Among the numerous PCB options, two types are widely used. One is Ceramic PCB Substrate and the other is Alumina Substrate PCB. In this article, we will introduce the characteristics and advantages of each substrate in detail.

Ceramic printed circuit boards are widely used in technology assembly due to their multiple characteristics and advantages. This type of printed circuit board uses aluminum nitride or beryllium oxide ceramic substrates, which can quickly conduct heat away from the heat-generating area and dissipate it to the entire circuit board surface.

Ceramic PCB substrates use a thermal conductivity of 9-20W/m , which is a mixture of ceramic powder and organic binder. Laser rapid activation metallization technology LAM technology can produce materials such as ceramic PCBs, so ceramic PCBs are highly adaptable, simpler in structure, and superior in performance, which can replace the entire traditional printed circuit board.

In terms of heat dissipation, ceramic materials have significant advantages over FR-4 and metal clad PCBs. Since there is no insulating layer between the components and the circuit board, the transfer of heat through the panel is greatly improved. Due to the high operating temperature (up to 350°C) and relatively low coefficient of thermal expansion (CTE) of ceramic materials, PCB design can have more compatibility options.

Characteristics of Ceramic PCB Substrates

Thermal conductivity, electrical conductivity and thermal conductivity are the characteristics of ceramic PCBs. Other advantages are as follows:

Excellent heat transfer ability
Protection from chemical attack
Requirement of equivalent mechanical tensile strength
High-density tracking should be easy to achieve
Compatibility with CTA components
Let’s learn about its benefits in detail.
Excessive expansion due to heat
The high coefficient of thermal expansion of ceramic PCB substrates is one of the reasons for their widespread use in the electronics industry. The thermal conductivity of ceramic bases stems from its proximity to silicon while being located below the most commonly used connecting metals. Therefore, they can be used as a long-lasting insulator. The strong thermal conductivity of ceramic PCBs, even at high temperatures, makes them suitable for many applications.

Stability
The use of ceramics can increase the application of electronic devices because of its stable dielectric properties and minimal RF losses. In addition, despite the obvious hardness of ceramics, it is inherently resilient to most chemicals due to ceramic-based PCBs. The new standard for chemical resistance will be resistance to regular moisture, solvents, and consumables, not just chemicals.

Versatility
Many applications that require high melting points can be achieved by using metal core PCBs. Precious metal pastes can be very reliable conductors thanks to the sintering technology. Ceramic PCBs undoubtedly affect high processing temperatures, as there are a wide range of devices that are suitable for various operating temperatures. In addition, it also provides excellent thermal conductivity and heat dissipation for multiple parts of the device, which is worth noting.

Durability
As you may know, ceramic PCBs are manufactured to last a long time. Due to the key characteristics of ceramics, especially its toughness, you can be sure that your board will not be damaged by normal use. Ceramic PCBs deteriorate much slower than base PCBs. Therefore, they can be replaced at will. Since it can decompose at a slower rate, the service life of the material is extended.

Adaptability
Last but not least, the use of metal core in the design of ceramic PCB substrates is one of the most important advantages of this technology. It can be converted into a rigid carrier. This makes it easy to use between fluids and solids, and can be used in many industrial locations because of the excellent roughness and wear resistance.

Alumina Substrate PCB and Its Features

Alumina is one of the most cost-effective and commonly used substrate materials in microelectronic applications. This substrate has excellent electrical insulation properties, mechanical strength, excellent thermal conductivity, chemical durability, and dimensional stability.

The layout of an alumina substrate PCB is similar to any other PCB. It is covered with copper, solder mask, and silkscreen layers. On the other hand, an aluminum circuit board has a metal substrate, rather than a fiberglass or plastic substrate. The bulk of its base is made of aluminum. Fiberglass and aluminum can be combined with metal to make up the metal core, or the metal core can be made entirely of metal. Single-sided aluminum PCBs are common, but there are also double-sided versions. It is very difficult to manufacture multi-layer aluminum PCBs.

