heavy copper pcb
heavy copper pcb

Heavy Copper PCB

Heavy Copper PCB: A circuit type with a copper foil layer thickness of ≥3oz

As the name suggests, heavy copper PCB, also known as thick copper PCB, is a type of circuit board that utilizes thicker copper foil layers. Copper thickness ranging from 1oz to 2oz (35–70 micrometers) falls within the category of traditional circuit boards. However, when the copper thickness reaches or exceeds 3oz, it qualifies as a heavy copper PCB, with copper exceeding 20oz being referred to as extreme copper PCB. Increasing the copper thickness can enhance the circuit’s current-carrying capacity, thermal conductivity, and reduce resistance. However, it also implies higher production costs. In this article, we will introduce FS Technology’s manufacturing capabilities in heavy copper PCB and elucidate their value.

Best Heavy Copper PCB Manufacturer

As mentioned earlier, heavy copper PCB boards are more costly and, therefore, less suitable for consumer electronics but find their effectiveness in industrial projects. Those familiar with FS Technology are likely aware of our extensive experience in industrial PCB assembly, which makes us well-versed in thick copper, whether in bare board construction or finished PCBA assembly. If you’re looking for a reliable Chinese manufacturer to handle thick copper PCB manufacturing, you should consider adding us to your list of candidates!

Heavy Copper PCB Manufacturing Capabilities

GradeIPC 2/IPC 3
MaterialFR-4 (all Tg ranges), Teflon, Ceramic
Minimum Track/Spacing (External layers)4oz Cu 9mil/9mil, 5oz Cu 11mil/11mil;
6oz Cu 13mil/13mil, 12oz Cu 20mil/32mil;
Minimum Track/Spacing (Internal layers)4oz Cu 8mil/12mil, 5oz Cu 10mil/14mil;
6oz Cu 12mil/16mil, 12oz Cu 20mil/32mil;
Maximum outer copper weight15oz
Maximum inner copper weight12oz
Extremely Heavy Copper20oz-200oz
Final Thickness0.020” – 0.275”
Number of Layers2–20 layers
Solder MaskPhotosensitive Coating Systems: Green, Red, Blue, Glossy Black, Matt black, White, Yellow;
Non-Photosensitive Coating Systems: White, Black
Silk ScreenAccording to Documents
Surface FinishingHASL, Immersion gold, OSP, Hard Gold, Immersion Silver, Enepig
Build Time2 Days – 5 Weeks
Delivery Time2 – 3 Days

Why Use Heavy Copper PCB

In circuit design, there are multiple approaches depending on the specific requirements. For instance, high-power circuits may opt for metal PCB, while high-frequency or high-speed projects may prefer ceramics or Rogers materials. Thick copper PCB board, although pricier, is a preferred choice for designers, and here’s why:

One of the primary motivations for using heavy copper circuit board is to increase a circuit’s current-carrying capacity. Copper boasts excellent electrical conductivity, meaning that circuits can efficiently transmit large currents. Furthermore, copper also has outstanding thermal conductivity. When electronic components generate heat, heavy copper PCB assist in rapidly transferring this heat to the surrounding environment, preventing device overheating, a crucial capability for high-power electronics. Additionally, the extra copper layers provide excellent mechanical stability and rigidity, preventing the circuit board from bending, warping, or deforming, thus extending the board’s lifespan. Last but certainly not least, better copper traces mean lower resistance, resulting in minimal voltage loss. This helps maintain consistent voltage levels within the circuit, particularly crucial for high-frequency signal transmission. The following table is a comparison of standard thickness PCB and heavy copper PCB:

AspectStandardHeavy Copper
Copper ThicknessTypically 1 oz -2 oz More than 3 oz
Current-Carrying (IEC standard)1 oz: 2-3 amps/cubic millimeter
2 oz: Above 4 amps/cubic millimeter
3 oz: Above 6 amps/cubic millimeter
Actual situation needs to be discussed with our engineers.
Thermal PerformanceLimited capabilities but meets regular project needsEffective heat dissipation with good thermal management
Voltage DropModerate voltage loss across tracesReduced voltage loss due to lower resistance traces
Mechanical StabilityRisk of bending and warpingGood mechanical stability and reduced risk of flexing
ReliabilityBest for standard applicationsHigh reliability for demanding environments and critical applications
CostCost-effective for standard designsPrice increases as thickness increases
CustomizationLimited flexibility in copper thicknessCustomizable copper thickness to meet certain requirements
Manufacturing ComplexitySimple and skillful, not prone to failureAdditional process steps are required to achieve
ApplicationsIt is cost-effective and full-featured, so it is widely used, such as consumer, medical, industrial, etc.To avoid high cost burden dedicated to high power projects

Heavy Copper PCB Board Manufacturing Technologies

Heavy copper printed circuit board is a critical component in many high-current and high-power projects, as they can handle large current loads and effectively dissipate heat. There are two primary methods for manufacturing heavy copper board, namely the embedded copper method and the blue Bar method, to meet the needs of different industries.

Embedded Copper Method

Embedded copper method is a common technique to increase PCB copper thickness. It involves embedding copper foils within the PCB layers, providing excellent current-carrying and heat dissipation capabilities. This method offers advantages, particularly in applications like automotive electronics, where high reliability is a paramount requirement. It enhances a circuit board’s current-carrying capacity, thermal management, and mechanical stability. However, it’s worth noting that the plated copper manufacturing process is limited by the thickness of semi-cured resin, and intricate manufacturing processes can result in higher production costs for heavy copper PCB.

Blue Bar Method

This method involves the use of specially manufactured prefabricated copper bars or foils to achieve the desired copper thickness. These copper bars typically have a rectangular shape and are referred to as ‘blue’ due to their color. They are integrated into the PCB stack-up, and by selecting the appropriate thickness of copper bars, precise control over the PCB’s copper thickness can be achieved. Compared to traditional copper foil stack-up processes, the blue tape method is often more cost-effective as it reduces waste and enhances production efficiency. However, it’s worth noting that it may have limitations when dealing with certain complex PCB layer structures.

Issue of Non-Uniform Thickness

In the manufacturing process of heavy copper PCB board, ensuring the resolution of non-uniform thickness is crucial. This issue can be caused by various factors, including copper foil variations, uneven pressure distribution, etching process defects, and material quality problems. To effectively address these challenges, choosing a professional manufacturing company like FS Technology is a wise choice.

At FS Technology, we take a series of measures to ensure high-quality manufacturing:

  • Sourcing high-quality copper foil materials from reputable suppliers to minimize variability issues.
  • Strictly controlling manufacturing parameters such as pressure, temperature, etching chemicals, and electroplating to ensure uniformity of the boards.
  • Utilizing advanced technologies like X-Ray and AOI for detecting any anomalies and ensuring consistency in the boards.
  • Employing selective copper plating processes to cover specified areas, ensuring consistent thickness in areas requiring heavy copper.

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