PCB manufacturing is a precise and complex process that relies on a series of high-precision specialized equipment. From photolithography, etching, lamination, drilling, plating, to testing, each production step is driven by corresponding core equipment.
1. Panel Cutting and Base Material Preparation Stage
Panel Cutting Machine
The panel cutting machine is used to cut large-sized copper-clad laminates (CCL) into required dimensions for production. It typically employs CNC or hydraulic control systems to achieve high-precision positioning, ensuring dimensional errors of less than 0.1mm. Common issues include burrs on cutting edges, panel deformation, or dimensional deviations, often caused by blade wear or positioning system errors. Regular blade replacement and equipment calibration are necessary.
Edge Grinding Machine
The edge grinding machine uses sand belts or milling cutters to polish panel edges, removing burrs and sharp edges generated during cutting. This improves operational safety and lamination quality. Common problems include uneven grinding or excessive wear, usually due to aging sand belts or improper feed speed. Parameters should be adjusted based on panel thickness, and the grinding unit must be regularly maintained.
2. Inner Layer Circuit Fabrication Stage
Coating Machine
The coating machine uniformly applies photoresist onto the copper-clad laminate surface using roller or slot-die coating methods, controlling the thickness to 5–20μm. Common issues include uneven coating, bubbles, or thickness deviations, often caused by nozzle clogging or unstable photoresist viscosity. Regular pipeline cleaning and monitoring of ambient temperature and humidity are required.
Exposure Machine
The exposure machine transfers circuit patterns onto the photoresist using ultraviolet (UV) or laser light, with a high-precision alignment system (accuracy ±5μm). Common problems include misalignment, insufficient exposure energy, or dust contamination, often due to aging optical systems or inadequate cleanliness. Regular calibration of the optical path and maintaining a dust-free environment are essential.
Etching Machine
The etching machine uses chemical solutions (e.g., acidic copper chloride) to remove unprotected copper layers, forming circuit patterns. Common issues include under-etching/over-etching, side etching, or line width deviations, often caused by uncontrolled chemical concentration or uneven spray pressure. Real-time monitoring of chemical parameters and optimizing the nozzle layout are necessary.
3. Drilling and Hole Metallization Stage
Laser Drilling Machine
Laser drilling machines (CO₂ or UV lasers) are used for micro-hole processing (0.1–0.3mm) with precision up to ±10μm. Common issues include hole position deviation, hole wall carbonization, or material scorching, often caused by focal length errors or unstable laser energy. Regular calibration of the optical system and parameter adjustments based on material properties are required.
Electroless Copper Deposition Line
Electrolytic copper plating forms a conductive layer (0.3–1μm thick) on hole walls through chemical deposition, involving baths for degreasing, activation, and chemical copper plating. Common issues include uneven hole wall coverage or deposition voids, typically caused by ineffective activation solutions or insufficient agitation. Process monitoring must be strengthened, and bath agitation methods must be optimized.
4. Lamination and Layer Stacking Stage
Vacuum Lamination Press
The lamination press bonds multilayer core boards and prepregs under high temperature and pressure (180–200°C, 300–500psi), using segmented temperature control technology. Common problems include delamination, bubbles, or uneven thickness, often due to uneven pressure distribution or excessive heating rates. Optimizing the lamination curve and regularly maintaining the heating plate flatness are essential.
Brown Oxidation Line
Brown oxidation treatment chemically generates a micro-rough layer on the copper surface to enhance interlayer adhesion. Common issues include uneven oxidation color or insufficient adhesion, often caused by weakened chemical oxidability or improper processing time. Regular analysis of tank fluid composition and control of conveyor speed are required.
5. Outer Layer Circuit and Surface Finish Stage
Pattern Plating Line
The plating line electrolytically increases circuit copper thickness (20–30μm) and applies tin protection, including pickling, copper plating, and tin plating processes. Common issues include uneven plating thickness, pinholes, or orange peel patterns, often due to uncontrolled current density or imbalanced additive ratios. Multi-point current monitoring and regular tank fluid filtration are necessary.
Solder Mask Screen Printer
The screen printer applies solder mask ink onto the board surface using screen alignment and squeegee control technology. Common problems include missed prints, uneven thickness, or misalignment, often caused by screen clogging or improper squeegee pressure. Selecting an appropriate screen mesh count and maintaining a clean environment are essential.
Hot Air Leveling (HAL) Machine
The HAL machine coats tin on solder pad surfaces (1–3μm thick) using hot air leveling to prevent oxidation and improve solderability. Common issues include tin bumps, thickness fluctuations, or copper dissolution, often due to uncontrolled tin bath temperature or inaccurate air knife angle. Regular tin pot cleaning and air knife calibration are necessary.
6. Profiling and Testing Stage
CNC Routing Machine
The routing machine cuts PCB outlines using milling cutters with an accuracy of ±0.05mm, supporting irregular slot and hole processing. Common problems include burrs, edge chipping, or dimensional deviations, often caused by cutter wear or insufficient dust extraction. Layered milling strategies and regular tool replacement are required.
Automated Optical Inspector (AOI)
The AOI scans circuit defects (e.g., shorts, opens) using multi-angle cameras with a recognition accuracy of 5μm. Common issues include high false positive rates or missed detections, often due to uneven lighting or improper algorithm threshold settings. Regular light source calibration and database updates are essential.
Flying Probe Tester
The flying probe tester checks electrical performance by contacting pads with probes, supporting high-density board testing. Common problems include poor probe contact or positioning errors, often due to probe wear or mechanical vibration. Impedance compensation technology and regular probe cleaning are necessary.
7. Auxiliary and Environmental Equipment
Wastewater Treatment System
This system treats wastewater containing heavy metals (e.g., copper, nickel) using precipitation, ion exchange, and membrane filtration technologies. Common issues include water quality fluctuations or resin saturation, requiring real-time monitoring of pH and heavy metal concentrations, as well as planning regeneration cycles.
VOCs Treatment Unit
This unit treats organic waste gases through activated adsorption or catalytic combustion to meet environmental emission standards. Common problems include reduced adsorption efficiency or catalyst deactivation, often due to excessive humidity or impurity accumulation. Pre-treatment of incoming air and regular replacement of adsorption materials are necessary.
Additional Notes:
- Modern PCB factories are gradually introducing intelligent management systems (e.g., MES) to achieve equipment data interconnection and closed-loop optimization of process parameters.
- High-end HDI board production requires Laser Direct Imaging (LDI) equipment to replace traditional exposure machines, improving line width accuracy to below 10μm.
- Common issue prevention requires combining SPC statistical process control and TPM total productive maintenance to establish preventive maintenance mechanisms.