LEDs and power conversion circuits are the most common applications for aluminum substrates. LEDs generate a lot of heat, and aluminum can dissipate this heat by directing the heat away from the components. Aluminum PCBs extend the life of LED devices and provide greater stability. Aluminum substrates are used in street lights, traffic lights, and even home lighting. They are able to change the current and regulate electronic devices using power converters. Aluminum PCBs are also used by creators in many other industries, although not as frequently.

Benefits of Using Aluminum-Based PCBs

Aluminum PCBs are among the best thermally conductive materials available. It is imperative that as much heat as possible be diverted away from critical circuit components to minimize circuit damage. Due to their strong heat resistance, they can withstand greater circuit density and higher power. Physically, aluminum alloys are very durable, reducing the danger of breakage. Aluminum has a smaller environmental impact than other metals, and the cost is reasonable.

On the other hand, alumina-based PCBs tend to have more specialized uses than traditional circuit boards. They are more expensive than regular PCBs without such components, but cheaper than adding conductors to a copper board. High-temperature applications may not justify the cost of an aluminum core. Aluminum flex PCBs can only be bent to their starting position if you want to create a flexible circuit. While it can bend to fit smaller electrical devices, it cannot withstand any type of vibration-induced stress.

Comparison of Different Materials
When choosing a substrate for your circuit board, consider several variables. Applications that require a lot of heat dissipation are best suited to aluminum core PCBs. These properties can increase the power and density of your design compared to regular PCBs. On the other hand, for designers with tighter budgets, circuit boards with non-metallic substrates may be more popular.

Ordinary PCB boards are made of epoxy resin and fiberglass boards, which are prone to chemical reactions under the irradiation of cosmic rays, resulting in changes in molecular structure and deformation of the product, which is why they cannot be used on airplanes.

Compared with ceramics, traditional PCB substrates have low density and light weight, which is conducive to long-distance transportation; epoxy resin boards have good resilience and are not easy to break.

However, general PCB boards are not resistant to high temperatures. The ignition point of paper PCBs is about 130℃, which is quite low. Even if high-temperature resistant materials are added, their high-temperature resistance cannot be changed; and the ignition point of most epoxy resins is about 200℃, and their high-temperature resistance is relatively poor.

Alumina substrate PCBs have high mechanical strength, good insulation, and good light resistance. They are often used in multi-layer wiring ceramic substrates, electronic packaging, high-density packaging substrates, etc.

FAQ
Why use aluminum to make circuit boards?
Aluminum can conduct heat away from key components, thereby reducing adverse effects on the circuit board. The aluminum base gives the product strength and service life, which cannot be achieved with ceramic or fiberglass bases.

How to distinguish PCB from substrate?
The difference between the two in materials is quite obvious. Aluminum substrate uses aluminum plate as the main material, while PCB board uses copper as the main material. Aluminum substrate uses PP material, which has better heat dissipation.

What is the manufacturing process of ceramic printed circuit board?
Crystal glass and bonding materials are combined with gold paste on metal plate to make low-temperature co-fired ceramic PCB, not HTCC. The circuit is then sliced ​​and laminated, and then heated in a gas furnace at about 900 degrees Celsius.

What is the definition of ceramic substrate?
Ceramic substrate is a process board that directly bonds copper foil to the surface (single or double sides) of alumina (Al2O3) or aluminum nitride (AlN) ceramic substrate at high temperature.

Ceramic PCB substrate and alumina substrate PCB each have their own advantages. Due to high thermal conductivity and low coefficient of expansion, ceramic PCB performs better than standard printed circuit boards in various applications. It also has the advantages of greater adaptability, simpler manufacturing, and higher reliability (CTE).

Ceramic PCB substrate is only used in high-quality products and is not used in most other products. Printed circuit boards are being replaced by ceramics to simplify manufacturing and design while improving performance. On the other hand, aluminum substrates are widely used in LED lamps of various sizes due to their excellent thermal conductivity and reasonable cost.