Heavy Copper PCBs for High-Power Applications

Heavy copper PCBs—featuring copper thicknesses ranging from 4 oz to 20 oz—are essential in high-power, high-current applications across industries like automotive, aerospace, and industrial controls. These thick copper PCBs offer superior heat dissipation, enhanced electrical conductivity, and increased mechanical strength, making them ideal for extreme operating environments.

At PCB YOU, we are a leading heavy copper PCB manufacturer specializing in customized heavy copper PCBs tailored to your specific application needs. Our expertise spans from rapid prototyping to full-scale production with turnkey pcb assembly services, ensuring both performance and reliability.

As a trusted heavy copper PCB supplier, we engineer boards that meet stringent global compliance standards while optimizing thermal management and current-carrying capacity. Whether you're building for industrial control systems or next-gen automotive technologies, our thick copper PCBs are designed to deliver exceptional durability and consistent performance in even the harshest conditions

A heavy copper PCB is a printed circuit board with copper weight ≥3 oz/ft² (approximately 105 μm) on one or more layers. These boards are designed to support high current capacity, provide superior heat dissipation, and offer enhanced mechanical strength.

PCB copper thickness refers to the amount of copper used in the conductive layers of a printed circuit board. It is usually measured in ounces per square foot (oz/ft²), which translates to a specific micron (µm) thickness.

When we say a PCB has 1 oz copper, it means:

1 ounce of copper spread evenly over one square foot area = 35 microns (µm) thick
(Or approximately 1.4 mils)

This measurement helps determine how much current the copper trace can carry and how well it dissipates heat. As the copper weight increases (e.g., 3 oz, 6 oz, 10 oz), the thicker copper layer supports higher current and better thermal performance.

These copper clad PCBs are ideal for engineers designing power PCBs that must carry large currents and manage significant heat loads.

PCB YOU has the capability to make extreme copper PCBs in the following specifications.

• We use standard as well as high Tg FR4 boards, which means the glass transition temperature (Tg) ranges between 140 degrees to 180 degrees Celsius.
• Spacing of trace layers is important for internal as well as external layers. For internal layers, we offer a minimum spacing of 4oz Cu 8mil/12mil, 5oz Cu 10mil/14mil, 6oz Cu 12mil/16mil, or 12oz Cu 20mil/32mil. For external layers, we allow a minimum spacing of 4oz Cu 9mil/9mil, 5oz Cu 11mil/11mil, 6oz Cu 13mil/13mil, 12oz Cu 20mil/32mil.
• We keep a minimum hole size of 10 mil with the board thickness ranging between 0.6 and 6 mm.
• Our options for surface finishing include lead free HASL, immersion gold, OSP, Hard Gold, Immersion Silver, and ENEPIG.
• The maximum copper weight we offer for inner layer is 12 oz, and 15oz for finished outer layer.
• We use a variety of colors for silkscreen as well as solder mask. Such as green, red, yellow, blue, white, black, purple, matte black, matte green, and matte red.
• We use advanced via processes to create via in pad, blind and buried vias, tenting, and plugged vias.
• We do testing and inspection at each stage using advanced methods such as automated optical inspection (AOI), fly probe testing, and more.

Some PCBs have higher traces to carry higher current levels (amperage). However, thicker copper is required to transfer signals across the board as power requirements increase. Using thick copper PCB technology enables a wide range of performance and reliability advantages:

• High Current Capacity
  Copper weights of 3 oz and above allow the PCB to safely carry high electrical currents without overheating.
• Superior Thermal Management
  The copper thickness acts as a heat spreader, reducing the need for external cooling mechanisms in high power PCB designs.
• Exceptional Mechanical Strength
  Heavy copper boards resist thermal cycling, mechanical shock, and vibration, making them ideal for rugged and industrial environments.
• Improved Reliability
  Enhanced plated through-hole (PTH) strength and robust via design reduce failure risks under stress.
• Reduced Layer Count
  Power and control signals can often be routed on fewer layers thanks to increased copper capacity.

This comparison can help guide users who are unsure of what they need:

At PCB You, we use advanced fabrication techniques to ensure the durability, performance, and precision of our heavy copper PCBs. The manufacturing process is specifically designed to handle the challenges of working with thick copper layers while maintaining tight tolerances and high reliability.

Key Steps in Our Heavy Copper PCB Manufacturing Process:

1. High-Temperature Lamination
   We begin by laminating high-performance dielectric materials with thick copper foils. The lamination process uses elevated temperatures and pressure to ensure strong bonding and structural integrity.
2. Differential or Step Plating
   To build up the desired copper thickness, we apply differential plating (also known as step plating). This method allows us to selectively increase copper in high-current areas without over-plating the entire board, ensuring both efficiency and precision.
3. Precision Etching
   Etching thick copper requires special techniques to avoid undercutting and maintain clean trace profiles. Our process ensures well-defined lines, even with copper thicknesses up to 20 oz.
4. Hole Wall Plating and Via Reinforcement
   Through-hole vias are reinforced with additional plating to ensure they can handle high current and thermal loads. This step is critical for the longevity and reliability of multi-layer heavy copper PCBs.
5. Surface Finishing
   We apply PCB surface finishes such as ENIG, HASL, or OSP to improve solderability, corrosion resistance, and component compatibility.
6. Quality Control & Testing
   Every board undergoes automated optical inspection (AOI), electrical testing, and cross-section analysis to confirm that copper thickness, trace geometry, and insulation meet or exceed IPC and customer standards.

Our heavy copper PCB fabrication services support industries that demand performance, durability, and electrical reliability:

• Electric Vehicles (EVs) – Battery management systems (BMS), inverters, DC/DC converters
• Aerospace & Defense – Avionics, radar systems, high-reliability power supplies
• Industrial Power Electronics – Motor drives, power converters, industrial controllers
• LED & Solar Power Systems – High-current LED modules, solar inverters
• Telecom & RF Systems – RF shielding with thermal grounding, power amplifier boards
• Medical Equipment – Defibrillators, MRI machines, high-power laser control circuits

When designing PCB for high current or power electronics, specific considerations must be made:

Trace Width and Spacing

To avoid overheating, wider traces are required. Our engineering team helps calculate trace width based on copper thickness and current load.

Via Design and Plating

For reliability, we implement plated through-holes (PTHs) with increased wall thickness and offer filled via options for high-power designs.

PCB Stack-Up and Insulation

We use high-Tg FR-4, polyimide, or ceramic substrates depending on your thermal and electrical needs, ensuring balanced stack-up and insulation.

Thermal Relief and Heat Management

Heavy copper designs naturally dissipate heat, but we also optimize thermal vias, copper pours, and heatsinks for added thermal conductivity.

• Expert Engineering Support – DFM analysis, current carrying capacity modeling, and copper weight selection
• End-to-End Services – PCB layout, fabrication, and assembly in one streamlined process
• High Reliability Builds – Designed for mission-critical and long-life-cycle applications
• Fast Turnaround Times – Prototyping and production with flexible lead times
• Global Standards Compliance – UL, ISO, RoHS, and REACH
• Responsive Customer Service – We collaborate with you from design to delivery

Request a Quote 

If you are looking for heavy copper PCB manufacturer for your new high-power applications, we will be happy to help. In case you need any further information on our heavy copper PCBs, custom high-power circuit design, or want to share your requirements.

👉 Request a Quote or Contact Us to get started.

Build stronger, smarter, and safer power electronics. Choose PCB You for your next Heavy Copper PCB project.