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Famous Heavy Copper PCB for Power Converters - Top China Suppliers & Factory for Strong Current Capacity and Heat Dissipation Quotes, Factory
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 oz) is approximately twice that of 35μm copper foil (1 oz) under the same line width.
• Good heat dissipation: The thick copper layer quickly conducts heat, reducing the risk of device overheating.
• High mechanical strength: Thick copper enhances the PCB's resistance to bending and impact.
• Good heat dissipation: The thick copper layer quickly conducts heat, reducing the risk of device overheating.
• 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, and more.
Key Design Points
🔶 1. Selection of Copper Foil Thickness
• Common specifications: 70μm (2 oz), 105μm (3 oz), 140μm (4 oz), and up to 420μm (12 oz) in extreme scenarios.
• Matching scenarios: For large current (≥5A) circuits, prefer 2–4 oz copper. For ultra-power scenarios (≥20A), select 6–12 oz copper.
• Matching scenarios: For large current (≥5A) circuits, prefer 2–4 oz copper. For ultra-power scenarios (≥20A), select 6–12 oz copper.
🔶 2. Trace and Current-Carrying Capacity Design
• Current-carrying capacity calculation: Thick copper trace capacity must be combined with copper thickness, line width, and temperature rise requirements (typically designed for a 10℃ temperature rise).
• Formula reference: I = K × W × T0.83 (I = current, K = coefficient, W = line width, T = copper thickness).
• Example: 2 oz copper (70μm), wire width 5mm → current-carrying capacity ≈ 15A (temperature rise 10℃).
• Formula reference: I = K × W × T0.83 (I = current, K = coefficient, W = line width, T = copper thickness).
• Example: 2 oz copper (70μm), wire width 5mm → current-carrying capacity ≈ 15A (temperature rise 10℃).
💡 Trace Optimization: Keep high-current traces as short and wide as possible. Avoid narrow necks — sudden changes in line width can cause local overheating. Multi-layer boards can use "parallel copper foil layers" (e.g., 2 layers of 2 oz = 4 oz equivalent) to enhance current capacity.
🔶 3. Via and Pad Design
• Vias: For high-current vias, increase hole diameter (≥0.5mm), increase the number of vias (estimated at 1A per hole), and ensure copper plating thickness on the hole wall is ≥20μm (vs. 8–12μm for ordinary PCBs).
• Pads: Thick copper pads should be enlarged (0.2–0.5mm larger than standard pads) to prevent the copper layer from dissipating heat too quickly during soldering, which may lead to false soldering.
• Pads: Thick copper pads should be enlarged (0.2–0.5mm larger than standard pads) to prevent the copper layer from dissipating heat too quickly during soldering, which may lead to false soldering.
🔶 4. Heat Dissipation and Insulation Design
• 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, the corresponding wire spacing should be ≥0.2mm to prevent creepage breakdown under high voltage.
• Insulation: Wire spacing for thick copper layers should be widened — for 70μm copper, the corresponding wire spacing should be ≥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 (approx. 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.
Thick copper etching: The etching rate is slow (approx. 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.
▶ 2. Lamination and Warpage Control
The coefficient of thermal expansion (CTE) of thick copper layers differs significantly from that of the substrate. During lamination, a "symmetrical structure" (with consistent copper thickness between 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.
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 copper thickness with current-carrying capacity requirements. In manufacturing, challenges such as thick copper etching and lamination warping must be addressed. Heavy copper PCBs are best suited for high-power, high-current industrial and energy applications.
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Frequently Asked Questions (FAQ)
Q
What is considered "heavy copper" in PCB manufacturing?
Heavy copper PCBs are generally defined as boards with copper thickness of 3 oz (105μm) or more per layer. Standard PCBs typically use 1 oz (35μm) copper. Heavy copper boards are specifically designed to handle higher current loads and provide better thermal management.
Q
What are the main advantages of using heavy copper PCBs over standard PCBs?
Heavy copper PCBs offer significantly higher current-carrying capacity, superior heat dissipation, enhanced mechanical strength, and longer product lifespan. They are ideal for applications that require continuous high-current operation and reliable thermal management, such as power converters, EV battery management systems, and industrial equipment.
Q
How do I determine the right copper thickness for my PCB design?
The appropriate copper thickness depends on your current requirements, allowable temperature rise, and trace width. As a general guideline: use 2–4 oz copper for currents ≥5A, and 6–12 oz copper for ultra-high-power applications ≥20A. Use the formula I = K × W × T0.83 to calculate the current-carrying capacity based on your design parameters.
Q
What are the common manufacturing challenges with heavy copper PCBs?
The primary manufacturing challenges include slower etching rates and the risk of side etching during the copper etching process, warpage caused by CTE mismatch between the thick copper layer and the substrate, and surface oxidation issues. These are addressed through controlled stepwise etching, symmetrical lamination structures, and appropriate surface treatments such as tin plating or nickel-gold plating.
Q
Which surface finish is recommended for heavy copper PCBs?
For heavy copper PCBs, tin plating (high-temperature tin layer) or ENIG (Electroless Nickel Immersion Gold) are the recommended surface finishes. OSP (Organic Solderability Preservative) is generally not recommended due to the risk of incomplete organic film coverage on thick copper surfaces, which can affect solderability and long-term reliability.
Q
What industries commonly use heavy copper PCBs?
Heavy copper PCBs are widely used across industries that demand high power and high reliability, including: new energy vehicles (EV battery management systems), industrial automation and frequency converters, power supply manufacturing (AC-DC and DC-DC converters), welding equipment control boards, aerospace and defense electronics, and renewable energy systems such as solar inverters and wind power controllers.
