Printed Circuit Board (PCB) manufacturing involves multiple processes, each tailored to specific design requirements, materials, and applications. Selecting the right manufacturing method is critical for achieving performance, cost efficiency, and scalability—whether you’re prototyping IoT devices or mass-producing automotive control systems.
This technical guide breaks down the most common types of PCB manufacturing processes, their pros and cons, and how KingsunPCB leverages cutting-edge technology to deliver high-quality boards for industries like aerospace, medical, and consumer electronics.
1. Subtractive Process (Etching)
Overview: The subtractive process is the traditional method where copper is selectively removed from a laminated substrate to form conductive traces.
Steps:
- Lamination: Apply copper foil to a dielectric substrate (e.g., FR-4).
- Photoresist Application: Coat the board with a UV-sensitive photoresist.
- Exposure & Development: Use a photomask to define traces, then develop to remove unexposed resist.
- Etching: Remove unwanted copper using chemical etchants (e.g., ferric chloride).
- Stripping: Remove remaining photoresist.
Advantages:
- Cost-effective for high-volume production.
- Suitable for standard designs with trace widths ≥0.1mm.
Limitations:
- Limited precision for HDI (High-Density Interconnect) designs.
- Chemical waste generation.
Applications: Consumer electronics, power supplies.
2. Additive Process (Semi-Additive & Fully Additive)
Overview: The additive process builds conductive traces by selectively depositing copper onto a substrate, minimizing waste.
Types:
Semi-Additive Process (SAP):
- Uses a thin seed layer of copper, followed by electroplating to build up traces.
- Ideal for ultra-fine traces (≤0.05mm) in HDI PCBs.
Fully Additive Process:
- Directly deposits copper onto the substrate without etching.
Advantages:
- High precision for complex designs.
- Reduced material waste.
Limitations:
- Higher cost due to advanced equipment.
- Longer production time.
Applications: High-frequency RF boards, medical implants.
3. Printed Electronics (Inkjet & Screen Printing)
Overview: Conductive inks are printed onto flexible or rigid substrates to create circuits.
Methods:
- Inkjet Printing: Digital printing for rapid prototyping.
- Screen Printing: Uses a mesh stencil for thicker ink deposits.
Advantages:
- Low cost for simple, low-density designs.
- Compatible with flexible substrates (e.g., PET, polyimide).
Limitations:
- Limited resolution (trace width ≥0.2mm).
- Lower durability compared to etched copper.
Applications: Wearables, disposable sensors.
4. Molded PCB Process
Overview: Integrates circuit traces into 3D molded plastic parts, combining mechanical and electrical functions.
Steps:
- Laser Direct Structuring (LDS): Laser activates areas on a plastic substrate for metallization.
- Electroless Plating: Deposits copper onto activated regions.
Advantages:
- Enables 3D circuit integration.
- Reduces assembly steps for compact devices.
Limitations:
- High tooling costs for molds.
- Limited to specific thermoplastics.
Applications: Automotive connectors, antenna modules.
5. HDI (High-Density Interconnect) Process
Overview: Combines microvias (≤0.1mm diameter), fine traces, and sequential lamination to achieve ultra-high density.
Key Techniques:
- Laser Drilling: Creates microvias for layer connections.
- Sequential Build-Up (SBU): Adds layers one at a time for precision.
Advantages:
- Supports complex, multilayer designs (up to 20+ layers).
- Reduces board size and weight.
Limitations:
- Requires specialized equipment (e.g., laser drills).
- Higher cost per unit.
Applications: Smartphones, military avionics.
6. Comparison of PCB Manufacturing Processes
| Process | Process | Layer Count | Cost | Best For |
| Subtractive | ≥0.1mm | 1–12 | Low | High-volume standard boards |
| Additive (SAP) | ≤0.05mm | 4–20+ | High | HDI, high-frequency |
| Printed Electronics | ≥0.2mm | 1–2 | Very Low | Flexible, disposable |
| Molded PCB | ≥0.15mm | 1–4 | Moderate | 3D integrated components |
| HDI | ≤0.075mm | 8–20+ | High | Compact, high-performance |
7. How KingsunPCB Optimizes PCB Manufacturing
To meet diverse B2B needs, we combine advanced processes with rigorous quality control:
- Laser Direct Imaging (LDI): Achieves ±0.01mm trace alignment for additive and HDI processes.
- Automated Optical Inspection (AOI): Detects defects as small as 0.02mm.
- Material Expertise: Rogers, polyimide, and metal-core substrates for specialized applications.
- Quick-Turn Prototyping: Functional samples in 24–48 hours.
8. Case Study: Automotive Control Unit with HDI Process
A client needed a 16-layer PCB for an electric vehicle’s control unit. Our solution:
- Used HDI with laser-drilled microvias (0.08mm diameter).
- Achieved impedance control of ±5% for high-speed signals.
- Reduced board size by 35% compared to traditional methods.
9. Choosing the Right PCB Process: Key Considerations
- Design Complexity: HDI and additive processes suit high-density layouts.
- Volume: Subtractive methods are cost-effective for mass production.
- Material Requirements: High-frequency designs need low-Dk/Df substrates.
- Lead Time: Printed electronics offer rapid prototyping.
10. FAQ: PCB Manufacturing Processes
Q: Which process is best for flexible circuits?
A: Additive or printed electronics processes, depending on trace density.
Q: Can HDI PCBs be mixed with rigid-flex technology?
A: Yes! We combine HDI with rigid-flex for aerospace and medical devices.
Q: What’s the minimum trace width for subtractive processes?
A: Typically 0.1mm, but advanced facilities can achieve 0.075mm.
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