What is Ceramic PCB?

Ceramic PCB, which is short for ceramic printed circuit board, is one kind of advanced printed circuit board. It can offer excellent performance and reliability, especially in the high-performance electronic application with strict requirements. Unlike traditional circuit boards made of organic materials such as fiberglass or epoxy resin, ceramic PCB uses ceramic materials that bring unique performance and functions. Because of its heat dissipation performance, current-carry ability, insulation, and coefficient of thermal expansion of ceramic PCB, it is widely used in high-power electronic modules, aerospace, and military electronics. Ceramic PCB uses bonding to connect copper foil and ceramic substrate under high temperature. In this case, ceramic PCB has a strong binding force, the copper foil does not easily fall off with high reliability, and high performance stability under high temperature and humidity environment.

Common Materials for Ceramic PCBs

Many materials can be used to manufacture ceramic PCBs. When choosing the material for ceramic PCB, the designer needs to pay attention to the two basic specifications: PCB thermal conductivity and coefficient of thermal expansion(CTE). Below, we talk about the most common materials for ceramic PCBs.

1. Alumina(Al2O3)

Alumina is the most commonly used substrate material in ceramic substrates because it has high strength and chemical stability compared to most other oxide ceramics in terms of mechanical, thermal, and electrical properties, and the raw material source is abundant, which is suitable for various technical manufacturing and different shapes. According to the percentage of aluminum oxide (Al2O3), it can be divided into 75 porcelain, 96 porcelain, and 99.5 porcelain. The electrical properties are almost unaffected by the different content of aluminum oxide, but its mechanical properties and thermal conductivity vary greatly. There are more glass phases in low-purity substrates, and the surface roughness is large. The higher the purity of the substrate, the smoother, denser, and lower the dielectric loss, but the higher the price.

2. BeO

It has a higher thermal conductivity than metallic aluminum and is used in situations where high thermal conductivity is required. The temperature drops rapidly after exceeding 300°C, but its development is limited by its toxicity.

3. AlN

Aluminum nitride ceramics are ceramics with aluminum nitride powder as the main crystal phase. Compared with alumina ceramic substrates, it has higher insulation resistance and insulation withstand voltage and a lower dielectric constant. Its thermal conductivity is 7 to 10 times that of Al2O3, and its coefficient of thermal expansion (CTE) is approximately matched with that of silicon wafers, which is crucial for high-power semiconductor chips. In terms of the production process, the thermal conductivity of AlN is greatly affected by the residual oxygen impurity content. Reducing the oxygen content can significantly improve thermal conductivity.

Ceramic PCB Two Sides

Types of Ceramic PCBs

There are various types and specifications of ceramic PCB, every type is designed and used to meet specific applications and requirements. Here are some common types of ceramic PCB;

1. Single-Sided Ceramic PCB: It is the basic ceramic PCB, and there is one conductive layer on ceramic substrate. It is normally used in some applications where requires high thermal conductivity but no need complex circuit.
2. Multilayer PCB: It is suitable for complex circuit design, high density interconnect, and applications that require signal integrity
3. Thick Film PCB: thick film technology is used to create conductive and resistance trace on ceramic PCB. Thick film PCB is famous for its durability, it can perform well in automotive and industrial environments and other applications under harsh environments.

Ceramic PCBs can also be divided into different types according to the manufacturing processes;

1. Direct Plating Copper(DPC) PCB: It is a ceramic circuit processing technology developed based on ceramic thin film processing. Aluminum nitride/aluminum oxide ceramics are used as the circuit substrate, a metal layer is composited on the substrate surface by sputtering, and the circuit is formed by electroplating and photolithography.
2. Laser Activation Metallization(LAM) PCB: It has high precision and good bonding strength. The conductive layer can be customized from 1μm to 1mm, and using pure copper instead of silver paste can solve the problem of hole conductivity and bonding strength, and the overall performance is more stable.
3. Direct Bond Copper(DBC) PCB: Using the DBC method, an appropriate amount of oxygen is introduced between the copper and ceramic before or during the deposition process. This method is used when high copper thicknesses of 140um (4oz)-350um (10oz) are required.
4. Low Temperature Co-fired Ceramic(LTCC) PCB: LTCC technology uses the same method as capacitors to make various ceramic devices. They are placed in a sintering furnace at 850-900°C to form. To achieve electrical interconnection between layers, holes must be punched before printing and filled with silver paste.
5. High Temperature Co-fired Ceramic(HTCC) PCB: During the manufacturing process, glass material will not be added. The difference between HTCC and LTCC is that HTCC PCBs are baked at about 1600–1700 °C in a gaseous atmosphere. HTCC PCBs have such a high co-firing temperature that they employ circuit traces made of high melting point metals such as tungsten, molybdenum, or manganese. At high temperatures, these PCBs can function properly without any damage as they are designed to operate even in harsh environments.

