PCB (Printed Circuit Board) manufacturing is a complex and precise process involving multiple key steps to transform design drawings into a fully functional circuit board. Below is an overview of its core manufacturing process.
Manufacturing Process Overview
PCB manufacturing typically begins with raw materials, undergoing a series of physical and chemical processes to ultimately form the finished board. The main processes include:
1. Raw Material Preparation and Cutting: Manufacturing begins with copper-clad laminate (consisting of an insulating substrate and copper foil). First, the copper-clad laminate is cut according to the design dimensions; this process is called "cutting."
2. Drilling: Through-holes are drilled into the copper-clad laminate according to design requirements for subsequent component pin mounting or interlayer electrical connections.
3. Electroless Copper Plating: A thin layer of copper is deposited on the walls of the drilled holes to make them conductive. This is a crucial step in achieving interlayer connections in multilayer boards.
4. Pattern Transfer: This is the core step in forming the circuit pattern. Common methods include:
* Photolithography: A photosensitive film is coated onto the copper surface, and then the circuit pattern is precisely transferred onto the copper foil through exposure and development. * **Screen Printing:** Conductive ink is directly printed onto the substrate using a screen printing plate to form circuitry.
5. Electroplating: A thick layer of copper is electroplated onto areas requiring enhanced conductivity and corrosion resistance (such as circuitry and via walls). A protective layer such as tin or nickel-gold may also be applied.
6. Etching: Unprotected copper foil (not covered by photosensitive film or ink) is dissolved away, clearly exposing the designed circuit pattern.
7. Solder Mask and Character Printing: A solder mask layer (usually green) is applied to the board surface, and characters are printed to protect the circuitry, prevent short circuits, and provide component identification.
8. **Surface Finishing and Shaping:** Surface treatments such as tin plating and immersion gold plating are applied to the pads to ensure solderability. Finally, the circuit board is machined to its final dimensions using processes such as router or V-cutting.
9. Inspection and Packaging: Finished products undergo quality inspections, including electrical continuity testing, to ensure they are defect-free before being packaged and shipped.
Differences Between Different PCB Types
The manufacturing process varies depending on the complexity of the PCB:
* Single-sided/Double-sided boards: The process is relatively simple, usually requiring only one or two sides of the circuitry to be fabricated and processed.
* Multilayer boards: Requires the individual fabrication of the inner layers, followed by lamination to bond multiple layers together, with precise alignment and metallization between the intermediate layers. The process is more complex.
* Flexible printed circuit boards (FPCs): Due to the flexible substrate, the manufacturing process has special requirements in material handling and curing.
Key Technology Trends
Modern PCB manufacturing is moving towards higher precision and higher density, employing advanced processes such as laser vias, blind and buried vias, and photolithography to achieve finer lines and higher integration.
Simultaneously, "AI+IoT" technologies are driving end-to-end digital upgrades, improving production efficiency and product quality.
The above process summarizes the basic steps of PCB manufacturing; specific details may vary depending on product specifications and manufacturer processes.