Introduction of Printed Circuit Board
We all know that printed circuit boards are a key part of any electronic device. To ensure the performance of final electronic products, a complex procedure is required to manufacture printed circuit boards. Many steps are involved in the manufacturing of PCBs. And every step has a deep impact on the performance of the printed circuit board. After successfully finishing the PCB, it fulfils the tasks accurately. To achieve a high volume production of well-performed PCBs, the PCB fabrication is done carefully. So, in the article, we will talk about the detailed steps in printed circuit board manufacturing.
Key Elements of a Printed Circuit Board
Firstly, we need to know the main parts of a PCB. Generally speaking, printed circuit boards consist of four main parts, they are base laminate, copper layer, solder mask and silkscreen layer.
PCB Manufacturing: The Step-by-Step Process
Electronic devices have a vital product in the form of green boards. The device will not work without these green boards. This board is the main part as it connects every component of the device firmly together. As can be easily observed, the size of the PCB is small, but its manufacturing process is quite complex. Many steps are critically performed in the manufacturing of this board. As every step has its important significance, let’s take a close look at the making of this green circuit board.
DFM by PCB Manufacturer
When the PCB design is prepared by a customer, detailed production instructions are made by the PCB manufacturer to know the base of the process. Software is used to process the design.
Cutting of Base Substrate
Before production, we need to cut big laminate sheets into small pieces, such as 18×24-inch panels. For both layers, copper is pre-bonded. Then, it is etched away to show the design form of the printed film in the later processes.
Internal Layer Copper Pattern Printing
The plotted printer helps print the design of PCBs. The printed form explains the layers and details of the board. The design of the copper pattern is printed on the body structure named laminate. The structure is covered by photo-reactive chemicals. It will harden the photo-sensitive film when exposed to UV light. It will help in the alignment of actual prints and blueprints of the board. For the alignment procedures, drilling of holes into the PCBs is done.
Copper Exposure
The hardness of Photoresist is done by passing the laminate and resists through the UV lights. When passed from the lights, the copper path became visible. Black ink will be removed. To erase the extra photoresist, the board is washed in an alkaline solution.
Inner Layers Alignement
For the procedure of alignment, new layered are needed. Holes are drilled to align the internal and external layers. To keep the layer straight, an optical driller is used. The driller punches the machine with a pin. After the punch, an examination of the board is done for the defect process. After this step, any mistake can’t be tolerated.
Lamination
The board shape is now clear because layers are bonded together. Now, the lamination starts and the metal clamp is used to join the layer. Epoxy resin is used as an alignment basin. Then, on the substrate layer, the prepreg is attached followed by the copper layer. In the end, the press plate is completed. Now, no more copper will be utilized.
That is a lamination of the board. In this process, pressure and heat are applied to the layers. The resin present in the prepreg melts. Due to the pressure, the layers are joined together.
Drilling
To connect ally copper layers, drills are needed on the PCB. Holes are made inside layers by using the computer-based drill.
Copper Plating
The PCB is now moving forward to the next step of plating. All layers are fused by using a chemical solution. The board is now washed completely by utilizing more chemicals. An additional layer of copper is coated on the board, which will cover drilled holes.
Imaging of the External Layer
Before starting the process of imaging, a photoresist layer is applied to the external layer of the PCB board. The photoresist will be hardened using UV lights. Any excess photoresist will be removed here.
External Layer Copper Etching
The panel will be again plated with copper. Later, the PCB board is guarded by a thin tin layer. Tin is used to protect the copper of the external layer. The extra copper under the resist layer is also balanced which later modifies the PCB connections.
Application of Solder Mask
Before the application of the solder mask, the panels are properly cleaned. A resin is applied with a solder mask. The mask normally has a green colour, which is typically visible on board. The extra mask is removed. And the needed mask is fixed on the board.
Silk Screen Printing
Silkscreen is also important in the manufacturing of PCBs. It prints the critical information. After the screening, coating is done on the circuit board. The process is done very carefully to ensure clear words that carry the information after this procedure’s curing process is finalized.
Surface Finishes
To protect the pads from oxidation, we need to apply a think layer of metal on the PCB surface, such as HAL, immersion gold, tin, silkscreen, OSP., etc. Besides, it is also helpful to get good-quality solder joints in the PCB assembly process.
E-testing
Before the PCBs are ready to use, an electrical test is performed on the board by testing equipment. The analysis will ensure the functions of PCBs. It will follow the design of the original printed blueprints. After all of these procedures, PCB is considered to be workable.
Conclusion
The PCB manufacturing process is completed, starting from design and ending with testing. Digital systems and automation are smoothly and effortlessly integrated into the fabrication and testing processes. PCB designers and the production team help in the design and manufacturing of printed circuit boards. Electrical companies rely on reliable PCB manufacturers to produce high-quality circuit boards as they help the electronic market facilitate product development and innovation.
Different steps are taken to form a good and valid PCB. From designing to the finishing of the board, every step is performed carefully. For accurate board, verification is done after the fabrication of the printed circuit board. Many of the steps in the process required complete computer guidance. To prevent any type of short-circuit or incompetent circuits, the accuracy of the circuit is ensured by 100% E-testing. Every PCB board is under careful inspection and testing before being delivered to the market. PCB technologies will keep developing as a result of expanding capabilities and demand, supporting the advancement of the electronics sector. It is no doubt a minor-sized circuit board that has wonders in the electronic field.