High-Quality Heavy Copper PCB for Power Converters - China Suppliers & Factory with Strong Current Capacity & Excellent Heat Dissipation Manufacturers, Companies
Product Description
What is Heavy Copper PCB?
Core Features and Application Scenarios
Power converters (AC-DC / DC-DC), BMS for new energy vehicles, industrial frequency converters, control boards for welding machines, etc.
Key Design Points
- Common specifications: 70μm (2 oz), 105μm (3 oz), 140μm (4 oz), and up to 420μm (12 oz) in extreme scenarios.
- Large current (≥5A) circuits: Prefer 2–4 oz copper.
- Ultra-power scenarios (≥20A): Select 6–12 oz copper.
- Current-carrying capacity calculation: Must combine copper thickness, line width, and temperature rise requirements (typically designed for a 10℃ rise).
- Formula reference: I = K × W × T0.83 — where I = current, K = coefficient, W = line width, T = copper thickness.
- Example: 2 oz copper (70μm), wire width 5mm → current-carrying capacity ≈ 15A (at 10℃ temperature rise).
- Trace optimization: Keep high-current traces as short and wide as possible. Avoid narrow necks (sudden line-width changes cause local overheating).
- Multi-layer boards: Use "parallel connection of multiple copper layers" (e.g., 2 layers of 2 oz = 4 oz equivalent) to enhance current-carrying capacity.
- Vias: Increase hole diameter (≥0.5mm), increase number of vias (~1A per hole), and ensure copper plating on hole wall ≥20μm (vs. 8–12μm for standard PCBs).
- Pads: Enlarge pad size by 0.2–0.5mm compared to standard pads to prevent false soldering caused by rapid heat dissipation during welding.
- Heat dissipation: Design the thick copper area as a "copper sheet heat sink," or add a metallized via array (via spacing ≤1mm) connected to the heat dissipation layer.
- Insulation: Widen trace spacing for thick copper layers (for 70μm copper: spacing ≥0.2mm) to prevent creepage breakdown under high voltage.
Manufacturing Process Difficulties and Control
Thick copper lamination: Requires high-temperature and high-pressure lamination (180℃ / 4MPa) to ensure peel strength between copper foil and substrate (≥1.2 N/mm).
Thick copper etching: Etching rate is slow (~1μm/min). Etching time must be carefully controlled to avoid side etching (side etching ≤0.05mm). A stepwise etching process should be adopted to reduce line width deviation.
The coefficient of thermal expansion (CTE) of thick copper layers differs significantly from that of the substrate. A "symmetrical structure" (consistent copper thickness between upper and lower layers) must be adopted during lamination, and a rigid support layer should be added to prevent PCB warping (warping degree ≤0.5%).
Thick copper surfaces are prone to oxidation. Tin plating (high-temperature tin layer) or nickel-gold plating is preferred; avoid OSP (incomplete organic film coverage).
The pad area needs an enlarged "solder mask opening window" to ensure adequate bonding force between solder and thick copper.
Core Summary
The core of heavy copper PCBs is "high current-carrying capacity + superior heat dissipation." In design, copper thickness must be matched to current-carrying requirements. In manufacturing, challenges such as thick copper etching and lamination warping must be resolved. Heavy copper PCBs are best suited for high-power, high-current industrial and energy applications.
