Ceramic printed circuit boards (PCB) or ceramic PCB are getting more popular amongst circuit boards for their great performance. When you are looking for the best type of ceramic PCBs, you need to be aware of some essential information. By measuring all the details and comparing it to other products, you can come to a decision that will help you with purchasing. In this article, you will find a thorough discussion about ceramic circuit boards and all the essential details. By knowing every small information, you can choose which type of Ceramic board is the best choice for you. Before finding the best ceramic PCB we need to have clear idea about what is ceramic PCB?
Definition of PCB and Ceramic PCB
Circuit boards are the most essential part of a device. The definition of typical circuit boards and Ceramic boards differ due to their different materials.
Printed circuit boards are the result of putting conductive pathways into a board that connects transistors, resistors, and integrated circuits. They are often used in multilayer by putting a non-conductive substrate in between. Before printed circuit boards, wire wrap and point-to-point construction systems were used but now they are hardly seen. The manufacturing and assembly of printed circuit boards are pretty easy and can be done automated. Laying out the circuit is hard and needs expert hands.
Ceramic PCBs are printed circuit boards with a ceramic base. In this case, conductive pathways are printed on Ceramic-based materials. It is better than metalcore or FR4 circuit boards for its higher conductivity and many other great features that make Ceramic-based circuits the best. Ceramic boards were made for fitting compact spaces while not having problems due to heat dissipation or the coefficient of thermal expansion. They are superior to traditional circuit boards in many ways which will be discussed below.
Ceramic boards are made of high-quality materials. These are not the ceramic that your floor has. Ceramic boards consist of metal cores. The metal cores are made of Aluminum Nitride, Beryllium oxide or Aluminum oxide. 96% to 98% of these materials are present in the circuit. Aluminum nitride and Beryllium oxide give the best performance but when you have a lower budget, the Aluminum oxide can be chosen. Aluminum nitride circuit boards’ conductivity ranges from 150-170W/mK while Aluminum oxide’s conductivity is 29W/mK which is much inferior to Alumina-based circuit boards. As a result, for more conductivity, you should choose Alumina-based printed circuit boards.
The conductor materials differ in different cases. For thick or thin-film technology, materials such as silver palladium (AgPd) or gold palladium (AuPd) are used. Direct Copper Bonded (DCB) conductors use only copper. The gold conductor is far better from silver for not having silver-corrosion problem but the conductivity can be increased by using silver traces covered with glass. While using delicate pieces of machinery, gold is a better choice.
Types of Ceramic PCBs
There are mainly three basic types of Ceramic-based printed circuit boards. These are differentiated according to the versatility of manufacturing methods. The three types are:
1. Thick Film Ceramic Board
Thick film ceramic boards have a conductor layer that exceeds 10 microns. The thickness is less than FR4 or DCB board. Using thick-film will allow us to utilize:
- Electric capacity
- Interchangeable conductor
2. Thin Film Ceramic PCB
Thick film ceramic boards have a conductor layer that is less than 10 micron. These boards are smaller in size and much more expensive. It is mostly suitable for microwave circuits.
3. DCB Ceramic PCB
Direct Copper Bonded (DCB) circuit boards where the aluminum nitride or aluminum-oxide is directly bonded with the copper foil under high temperature. Being very thin, it is good for:
- High-quality electrical isolation
- Fine solderability and high bonding strength
- High thermal conductivity
Like FR4 PCB, it can be etched into different layouts.
Uses of Ceramic PCBs
For their high-quality thermal and mechanical advantages, Ceramic PCBs are used in various fields. The board’s unique feature and high thermal conductivity have enabled it to be used in devices big and small.
All RAM requires high-quality ceramic-based boards. Ceramic board is used in DDR SDRAM and other parts that are related to memory. As the memory module needs to be well-made and should have the ability to endure extreme usage, Ceramic-based boards are used.
