What is ceramic PCB and Types of ceramic PCBs?
With the development of chip components and surface mount technology (SMT) in electronics industry, traditional printed circuit boards with organic laminates as based material are developing towards high density, high precision, and high reliability. Needless to say, ceramic PCB, as a relatively new type of printed circuit board, which has been widely used in electronics industry for years, and it is a more viable option for PCB designers, considered as an effective solution for miniaturization accomplishment of modern electronics products and electronic assembly technology. You will find that ceramic PCB has an advantage over traditional printed circuit board, what’s more, ceramic PCB is more versatile, less complex and offer superior performance because of its high thermal conductivity and minimal expansion coefficient (CTE).
What is ceramic PCB?
Ceramic PCB is a kind of heat conducting ceramic powder and organic binder, and the heat conduction organic ceramic PCB is prepared at a thermal conductivity of 9-20W/m. In other words, ceramic PCB is a printed circuit board with ceramic base material, which is highly thermally conductive materials such as alumina, aluminum nitride, as well as beryllium oxide, which can make a quick effect on transferring heat away from hot spots and dissipating it over the whole surface. What’s more, ceramic PCB is fabricated with LAM technology, which is a laser rapid activation metallization technology. So ceramic PCB is highly versatile that can take place of the entire traditional printed circuit board with a less complicated construction with enhanced performance.
Types of ceramic PCBs
There are three main types of ceramic PCB in the electronic market based on the manufacturing method.
* High temperature ceramic PCB
* Low temperature ceramic PCB
* Thick film ceramic PCB
High temperature
As you know, high temperature may be the most popular types pf ceramic. In general, The ceramic PCB designed for high temperatures is often regarded as high temperature co-fired ceramic (HTCC) circuit, which is made up of raw ceramics with solvent, mixing adhesive, plasticizer, lubricant as well as aluminum oxide.
First of all, it fabricates with the raw ceramic material, secondly coat the material, and then carry out the circuit tracing on tungsten or molybdenum metals. Finally, if the circuit tracing is achieved, it can bake the boards between 1600 and 1700 degrees Celsius for up to 48 hours after lamination. All HTCC baking is done in a gaseous environment, such as in hydrogen gas.
Low temperature
Unlike HTCC, low temperature co-fired ceramic PCB is made up of combining crystal glass with an adhesive substrate on sheet metal with gold paste. And then cut and laminate the circuit board before placed in a gaseous oven at roughly 900 degrees Celsius.
What’s more, low temperature co-fired ceramic PCB profits by less warpage and evolutionary shrink tolerance. In other words, comparing to HTCC and other types of ceramic PCB, ceramic PCB has s better mechanical intensity and thermal conductivity. So as using the heat dissipation products such as LED lights, there is a advantage for the thermal benefit of LTCC.
Thick film ceramic
Thick film ceramic PCB, the thickness of its conductor layer may exceed 10 microns, but not more than 13 microns. In general, the conductor layer is printing the silver or gold palladium on the surface of ceramic PCB. That is to say, thick film ceramic PCB includes gold and dielectric pastes, which is done on a ceramic base material, and the pastes and backed at a temperature of 1000 degrees Celsius or below after working. So the thick film ceramic PCB is widely used for most PCB manufacturers because of the high cost of gold conductor paste.
The main advantage of thick film ceramic PCB over traditional PCB is that thick film ceramic can protect copper from oxidizing. So a ceramic PCB manufacturer can put interchangeable conductors, semi-conductors, conductors, electric capacitors, or resistors on the ceramic board. After achieving the process of printing and high-temperature sintering, all the components on the board can be laser-trimmed to their desired values.
There is a confusion about how many layers in a ceramic PCB, but it is decided by the types of ceramic PCB. The minimum number of layers used in ceramic PCB is two layers, however, there may be some more layers according to the product’s properties.
