What do you know about thick copper PCB？

Definition of Thick Copper PCBs Thick copper PCBs refer to printed circuit boards that utilize a significantly thicker copper layer as the conductive layer during the manufacturing process. Typically, the copper layer in standard PCBs ranges from 1 ounce (approximately 35 microns) to 2 ounces (approximately 70 microns). In contrast, thick copper PCBs feature copper layers far exceeding this range,

 

Thick copper PCBs are among the most commonly used materials in electronic engineering due to their exceptional conductivity and mechanical strength. They are widely applied in various electronic devices. This article provides an introduction to thick copper PCBs, covering their definition, characteristics, and applications.

Definition of Thick Copper PCBs

Thick copper PCBs refer to printed circuit boards that utilize a significantly thicker copper layer as the conductive layer during the manufacturing process. Typically, the copper layer in standard PCBs ranges from 1 ounce (approximately 35 microns) to 2 ounces (approximately 70 microns). In contrast, thick copper PCBs feature copper layers far exceeding this range, reaching thicknesses of 4 ounces (approximately 140 microns) or more. This design greatly enhances their conductivity, current-carrying capacity, and thermal performance.

Features of Thick Copper PCBs

1. Outstanding Conductivity: The increased copper thickness results in lower resistivity and superior electrical conductivity, enabling more efficient current transmission while minimizing signal attenuation and distortion.
2. Higher Current-Carrying Capacity: Thick copper PCBs can handle larger current loads, offering distinct advantages in high-power electronic devices, high-current circuits, and applications requiring high stability.
3. Excellent Thermal Performance: The thicker copper layer effectively dissipates heat, reducing the temperature rise of the circuit board and enhancing the stability and reliability of the equipment.

Applications of Thick Copper PCBs

Thick copper PCBs have a wide range of applications. Below are some common use cases:

1. High-Power Electronic Devices
   Thick copper PCBs can withstand the high current and heat demands of power-intensive devices, making them widely used in power modules, motor controllers, UPS systems, solar inverters, electronic ignition systems, and electric vehicle charging stations.
2. Industrial Control
   In the field of industrial control, high-reliability PCBs with resistance to high temperatures and corrosion are essential for stable circuit design and signal transmission. Thick copper PCBs meet these requirements, making them a preferred choice in industrial control applications.
3. LED Lighting
   LED lighting systems require PCBs with excellent thermal conductivity and reliability for effective heat dissipation and stable circuit designs. Thick copper PCBs fulfill these needs, making them indispensable in the LED lighting industry.
4. Aerospace
   Aerospace applications demand PCBs with high reliability and resistance to corrosion for stable circuit design and signal transmission. Thick copper PCBs meet these stringent requirements, ensuring their widespread use in the aerospace sector.
5. Automotive
   The automotive industry requires PCBs capable of withstanding extreme temperatures, corrosion, and various environmental factors to ensure stable circuit design and signal transmission. Thick copper PCBs satisfy these demands, making them ideal for automotive applications.
6. Telecommunication
   In telecommunication, high-reliability PCBs with excellent signal integrity are essential for stable circuit design and signal transmission. Thick copper PCBs excel in these areas, making them widely adopted in the telecom industry.
7. Medical Devices
   Medical equipment demands precision and stability in circuit design to ensure device reliability and safety. Thick copper PCBs fulfill these requirements, making them a vital component in medical devices such as pH meters, blood glucose monitors, and electrocardiogram machines.

Thick Copper PCB Manufacturing Process

Due to their increased copper thickness, thick copper PCBs present several challenges in manufacturing. SHINELINK has developed a dedicated thick copper product line to systematically address these issues, ensuring high-quality production.

Etching of Thick Copper PCBs

The etching process becomes more complex as the thicker copper layers increase the difficulty of chemical exchange and lead to greater undercutting. This is addressed by implementing multiple rapid etching cycles and increasing the etching compensation factor.
SHINELINK has customized a specialized DES etching line for thick copper, capable of single-pass etching for up to 6oz thick copper PCBs.

Lamination of Thick Copper PCBs

Burkle press

During lamination, the deeper spacing between lines requires multiple pre-pregs with excellent flow properties to achieve adequate resin filling. Additional rivets are used to strengthen the fixation between core layers, reducing the risk of layer shifting. The increased copper thickness slows the actual heating rate during lamination, necessitating extended high-temperature curing phases to enhance pre-preg curing.
SHINELINK utilizes Burkle’s fully automated multilayer lamination lines and specialized oxidation-resistant chemicals to ensure lamination quality. By combining Mass LAM and Pin LAM technologies, SHINELINK can produce thick copper PCBs with up to 50 layers.

Drilling of Thick Copper PCBs

When the board thickness exceeds 2.0mm, segmented drilling techniques are used to mitigate drilling challenges. Adjustments to feed and retract rates optimize drilling quality, while slower tool engagement speeds help prevent pad tearing on thick copper boards.

Solder Mask Application on Thick Copper PCBs

In solder mask printing, the deep line gaps and height differences between copper and the substrate can lead to issues such as insufficient oil coverage, red line exposure, pinholes, and bubbles. To resolve these, the ink viscosity is diluted, and multiple printing passes are employed.
SHINELINK employs fully automated solder mask spray lines featuring pre-treatment, dual-sided spraying, pre-baking, and automated inline systems. With specialized high-pressure spray heads and high-viscosity branded inks, SHINELINK achieves uniform solder mask thickness and excellent solderability in a single spray for up to 4oz thick copper.

SHINELINK Thick Copper PCB Manufacturing

The production of heavy copper PCBs requires meticulous care, as improper handling during the manufacturing process can lead to suboptimal performance. Partnering with an experienced manufacturer is essential to ensure quality and reliability.

SHINELINK provides advanced PCB manufacturing facilities for a wide range of PCB types. With over a decade of expertise in heavy copper PCB production, SHINELINK has developed a reputation for delivering high-quality results.

Utilizing state-of-the-art automated machinery, SHINELINK ensures the development of highly reliable PCBs. To date, the company has successfully manufactured:

• Two-layer PCBs with copper thicknesses of up to 20 ounces.
• Multilayer PCBs with copper weights ranging from 4 to 6 ounces.

SHINELINK’s commitment to innovation and precision has established it as a trusted provider of robust thick copper PCB solutions.