The PCB fabrication process is an essential element of the electronics production lifecycle. PCB fabrication employs many new areas of technology that have led to significant improvements in reducing the size of the components and rails used and the reliability of the board.
Producing a PCB is a complex process that involves many steps. Here, we will introduce you to the entire PCB fabrication process of our factory. It has 20 steps. This ultimate guide covers the most important steps in the production of PCBs.
We guarantee and ensure that our products meet our promises through more stringent product specifications and quality controls than other suppliers.
The PCB fabrication process is an essential element of the electronics production lifecycle. PCB Fabrication Process employs many new areas of technology that have led to significant improvements in reducing the size of the components and rails used and the reliability of the board.
Producing a PCB is a complex process that involves many steps. Here, we will introduce you to the entire PCB fabrication process of our factory. It has 20 degrees. This ultimate guide covers the most critical steps in the production of PCBs.
We ensure that our products meet our promises through stringent product specifications and quality controls than other suppliers.
1. PCB Fabrication Process—PCB Design and Layout
The beginning step of any PCB manufacture is, of course, the design. To design the PCB layout in any readily available simulator.PCB manufacture and design always start with a plan: the designer lays out a blueprint for the PCB that fulfills all the requirements as outlined.
You have to take care of certain things while designing the PCB layout, such as the width of the routes, connecting different elements, and placing vias of a specific size.
Prototype circuit boards should be rigorously compatible with the designer who creates a PCB layout using PCB design software.
NOTE: Before PCB fabrication, designers should inform their contract manufacturer about the PCB design software version used(Commonly-used PCB design software includes Altium Designer, OrCAD, Pads, KiCad, Eagle, etc. ) to design the circuit, it helps avoid issues caused by discrepancies.
Different PCB design software possibly calls for additional Gerber file generation steps(we provide knowledge about generating Gerber files in Altium and Eagle); they all encode comprehensive vital information, including copper tracking layers, drill drawing, apertures, component notations, and other options.
So it needs a thorough examination, designers forward PCB files to PC Board Houses for manufacturing.
To ensure the design fulfills minimum tolerances during the manufacturing process, almost all PCB Fab Houses run Design for Manufacture (DFM) checks before circuit boards fabrication.
After all the checks are complete, the PCB design can be printed.
The customer sends us a document; it is submitted to the engineer for review and accurate quotation again; help confirm whether the production documents are missing or wrong; also determine the process steps and associated checks. Then start to arrange production after confirmation.
2. PCB Fabrication Process—Production Prepare
Cutting and laminating according to the size of the finished board or the size of the panel;
The primary purpose of drying is to remove the moisture in the board and prevent it from warping during processing. Generally, it is dried at 150℃ for 3-4 hours.
Inner Layer Imaging
A dry film is applied to the bare copper core board, and all photo images reactions are performed on the dry film.
Inner layer development
The exposed core plate is developed, the unexposed dry film is set to reveal the original copper skin, and the exposed dry film is retained.
Photo-imaging is the primary process of open and short circuits. Therefore, the environmental sanitation requirements are very high. The air shower door must clean personnel entering. All operators need to wear anti-static clothing.
3. PCB Fabrication Process—Inner Layer Etching
The copper skin covered by the dry film is protected through the etching line, while the copper skin not protected by the dry film is etched away.
The line pattern that needs to be retained at this time will be displayed by etching.
Unloading the film
Retreat the dry film of the copper sheet on the core board, and the line pattern to be retained is finally formed.
4. Inner Layer AOI
This is an automatic optical inspection to check whether the core plate after etching has an open or short circuit and the etching is clean or not.
5. PCB Fabrication Process—Lamination
The copper foil is pressed to one board through an insulating medium (PP) between the layers.
Drilling the laminated plate. At this time, there is no metal in the hole; that is, the layer cannot be connected to the layer.
7. PCB Fabrication Process—Electroless copper deposition
The hole is coated with a skinny layer of copper through the chemical reaction, about 2-3 um.
8. Horizontal Electrolytic Plating
Since there is already a thin layer of metallic copper in the hole, the copper in the base plate and the copper in the gap can be thickened to 5-8um by an electron transfer reaction.
9. PCB Fabrication Process—Outer Layer Imaging
Outer Layer Film
A dry film is applied to the bare copper core board, and all photo images reactions are performed on the dry film. The hole has been drilled on the plate; the dry film is attached to the plate to protect the spot.