Multilayer Interconnect Board
Ceramic allows more components than traditional PCBs on the same surface. Ceramic’s capacity for facing weight is very high. This is why ceramic-based PCBs are better than conventional boards when used as multilayer interconnected boards.
Receiving & Transmission Modules
Transmission and receiving modules were first created using Ceramic PCB by American firm Westinghouse. Since radars need to be highly accurate, the board used in them should have compatible CTE and high thermal conductivity. Ceramic boards are very useful for receiving and transmission modules.
This may sound like using circuit boards to make circuit boards. LTCC or low-temperature ceramic circuits have been used by different computing firms that assisted them in making supreme-quality analog and digital boards with excellent circuit tracing. By creating a host of lightweight circuits, personal computers have become lightweight.
HTCCs (High-temperature ceramic circuits) and LTCCs (Low-temperature ceramic circuits) are used in solar panels and many photovoltaic panels. To ensure high-quality thermal conductivity and longevity, PV panels use multilayer ceramic boards.
Electric Power Transmitter
Wireless chargers are getting more popular. These wireless transmitters have been made possible by using Ceramic printed circuit boards. Their high-quality thermal properties make them perfect for electric power transmitter. By creating an electromagnetic field, Ceramic boards can transfer electrical energy. Sometimes, the receiver is also made from Ceramic-based circuit boards.
High Power LED
Ceramic circuit boards are mostly used in this field. Thick-film ceramic boards have superior thermal efficiency. Since LED lights produce a lot of heat (70%), it is essential for a system to have high-quality material that can withstand the heat. Ceramic boards do not have any adverse effects due to the immense heat and that’s why it is perfect for high power LED.
Using the micro-fabrication method, semiconductor chips have superior tracing with high integration and tracing. A modern-day semiconductor chip needs Ceramic circuit boards to function well. This is mostly because it needs to be fitted into tight space and traditional PCBs fail to do that.
Advantages of Ceramic PCBs
There are some great features of ceramic printed circuit boards that are not available in other PCBs. Such features have made it unique and usable in conditions that traditional PCBs can’t withstand. There can be a lot of advantages that can be mentioned but the following ones are the most well-known. Know that the following are not specified to a specific type of Ceramic board but apply to general ceramic-based circuit boards.
1.High-quality thermal conductivity
Thermal conductivity is a term that means the ability to transfer heat energy. The thermal conductivity of the Ceramic circuit board is higher than any other PCBs. This high thermal conductivity allows it to be used in high temperature as it can withstand it very well and don’t get damaged at all. For high durability of electrical devices and great performance, many use ceramic boards as it gives good temperature control. Traditional PCBs can get easily damaged by excessive heat and that’s why high-powered LED lights use Ceramic PCB. The thermal conductivity values are:
- 24W~28W/m-K for aluminum oxide
- 150W~240W/m-K for aluminum nitrite
- 220~250W/m-K for Beryllium oxide
2. Easy multi-layering
Ceramic can allow easy multi-layering for having high mechanical strength. It can easily support the weight of other components which lets anyone have multiple layers. More layer of such circuit boards means it the device can do more complex works. This results in increased performance for devices.
3. Superior insulation
Having good insulation leaves a board unaffected from any type of voltage issues. Typically printed circuit boards face a lot of problems for voltage-related issues. In the case of Ceramic printed circuit boards, such issues don’t occur since Ceramic has very high-quality insulation. Such insulation lets Ceramic-based PCBs insulate the electrical resistance effectively. It also gives extra safety with its ability to withstand the inconsistency of voltage. By using a ceramic-based PCB, an electrical device has better protection against voltage problems which results in safer and more durable products.
4. Low dielectric constant
Ceramic-based boards have low dielectric constant. What it does is allowing the board to work perfectly even in high temperature and high humidity environment. As a result, in extreme conditions, a Ceramic board is more likely to be able to work without any problems than traditional PCBs. It does not only adds to the safety of an electric device but also increases the quality.
