing steps below.
The first step is the design of the Printed Circuit Board. Generally, the client tends to provide the manufacturer with the design. However, the consumer can reach out to the manufacturing company to get the PCB design.
Regardless of the technique, you use for Printed Circuit Board design, the basic pattern remains the same. You would create a blueprint for the design. To create the design, you would use certain software.
To focus on the details of the external as well as the inner layers of a Printed Circuit Board, you can take help from a trace width calculator.
To print the Printed Circuit Board design, you would need a special printer—Plotted Printer. The output of this particular printer is a film. This film displays every layer of the Printed Circuit Board in detail.
To print the inside of the board, the printer generally uses two different colors. This provides clarity to the onlooker.
- For non-conductive areas, the printer uses Clear Ink.
- For conductive copper circuits and traces, the printer uses Black Ink.
- In the case of outer layers, it uses the same colors. However, the meaning is reversed.
After you have finalized the design and printed it. Now, you step into the manufacturing of Printed Circuit Board. First and foremost, you need to work on the substrate of a Printed Circuit Board. In most cases, the substrate is either glass fiber or epoxy.
Since the substrate is responsible for holding the components to the board, therefore, you need to choose it with care. You form this insulating material by passing it through an oven. This process semi cured the insulating material.
You will have to pre-bound copper to both sides of the layers. Later, the etching is done to show the design according to the printed film.
Inner Layer Printing
For inner layers PCB board manufacturing prints the design to a laminate. Laminate is basically the structure’s body. Next, you would have to cover the structure with a photo-sensitive film. Manufacturers use photo-reactive chemicals to create this photo-sensitive film.
These photo-reactive chemicals harden as soon as you expose them to the ultraviolet light. Doing this assists the alignment process of the Printed Circuit Board. You would also drill the holes into the PCB.
After the alignment, it is time to harden the photoresist. For this purpose, the laminate would be exposed to the ultraviolet light. Moreover, to reveal copper pathways, you would be needing these lights.
To prevent the areas from hardening that you plan to remove afterward, you would be using the black ink. After proper exposure, you would use an alkaline solution to wash the board. The solution would then remove all excess photoresist.
Removing Unwanted Copper
After removing the unwanted photoresist, you need to work of eliminated undesirable copper. You would need another chemical solution to eat away the unwanted copper. The solution would have no impact on the hardened photoresist.
After thoroughly cleaning all the layers, it is time to inspect them. You should make sure that everything is aligned properly. The holes are helpful with the alignment of inner and outer layers. Moreover, to ensure that the layers are properly lined up, PCB manufacturer uses an optical punch machine.
After the optical machine punches the drills the pins, another machine comes into action. This machine checks on the board to find any defect. This step extremely important as after this, you will not be able to make any changes to the Printed Circuit Board.
So, make sure that you pay close attention to it and ensure that everything is according to the blueprint.
Once you start fusing the layers together, you will notice that the board is forming the respective shape. Before the instigation of the laminating process, use metal clamps to hold the layers together. The first layer to go onto the alignment basin is the prepreg layer.
Next, you would have to put a substrate layer over the prepreg and then follow it with a copper foil layer. Then, again the prepreg resin and so on. In the end, you will apply another copper layer. The manufacturer considers this as the press plate.
Once you have installed the layers, now you need to press them. PCB board manufacturing uses a mechanical press for this particular purpose. To ensure proper alignment and to secure the layers, machines punch the pins through them.
It is possible to remove these pins in the later stage. However, this mainly depends upon the technology that the PCB Board manufacturer is using.
If everything goes well, Printed Circuit Board would head to the laminating press. Here, heat along with pressure is to be applied to these layers. The layers fuse together because of the epoxy that melts inside the prepreg due to the heat.
In order to expose the inner panels and substrate, you would have to drill holes into the layers. To ensure accuracy, the holes are computer-guided. After this, you would have to remove the unwanted copper.
After going through the above steps, the board is now fully ready to be plated. To fuse, the layers together, use a chemical solution. Next, comes the cleaning of the board with other types of chemicals. While cleaning the chemicals add an additional thin layer of copper. This layer would sweep into the holes drilled holes.
Imaging of outer layer
Before the Printed Board is sent to imaging, it is important to apply a photoresist layer to the outside layer. The layer application is similar to that of the application of photoresist to other layers.
Plate the panel with a thin copper layer. After that, apply a thin tin guard layer onto the board. The tin layer ensures that the copper layer is not etched off.
The tin guard layer protects the required copper and the same chemical solution as above is used to remove unnecessary copper. Also, the Printed Circuit Board connection is established.
Before you apply the solder mask, make sure to clean all the panels. Then, onto the solder mask film, manufacturers apply an epoxy. Solder mask is responsible for the green color that you typically see of a Printed Board.
You bake the required solder mask onto the board. However, to get rid of unwanted solder mask, you would use ultraviolet light.
It is an important step as it prints all the important information of the PCB onto the PCB. After this step, a Printed Circuit Board goes through just one last coating.
The surface finish greatly depends upon the consumer’s requirement. In most cases, PCB board manufacturing companies use a solderable finish as it increases the bond of the solder.
Finally, the manufacturer tests the Printed Circuit Board to ensure it has no errors.