Famous High-Quality Heavy Copper PCBs from China Factory - Ideal for Power Converters and Strong Current Applications, Top Suppliers Quotes, Pricelist
Product Description
What is Heavy Copper PCB?
The core is used in high-current and high-power scenarios (such as power supplies, new energy, industrial control, etc.). The key points of its design, manufacturing and application are as follows:
Core Features & Application Scenarios
- 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.
- Power converters (AC-DC/DC-DC), BMS for new energy vehicles, industrial frequency converters, control boards for welding machines, etc.
Key Design Points
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.
Trace and Current-Carrying Capacity Design
• Current-carrying capacity calculation: Combined with copper thickness, line width, and temperature rise requirements (usually designed based on a temperature rise of 10℃).
Example: 2 ounces of copper (70μm), wire width 5mm, current carrying capacity approximately 15A (temperature rise 10℃).
• Trace optimization: Keep high-current traces as short and wide as possible. Multi-layer boards can adopt "parallel connection of multiple layers of copper foil" to enhance capacity.
Via and Pad Design
• Vias: Increase hole diameter (≥0.5mm) and increase the number of vias (estimated at 1A per hole). The copper plating thickness on the hole wall should be ≥20μm.
• Pads: Thick copper pads need to be enlarged in size (0.2 to 0.5mm larger than ordinary pads) to prevent rapid heat dissipation during welding, avoiding false soldering.
Heat Dissipation and Insulation Design
• Heat dissipation: Design thick copper areas as "copper sheet heat sinks" or add metallized via arrays (via spacing ≤1mm) to connect to the heat dissipation layer.
• Insulation: Widen the wire spacing for thick copper layers (for 70μm copper, wire spacing should be ≥0.2mm) to prevent creepage breakdown under high voltage.
Manufacturing Process Difficulties & Control
Copper Foil Lamination & Etching
• Thick copper lamination: High-temperature and high-pressure lamination (180℃/4MPa) is required to ensure the peel strength between copper foil and substrate (≥1.2N/mm).
• Thick copper etching: Etching rate is slow (about 1μm/min). Etching time must be controlled to avoid side etching (side etching amount ≤0.05mm). A stepwise process should be adopted.
Lamination & Warpage Control
• The coefficient of thermal expansion (CTE) of thick copper layers differs significantly from the substrate. When laminating, a "symmetrical structure" (with consistent copper thickness between upper and lower layers) must be adopted alongside a rigid support layer (warping degree ≤0.5%).
Surface Treatment
• The surface of thick copper is prone to oxidation. Tin plating (high-temperature tin layer) or nickel-gold plating is preferred over OSP.
• The pad area needs to be enlarged with a "solder mask opening window" to ensure the bonding force between the solder and thick copper.
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.
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Frequently Asked Questions (FAQ)
What is considered a Heavy Copper PCB?
A Heavy Copper PCB (or thick copper PCB) typically features copper thicknesses ranging from 2 ounces (70μm) to 12 ounces (420μm) or more. They are designed to support high-current loads and improve thermal management in demanding environments.
What are the main advantages of using heavy copper boards?
The key benefits include strong current-carrying capacity, excellent heat dissipation to protect components from overheating, and high mechanical strength at connector sites and in multilayer configurations.
How is the current-carrying capacity calculated for thick copper?
It is calculated based on the formula I = K × W × T0.83, where I is the current, W is the trace width, and T is the copper thickness. Design choices must factor in an acceptable temperature rise, which is typically targeted at 10°C.
What are the typical applications for Heavy Copper PCBs?
They are commonly used in power converters (AC-DC/DC-DC), Battery Management Systems (BMS) for new energy vehicles, industrial frequency converters, welding equipment control boards, and power distribution systems.
What manufacturing difficulties occur with heavy copper?
The main challenges include controlling the slow etching process to prevent side etching, managing the lamination process to prevent warpage caused by differences in CTE (Coefficient of Thermal Expansion), and ensuring reliable surface treatment coverage.
How do you prevent warpage in heavy copper PCB manufacturing?
To control warpage, manufacturers design a symmetrical stack-up structure with consistent copper thickness on both the top and bottom layers. Rigid support layers are also added during lamination to keep the warping degree under 0.5%.