5. Low thermal expansion
We know that metal expands when it gets the touch of heat. It causes a lot of issues in a Circuit board and sometimes they get heavily damaged. To keep the thermal expansion at a minimum level, you should use the Ceramic PCB. Ceramic has a very high heat capacity and will not expand in contact with heat. This is another criteria where Ceramic boards take the win.
6. High cosmic ray resistance
Ceramic boards are used in aerospace. Its high cosmic ray resistance makes it suitable for such a field. Space has a very high quantity of cosmic rays and radiation. Such radiation can damage anything including boards. General PCBs can get damaged over time with the contact of radiation. This is why ceramic PCBs are used in aerospace.
One thing that developers have always wanted is circuit boards to be smaller and fit compact spaces. Thanks to Ceramic boards that now complex works can be done in a small space. That is why we have smaller devices that can work great.
Ceramic boards are very durable as they can withstand extreme heat and pressure. They work well because of Ceramic’s high-quality weight and heat withstand capacity. They last longer than traditional circuit boards and this is why they’re a better choice.
Main flaws of Ceramic PCBs
There are only a few disadvantages that can be found in ceramic PCBs. If considering all the advantages and flaws, Ceramic PCB surely takes the win amongst all other boards. Some of the main disadvantages are stated below.
There is a reason why Ceramic-based circuit boards are mostly used in aerospace and complex machinery. They are more expensive compared to other printed circuit boards. For this reason, such PCBs are hardly found in household electrical devices. But one thing to consider in this case is the after cost. Other printed circuit boards might get damaged and for repairing or replacing, you might have to spend an extra amount. On the other hand, Ceramic boards are very durable and you won’t have to worry about repair costs.
Handling Ceramic-based boards can be very complex as the material is fragile and small. If any problems occur with the board, it will take some effort to fix it. As Ceramic PCBs are made for tight spaces, they are very small and this makes them even harder to handle.
Ceramic printed circuit boards are scarce. The scarcity of these boards makes them more expensive. Unlike other circuit boards, Ceramic-based boards have low availability. This makes them hard to find. You might have to spend some time until you find your preferred circuit board. There are some online selling services that provide high-quality Ceramic boards but there is no exception to the high price. Ceramic PCBs are also made in smaller quantities which adds to the scarcity.
Difference between Ceramic boards and other PCBs
Many factors make Ceramic printed circuit board different from other PCBs. Some of the main factors are:
Ceramic circuit boards have high-quality materials such as aluminum nitride or aluminum oxide. Such materials are generally better than the materials used in other PCBs as they can withstand a high amount of heat and have higher conductivity.
2. Multilayer ability
Making a circuit board multilayer enables it for heavy-duty works. Ceramic has a high-quality weight lifting capacity. For that, it has a high multilayer ability than other boards. Multilayer PCBs serve by giving an increased performance than a single PCB. Another factor is, traditional PCBs take up a lot of space while being in Multilayer while Ceramic-based printed circuit boards take up small space.
Ceramic circuit boards are used in devices that need to be able to withstand high temperatures and voltage. Typical household items generally have traditional PCBs installed. Devices that have high heat emission or need extreme precision used ceramic PCB. For example, high powered LEDs that emit extreme heat. In this case, using traditional PCB is not a good idea.
Looks don’t matter but it is worth mentioning. Ceramic circuit boards look stronger and have an aesthetic value to it. Traditional PCBs don’t have much good look and one can easily differentiate both of them by just looking.
Ceramic boards are very compact. They are not big in size which makes them a great choice for small devices. On the other hand, all other circuit boards are bigger and take up much space. Being smaller, it is harder to handle.
