What Is the Standard PCB Thickness

When you select any PCB for any application, we always look at its construction materials, heat resistance, and thermal conductivity. Yes, these factors determine how a PCB will work. Nonetheless, we often forget one important PCB performing factor- the thickness.

The thickness of the printed circuit board also controls its performance and durability. Hence, most manufacturers will follow a standard PCB thickness in their various PCBs. But what is the actual standard for PCB thickness?

Does it vary due to the circuit board application? Or what factors affect the circuit board substrate thickness? And finally, how does it impact the PCB performance?

Let’s find the answer.

Our Recommended Heat Sink PCB

Device circuits produce heat while they operate continuously, which can cause overheating and shorts that could harm the device. Air ventilation and heat dissipation are crucial. Printed circuit boards are also affected by this. One big aspect of PCB manufacture and assembly is thermal management. It is the technique of maintaining electrical systems and electronic components’ temperatures within the specified ranges.

FX PCB is specialized in heat sink PCB or PCBA service, and you can ask us any question about your heat sink printed circuit board design, or you can get the price from us in 24 hours.

What Is The Standard PCB Thickness?

When we determine the PCB thickness at a standard level, we must realize that the number of layers on a PCB will be the key player in deciding its actual thickness. Since the layers on PCB depend on its application, the PCB thickness will also vary slightly due to its application range.

For instance, some devices will need thicker PCBs, while other devices may require thinner PCB. Thus, the thickness will vary too.

Nonetheless, the industry standard for PCB thickness is 0.063 inches or 1.57mm. This measurement has been a long-term standard for PCB manufacturers ever since printed circuit boards were invented. The reason is quite surprising.

Yes, it was not the industrial needs or device requirements that set the standard thickness for PCB. Instead, it was the plywood sheet thickness that initially determined the PCB thickness. Initially, plywood sheets were used as the substrate of many electronic devices, and these plywood sheets have 0.063 inches of thickness which later become the standard for PCB thickness.

However, more complex devices on the way and invention of better PCB substrates such as epoxy or resin have developed varied thicknesses for printed circuit boards.

Nowadays, the thickness range of PCB differs from 0.008 inches to 0.240 inches. You can choose the exact thickness depending on your applications and device requirements.

Two things directly influence the thickness of PCBs. These factors are-

Copper PCB thickness:Copper works as the main application space and functioning of the PCBs. So, its thickness directly affects the circuit board thickness as well. The measurement is calculated on an ounce (oz). First off, 1 ounce of copper is spread over in one square feet space evenly. Then, its thickness is calculated, which is approximately 1.37 mils or 1.37 thousandths of an inch.
Trace PCB thickness: The designer will determine the PCB trace thickness depending on its necessity in different jobs. As electricity passes through the PCB, the trace may get overheat, and the circuit board may get damaged. Hence, the trace thickness needs to be enough to withstand the circuit board overheating capacity.

What Is The Standard PCB Thickness?

FR stands for fire retardant, and thus, FR4 PCB is meant for fire retardant PCB substrate. Since these PCBs are easy to manufacturer and inexpensive, it is one of the most used and popular printed circuit boards in the industry.

The standard thickness for FR4 PCB varies from 3″ to 10″. Its thickness varies significantly because manufacturers and device designers ask for different thicknesses of FR4 PCB for different applications. Also, its thickness depends on the number of layers it has.

The standard thickness of two-layer PCB:

Multiple layers for PCB have become the new trend for device manufacturers since they can dissipate heat better and have high-performing capacity. So, it is essential that you too understand the standard thickness of two-layer PCBs.

Since it has multiple layers, its standard thickness also varies in different layers. For instance, its top solder mask features 0.01mm thickness and the top layer thickness is usually 0.035mm. The bottom layer and bottom solder mask have a similar thickness. But the core thickness is 1.5mm.

The standard thickness of four-layer PCB:

Four layers of PCBs have become popular in the industry lately. The standard thickness of these printed circuit boards is around 0.125”. The bottom and top layersare made using 1-sheet of 1080 and 2-sheet of 2116 copper metal. The core has a 0.093” thickness.

Factors Affecting the Standard PCB Thickness

There are two types of main factors that will affect the printed circuit board thickness. These two main factors are-

Design factors: These factors will impact the thickness during the PCB manufacturing and design stage. The list includes mostly weight, flexibility, and circuit board size. Also, the number of layers, materials used on the PCB, and copper thickness play a crucial role in determining the real PCB thickness. Next, the operating environment, signal types, and types of vias also fall into design factors that affect the PCB thickness.
Manufacturing factors: The manufacturing process of the PCB will also determine its standard thickness. The list includes copper thickness, equipment used to drill holes, number of layers, and panels’ method.

How to Choose the Right PCB Thickness

Since different applications and devices will require the various thickness of the PCB, it is essential to know how to fix its thickness. It would be best if you looked at these facts for this purpose-

First, consider the board weight. Thinner circuit boards will break easily. So, you must go with a thicker PCB. But, thinner boards are preferable for specific jobs.
Next, you have to look at the PCB flexibility. Thinner PCBs are generally flexible, whereas thicker PCBs are rigid. So, determine whether you need flexible PCB or rigid PCB and determine its thickness accordingly.
If the device has enough space, a thicker and larger PCB is preferable. Larger PCBs have better heat dissipation with the large substrate. For smaller PCBs, choosing thinner or smaller printed circuit boards is the right option.
Also, consider the type and number of electrical and electronic components connections you will mount on the PCB. Usually, a thicker PCB is ideal for an increased number of components and connections as they need more space and better heat dissipation.
The thickness of the printed circuit board must match its impedance level. The impedance is controlled by the dielectric that is used to manufacture the PCBs. Both impedance and PCB thickness need to match for its durability.

Final Words

The standard PCB thickness was previously 0.063 inches or 1.57mm. But, modern-day PCB has developed different thicknesses for different applications varying from 0.008 inches to 0.240 inches mostly. The layers on the printed circuit board, copper thickness, traces thickness, and the circuit board manufacturing process will control the thickness.

FX PCB has different manufacturing processes for various PCBs, making sure you get the perfect thickness of the PCBs to meet your requirements.

Peter Gong

I am Peter Gong. I have been working in PCB and PCBA industry for 15+ years now. I have been a part of the PCB revolution with my dedication to circuit board technologies and creative ideas. I write in FX PCB to impart my knowledge on PCB and PCBA for all circuit board lovers, manufacturers, and users.