What Are The Types Of PCB Substrates

PCB substrate is a key material in the manufacturing process of printed circuit boards, which determines the physical and electrical properties of the board.There are various types of PCB substrates, which can be selected according to different application needs and performance requirements. The following are some common types of PCB substrates:

Organic Substrate Materials:

FR-4 (epoxy resin glass cloth laminate): 

This is the most common type of PCB substrate, made of epoxy resin and glass fibre cloth laminated, with good mechanical strength and electrical insulation properties, widely used in a variety of electronic equipment.

Polyimide (PI): 

With excellent high temperature resistance and electrical properties, it is commonly used in electronic equipment in high temperature environments, such as aerospace and military applications.

Phenolic Resin (Bakelite): 

An older substrate material with some mechanical strength and electrical properties, but with limited performance compared to modern materials.

Inorganic Substrate Materials:

Aluminium Substrate: 

Has good heat dissipation properties and is suitable for LED lighting products and high power electronic devices.

Copper Substrate: 

Has better thermal conductivity than aluminium substrate, suitable for high-frequency circuits and application scenarios with large changes in high and low temperatures.

Special Substrate Materials:

Ceramic Substrates: 

With excellent thermal stability and electrical insulation properties, commonly used in high-frequency, high-power and high-temperature electronic equipment.

Metal Substrates: 

In addition to aluminium and copper substrates, but also includes iron substrates, etc. These materials are mainly used in specific high heat dissipation needs occasions.

Flexible Substrate Materials:

Polytetrafluoroethylene (PTFE): 

Known for its excellent chemical stability and low dielectric loss, suitable for high frequency signal transmission lines.

Composite Substrate Materials:

CEM Series: 

A composite of paper and glass fibre cloth base with some mechanical strength and electrical properties, but usually used for applications with lower performance requirements.

Accumulated Multilayer Substrates:

This substrate consists of multiple layers of organic or inorganic materials stacked on top of each other for the manufacture of multilayer PCBs to meet the design needs of complex circuits.

Each substrate has its own unique performance characteristics, such as dielectric constant, coefficient of thermal expansion, thermal resistance, mechanical strength, etc. These characteristics affect the performance of the circuit board and the applicable occasions. When designing and manufacturing PCBs, choosing the right substrate is critical to ensuring the performance and reliability of the board.

The different types of PCB substrates each have unique roles and application scenarios, and the following is an overview of their respective roles:

FR-4 (epoxy resin glass cloth laminate): 

As the most common PCB substrate, it provides good mechanical strength and electrical insulation properties, and is suitable for a wide range of electronic devices, including consumer electronics, industrial controls, automotive electronics, and more.

Polyimide (PI): 

Due to its excellent high temperature resistance and electrical properties, PI materials are mainly used for electronic devices in high temperature environments, such as aerospace, military and medical equipment, and other applications requiring high reliability.

Phenolic Resin (Bakelite): 

Although an older material, it is still useful in certain specific applications, especially where cost is sensitive and performance requirements are not particularly high.

Aluminium Substrates: 

The main role of aluminium substrates is to provide good heat dissipation, and it is commonly used in LED lighting products, high power electronic devices and power supply modules, as well as other applications where effective thermal management is required.

Copper Substrates: 

Copper substrates are suitable for high-frequency circuits and environments with large variations in high and low temperatures, such as precision communication equipment and high-performance computing devices, due to their excellent thermal conductivity.

Ceramic Substrates: 

Ceramic substrates are mainly used in high-frequency, high-power, and high-temperature electronic equipment, such as radar, satellite communications, and medical equipment, due to their excellent thermal stability and electrical insulation properties.

Metal Substrates: 

In addition to aluminium and copper substrates, other metal substrates such as iron substrates are mainly used in specific applications with high heat dissipation requirements, such as large industrial equipment and power converters.

Polytetrafluoroethylene (PTFE): 

Known for its chemical stability and low dielectric loss, PTFE material is suitable for high-frequency signal transmission lines, such as wireless communication equipment and high-performance test equipment.

CEM Series: 

This composite substrate material combines the properties of paper and glass fibre cloth bases and is suitable for applications with lower performance requirements, such as some basic electronic control devices and household appliances.

Accumulated Multilayer PCB Substrates: 

Multilayer PCB substrates provide greater design flexibility and more complex circuit layout capabilities by stacking multiple layers of material for high-performance electronic devices such as computer motherboards, high-end networking equipment and complex signal processing systems.

The selection of each substrate depends on the board's end application, performance requirements, cost considerations, and the feasibility of the manufacturing process. Design engineers need to select the most appropriate type of PCB substrate based on specific project requirements.