How to Choose the Thickness of PCB

First,

In the world of electronic products, the PCB is often referred to as the "heart" of the device. It interconnects all components, making board thickness one of the most important parameters. Choosing the right PCB thickness directly affects the electrical performance, mechanical stability, thermal management, and long-term reliability of the final electronic product.

The process of selecting PCB thickness is influenced by various factors, such as product application scenarios, board material, and number of copper layers. Therefore, these factors must be comprehensively considered when selecting the PCB thickness.

Characteristics and Application of different PCB thicknesses

JLCPCB offers standard FR-4 thicknesses including 0.4 mm, 0.6 mm, 0.8 mm, 1.0 mm, 1.2 mm, 1.6 mm, and 2.0 mm (thicknesses above 2.5 mm are available for high-layer boards up to 4.5 mm overall). Each thickness range has distinct advantages and limitations.

Ultra-thin PCB (below 0.6 mm)

Ultra-thin PCBs (≤ 0.6 mm) are lightweight, flexible, and ideal for space-constrained products such as smartphones, tablets, wearables, robotics, laptops, and drones. However, they have limited mechanical strength and are prone to warping. At JLCPCB, 0.4 mm boards only support ENIG finish and cannot be panelized; 0.6 mm boards have maximum size restrictions.

Mid-Range Thin PCBs (0.6-1.6 mm)

Mid-range thin PCBs (0.8–1.6 mm) offer the best overall balance between mechanical strength, weight, cost, and manufacturability. This thickness range is suitable for the vast majority of electronic products, including computer motherboards, consumer electronics, IoT devices, home appliance control boards, and industrial controllers. The stiffness and stability are moderate, making them ideal for most standard applications. The 1.6 mm thickness is the most widely used industry standard for FR-4 substrates.

At JLCPCB, PCBs with thicknesses from 0.8 mm to 1.6 mm start at only $2, providing excellent cost performance. In addition, these thicknesses perform very well in multilayer boards (especially 4 to 8 layers) for controlled impedance routing, ensuring good signal integrity in high-speed designs.

Thicker PCBs (above 1.6 mm)

Thicker PCBs (above 1.6 mm, typically 2.0 mm and above) provide superior rigidity, load-bearing capacity, and thermal mass. They are particularly suitable for applications that require high-power components, heavy parts, or large board sizes. Common use cases include automotive electronics, industrial control systems, aerospace equipment, railway transportation, and high-current power boards. In harsh environments with high vibration, shock, or extreme temperatures, thicker boards offer significantly better mechanical stability and durability. They also help prevent warping and deformation in large-outline PCBs. Additionally, the greater thermal mass allows for better heat dissipation from high-current traces. However, thicker boards come with higher material costs and may require longer processing times.

Impact of Layer Stack-up on Thickness

The final board thickness is not only determined by the chosen thickness value but also by the layer stack-up. More layers require additional prepreg and core materials. For example, a 6-layer board at 1.6 mm needs a carefully designed stack-up (e.g., SIG/GND/PWR/SIG/GND/SIG) to maintain impedance and signal integrity. JLCPCB provides standard stack-up templates to help designers achieve target thickness while meeting electrical requirements.

Key factors affecting PCB thickness:

1. The number of PCB layers: The more copper layers a circuit board has, the greater its thickness will typically be.

2. Signal type: Circuit boards carrying high-power signals typically require thicker copper layers and wider traces, while circuit boards in low-power environments can be thinner.

3. Material selection: Different materials have varying thickness characteristics, and selecting different materials can impact the thickness of the circuit board.

4. Operating environment: In harsh environments (e.g., high vibration or mechanical stress), thin or flexible boards may not be the most suitable choice. Thicker copper traces, however, have greater thermal mass and better heat dissipation, making them more suitable for high currents and temperature variations.

5. Copper Thickness: The overall thickness of the PCB is influenced by the thickness of the copper layers it has. Thicker copper layers, such as 2 ounces or 3 ounces of copper, have a greater impact on the overall thickness compared to thinner copper layers. Contribute more than one ounce of copper.

6. Special requirements: Certain applications may necessitate customized circuit board thickness, such as high-density boards or circuit boards used in unique environments.

How to Choose the Appropriate PCB Thickness

When selecting a PCB type, you need to consider whether the thickness of the circuit board is suitable for the application requirements. Generally speaking, when choosing the thickness of a PCB, the following factors should be considered:

Clarify application needs and performance requirements: Before selecting the PCB thickness, it is important to have a clear understanding of the application performance requirements, various different scenarios, and component load-bearing requirements. This will ensure that the chosen thickness is able to meet the product's specific requirements.

Safety of the circuit board: If the circuit board must handle high voltage or high current, a thicker PCB is recommended to ensure safe operation and adequate clearance/creepage distances.

Mechanical properties of the circuit board: If the circuit board needs to withstand high mechanical influence, it is advisable to choose a thicker PCB to ensure its mechanical strength

Production cost: Thicker the PCB, the higher production cost. Therefore, when selecting a PCB, it is important to ensure product performance while also considering the maturity of production technology and the cost of the PCB thickness.

Generally speaking, the expected turnaround time for receiving custom PCB layer thicknesses is longer due to the unusual thickness specifications.

PCB Thickness Selection FAQ

Conclusion

Choosing the appropriate PCB thickness is a crucial factor in ensuring optimal board performance and reliability. Taking into account factors such as engineers' application needs, cost, and manufacturing capabilities, JLCPCB acts as a PCB manufacture and supports PCB production from 1 to 20 layers and offers a thickness range of 0.7mm to 2.5mm.Engineers can choose the appropriate thickness based on their specific requirements. Whether standard FR-4 or specialized materials are required, JLCPCB can provide customized solutions to meet specific thickness requirements.