Among the various stackups available for a 10-layer PCB, the second one with a core thickness of 210um stands out as the most commonly chosen option due to its ability to meet the isolation requirements of general-purpose PCBs. This standardized stackup offers several advantages, making it a popular choice among manufacturers.

One of the key benefits of using a standard 10-layer stackup is its ability to streamline the PCB fabrication process. Manufacturers can readily utilize established processes and materials, eliminating the need to deviate from regular timelines. As a result, this reduces additional manufacturing costs and lead times, making it a cost-effective and efficient solution for many projects.

What is the thickness of a 10-layer PCB?

The thickness of standard 10-layer PCBs can vary significantly, ranging from 1.33mm to 3.0mm. However, this thickness is determined by several critical factors within the design and manufacturing process. These factors include the thickness of copper, prepreg, and core materials used in the PCB construction.

When high isolation requirements are necessary for the PCB, designers may opt for double-layer prepreg to enhance the board's isolation capabilities. Additionally, for applications requiring the handling of high currents without compromising signal traces, thicker copper materials with a thickness of 105um (3oz) or more may be utilized.

These variables significantly impact the overall thickness of the 10-layer PCB. Depending on the specific project's requirements and performance demands, the thickness may be adjusted to accommodate the necessary features and functionalities.

What materials are used in a 10-layer PCB?

The construction of a 10-layer PCB involves a sandwich structure consisting of four crucial components: copper, prepreg, core, and solder mask.

Copper

As a fundamental conductive material in a 10-layer PCB, copper plays a critical role. In applications with high current or substantial heat generation, thicker copper layers, up to 3 oz, can be utilized on the outer layers to facilitate effective heat dissipation and manage current flow without causing significant damage or loss to the PCB.

Prepreg

Serving as a dielectric material, prepreg is employed to bond the PCB core and copper layers together. The thickness of the prepreg is also pivotal in determining the isolation between various signal layers.

Solder Mask

Acting as a protective barrier, the solder mask consists of a liquid epoxy material. By applying the solder mask to the outer layer of the PCB, it safeguards against shorts and opens, ensuring the reliability of the PCB.

Core

The core acts as the foundational material for the 10-layer PCB, providing essential mechanical support and isolation. PCBs employ diverse core materials based on specific electrical and mechanical requirements:

• FR-4 Material: The widely-used FR-4 material serves as a standard choice for PCB cores. Its popularity stems from affordability and reduced lead times. While it exhibits a high glass transition temperature of up to 180°C, it may not be suitable for high-temperature applications. Nevertheless, its self-extinguishing properties enhance safety.
• Metal Core or Metal Backplane PCB Material: For specific applications necessitating high glass transition temperatures, extra mechanical strength, and higher dissipation rates, metal core PCBs employ metals like copper and aluminum as the base material.
• Ceramics: PCBs with ceramic substrates, such as aluminum nitride and beryllium oxide, offer high thermal conductivity, minimal coefficient of thermal expansion (CTE), and a stable dielectric constant (DK), effectively minimizing signal loss.
• High-Frequency Laminate: Specially designed for circuits requiring fast signal transmission, controlled impedance, low signal loss, and minimal dielectric constant (DK) and dissipation factor (DF), high-frequency laminates are ideal for critical applications.

How to lay out signal, power and ground planes on a 10-layer PCB stackup?

With its increased layer count compared to 2-layer and 4-layer PCBs, a 10-layer PCB offers more layout options and ample space, eliminating concerns about insufficient room. However, even with this extra space, it is crucial to adhere to the fundamental rules of PCB design.

While the additional layers allow for easier routing of signal traces, it is essential to prioritize signal and power integrity during the design process.

To ensure signal integrity and prevent electromagnetic interference (EMI), careful consideration must be given to the placement of power and ground planes. Ground planes serve as the DC return path for signals, particularly critical for high-speed signals that can generate more EMI without a proper return path. Having adjacent ground planes provides a direct return path and acts as a shield against crosstalk between layers.

To mitigate voltage drop in a 10-layer PCB, it is advisable to include at least one power plane, ideally placed close to the plane with the highest frequency signals.

In environments with high electromagnetic interference, dedicating the top and bottom layers as ground planes can provide shielding for the circuit against external EMI.

For a 10-layer PCB designed for Low Frequency (LF) to Intermediate Frequency (IF) applications, a suitable stackup may involve alternating signal and ground layers with power planes close to high-frequency signal layers, providing a well-organized layout for efficient signal flow and proper power distribution.

By adhering to these principles and carefully designing the layer stackup, a well-structured 10-layer PCB can effectively handle complex circuitry, maintain signal integrity, and deliver reliable performance in a variety of applications.