Comprehensive Introduction of Ceramic PCB Substrate Products
Generally, ceramic PCBs are used for applications where strict performance is required. For example, military applications, space program components, high-power laser applications, etc. But with manufacturing process improvements and reduced costs, they are also entering general industry applications, where more thermal performance is required.
This article will provide a comprehensive introduction of ceramic PCBs in terms of their characteristics, categories, advantages and disadvantages, and applications.
What is the ceramic substrate?
Ceramic PCB is a special process board, that has 10 to 100 times more heat transfer properties than metal core PCBs and has good high-frequency performance and electrical properties.
The ultra-thin composite substrate has excellent electrical insulation performance, high thermal conductivity, excellent soft brazing property and high adhesion strength, and can etch all kinds of graphics just like PCB board, with great current carrying capacity. Therefore, the ceramic substrate has become the basic material of high power electronic circuit structure technology and interconnection technology.
Types of Ceramic PCBs
From the level of substrates, ceramic PCBs include the aluminum, AlN, BeO, Si₃N₄, hybrid substrate boards, etc. From the layers of the circuit boards, there are the single-layer, double-layer, and multilayer. Here we only put the ceramic PCB types according to the different ceramic substrates.
Aluminum oxide (Al₂O₃) PCB, or alumina PCB, is the most used ceramic PCB in the current market due to its cheaper price and nice properties. Alumina has good thermal conductivity and electrical resistance. For this reason, when alumina PCB is used, there is no need for adding an insulation layer.
In the alumina PCB market, there are 75%, 96%, and 99% alumina PCBs. The higher purity, the better properties, and also, the higher costs. If your devices have not very high power requirements, alumina PCB is good enough.
Aluminum Nitride PCB
Aluminum nitride PCBs are considered to be the most promising ceramic PCBs in the future. Using them, the thermal is dissipated from the ICs and other expensive components immediately. So high-power devices, such as LED ship lights, truck lamps, solar battery modules, large-scale integrated circuits, and so on adopt AlN PCBs as their base plates. Thermal doesn’t accumulate in their chips so that the devices work properly at high currents and for long periods.
Silicon Nitride PCB
Unlike the fragile traditional ceramic materials, under high temperatures, silicon nitride PCBs or Si₃N₄ PCBs have good mechanical strength and fracture toughness. Also, Si₃N₄ PCBs have high thermal conductivity (80+W/mK). Besides, silicon nitride PCBs have matched thermal expansion coefficient with Si.
As you know, IGBT modules for vehicles require much higher thermal conductivity than industrial class IGBTs. And vehicles modules are working in vibrating environments. For safety, the material for cars should also have good impact resistance.
Silicon Carbide PCB
Silicon carbon (SiC) is in fact, diamond, but only the different carbon ratios. So silicon carbide PCBs have an extremely high thermal resistance. Working at 1000°C is easy for SiC PCBs. That’s why they can be used in laser fields.
SiC has the property Si, so it has close characteristics of semiconductors. In other words, unlike other ceramic PCBs, a SiC PCB doesn’t have high insulation.
Advantages of Ceramic Printed Circuit Boards
● Because of the numerous advantages, a ceramic PCB is regarded as the best option for various applications. Here are some advantages that make ceramic PCBs a preferred choice.
● High Thermal Expansion: Ceramic PCBs have a high thermal coefficient of expansion. Even at high temperatures, ceramic PCBs have a high thermal conductivity and are an excellent choice for a wide range of devices.
● High Pressure: Ceramic PCBs are extremely adaptable and work successfully even under extreme pressure. Ceramic circuit boards are ideal for heavy-duty applications.
● High Insulation: Ceramic is also extremely insulating meaning heat will be less likely to pass through the substrate protecting the components of the circuit board from damage.
● High Temperature: Even in extreme weather and temperature, ceramic remains workable offering increased durability and dependability in a variety of industries.
● High Frequency: Ceramic has a high frequency and may be used in industries such as aerospace and medical that require the high-frequency transmission of data and electrical signals.
● Cost Efficient: Ceramic PCBs improve performance while reducing fabrication and design complexity. Therefore, ceramic boards are less expensive compared to metal (Cu/AL) core PCBs.
Disadvantages of ceramic circuit board
● Fragile: this is the main one of the shortcomings, can only make a small area of the circuit board.
● High price: There are more and more requirements for electronic products. Ceramic circuit board can only meet some high-end products, and low-end products will not be used at all.
Uses of Ceramic PCB
The ceramic PCB made on ceramic is considered a type of metal core PCB. While other circuit boards such as FR4 or Aluminum can be used for electrical equipment, Ceramic circuit boards provide extra safety. The PCB also keeps the devices risk-free. Typically, Ceramic board is used in the followings:
● Spotlights and high-current LEDs
● Exchange converters
● Power controllers
● Variable optical systems
● Power regulators for cars
● Industrial power equipment
● Semiconductor refrigeration devices
● IC arrays
● Audio amplifiers
● Solar cell substrates
● High power transistors and transistor arrays
● Power applications
All in all, ceramic PCBs have wide application fields due to high thermal conductivity, low CTE and low dielectric constant. While choosing the right ceramic circuit board manufacturer, you must ensure that the builder has superior processing. The oxidation must be controlled to provide maximum thermal conductivity and higher temperature resistance.