Ceramic-based circuit boards are typically higher in price compared to general PCBs. Prices can differ according to the quality and the materials of aboard. Ceramic PCBs can cost as low as 0.15 to 0.40 USD per piece but you have to be sure of the quality. Single-sided and double-sided boards differ in prices. Consider having a higher budget for better products. If you buy Alumina-based boards, it might cost you a little more because it is a high-quality material. For lower budgets, you can choose, aluminum oxide. In the case of tracing, you can choose silver or copper if you have a lower budget but gold is the best amongst all tracing materials but it costs a lot more.
Things to consider when buying Ceramic PCBs
For making a worthy purchase, always consider a few important factors before buying Ceramic PCBs. All little factors can play a huge role in electronic devices and that’s why they have to be known well. Some of the most important factors are:
As we have mentioned previously, Ceramic boards are made of Aluminum Nitride, Beryllium oxide or Aluminum oxide. If you want to have high-quality circuit boards, conditions buying boards that have Aluminum nitride, or Beryllium oxide. For a lower budget, you can consider buying ones with Aluminum oxide. You need to understand which one is used in which cases so that you can decide easily. Alumina-based boards have higher conductivity and used for complex devices.
When you’re buying a thin-film board, consider choosing gold plated ones since gold is much better than silver. Gold is also much more expensive than silver and for a lower budget, you can consider having silver. Silver traces might get damaged for silver corrosion issues while gold traces have hardly any issues.
For professional usage and utilization in complex pieces of machinery, use thin-plate Ceramic PCBs as they fit into compact spaces very well. If you want your board to be etched into different layouts, you can buy Direct Copper Bonded (DCB), circuit boards.
Using a Ceramic-based circuit board for simple devices is a bad idea. It will bring loss to a manufacturer. Only use Ceramic boards when the device is delicate and needs extra durability and functionality. If you need Ceramic boards for LED applications, choose Aluminum oxide as a base material as they are cheaper in price compared to Alumina-based circuit boards. Aluminum oxide is also suitable for sensor modules. For high powered LEDs that emit a high amount of heat, you need to use alumina-based ceramic boards. Such boards are also suitable for sensors and testing components as well as ICs.
Frequently asked questions
1. What is the bending strength of Alumina Ceramic Substrate?
Alumina (Al2O3) Ceramic Substrate has a bending strength of 400 Mpa. The material is slightly fragile and needs care to be handled.
2. What is the dielectric constant?
For a substance, the ratio of permittivity and permittivity in space is known as a dielectric constant. With good dielectric content, a conductor is able to withstand a high amount of radiation and cosmic rays.
3. Which materials are the best for boards?
Aluminum nitride and beryllium oxide are the two best amongst Ceramic PCBs with high heat-resistance capacity and better durability. They have high conductivity and better performance than Aluminum oxide boards.
4. Which materials should I use for tracing?
You can use Gold, Silver or Copper. Gold is the best one amongst them with a very small probability of damage. Using silver might bring problems because of the silver corrosion issues. Copper is the cheapest one amongst all three.
5. What is the breakdown voltage of a Ceramic PCB?
The breakdown voltage of an alumina-based board is 34 KV/mm. Ceramic can withstand higher voltage compared to other circuit boards which makes it exceptional.
6. How good is Ceramic PCBs’ frequency performance?
Ceramic printed circuit boards have high-quality frequency performance than the traditional boards that range from low to mid.
7. What is the highest operating temperature of Ceramic PCBs?
Ceramic boards can function in temperature as high as 350° C. Its high thermal conductivity makes it the best material for using in high-temperature environments.
8. What does CTE mean?
CTE stands for the coefficient of thermal expansion that refers to the expansion of materials due to heat. Ceramic has very low thermal expansion and can stay still in extreme temperatures.
Ceramic PCBs are the answer to many great problems we had before with traditional circuit boards. With the utilization of Ceramic-based circuit boards, a company or brand can produce higher-quality devices that are able to withstand high temperatures. Using Ceramic is a milestone in the field of printed circuit boards and it is now used in great quantities. To be on the competition, a brand has to start utilizing these materials for providing better devices to clients. Ceramic boards are truly the future.