The Impact of Material Selection on PCB Performance

With PCB manufacturing, one of the most critical steps early on in the process involves selecting the materials to use in the production of the board. While the glass-reinforced epoxy laminate known as FR-4 is the most commonly used PCB material, and materials like polyimide and polytetrafluoroethylene (PTFE) are popular too, there are other PCB material options available, each having its own advantages and disadvantages.

As you select the materials for your PCB, you must keep several key factors in mind if you want to ensure that it meets the requirements of its intended application.

One important factor to think about during the PCB material selection process is electrical performance. You need to evaluate a material’s dielectric properties, signal integrity, thermal conductivity, and thermal expansion to determine whether or not it is suitable for your PCB.

On the other hand, you must consider a material’s mechanical properties, including its flexibility, rigidity, and tensile strength. All of these factors can impact your PCB’s ability to withstand various stresses.

If your PCB will likely be used in harsh conditions, you may also want to make environmental and chemical resistance part of your PCB material selection process. Take into account matters such as the material’s moisture resistance, chemical resistance, and the UL94 flammability rating.

How Different Materials Can Affect PCB Performance

Before you decide on a PCB material to use, it is necessary to carefully consider all the different PCB options available. Aside from its impact on the cost of your PCB and whether or not it will be compliant with various regulations and mandates, PCB material selection can have a major impact on its performance.

The following are some of the main ways that various materials can impact the performance of your PCB:

1. Impact on a PCB’s electrical conductivity

One of the most crucial matters in PCB material selection is a PCB’s electrical conductivity. There are several electrical properties that you must consider when deciding on the right material. A PCB’s impedance and signal integrity can be affected by the dielectric constant (Dk) of the material, so it is important to pick a material with a Dk that remains constant over different frequencies.

To improve the level of your PCB’s signal integrity, you should also choose a material that has higher surface resistivity. To keep isolation between the various layers of your PCB, it is necessary to pick a material with a higher volume resistivity.

All in all, materials with a lower Dk tend to provide better signal integrity, especially at higher frequencies. Materials with a higher dielectric strength can usually withstand higher voltages without breaking down.

2. Impact on a PCB’s heat management

When a PCB is used, it dissipates heat, and the rate at which this heat is dissipated is directly impacted by the materials of the PCB. This is why thermal management must be a key part of the PCB material selection process.

If factors like a material’s glass transition temperature (the temperature at which the substrate changes from a hard to soft state) or decomposition temperature (the temperature at which the substrate permanently decomposes) are not considered, the PCB may not remain stable upon reaching certain temperatures.

It is also important to look into a given material’s coefficient of thermal expansion (CTE) and ensure it is lower. A higher CTE can lead to a PCB experiencing delamination and warping when it undergoes certain changes in temperature.

A material’s thermal conductivity matters too, since this impacts how well it can conduct heat, influencing the PCB’s reliability and longevity. To make the right choice for PCB material selection, consider the environments in which your PCB will be used and how extreme the temperatures will be.

3. Impact on a PCB’s mechanical performance

Longevity and durability are very important in relation to its performance, and these factors are largely determined by the mechanical properties of the board’s materials.

First, you should pick a material with a bending strength that adheres to the standards outlined in IPC 6013C to ensure the PCB can avoid deformation or breakage when bent, especially if it is being used in an application where this is necessary (such as in wearable tech). If you do not choose a material with a high enough degree of flexibility or tensile strength, cracking and fractures could occur when the PCB is exposed to factors like vibrations or shocks.

If your PCB will be exposed to certain temperature shifts or moisture, it is also important to keep the material’s time-to-delamination in mind. This refers to the amount of time a PCB material can withstand high temperatures before its layers begin to separate. Such separation can occur during the soldering stage when the PCB is still being manufactured, during thermal cycling when it is in operation, or during exposure to certain environments.

How Circuits Central Can Help You Manufacture High-Performing PCBs

PCB material selection is one of the most critical aspects when designing and producing a PCB that performs well and can withstand the conditions it will be exposed to in its given application. Circuits Central can ensure that you pick the right PCB board material to use for your next project.

Selecting the right PCB material can be challenging when there are so many options available. Fortunately, the experts at Circuits Central have the knowledge and experience to answer any questions you may have. We will ensure that your PCBs meet the highest standards of reliability, no matter what kinds of applications they are to be used in.

As a world-class manufacturer of PCBs, we offer a full spectrum of services, including everything from PCB design assistance and PCB prototyping to PCB assembly and post-manufacturing testing.

With over 25 years of experience under our belt, our solutions are dependable and precisely engineered to meet the highest standards of quality, performance, and reliability across a wide range of industries, from communications to aerospace. Our comprehensive services are also very flexible, and we will work closely with you to tailor our solutions so that they meet your unique specifications and requirements.

For more information about how we can assist in your PCB material selection process, or to learn more about our wide assortment of PCB design and assembly services, call Circuits Central at 1-888-602-7264 or contact us here.