China Heavy Copper PCB for Power Converters - China Suppliers' Superior Factory Products for Enhanced Heat Dissipation and Current Capacity Supplier, Pricelist
Product Description
What is Heavy Copper PCB?
Core Features and Application Scenarios
Core Advantages
- Strong current-carrying capacity: The current-carrying capacity of 70μm copper foil (2 ounces) is approximately twice that of 35μm copper foil (1 ounce) (under the same line width).
- Good heat dissipation: The thick copper layer can quickly conduct heat, reducing the risk of overheating of the device.
- High mechanical strength: Thick copper enhances the PCB's resistance to bending and impact.
Typical Applications
Power converters (AC-DC/DC-DC), BMS for new energy vehicles, industrial frequency converters, control boards for welding machines, etc.
Key Design Points
1. Selection of Copper Foil Thickness
- Common specifications: 70μm (2 ounces), 105μm (3 ounces), 140μm (4 ounces), and up to 420μm (12 ounces) in extreme scenarios.
- Matching scenarios: For large current (≥5A) circuits, 2 to 4 ounces of copper should be preferred. For ultra-power scenarios (≥20A), 6 to 12 ounces of copper should be selected.
2. Trace and Current-Carrying Design
- Current-carrying calculation: Combines copper thickness, line width, and temperature rise (designed on a 10℃ rise). Formula reference: I = K × W × T0.83 (I=Current, K=Coefficient, W=Width, T=Thickness). Example: 2 oz (70μm), 5mm width carries ~15A (10℃ rise).
- Trace optimization: Keep high-current traces short and wide to avoid narrow necks (local overheating). Multi-layer boards can adopt "parallel copper foil connection" (e.g., 2 layers of 2 oz equal 4 oz).
3. Via and Pad Design
- Vias: Increase hole diameter (≥0.5mm), add multiple vias (~1A/hole), and ensure hole wall plating thickness is ≥20μm (vs 8-12μm standard).
- Pads: Enlarge pad sizes (0.2-0.5mm larger than ordinary pads) to prevent fast thermal dissipation during welding that causes false soldering.
4. Heat Dissipation & Insulation
- Heat dissipation: Design thick copper areas as "copper sheet heat sinks", or use metallized via arrays (spacing ≤1mm) to connect thermal layers.
- Insulation: Widen wire spacing (for 70μm copper, spacing ≥0.2mm) to prevent creepage breakdown under high voltage.
Manufacturing Process Difficulties and Control
Thick copper lamination: High-temperature and high-pressure lamination (180℃/4MPa) is required to ensure peel strength between copper foil and substrate (≥1.2N/mm).
Thick copper etching: Slower etching rate (~1μm/min) requiring precise control to avoid side etching (side etching amount ≤0.05mm). A stepwise etching process reduces line width deviation.
The coefficient of thermal expansion (CTE) of thick copper layers differs significantly from the substrate. A "symmetrical structure" (consistent copper thickness between upper and lower layers) and a rigid support layer must be adopted to keep warpage ≤0.5%.
Thick copper oxidizes easily. Prefer high-temperature tin plating or nickel-gold plating; avoid OSP due to incomplete organic film coverage.
Enlarge pad areas with solder mask opening windows to maximize bonding strength between solder and thick copper.
Core Summary
The core of heavy copper PCBs is "high current carrying capacity + heat dissipation". In terms of design, it is necessary to match the copper thickness and current carrying capacity requirements. In manufacturing, problems such as thick copper etching and lamination warping need to be solved. They are suitable for high-power and high-current industrial and energy scenarios.
