How is a pcb made step by step
The circuit board is divided by side, which can be divided into Single Side, Double Side, Multi-Layer pcb board.The manufacturing process of different types of printed circuit boards is different. The more the number of side, the more complex the pcb manufacturing steps. The following is the PCB manufacturing flow chart of FS Technology:
Manufacturing Flow Chart of Single Sided PCB
Double-sided PCB Fabrication Flow Chart
Multilayer PCB Manufacturing Flow Chart
Design is an important step in pcb production, the boards should be strictly compatible and designers create a PCB layout 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 manufacturers about the version of the PCB design software used to design the circuit, it helps to avoid problems caused by differences.
Once a PCB design is approved for production, designers export the design to a format supported by their manufacturer. The most commonly used program is called Gerber.
Inner Layer Image Transfer
After the designer outputs the PCB schematic file and manufacturer, the PCB printing begins with DFM inspection. Manufacturers use a special printer called a plotter to make photo film of the PCB to print the circuit board. Manufacturers will use these films to image PCBs. Although it is a laser printer, it is not a standard laser inkjet printer. Plotters use incredibly precise printing techniques to provide highly detailed thin films of PCB designs.
This step in PCB manufacturing prepares the actual PCB to be made. The basic form of PCB consists of laminates whose core material is epoxy resin and fiberglass, also known as substrate material. Laminate is an ideal body to receive the copper that makes up the PCB. The substrate material provides a strong and dust-proof starting point for the PCB. Copper is pre-bonded on both sides. The process involves trimming the copper to reveal the thin film’s design.
In PCB construction, cleanliness is important, so cleaning is also listed as one of the printed circuit board manufacturing steps. Clean the copper side laminate and pass it to a decontaminated environment. At this stage it is important that no dust particles are deposited on the laminate. The wrong dirt can cause a circuit to short or remain open.
Next, the cleaning panel receives a layer of photosensitive film called photoresist. Photoresists include a layer of photoreactive chemicals that harden after exposure to ultraviolet light. This ensures an exact match from photographic film to photoresist. These films fit onto the pins, securing them to the laminate.
The film and circuit board line up and receive UV light. The light passes through the transparent portion of the film, hardening the photoresist on the copper below. The black ink from the plotter prevents light from reaching areas that shouldn’t be hardened and can remove them.
After the board was ready, any photoresist that was washed with an alkaline solution did not harden. A final pressure wash removes anything else left on the surface. The board is then dried.
As the product emerges, the resist covers the copper areas appropriately to maintain the final form. Technicians check the board to make sure no errors occur at this stage. All the resist present at this point represents the copper that will be present in the finished PCB.
The above pcb production steps are only applicable to boards with more than two layers. Simple double-layer boards can be drilled directly. Multilayer boards require more steps.
Drill holes in the stacking board. All subsequent components, such as copper connections through holes and leads, rely on precision drilling for precision. To find the location of a borehole target, the X-ray locator identifies the correct borehole target point. Then, drill the appropriate pilot holes to secure a series of more specific stacks of holes.
After drilling, the panels are moved to plating. The process uses chemical deposition to fuse the different layers together. After thorough cleaning, the panels go through a series of chemical baths. In the bath, the chemical deposition process deposits a thin layer – about 1 micron thick – of copper on the surface of the panel. Copper goes into the most recent drill hole.
With the photoresist removed and the hardened resist covering the copper we want to keep, the board goes to the next stage: unwanted copper removal. Just like alkaline solutions remove resist, stronger chemicals will remove excess copper. A copper solvent solution bath removes all exposed copper. At the same time, the desired copper remains fully protected under the hardened layer of photoresist.
Not all copper plates are the same. Some heavier boards require larger amounts of copper solvent and different exposure times. Also, heavier copper boards require extra attention to track spacing. Most standard PCBs rely on similar specifications.
Now that the solvent has removed the unwanted copper, the hardened resist protecting the preferred copper needs to be washed away. Another solvent accomplishes the task. The board now flashes only the copper substrate needed for the PCB.
Before applying the solder mask to both sides of the board, clean the panel and cover with epoxy solder mask ink. The circuit board receives UV light through the solder mask to photographic film. The covered portion remains unhardened and will be removed.
Finally, the board goes into the oven to cure the solder mask.
The near-finished circuit board receives inkjet writing on its surface to indicate all the important information related to the PCB. The PCB finally goes to the final coating and curing stage.
To add extra soldering capability to the PCB, we electroless plating them with gold or silver. At this stage, some PCBs can also receive hot air flat pads. Hot air leveling results in an even pad. This process results in the creation of a surface finish. PCBCart can handle many types of surface treatments according to the specific requirements of customers.
At this stage, the pcb making steps have basically been completed. All individual layers await their union. With the layers prepared and confirmed, they just need to be fused together. The outer layer must be attached to the substrate. The process takes place in two steps: layering and bonding.
Cut out different boards from the original panels. The approach taken is either centered on the use of routers or V-grooves. The router leaves small tabs along the edge of the board, while the V-grooves cut diagonal channels along the sides of the board. Both ways allow the board to be easily ejected from the panel.
The above is all the answers to “how is a pcb manufactured step by step”. In the actual pcb manufacturing process, due to the different requirements of customers for different circuit board materials and different requirements for pcb process, there will be slight gaps in pcb manufacturing steps. FS Technology will continue to update this topic in the PCB Knowledge Blog, of course, if you have unique insights into the manufacturing steps of pcb, you can leave us a message at any time.