Outer Layer Exposure
Outer layer development
This step is different from the Inner layer development because after the inner layer is developed, the copper under the dry film is the last copper to be retained: after the outer layer is formed, the copper of the dry film is the previous copper to be etched, and the copper that needs to be preserved is exposed at this time.
10. Graphic Plating
Thick copper plating
The bare copper (which needs to be retained at the end) is plated to the finished copper thickness. Generally, the copper plating thickness is 18-25 um. At this time, the surface copper thickness and the copper thickness in the hole are plated together to reach the finished copper and holes copper thickness requirements.
The surface of the copper has been thickened with a layer of white metallic tin to protect the copper foil.
Getting rid of the film
The dry film attached to the board is removed. At this time, the copper under the dry film will be exposed (it will be etched away), and the copper that needs to be retained will be protected by tin underneath.
11. PCB Fabrication Process—Outer Layer Etching
The tin protects the desired copper during this stage. The exposed copper will be etched away by etching the line, while the copper-covered container will remain.
The tin used to protect the copper is removed. At this time, the copper that needs to be preserved will be exposed. Up to now, all the outer circuit patterns have been completed.
12. Solder Mask
Coat the entire panel with a liquid solder mask. The board is then exposed to high-intensity UV light. Solder mask is applied to protect copper circuitry from oxidation, damage, and corrosion.
WellPCB prints the solder mask under customers’ requirements and does not have an extra charge.
13. PCB Fabrication Process—Silkscreen
Silkscreening is a vital step since this process is what prints essential information onto the board. Then PCB finally passes onto the coating and surface finishing process.
14. Surface Finish
This step is to enable protection of the surface and good solderability. Joint surface finishes include Electroless Nickel Immersion Gold, Hot Air Solder Leveling(HASL), Lead-Free HASL, Immersion Silver, OSP( anti-oxidation), etc.
Following the implementation of the Rohs directive in the EU, all products containing lead and bromine will not be allowed to enter the EU market; therefore, the traditional pewter process will be gradually replaced.
WellPCB defaults to the lead-free HASL for our customers. If you need any other way to deal with it, please check the box when you place the order.
15. PCB Fabrication Process—Profile
The engineering department creates a shape program based on the border provided by the customer.
The shaping process is based on the engineering department providing milling.
16. Other Surface Finishing Process
Such as V-CUT, gold finger beveling will be done after the profile process.
This is the process of cutting the manufacturing panels into specific sizes and shapes based on the Gerber data’s custom design.
The method employed either centers on using a router or a v-groove. A router leaves small tabs along the board edges while the v-groove cuts diagonal channels along both sides of the board. Both ways permit the boards to pop out from the panel easily.
PCB connection points are primarily subject to constant plugging and unplugging due to their nature of interconnecting PCBs. Hence, without a strong contact edge, they are prone to wear-and-tear that can cause device malfunctioning. The act of plaiting the connectors with other metals (in this case, gold) enhances the durability of the edge connectors.
17. PCB Fabrication Process—Electrical Testing
So far, the board production has been completed, but another important thing is to conduct electrical testing to ensure functionality. The main tests that are performed are the circuit continuity and isolation tests.
Basic electrical reliability testing, used for checking the integrity of the tracks and the through-hole interconnections-checking to ensure there are no open circuits or no short circuits on the finished board. WellPCB using Flying Probe Testing depends on moving probes to test the electrical performance of each net on a bare circuit board. To ensure optimum performance and quality, we check each net to ensure complete (no open circuits) and not short to any other trap.
18.Final Visual Inspection(FQA、FQC)
This is the final step in the PCB fabrication process. The professional quality control team will perform the final inspection of each PCB, including visual inspection, finished product size inspection, aperture hole number measurement, warpage measurement, etc. If the review is qualified, we will print a test report for customer reference.
19. PCB Fabrication Process—Package&Delivery
After inspection, the PCBs are vacuum-sealed to keep out dirt and moisture. Securely boxed, sealed, and shipped off to customers all over the world by courier. WellPCB suggests DHL and FEDEX, which are more convenient and fast – generally 1-4 Days so you can receive the board as soon as possible and start your project soon.
I believe that you have a general understanding of the fabrication process of pcb after reading this guide. If you are ready with your pcb design and want to implement it for your project, try using our quotation system and upload your CAD or Gerber files. And our experienced professionals are available for consultation and to advise you when needed.
If you want to learn more about pcb manufacturing steps or problems encountered in file generation, you can contact us. We are always at your service.