1 / 1
ODM Heavy Copper PCB for Power Converters - High Current Capacity and Heat Dissipation | China Suppliers & Factory Manufacturer, Companies
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 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
📐 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 Capacity
-
Current-carrying capacity calculation: Needs to be combined with the copper thickness, line width, and temperature rise requirements (usually designed based on a temperature rise of 10℃).
Formula reference: I = K × W × T0.83 (I=current, K=coefficient, W=line width, T=copper thickness).
Example: 2oz copper (70μm), wire width 5mm, capacity ≈ 15A. - Trace optimization: For high-current traces, keep them short and wide to avoid narrow necks. Multi-layer boards can adopt "parallel connection of multiple layers of copper foil" to enhance capacity.
3. Via and Pad Design
- Vias: For high-current vias, hole diameter should be increased (≥0.5mm), number of vias increased (estimated at 1A per hole), and 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 the copper layer from dissipating heat too quickly during welding, which may lead to false soldering.
4. Heat Dissipation and Insulation
- Heat dissipation: The thick copper area can be designed as a "copper sheet heat sink", or a metallized via array (via spacing ≤1mm) can be added to connect to the heat dissipation layer.
- Insulation: Wire spacing for thick copper layers should be widened (for 70μm copper, spacing ≥0.2mm) to prevent creepage breakdown under high voltage.
🛠️ Manufacturing Process Difficulties and Control
1. Copper Foil Lamination and Etching
Thick copper lamination: High-temperature and high-pressure lamination (180℃/4MPa) is required to ensure the peel strength between the copper foil and the substrate (≥1.2N/mm).
Thick copper etching: The etching rate is slow (about 1μm/min), and the etching time needs to be controlled to avoid side etching (side etching amount ≤0.05mm). A stepwise etching process should be adopted to reduce line width deviation.
2. Lamination and Warpage Control
The coefficient of thermal expansion (CTE) of thick copper layers differs significantly from that of the substrate. When laminating, a "symmetrical structure" (with consistent copper thickness between the upper and lower layers) should be adopted, and a rigid support layer should be added to prevent PCB warping (warping degree ≤0.5%).
3. Surface Treatment
The surface of thick copper is prone to oxidation. It is preferred to choose tin plating (high-temperature tin layer) or nickel-gold plating to avoid OSP (incomplete organic film coverage).
The pad area needs to be enlarged with a "solder mask opening window" to ensure the bonding force between the 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.
📩 Send Inquiry
❓ Frequently Asked Questions (FAQ)
Q1
What is considered a Heavy Copper PCB?
A Heavy Copper PCB typically features copper weights ranging from 2 ounces (70μm) to 12 ounces or more per square foot, which is significantly thicker than the standard 1 ounce (35μm) used in conventional boards.
Q2
Why use Heavy Copper instead of standard PCB?
Heavy copper provides superior current-carrying capacity, enhanced heat dissipation capabilities, and increased mechanical strength, making it ideal for high-power and high-temperature applications.
Q3
Can heavy copper circuits be combined with standard circuits on the same board?
Yes, this is known as an Extreme Copper PCB. It allows power circuits (heavy copper) and control circuits (standard copper) to be integrated onto a single board, saving space and reducing overall weight.
Q4
What are the main challenges in manufacturing Heavy Copper PCBs?
The main challenges include controlling the etching process to prevent excessive side etching, managing lamination warpage due to thermal expansion differences, and ensuring proper solder mask coverage over thick traces.
Q5
How does heavy copper affect via design?
Vias in heavy copper boards require larger diameters (≥0.5mm) and thicker copper plating on the hole walls (≥20μm) to safely conduct high currents across layers without overheating.
Q6
Which surface finish is best for Heavy Copper PCBs?
Tin plating or Electroless Nickel Immersion Gold (ENIG) is highly recommended. OSP is usually avoided as it may not fully cover the thick copper, leading to potential oxidation issues.
