Ceramic PCB, also known as Rogers PCB, is a thermally conductive ceramic powder and organic binder. As a relatively new printed circuit board, ceramic PCB has been widely used in the electronics industry for many years.
With the development of chip components and surface mount technology (SMT) in the electronics industry, traditional printed circuit boards based on organic laminates are developing towards high density, high precision and high reliability. Rogers PCB is considered to be an effective solution to realize the miniaturization of modern electronic products, and it is a more feasible choice for PCB designers. Product and electronic assembly technology. You will find that ceramic PCBs are better than traditional printed circuit boards, and, due to their high thermal conductivity and minimal coefficient of expansion (CTE), ceramic PCBs are more versatile, simpler, and have better performance.
Ceramic PCB is a kind of thermal conductive ceramic powder and organic binder, its thermal conductivity is 9-20W/m. In other words, a ceramic PCB is a printed circuit board with a ceramic substrate. The ceramic substrate is a high thermal conductivity material, such as aluminum oxide, aluminum nitride, and beryllium oxide, which can quickly and effectively transfer heat from hot spots and dissipate. It spreads over the entire surface. In addition, ceramic PCBs are manufactured using LAM technology, which is a laser rapid activation metallization technology. Therefore, the ceramic PCB has a high degree of versatility, can replace the entire traditional printed circuit board with a simpler structure, and improve performance.
According to the manufacturing method, there are three main types of ceramic PCBs in the electronics market.
High temperature is probably the most popular type of ceramics. In general, ceramic PCBs designed for high temperatures are generally considered to be high temperature co-fired ceramic (HTCC) circuits, which consist of green ceramics with solvents, mixed binders, plasticizers, lubricants and alumina.
First, it is made of ceramic raw materials, and secondly, the material is coated, and then the circuit is traced on tungsten or molybdenum metal. Finally, if circuit tracking is achieved, the circuit board can be baked between 1600 and 1700 degrees Celsius after lamination for up to 48 hours. All HTCC baking is carried out in a gas environment, such as hydrogen.
Different from HTCC, the low-temperature co-fired ceramic PCB is made by mixing the crystal glass and the adhesive base on the metal substrate with gold paste. The circuit board is then cut and laminated, and then placed in a gaseous oven at approximately 900 degrees Celsius.
More importantly, low-temperature co-fired ceramic PCBs can benefit by reducing warpage and improving shrinkage resistance. In other words, compared with HTCC and other types of ceramic PCB, ceramic PCB has better mechanical strength and thermal conductivity. Therefore, when using heat dissipation products such as LED lights, LTCC has a heat dissipation advantage.
For thick film ceramic PCBs, the thickness of the conductor layer can exceed 10 microns, but not more than 13 microns. Generally, the conductor layer is printed with silver or gold palladium on the surface of the ceramic PCB. That is, the thick film ceramic PCB includes gold and dielectric paste completed on a ceramic substrate, and the paste is pasted and backed at a temperature of 1000 degrees Celsius or lower after processing. Therefore, thick film ceramic PCBs are widely used by most PCB manufacturers due to the high cost of gold conductor paste.
Compared with traditional PCB, the main advantage of thick film ceramic PCB is that thick film ceramic can protect copper from oxidation. Therefore, ceramic PCB manufacturers can place interchangeable conductors, semiconductors, conductors, capacitors or resistors on the ceramic board. After the printing and high-temperature sintering process is completed, all components on the board can be laser trimmed to the desired value.
How many layers there are in a ceramic PCB is a puzzle, but it depends on the type of ceramic PCB. The minimum number of layers used in a ceramic PCB is two, but there may be more layers depending on the characteristics of the product.
Heat dissipation is the main advantage that ceramics have over more traditional materials such as FR-4 and metal composite PCBs. Because these components are placed directly on the board and there is no isolation layer, the heat flow through the board is more efficient. In addition, ceramic materials may withstand higher operating temperatures (up to 350°C), and the coefficient of thermal expansion (CTE) is very low, which provides more compatibility options for PCB design.
Compared with the traditional PCB whose substrate material is epoxy glass fiber, polyimide, polystyrene and phenolic resin, ceramic PCB has the following characteristics:
Excellent thermal conductivity
Resistant to chemical attack
Compatible mechanical strength
Easily achieve high-density tracking
CTA component compatibility