 

Advantages of Ceramic PCBs

Ceramic PCB has various advantages, which make it a good choice for the application requires high performance, reliability and efficiency.

1. High Thermal Conductivity: Al2O3, AlN, SiC and etc ceramic materials have excellent thermal conductivity. It means ceramic PCB can effectively dissipate heat, to avoid overheat and ensure high-power electronics devices can work normally and reliably.
2. Excellent Electronic Properties: Ceramic material has low dielectric loss and nice electronic properties, especially under high frequency. It makes ceramic PCB very suitable for use in radio frequency, microwave and high-speed digital circuit and similar applications since the signal integrity and low signal loss is very important.
3. Mechanical Strength and Durability: compare with organic PCB, ceramic PCB has better mechanical strength and rigidity. The rigidity makes ceramic PCB can stand mechanical stress, shaking and shock and ensures ceramic PCB is more suitable in challenging environment.
4. Chemical Resistance: Ceramic has strong resistance on chemical, solution, acid and alkali. This resistance makes ceramic PCB ideal for applications in industries where exposure to harsh chemicals is common, such as the automotive, aerospace and industrial sectors.
5. High Temperature Resistance: Comparing with traditional organic PCB, ceramic PCB can stand higher temperature, which is very important for automotive and aerospace industries, since the electronics products must work reliably under high temperature.
6. Smaller in Size: Ceramic PCB can take fine circuit, smaller components and high density interconnect, so designer can make compact designs. This feature is important for application which requires smaller size without sacrificing performance.
7. Signal Integrity: Ceramic PCB can ensure excellent signal integrity on the basis of its low dielectric loss and high dielectric constant, especially under high frequency. With this feature, ceramic PCB is suitable for high speed data transmission and communication system.
8. Harsh Environment Compatibility: since ceramic has heat, chemical resistance properties, it can work well under harsh environment, for example, oil and gas exploration, aerospace and military applications.
9. Reliability and Long Life Time: The combination of high thermal performance, ruggedness, and chemical resistance contributes to the long-term reliability of ceramic PCB, reducing the risk of failure and extending the life of electronic devices.
10. Customized Available: Ceramic PCB can be customized to meet specific design requirement, including base material, layer configuration, layout, component location, which ensures designers can optimize circuit based on the application.
11. EMI/EMC Performance: Ceramic materials inherently offer better electromagnetic interference (EMI) and electromagnetic compatibility (EMC) performance due to their electrical properties and shielding capabilities

Ceramic PCB Side View

Disadvantages of Ceramic PCB

As we talked above, ceramic PCB has many advantages comparing with other PCB, there are still some potential disadvantages need to consider.

1. Fragile: due to the original properties of ceramic, it is fragile during handling, assembly process and testing. So the engineering staff need to pay more attention to the ceramic PCB in mentioned process.
2. Cost Consideration: Ceramic is a price-reasonable material. However, after considering all factors, it is still much more expensive than traditional PCB. So the designer needs to consider whether it is a more cost-effective option to make the design ceramic PCB.

Application of Ceramic PCB

• Big power electronic module, solar energy battery components
• High frequency power switch, solid state relays
• Automotive electronics, aerospace, and military electronic products
• High-power LED lighting products
• Telecommunication antenna, automotive fire lighter

Ceramic PCB has become an ideal choice for high-power and high-frequency applications due to its excellent thermal conductivity, high stability and excellent performance. In the fields of 5G and new energy, it is driving electronic technology towards a more efficient and reliable direction, and is a key material for future high-end electronic manufacturing.

Jerico PCB has been working deeply in ceramic PCB fabrication for 16 years, since 2009. We supported hundreds of projects from concept to prototype to mass production with our reliable and high-performance ceramic PCB fabrication service in new energy and telecommunication areas. We believe that if we do what we are good at, we will be more professional day by day with our customers’ support and trust. Let’s talk about your ceramic PCB project today and see how we can bring you success.